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Environmental Research Technological Development
and Innovation (ERTDI) Programme 2000-2006
Environmental Protection Agency
Regional Inspectorate, McCumiskey House, Richview, Clonskeagh Road, Dublin 14, Ireland
Telephone: +353 (0)1 268 0100 Fax: +353 (0)1 268 0199 Website: www.epa.ie
Printed on recycled paper
ERTDI Report Series No. 51
BIODIVERSITY IN IRISH
PLANTATION FORESTS
Final Report
Environmental Research Technological Development and Innovation (ERTDI)
Programme 2000-2006
The Environmental Research Technological Development and Innovation
Programme was allocated €32 million by the Irish Government under the
National Development Plan 2000-2006. This funding is being invested in the
following research areas:
❚Environmentally Sustainable Resource Management
❚Sustainable Development
❚Cleaner Production
❚National Environmental Research Centre of Excellence
The Environmental Protection Agency is implementing this programme on
behalf of the Department of the Environment, Heritage and Local Government.
NATIONAL COUNCIL FOR FOREST RESEARCH & DEVELOPMENT
A
N CHOMHAIRLE NÁISIÚNTA UM THAIGHDE AGUS FORBAIRT FORAOISE
BIODIVERSITY IN IRISH PLANTATION FORESTS -Final Report
NATIONAL COUNCIL FOR FOREST RESEARCH & DEVELOPMENT
A
N CHOMHAIRLE NÁISIÚNTA UM THAIGHDE AGUS FORBAIRT FORAOISE
ERTDI No51 v7:SEA ERTDI No18 Reprint 01/08/2007 11:51 Page 1
Environmental Protection Agency
The Environmental Protection Agency (EPA) is
a statutory body responsible for protecting
the environment in Ireland. We regulate and
police activities that might otherwise cause
pollution. We ensure there is solid
information on environmental trends so that
necessary actions are taken. Our priorities are
protecting the Irish environment and
ensuring that development is sustainable.
The EPA is an independent public body
established in July 1993 under the
Environmental Protection Agency Act, 1992.
Its sponsor in Government is the Department
of the Environment, Heritage and Local
Government.
OUR RESPONSIBILITIES
LICENSING
We license the following to ensure that their emissions
do not endanger human health or harm the environment:
waste facilities (e.g., landfills,
incinerators, waste transfer stations);
large scale industrial activities
(e.g., pharmaceutical manufacturing,
cement manufacturing, power plants);
intensive agriculture;
the contained use and controlled release
of Genetically Modified Organisms (GMOs);
large petrol storage facilities.
NATIONAL ENVIRONMENTAL ENFORCEMENT
Conducting over 2,000 audits and inspections of
EPA licensed facilities every year.
Overseeing local authorities’ environmental
protection responsibilities in the areas of - air,
noise, waste, waste-water and water quality.
Working with local authorities and the Gardaí to
stamp out illegal waste activity by co-ordinating a
national enforcement network, targeting offenders,
conducting investigations and overseeing
remediation.
Prosecuting those who flout environmental law and
damage the environment as a result of their actions.
MONITORING, ANALYSING AND REPORTING ON THE
ENVIRONMENT
Monitoring air quality and the quality of rivers,
lakes, tidal waters and ground waters; measuring
water levels and river flows.
Independent reporting to inform decision making by
national and local government.
REGULATING IRELAND’S GREENHOUSE GAS EMISSIONS
Quantifying Ireland’s emissions of greenhouse gases
in the context of our Kyoto commitments.
Implementing the Emissions Trading Directive,
involving over 100 companies who are major
generators of carbon dioxide in Ireland.
ENVIRONMENTAL RESEARCH AND DEVELOPMENT
Co-ordinating research on environmental issues
(including air and water quality, climate change,
biodiversity, environmental technologies).
STRATEGIC ENVIRONMENTAL ASSESSMENT
Assessing the impact of plans and programmes on
the Irish environment (such as waste management
and development plans).
ENVIRONMENTAL PLANNING, EDUCATION AND
GUIDANCE
Providing guidance to the public and to industry on
various environmental topics (including licence
applications, waste prevention and environmental
regulations).
Generating greater environmental awareness
(through environmental television programmes and
primary and secondary schools’ resource packs).
PROACTIVE WASTE MANAGEMENT
Promoting waste prevention and minimisation
projects through the co-ordination of the National
Waste Prevention Programme, including input into
the implementation of Producer Responsibility
Initiatives.
Enforcing Regulations such as Waste Electrical and
Electronic Equipment (WEEE) and Restriction of
Hazardous Substances (RoHS) and substances that
deplete the ozone layer.
Developing a National Hazardous Waste Management
Plan to prevent and manage hazardous waste.
MANAGEMENT AND STRUCTURE OF THE EPA
The organisation is managed by a full time Board,
consisting of a Director General and four Directors.
The work of the EPA is carried out across four offices:
Office of Climate, Licensing and Resource Use
Office of Environmental Enforcement
Office of Environmental Assessment
Office of Communications and Corporate Services
The EPA is assisted by an Advisory Committee of twelve
members who meet several times a year to discuss
issues of concern and offer advice to the Board.
An Ghníomhaireacht um Chaomhnú Comhshaoil
Is í an Gníomhaireacht um Chaomhnú
Comhshaoil (EPA) comhlachta reachtúil a
chosnaíonn an comhshaol do mhuintir na tíre
go léir. Rialaímid agus déanaimid maoirsiú ar
ghníomhaíochtaí
a d'fhéadfadh truailliú a chruthú murach
sin. Cinntímid go bhfuil eolas cruinn ann
ar threochtaí comhshaoil ionas go nglactar
aon chéim is gá. Is iad na príomh-nithe a
bhfuilimid gníomhach leo ná comhshaol na
hÉireann a chosaint agus cinntiú go bhfuil
forbairt inbhuanaithe.
Is comhlacht poiblí neamhspleách í an
Ghníomhaireacht um Chaomhnú Comhshaoil
(EPA) a bunaíodh i mí Iúil 1993 faoin
Acht fán nGníomhaireacht um Chaomhnú
Comhshaoil 1992. Ó thaobh an Rialtais, is í
an Roinn Comhshaoil agus Rialtais Áitiúil a
dhéanann urraíocht uirthi.
ÁR bhFREAGRACHTAÍ
CEADÚNÚ
Bíonn ceadúnais á n-eisiúint againn i gcomhair na nithe
seo a leanas chun a chinntiú nach mbíonn astuithe uathu
ag cur sláinte an phobail ná an comhshaol i mbaol:
áiseanna dramhaíola (m.sh., líonadh talún,
loisceoirí, stáisiúin aistrithe dramhaíola);
gníomhaíochtaí tionsclaíocha ar scála mór (m.sh.,
déantúsaíocht cógaisíochta, déantúsaíocht
stroighne, stáisiúin chumhachta);
diantalmhaíocht;
úsáid faoi shrian agus scaoileadh smachtaithe
Orgánach Géinathraithe (GMO);
mór-áiseanna stórais peitreail.
FEIDHMIÚ COMHSHAOIL NÁISIÚNTA
Stiúradh os cionn 2,000 iniúchadh agus cigireacht
de áiseanna a fuair ceadúnas ón nGníomhaireacht
gach bliain.
Maoirsiú freagrachtaí cosanta comhshaoil údarás
áitiúla thar sé earnáil - aer, fuaim, dramhaíl,
dramhuisce agus caighdeán uisce.
Obair le húdaráis áitiúla agus leis na Gardaí chun
stop a chur le gníomhaíocht mhídhleathach
dramhaíola trí comhordú a dhéanamh ar líonra
forfheidhmithe náisiúnta, díriú isteach ar chiontóirí,
stiúradh fiosrúcháin agus maoirsiú leigheas na
bhfadhbanna.
An dlí a chur orthu siúd a bhriseann dlí comhshaoil
agus a dhéanann dochar don chomhshaol mar
thoradh ar a ngníomhaíochtaí.
MONATÓIREACHT, ANAILÍS AGUS TUAIRISCIÚ AR
AN GCOMHSHAOL
Monatóireacht ar chaighdeán aeir agus caighdeáin
aibhneacha, locha, uiscí taoide agus uiscí talaimh;
leibhéil agus sruth aibhneacha a thomhas.
Tuairisciú neamhspleách chun cabhrú le rialtais
náisiúnta agus áitiúla cinntí a dhéanamh.
RIALÚ ASTUITHE GÁIS CEAPTHA TEASA NA HÉIREANN
Cainníochtú astuithe gáis ceaptha teasa na
hÉireann i gcomhthéacs ár dtiomantas Kyoto.
Cur i bhfeidhm na Treorach um Thrádáil Astuithe, a
bhfuil baint aige le hos cionn 100 cuideachta atá
ina mór-ghineadóirí dé-ocsaíd charbóin in Éirinn.
TAIGHDE AGUS FORBAIRT COMHSHAOIL
Taighde ar shaincheisteanna comhshaoil a chomhordú
(cosúil le caighdéan aeir agus uisce, athrú aeráide,
bithéagsúlacht, teicneolaíochtaí comhshaoil).
MEASÚNÚ STRAITÉISEACH COMHSHAOIL
Ag déanamh measúnú ar thionchar phleananna agus
chláracha ar chomhshaol na hÉireann (cosúil le
pleananna bainistíochta dramhaíola agus forbartha).
PLEANÁIL, OIDEACHAS AGUS TREOIR CHOMHSHAOIL
Treoir a thabhairt don phobal agus do thionscal ar
cheisteanna comhshaoil éagsúla (m.sh., iarratais ar
cheadúnais, seachaint dramhaíola agus rialacháin
chomhshaoil).
Eolas níos fearr ar an gcomhshaol a scaipeadh (trí
cláracha teilifíse comhshaoil agus pacáistí
acmhainne do bhunscoileanna agus do
mheánscoileanna).
BAINISTÍOCHT DRAMHAÍOLA FHORGHNÍOMHACH
Cur chun cinn seachaint agus laghdú dramhaíola trí
chomhordú An Chláir Náisiúnta um Chosc
Dramhaíola, lena n-áirítear cur i bhfeidhm na
dTionscnamh Freagrachta Táirgeoirí.
Cur i bhfeidhm Rialachán ar nós na treoracha maidir
le Trealamh Leictreach agus Leictreonach Caite agus
le Srianadh Substaintí Guaiseacha agus substaintí a
dhéanann ídiú ar an gcrios ózóin.
Plean Náisiúnta Bainistíochta um Dramhaíl
Ghuaiseach a fhorbairt chun dramhaíl ghuaiseach a
sheachaint agus a bhainistiú.
STRUCHTÚR NA GNÍOMHAIREACHTA
Bunaíodh an Ghníomhaireacht i 1993 chun comhshaol
na hÉireann a chosaint. Tá an eagraíocht á bhainistiú
ag Bord lánaimseartha, ar a bhfuil Príomhstiúrthóir
agus ceithre Stiúrthóir.
Tá obair na Gníomhaireachta ar siúl trí ceithre Oifig:
An Oifig Aeráide, Ceadúnaithe agus Úsáide
Acmhainní
An Oifig um Fhorfheidhmiúchán Comhshaoil
An Oifig um Measúnacht Comhshaoil
An Oifig Cumarsáide agus Seirbhísí Corparáide
Tá Coiste Comhairleach ag an nGníomhaireacht le
cabhrú léi. Tá dáréag ball air agus tagann siad le chéile
cúpla uair in aghaidh na bliana le plé a dhéanamh ar
cheisteanna ar ábhar imní iad agus le comhairle a
thabhairt don Bhord.
ERTDI No51 v7:SEA ERTDI No18 Reprint 01/08/2007 11:51 Page 2
Environmental Protection Agency
The Environmental Protection Agency (EPA) is
a statutory body responsible for protecting
the environment in Ireland. We regulate and
police activities that might otherwise cause
pollution. We ensure there is solid
information on environmental trends so that
necessary actions are taken. Our priorities are
protecting the Irish environment and
ensuring that development is sustainable.
The EPA is an independent public body
established in July 1993 under the
Environmental Protection Agency Act, 1992.
Its sponsor in Government is the Department
of the Environment, Heritage and Local
Government.
OUR RESPONSIBILITIES
LICENSING
We license the following to ensure that their emissions
do not endanger human health or harm the environment:
waste facilities (e.g., landfills,
incinerators, waste transfer stations);
large scale industrial activities
(e.g., pharmaceutical manufacturing,
cement manufacturing, power plants);
intensive agriculture;
the contained use and controlled release
of Genetically Modified Organisms (GMOs);
large petrol storage facilities.
NATIONAL ENVIRONMENTAL ENFORCEMENT
Conducting over 2,000 audits and inspections of
EPA licensed facilities every year.
Overseeing local authorities’ environmental
protection responsibilities in the areas of - air,
noise, waste, waste-water and water quality.
Working with local authorities and the Gardaí to
stamp out illegal waste activity by co-ordinating a
national enforcement network, targeting offenders,
conducting investigations and overseeing
remediation.
Prosecuting those who flout environmental law and
damage the environment as a result of their actions.
MONITORING, ANALYSING AND REPORTING ON THE
ENVIRONMENT
Monitoring air quality and the quality of rivers,
lakes, tidal waters and ground waters; measuring
water levels and river flows.
Independent reporting to inform decision making by
national and local government.
REGULATING IRELAND’S GREENHOUSE GAS EMISSIONS
Quantifying Ireland’s emissions of greenhouse gases
in the context of our Kyoto commitments.
Implementing the Emissions Trading Directive,
involving over 100 companies who are major
generators of carbon dioxide in Ireland.
ENVIRONMENTAL RESEARCH AND DEVELOPMENT
Co-ordinating research on environmental issues
(including air and water quality, climate change,
biodiversity, environmental technologies).
STRATEGIC ENVIRONMENTAL ASSESSMENT
Assessing the impact of plans and programmes on
the Irish environment (such as waste management
and development plans).
ENVIRONMENTAL PLANNING, EDUCATION AND
GUIDANCE
Providing guidance to the public and to industry on
various environmental topics (including licence
applications, waste prevention and environmental
regulations).
Generating greater environmental awareness
(through environmental television programmes and
primary and secondary schools’ resource packs).
PROACTIVE WASTE MANAGEMENT
Promoting waste prevention and minimisation
projects through the co-ordination of the National
Waste Prevention Programme, including input into
the implementation of Producer Responsibility
Initiatives.
Enforcing Regulations such as Waste Electrical and
Electronic Equipment (WEEE) and Restriction of
Hazardous Substances (RoHS) and substances that
deplete the ozone layer.
Developing a National Hazardous Waste Management
Plan to prevent and manage hazardous waste.
MANAGEMENT AND STRUCTURE OF THE EPA
The organisation is managed by a full time Board,
consisting of a Director General and four Directors.
The work of the EPA is carried out across four offices:
Office of Climate, Licensing and Resource Use
Office of Environmental Enforcement
Office of Environmental Assessment
Office of Communications and Corporate Services
The EPA is assisted by an Advisory Committee of twelve
members who meet several times a year to discuss
issues of concern and offer advice to the Board.
An Ghníomhaireacht um Chaomhnú Comhshaoil
Is í an Gníomhaireacht um Chaomhnú
Comhshaoil (EPA) comhlachta reachtúil a
chosnaíonn an comhshaol do mhuintir na tíre
go léir. Rialaímid agus déanaimid maoirsiú ar
ghníomhaíochtaí
a d'fhéadfadh truailliú a chruthú murach
sin. Cinntímid go bhfuil eolas cruinn ann
ar threochtaí comhshaoil ionas go nglactar
aon chéim is gá. Is iad na príomh-nithe a
bhfuilimid gníomhach leo ná comhshaol na
hÉireann a chosaint agus cinntiú go bhfuil
forbairt inbhuanaithe.
Is comhlacht poiblí neamhspleách í an
Ghníomhaireacht um Chaomhnú Comhshaoil
(EPA) a bunaíodh i mí Iúil 1993 faoin
Acht fán nGníomhaireacht um Chaomhnú
Comhshaoil 1992. Ó thaobh an Rialtais, is í
an Roinn Comhshaoil agus Rialtais Áitiúil a
dhéanann urraíocht uirthi.
ÁR bhFREAGRACHTAÍ
CEADÚNÚ
Bíonn ceadúnais á n-eisiúint againn i gcomhair na nithe
seo a leanas chun a chinntiú nach mbíonn astuithe uathu
ag cur sláinte an phobail ná an comhshaol i mbaol:
áiseanna dramhaíola (m.sh., líonadh talún,
loisceoirí, stáisiúin aistrithe dramhaíola);
gníomhaíochtaí tionsclaíocha ar scála mór (m.sh.,
déantúsaíocht cógaisíochta, déantúsaíocht
stroighne, stáisiúin chumhachta);
diantalmhaíocht;
úsáid faoi shrian agus scaoileadh smachtaithe
Orgánach Géinathraithe (GMO);
mór-áiseanna stórais peitreail.
FEIDHMIÚ COMHSHAOIL NÁISIÚNTA
Stiúradh os cionn 2,000 iniúchadh agus cigireacht
de áiseanna a fuair ceadúnas ón nGníomhaireacht
gach bliain.
Maoirsiú freagrachtaí cosanta comhshaoil údarás
áitiúla thar sé earnáil - aer, fuaim, dramhaíl,
dramhuisce agus caighdeán uisce.
Obair le húdaráis áitiúla agus leis na Gardaí chun
stop a chur le gníomhaíocht mhídhleathach
dramhaíola trí comhordú a dhéanamh ar líonra
forfheidhmithe náisiúnta, díriú isteach ar chiontóirí,
stiúradh fiosrúcháin agus maoirsiú leigheas na
bhfadhbanna.
An dlí a chur orthu siúd a bhriseann dlí comhshaoil
agus a dhéanann dochar don chomhshaol mar
thoradh ar a ngníomhaíochtaí.
MONATÓIREACHT, ANAILÍS AGUS TUAIRISCIÚ AR
AN GCOMHSHAOL
Monatóireacht ar chaighdeán aeir agus caighdeáin
aibhneacha, locha, uiscí taoide agus uiscí talaimh;
leibhéil agus sruth aibhneacha a thomhas.
Tuairisciú neamhspleách chun cabhrú le rialtais
náisiúnta agus áitiúla cinntí a dhéanamh.
RIALÚ ASTUITHE GÁIS CEAPTHA TEASA NA HÉIREANN
Cainníochtú astuithe gáis ceaptha teasa na
hÉireann i gcomhthéacs ár dtiomantas Kyoto.
Cur i bhfeidhm na Treorach um Thrádáil Astuithe, a
bhfuil baint aige le hos cionn 100 cuideachta atá
ina mór-ghineadóirí dé-ocsaíd charbóin in Éirinn.
TAIGHDE AGUS FORBAIRT COMHSHAOIL
Taighde ar shaincheisteanna comhshaoil a chomhordú
(cosúil le caighdéan aeir agus uisce, athrú aeráide,
bithéagsúlacht, teicneolaíochtaí comhshaoil).
MEASÚNÚ STRAITÉISEACH COMHSHAOIL
Ag déanamh measúnú ar thionchar phleananna agus
chláracha ar chomhshaol na hÉireann (cosúil le
pleananna bainistíochta dramhaíola agus forbartha).
PLEANÁIL, OIDEACHAS AGUS TREOIR CHOMHSHAOIL
Treoir a thabhairt don phobal agus do thionscal ar
cheisteanna comhshaoil éagsúla (m.sh., iarratais ar
cheadúnais, seachaint dramhaíola agus rialacháin
chomhshaoil).
Eolas níos fearr ar an gcomhshaol a scaipeadh (trí
cláracha teilifíse comhshaoil agus pacáistí
acmhainne do bhunscoileanna agus do
mheánscoileanna).
BAINISTÍOCHT DRAMHAÍOLA FHORGHNÍOMHACH
Cur chun cinn seachaint agus laghdú dramhaíola trí
chomhordú An Chláir Náisiúnta um Chosc
Dramhaíola, lena n-áirítear cur i bhfeidhm na
dTionscnamh Freagrachta Táirgeoirí.
Cur i bhfeidhm Rialachán ar nós na treoracha maidir
le Trealamh Leictreach agus Leictreonach Caite agus
le Srianadh Substaintí Guaiseacha agus substaintí a
dhéanann ídiú ar an gcrios ózóin.
Plean Náisiúnta Bainistíochta um Dramhaíl
Ghuaiseach a fhorbairt chun dramhaíl ghuaiseach a
sheachaint agus a bhainistiú.
STRUCHTÚR NA GNÍOMHAIREACHTA
Bunaíodh an Ghníomhaireacht i 1993 chun comhshaol
na hÉireann a chosaint. Tá an eagraíocht á bhainistiú
ag Bord lánaimseartha, ar a bhfuil Príomhstiúrthóir
agus ceithre Stiúrthóir.
Tá obair na Gníomhaireachta ar siúl trí ceithre Oifig:
An Oifig Aeráide, Ceadúnaithe agus Úsáide
Acmhainní
An Oifig um Fhorfheidhmiúchán Comhshaoil
An Oifig um Measúnacht Comhshaoil
An Oifig Cumarsáide agus Seirbhísí Corparáide
Tá Coiste Comhairleach ag an nGníomhaireacht le
cabhrú léi. Tá dáréag ball air agus tagann siad le chéile
cúpla uair in aghaidh na bliana le plé a dhéanamh ar
cheisteanna ar ábhar imní iad agus le comhairle a
thabhairt don Bhord.
ERTDI No51 v7:SEA ERTDI No18 Reprint 01/08/2007 11:51 Page 2
Environmental RTDI Programme 2000–2006
Biodiversity in Irish Plantation Forests
(BIOFOREST Project, http://bioforest.ucc.ie)
(2000-LS-3.1-M2)
Final Report
Prepared for the Environmental Protection Agency and
the National Council for Forest Research and Development
by
Department of Zoology, Ecology and Plant Science, University College Cork
Department of Botany, Trinity College Dublin
Coillte Teoranta
Authors:
S. Iremonger, J. O’Halloran, D.L. Kelly, M.W. Wilson, G.F. Smith, T. Gittings, P.S. Giller,
F.J.G. Mitchell, A. Oxbrough, L. Coote, L. French, S. O’Donoghue, A.-M. McKee, J. Pithon,
A. O’Sullivan, P. Neville, V. O’Donnell, V. Cummins, T.C. Kelly and P. Dowding
ENVIRONMENTAL PROTECTION AGENCY
An Ghníomhaireacht um Chaomhnú Comhshaoil
PO Box 3000, Johnstown Castle, Co. Wexford, Ireland
Telephone: +353 53 916 0600 Fax: +353 53 916 0699
E-mail: info@epa.ie Website: www.epa.ie
ii
© Environmental Protection Agency 2007
ACKNOWLEDGEMENTS
This report has been prepared as part of the Environmental Research Technological Development and Innovation
Programme under the Productive Sector Operational Programme 2000–2006. The programme is financed by the Irish
Government under the National Development Plan 2000–2006. It is administered on behalf of the Department of the
Environment, Heritage and Local Government by the Environmental Protection Agency which has the statutory function
of co-ordinating and promoting environmental research.
The authors thank COFORD and the EPA, the bodies that funded this research, without which this work would not have
been possible. In particular we thank Dr Eugene Hendrick, Joe O'Carroll and Lauren MacLennan of COFORD and Helen
Walsh, Loraine Fegan, Dr Conor Clenaghan, Dr Karl Richards and Dr Garret Kilroy of the EPA. We are grateful also to
Coillte Teoranta for the use of its forests and for all the assistance given with site selection, access and implementation.
We also thank the private landowners who gave us permission to use their land for this study and provided us with land
management information, and the foresters who provided us with information on site preparation and afforestation
methodologies. We thank the many people who assisted us with field and lab work: Jacqueline Bolli, Maire Buckley,
Noirín Burke, Erika Buscardo, John Cleary, Sinéad Cummins, Aoife Delaney, Bastian Egeter, Gerry Farrell, Richard
Jack, Siobhán McNamee, Susan Murphy, Deirdre Ninaber, Eleanor O'Brien, Julianna O'Callaghan, Blathnaid O'Loughlin
and Terence Shelley. We thank the members of the BIOFOREST Steering Group who made excellent observations and
truly steered the project at the start when the details were being decided. They are: Prof. Tor-Björn Larsson, European
Environment Agency; Prof. Jari Niemelä, Helsinki University; Dr Jonathan Humphrey, Forest Research, UK; Dr Allan
Watt, Centre for Ecology and Hydrology, Banchory, UK; Noel Foley, Forest Service, Ireland; Dr John Cross, National
Parks and Wildlife Service, Ireland. We are also grateful to the many other people and institutions that assisted the
BIOFOREST project. These are acknowledged in the individual Technical Reports for each sub-project.
DISCLAIMER
The findings and results presented in this report reflect the situation up to July 2006. Although every effort has been
made to ensure the accuracy of the material contained in this publication, complete accuracy cannot be guaranteed.
Neither the Environmental Protection Agency nor the author(s) accept any responsibility whatsoever for loss or damage
occasioned or claimed to have been occasioned, in part or in full, as a consequence of any person acting, or refraining
from acting, as a result of a matter contained in this publication. All or part of this publication may be reproduced
without further permission, provided the source is acknowledged.
BIODIVERSITY
The Biodiversity Section of the Environmental RTDI Programme addresses the need for research in Ireland to inform
policymakers and other stakeholders on a range of questions in this area. The reports in this series are intended as
contributions to the necessary debate on biodiversity and the environment.
DECLARATION
All results presented in this report are included in a DVD which will be made publicly available one year from the
publication of this report.
ENVIRONMENTAL RTDI PROGRAMME 2000–2006
Co-published by the Environmental Protection Agency and the
National Council for Forest Research and Development, Ireland
PRINTED ON RECYCLED PAPER
ISBN: 1-84095-203-2
Price: €15 06/07/300
iii
Details of Project Partners
Dr S. Iremonger
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
E-mail: s.iremonger@gmail.com
Prof. J. O’Halloran
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Tel.: +353 21 4904653
E-mail: j.ohalloran@ucc.ie
Dr D.L. Kelly
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Dr M.W. Wilson
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Dr G.F. Smith
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Dr T. Gittings
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Prof. P.S. Giller
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Dr F.J.G. Mitchell
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Dr A. Oxbrough
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Dr L. Coote
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Dr L. French
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Ms S. O’Donoghue
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
iv
Dr A.-M. McKee
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
Dr J. Pithon
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Dr A. O’Sullivan
Coillte Teoranta
Newtownmountkennedy
Co. Wicklow
Ireland
Mr P. Neville
Coillte Teoranta
Newtownmountkennedy
Co. Wicklow
Ireland
Ms V. O’Donnell
Coastal and Marine Resources Centre
University College Cork
Cork
Ireland
Ms V. Cummins
Coastal and Marine Resources Centre
University College Cork
Cork
Ireland
Dr T.C. Kelly
Department of Zoology, Ecology and Plant Science
University College Cork
Cork
Ireland
Dr P. Dowding
Department of Botany
School of Natural Sciences
Trinity College Dublin
Dublin
Ireland
v
Table of Contents
Acknowledgements ii
Disclaimer ii
Details of Project Partners iii
Executive Summary ix
1 Introduction 1
1.1 International Activities for Conservation of Biodiversity and Sustainable
Forest Management 1
1.2 Irish Forestry 1
1.3 BIOFOREST Project 2
2Methods 4
2.1 Measuring Biodiversity 4
2.2 Vegetation 4
2.2.1 Terrestrial vegetation sampling 4
2.2.2 Epiphyte sampling 5
2.2.3 Data analysis 5
2.3 Spiders 6
2.3.1 Spider sampling 6
2.3.2 Data analysis 6
2.4 Hoverflies 6
2.4.1 Hoverfly sampling 6
2.4.2 Data analysis 7
2.5 Birds 7
2.5.1 Data analysis 8
2.6 General Data Analysis 8
vi
3 Project 3.1.1: Biodiversity of Afforestation Sites 9
3.1 Introduction 9
3.2 Review of Methods of Biodiversity Assessment 9
3.2.1 Introduction 9
3.2.2 Methods 9
3.2.3 Irish practice 9
3.2.4 United Kingdom practice 10
3.3 Habitats Review 10
3.4 Biodiversity Survey 11
3.4.1 Study design and site selection 11
3.4.2 Vegetation 12
3.4.3 Hoverflies 13
3.4.4 Spiders 14
3.4.5 Birds 15
3.4.6 Indicators 16
3.5 Conclusions 18
4 Project 3.1.2: Assessment of Biodiversity at Different Stages of the Forest Cycle 21
4.1 Introduction 21
4.2 Study Design and Site Selection 21
4.3 Vegetation 22
4.4 Spiders 23
4.5 Hoverflies 24
4.6 Birds 24
4.7 Indicators 25
4.8 Conclusions 27
5 Project 3.1.3: Investigation of Experimental Methods to Enhance Biodiversity
in Plantation Forests 28
5.1 Introduction 28
vii
5.2 Extensive Survey 28
5.2.1 Introduction 28
5.2.2 General methods 29
5.2.3 Terrestrial vegetation 29
5.2.4 Epiphytes 30
5.2.5 Spiders 30
5.2.6 Hoverflies 31
5.2.7 Birds 32
5.2.8 Conclusions 32
5.3 Experimental Manipulation 33
5.4 Special Report on Hen Harriers 34
6 Recommendations for Policy and Practice 36
6.1 Strategic Forest Planning 39
6.2 Pre-Afforestation Site Assessment 40
6.3 Forest Establishment 41
6.4 Forest Management 43
6.5 Further Research 43
References 46
Appendix 1 48
Appendix 2 51
ix
Executive Summary
Introduction
The Republic of Ireland published a strategic plan for the
forest sector in 1996 (DAFF, 1996) which involved
increasing the forest cover dramatically. Ireland is one of
the least forested countries in Europe, even though
forestry plantations have increased forest cover from less
than 1% of land cover to about 10% in the last century.
The plan aims to increase this to 17% by 2030, mainly by
planting new commercial forests at approximately 20,000
ha per year. This increase represents a huge change in
land use and land cover across Ireland, and has far-
reaching economic, social and ecological consequences.
The most widely planted species in these commercial
forests is Sitka spruce (
Picea sitchensis
), a non-native
conifer, and many forest industries are associated with
this species. Having changed some funding policies in the
late 1990s to promote the use of broadleaves in
plantations, the planting of ash (
Fraxinus excelsior
)
increased significantly and broadleaves now constitute
20% of new plantings.
In order to promote forest biodiversity and fully practice
sustainable forest management (SFM), it is necessary to
know what organisms are associated with the forest
plantations, and what the manager should be aiming at. A
multitude of questions needed to be answered, from the
most basic (What organisms are living in or associated
with the plantations? What are the differences between
these and the flora and fauna of native/semi-natural
forests?) to the more complex (Has afforestation
improved the general biodiversity of the area? What effect
does previous habitat type have on the diversity of the
developing forest? What policies and practices support
the creation and maintenance of the most diverse
plantations?). Until recently very little was known about
the ecology of these forests and their associated flora and
fauna: ecologists were more likely to investigate natural
land-cover types than these more artificial ones. Irelandʼs
native and semi-natural woodlands are very different
ecologically to most forest plantations. The former are
generally dominated by a broadleaf mix and are not clear-
felled at commercial maturity whereas the latter have
traditionally been dominated by a non-native conifer
monoculture on a clear-felling cycle of 35–55 years.
Design of the BIOFOREST Project
Against the forestry background described above, the
Environmental Protection Agency (EPA) and the Council
for Forest Research and Development (COFORD)
arranged to jointly fund research on forest biodiversity
from National Development Plan funds, in the ERTDI
programme. The resulting BIOFOREST project was a
large-scale project running from 2001 to 2006 with the aim
of providing much-needed basic information on
biodiversity in Irish plantation forests. The focus of this
research was to illustrate the effects of different aspects
of management on biodiversity within forests, from the
planning stage through to the mature forest. The research
had an applied orientation and objectives to feed directly
into the updating of forest policy and practice documents.
This large-scale project (2000-LS-3.1-M2) was structured
as three smaller projects, each addressing a separate
aspect of forest biodiversity. These were:
• Project 3.1.1:
Biodiversity Assessment of
Afforestation Sites
• Project 3.1.2:
Assessment of Biodiversity at Different
Stages of the Forest Cycle
• Project 3.1.3:
Investigation of Experimental Methods
to Enhance Biodiversity in Plantation Forests
.
The BIOFOREST research team comprised the following
organisations:
• Department of Zoology, Ecology and Plant Science
(ZEPS), Environment Research Institute (ERI),
University College, Cork (UCC)
• Department of Botany, School of Natural Sciences,
Trinity College, Dublin (TCD)
• Coillte Teoranta, The Irish Forestry Board (Coillte).
The research team was guided with input from a Steering
Group that included external experts from other
organisations in Ireland (e.g. Dúchas/National Parks and
Wildlife Service) and abroad (Denmark, Finland, the UK).
The input of other external experts was requested as
necessary and supported by COFORD and the EPA.
S. Iremonger et al., 2000-LS-3.1-M2
x
Assessment of biodiversity in any habitat or landscape is
a difficult task to achieve on a comprehensive scale, given
the range of components of biodiversity (different biota)
that could be measured if logistics allowed. At most,
studies aimed at assessing biodiversity directly can
expect to measure the occurrence and diversity of only a
small proportion of biota, whether animal, plant, fungal or
microbial. Choosing the appropriate groups to study
raises questions of subjectivity, and different groups may
respond differently to habitat and other environmental
variables. Nonetheless, this project required the
development of inventories, and specific groups of
organisms that include taxa known to have utility as
biodiversity indicators elsewhere were targeted. An
additional approach was to try to identify features of the
habitat or landscape that could be used to predict
biodiversity, at least in relative terms, for comparisons
over space or time. Indicators of biodiversity can be
viewed in three categories: structural, compositional and
functional.
This study included these three main indicator types. The
main taxonomic groups included in the project were
spiders, hoverflies, birds and plants. These were chosen
on the basis that they represented a range of functional
groups whose taxonomy and ecology were sufficiently
well known to facilitate their use as indicators. In all three
sub-projects interdisciplinarity was stressed, and
wherever possible the different groups were studied in the
same study sites and during the same periods. Studying
different groups in this manner gives better insight into the
functioning of the ecosystem, thereby shedding more light
on possible management methods and best practice.
Project 3.1.1: Biodiversity Assessment of
Afforestation Sites
The main objectives of this project were to:
• Assess the biodiversity of frequently afforested
habitats.
• Develop methodologies for biodiversity assessment
and identify indicator species in these habitats.
• Assess the efficacy of the
Forest Biodiversity
Guidelines
(Forest Service, 2000) and recommend
improvements.
The final technical report for the project (Smith
et al
.,
2006) includes all of these items. The work included a
special report on pre-afforestation assessment practices
(Gittings
et al.,
2004), and contributed to two university
theses (Bolli, 2002; Buscardo, 2005).
Project 3.1.2: Assessment of Biodiversity at Different
Stages of the Forest Cycle
The main objectives of this project were to:
• Assess the range of biodiversity in representative
forests at key stages of the forest cycle.
• Review possibilities for enhancement of biodiversity
in plantation forests and make recommendations.
• Assess the effectiveness of the
Forest Biodiversity
Guidelines
in light of the results of this study.
The final technical report for the project (Smith
et al
.,
2005) includes all of these items. This project produced
two PhDs (French, 2005; Oxbrough, 2006), although
parts of Oxbroughʼs thesis also came from Projects 3.1.1
and 3.1.3.
Project 3.1.3: Investigation of Experimental
Methods to Enhance Biodiversity in Plantation
Forests
The main aim of this project was to:
• Identify those forestry management practices (with
the possibility of using experimental plots) which are
best suited to maintaining and enhancing biodiversity
in plantation forests.
This was fine-tuned during the period that the other two
projects were under way, in consultation with the projectʼs
international Steering Group and other experts. The main
activities outlined were:
• An extensive survey of open-space habitats (glades,
rides and roadsides) within plantation forests.
• The establishment of an experiment on the
manipulation of open space in the forest, focusing on
roads.
• A separate study on Hen Harrier habitat
requirements.
The final technical report for the project (Iremonger
et al
.,
2006) includes all of these items. This project also
produced a special report on Hen Harriers (Wilson
et al.
,
2005) and a PhD (Coote, 2007).
Biodiversity in Irish plantation forests
xi
Conclusions and Recommendations
The individual projects concluded, in general, that forestry
plantations can make a significant positive contribution to
biodiversity in the landscape if properly planned and
managed, and can have a negative effect if not. The
promotion of biodiversity in forestry needs the support of
good policies and practices. Fifty-seven
recommendations are made, addressing different aspects
of forestry from strategic planning to localised planning
and practice. The needs for future research are outlined.
The recommendations are listed below; the full text gives
context and rationale for these.
Strategic forest planning
1. Require all non-urban local authorities to prepare
Indicative Forestry Strategies.
2. Compile specialist reports identifying biodiversity
constraints outside designated sites.
3. Complete countywide habitat surveys and
biodiversity action plans and establish a biological
records centre.1
4. Survey invertebrate biodiversity in semi-natural
habitats of conservation importance.
5. Establish ecological advisory units in each local
authority.
6. Establish a system of professional accreditation for
ecological consultants in Ireland.
7. Incorporate requirements for biodiversity
assessment (in 21, below) in Environmental Impact
Assessment (EIA)
Advice Notes
.
8. Develop guidelines for the choice of invertebrate
taxa for EIAs.
9. Develop a more thorough classification of vegetation
communities in Ireland.
10. Afforestation and agricultural improvement should
be regulated in areas with Hen Harriers.
11. Develop a mosaic of different stand age classes in
heavily afforested areas occupied by Hen Harriers.
Pre-afforestation site assessment
12. Develop screening criteria to identify afforestation
projects requiring a sub-threshold EIA.
13. Forest Service should employ ecologists.
14. Pre-afforestation site surveys should map habitats
using a standard classification and note the
presence of indicators and other biodiversity
features.
15. Consider site biodiversity in context of the
surrounding landscape prior to afforestation.
16. Foresters submitting grant applications should have
completed accredited ecological training courses or
employ qualified ecologists.
17. A sample of grant applications from each self-
assessment company to be inspected by a Forest
Service ecologist.
18. More comprehensive consultation procedures for
grant applications.
19. Local authorities to comment on conservation issues
pertaining to grant applications.
20. Refer applications where biodiversity concerns have
been raised to a Forest Service ecologist to
determine whether a more thorough assessment is
required.
21. Biodiversity assessments in afforestation
Environmental Impact Statements (EISs) must
conform to specified standards.
22. Biodiversity assessments contained in EISs to be
reviewed by a Forest Service ecologist, or an
accredited external ecologist.
23. Proposed changes in land use should be regarded
as being potentially damaging to Hen Harriers if they
decrease the proportion of suitable habitat to below
30%.
Forest establishment
24. Semi-natural habitats should not be afforested,
unless there are mitigating circumstances.
1. The Irish National Biodiversity Data Centre was officially
opened in January 2007 on the Carriganore Campus of the
Waterford Institute of Technology. The Centreʼs duties cover
the collection of records from public bodies and private
collectors, their validation, collation, classification and
digitisation plus education, research and training in
biodiversity.
S. Iremonger et al., 2000-LS-3.1-M2
xii
25. Establish plantations in close proximity to semi-
natural woodland.
26. Create a mosaic of stands of different age and
structure at the landscape scale.
27. Include a mixture of canopy species when planting.
28. Review the adequacy of the existing requirement for
5–10% open space in the
Forest Biodiversity
Guidelines.
29. Stipulate a minimum width of 15 m for linear open-
space features included in the Area for Biodiversity
Enhancement (ABE).
30. Leave small unplanted areas to maintain gaps
through the forest cycle.
31. Leave small areas of wet habitat and avoid drainage
where possible.
32. Include open space within broadleaved component
of plantation.
33. Retain scrub, hedgerows and other marginal and
additional habitats and allow for adequate buffer
zones.
34. Design complex edges to plantations to increase
proportion of edge habitat.
35. Leave boundaries unplanted to allow development of
complex edge structure.
Forest management
36. Provide guidelines to help foresters to identify
potentially important habitats for ground flora, spider
and hoverfly diversity.
37. Rigorously thin Sitka spruce forests to prevent
canopy closure.
38. Promote broadleaved woody vegetation in young
conifer plantations.
39. Ensure grazing pressure is low enough to allow
broadleaved tree and shrub vegetation to develop.
40. Retain mature Sitka spruce stands, where there is no
risk of damage to adjoining semi-natural habitats.
41. Retain large diameter dead wood.
Future research
42. Test and refine the indicators identified in this
project.
43. Conduct a comprehensive national survey and
classification of grasslands.
44. Investigate forestry and biodiversity at whole-farm
and landscape scales.
45. Investigate the implications for biodiversity of
different tree species mixtures.
46. Investigate the biodiversity of open spaces in
plantations in agricultural lowland landscapes.
47. An investigation of the biodiversity of over-mature
commercial plantations.
48. A study of the biodiversity of second-rotation forests.
49. A study of the biodiversity in forests under
continuous cover management.
50. Monitor forest biodiversity in permanent plots.
51. Investigate the inclusion of native woodland
elements into commercial plantations.
52. Further investigate the biodiversity of different open-
space habitats within forests.
53. Determine the influence of grazing pressure on
broadleaved tree and shrub vegetation in open
spaces.
54. Investigate the biodiversity of other taxa found in
Irish forests and afforested habitats.
55. Develop a custom-designed GIS for analysis of
habitat in areas with Hen Harriers.
56. Collect more detailed habitat data from the areas
with Hen Harriers.
57. Improve our understanding of Hen Harrier habitat
requirements.
References
DAFF, 1996.
Growing for the Future: A Strategic Plan for the
Development of the Forestry Sector in Ireland
. Department
of Agriculture, Food and Forestry, Dublin, Ireland.
Bolli, J., 2002.
Biodiversity Assessment of Afforestation Sites.
Environmental Sciences Degree Thesis, ETH, Zürich,
Switzerland.
Biodiversity in Irish plantation forests
xiii
Buscardo, E., 2005.
The Effects of Afforestation on Biodiversity
of Grasslands in Ireland
. MSc Thesis, University of Coimbra,
Portugal.
Coote, L., 2007.
Epiphyte Diversity in Irish Plantation Forests.
PhD Thesis, Trinity College, University of Dublin, Ireland.
Forest Service, 2000.
Forest Biodiversity Guidelines
. Forest
Service, Department of the Marine and Natural Resources,
Dublin, Ireland.
French, L., 2005.
Ground Flora Communities in Irelandʼs
Plantation Forests: their Diversity, Structure and
Composition
. PhD Thesis, Trinity College, University of
Dublin, Ireland.
Gittings, T., McKee, A.-M., OʼDonoghue, S., Pithon, J., Wilson,
M., Giller, P., Kelly, D., OʼHalloran, J., Mitchell, F. and
Iremonger, S., 2004.
Biodiversity Assessment in Preparation
for Afforestation: A Review of Existing Practice in Ireland
and Best Practice Overseas
. Report for COFORD and the
EPA, Dublin, Ireland.
Iremonger, S., Gittings, T., Smith, G.F., Wilson, M., Oxbrough,
A., Coote, L., Pithon, J., OʼDonoghue, S., McKee, A.-M.,
OʼHalloran, J., Kelly, D.L., Giller, P., OʼSullivan, A., Neville,
P., Mitchell, F.J.G., OʼDonnell, V., Kelly, T. and Dowding, P.,
2006.
Investigation of Experimental Methods to Enhance
Biodiversity in Plantation Forests
. Report for COFORD and
EPA, Dublin, Ireland.
Oxbrough, A., 2006.
The Effect of Plantation Forests on Ground-
Dwelling Spiders.
PhD Thesis, University College, Cork,
Ireland.
Smith, G., Gittings, T., Wilson, M., French, L., Oxbrough, A.,
OʼDonoghue, S., Pithon, J., OʼDonnell, V., McKee, A.-M.,
Iremonger, S., OʼHalloran, J., Kelly, D., Mitchell, F., Giller, P.
and Kelly, T., 2005.
Assessment of Biodiversity at Different
Stages of the Forest Cycle
. Report for COFORD and the
EPA, Dublin, Ireland.
Smith, G.F., Gittings, T., Wilson, M., Oxbrough, A., Iremonger,
S., O'Donoghue, S., McKee, A.-M., O'Halloran, J., Kelly, D.
L., Pithon, J., O'Sullivan, A., Neville, P., Mitchell, F.J.G.,
Giller, P., O'Donnell, V. and Kelly, T., 2006.
Biodiversity
Assessment of Afforestation Sites.
COFORD and the EPA,
Dublin, Ireland.
Wilson, M., Gittings, T., O'Halloran, J., Kelly, T. and Pithon, J.,
2005.
The Distribution of Hen Harriers in Ireland in Relation
to Land-Use Cover in General and Forest Cover in
Particular
. Report for COFORD and EPA, Dublin, Ireland.
1
1 Introduction
1.1 International Activities for Conserv-
ation of Biodiversity and Sustainable
Forest Management
Currently across the globe there is unprecedented
interest in the earthʼs biological diversity, or ʼbiodiversityʼ.
The United Nations Convention on Biological Diversity
(CBD) was signed by 150 countries, including Ireland, at
the United Nations Conference on Environment and
Development (UNCED) in 1992, and the convention came
into force in 1993. The treaty was a landmark in the
environment and development field, as it took for the first
time a comprehensive, rather than a sectoral, approach to
conservation of the Earthʼs biodiversity and sustainable
use of biological resources. It recognised that both
biodiversity and biological resources should be conserved
for reasons of ethics, economic benefit and indeed human
survival. It implicitly accepted the telling point that the
environmental impact which future generations may most
regret about our time is the loss of biological diversity, in
part because most of it – for example loss of species –
cannot be reversed. 'Biological diversity' was defined as
“
the variability among living organisms from all sources
including, inter alia, terrestrial, marine and other aquatic
ecosystems and the ecological complexes of which they
are part; this includes diversity within species, between
species and of ecosystems
".
Forest ecosystems have come under special scrutiny,
particularly through the activities associated with the
Convention for Sustainable Development (CSD). The
CSD set up an Intergovernmental Panel on Forests,
which progressed internationally agreed procedures for
forest planning and management. The subsequent
Intergovernmental Forum on Forests worked towards
implementing the procedures, particularly at the
international level. Meanwhile, there have been regional
initiatives working at government level towards supporting
Sustainable Forest Management (SFM). The Helsinki
Process applies to European countries and the Montreal
Process to temperate countries outside of Europe. Other
proposals exist for tropical countries (Conference of the
Parties IV, 1998). Ireland is a Signatory State to the
Helsinki Process, which follows ministerial conferences
on the protection of forests in Europe, the first two of
which were in Strasbourg (1990) and Helsinki (1993). The
definition of SFM adopted by the Helsinki conference was
“
the stewardship and use of forests and forest lands in a
way, and at a rate, that maintains their biodiversity,
productivity, regeneration capacity, vitality and their
potential to fulfil, now and in the future, relevant
ecological, economic and social functions, at local,
national and global levels, and that does not cause
damage to other ecosystems
”
.
An outcome from the Helsinki conference was Resolution
H2, in which the countries endorsed guidelines to the
conservation of biodiversity in European forests.
International pressure to manage forests sustainably has
resulted in systems of certification for sustainably
managed forests. Each country adapts certain principles
to their own systems and forests are evaluated and
certified as sustainably managed. The system standard
for Ireland is still being revised, but is operational (Soil
Association, 2004). There is pressure on forest owners to
comply with these principles and guidelines.
1.2 Irish Forestry
The Republic of Ireland is one of the least forested
countries in Europe, even though forestry plantations
have increased forest cover from less than 1% of land
cover to about 10% in the last century. Forest policy aims
to increase the country's forest cover to 17% by 2030,
mainly by planting new commercial forests (DAFF, 1996).
By far the most widely planted species in these
commercial forests is Sitka spruce (
Picea sitchensis
), a
non-native conifer, and many forest industries are
associated with this species (DAFF, 1996). Following
international trends and agreements outlined above, the
Irish forestry sector must promote forest biodiversity
through abiding by the guidelines specified by the Helsinki
Process. Having changed some funding policies in the
late 1990s to promote the use of broadleaves in
plantations, the planting of ash (
Fraxinus excelsior
)
increased significantly and is now one of the most
frequently planted species. The Irish Forest Service
published a number of documents in 2000 to help promote
best practice and good international standards (Forest
Service, 2000b,c,d,e,f), including guidelines for
S. Iremonger et al., 2000-LS-3.1-M2
2
biodiversity. These documents indicate progress towards
compliance with the requirements of SFM.
In order to practise SFM and promote forest biodiversity,
it is necessary to know what organisms are associated
with these forests, and what the manager should be
aiming at. A multitude of questions need to be answered,
beginning with the most basic and progressing to the
more complex, including: What organisms are living in or
associated with the plantations? What are the differences
between these and the flora and fauna of native/semi-
natural forests? Has afforestation improved the general
biodiversity of the area? What effect does previous habitat
type have on the diversity of the developing forest? What
policies and practices support the creation and
maintenance of the most diverse plantations? Until
recently very little was known about the ecology of these
forests and their associated flora and fauna; ecologists
were more likely to investigate natural land-cover types
than these more artificial ones. Irelandʼs native and semi-
natural forests are very different ecologically to most
forestry plantations. The former are generally dominated
by a broadleaf mix and are not clear-felled at commercial
maturity whereas the latter have traditionally been
dominated by a non-native conifer monoculture on a
clear-felling cycle of 35–55 years.
1.3 BIOFOREST Project
Against the forestry background described above, the
Environmental Protection Agency (EPA) and the National
Council for Forest Research and Development
(COFORD) arranged to jointly fund research on forestry
and biodiversity in the ERTDI programme. The focus of
this research was to illustrate the effects of different
management methods on biodiversity within forests, from
the planning stage through to the mature forest.
The BIOFOREST Project was a large-scale project
running from 2001 to 2006 with the aim of providing some
much-needed basic information on biodiversity in Irish
plantation forests. The research had a particularly applied
orientation and objectives to feed directly into the
updating of forest policy and practice documents. The
project was funded from the National Development Plan
funds through the EPA and COFORD as part of the
Environmental RTDI Programme 2000–2006. The project
was launched officially at a ceremony during the
COFORD conference
Opportunities for Enhancement of
Biodiversity in Plantation Forests
October 2002, in Cork,
by the Minster of State at the Department of the Marine
and Natural Resources, Hugh Byrne.
This large-scale project (2000-LS-3.1-M2) was structured
as three smaller projects, each addressing a separate
aspect of forest biodiversity. These were:
• Project 3.1.1:
Biodiversity Assessment of
Afforestation Sites
• Project 3.1.2:
Assessment of Biodiversity at Different
Stages of the Forest Cycle
• Project 3.1.3:
Investigation of Experimental Methods
to Enhance Biodiversity in Plantation Forests
.
The objectives were to build a picture of biodiversity in a
spectrum of Irish plantation forests and how this is
affected by previous land cover, land use and current
management methods. They were designed to add
significantly to knowledge of Irish forests and help to guide
future land-use planning and forestry practices.
The BIOFOREST research team comprised the following
organisations:
• Department of Zoology, Ecology and Plant Sciences
(ZEPS), Environment Research Institute (ERI),
University College, Cork (UCC)
• Department of Botany, School of Natural Sciences,
Trinity College, Dublin (TCD)
• Coillte Teoranta, The Irish Forestry Board (Coillte).
This consortium brought together a team of researchers
and partner organisations that have extensive experience
in ecology, biodiversity assessment and forest
biodiversity studies across a broad spectrum of botanical
and zoological groups. The UCC group is involved in
large-scale biodiversity studies funded by the EU,
COFORD and the Heritage Council and was a partner in
a large concerted action related to biodiversity indicators
in forests (BEAR). The TCD group is one of the foremost
forest plant ecology groups in the country and has wide
experience in general botanical surveys, forest and
woodland plant biodiversity studies and in production of
forest biodiversity guidelines. Coillte Teoranta, the Irish
Forestry Board, is the primary forest owner and manager
in Ireland, and the staff on the project have specific
expertise in forest ecology.
Biodiversity in Irish plantation forests
3
The research team was guided with input from a Steering
Group that included external experts from other
organisations in Ireland (e.g. Dúchas/National Parks and
Wildlife Service, NPWS) and abroad (Denmark, Finland,
the UK). The input of other external experts was
requested as necessary and supported by COFORD and
the EPA. Staff names and groupings are listed in
Appendix 2.
Assessment of biodiversity in any habitat or landscape is
a difficult task to achieve on a comprehensive scale, given
the range of components of biodiversity (different biota)
that could be measured if logistics allowed. At most,
studies aimed at assessing biodiversity directly can
expect to measure the occurrence and diversity of only a
small proportion of biota, whether animal, plant, fungal or
microbial. Choosing the appropriate groups to study
raises questions of subjectivity, and different groups may
respond differently to habitat and other environmental
factors. Nonetheless, this project required the
development of inventories, and specific groups of
organisms that include taxa known to have utility as
biodiversity indicators elsewhere were targeted. An
additional approach was to try to identify features of the
habitat or landscape that could be used to predict
biodiversity, at least in relative terms, for comparisons
over space or time. Larsson
et al.
(2001) identified a
number of potential indicators of biodiversity which can be
broadly divided into three classes:
1. Structural indicators (e.g. area of forest from national
through landscape down to stand scales, field
boundary connectivity between forests or other
habitats on a landscape scale, or amount of dead
wood on a stand scale)
2. Compositional indicators (measurements of actual
components of biodiversity, e.g. number or diversity
of tree species on different scales, numbers or
diversity of species of particular animal groups, etc.,
if these are considered likely to reflect or predict
overall biodiversity)
3. Functional indicators (e.g. frequency and intensity of
natural or human activities, including land
management).
This study developed indicators in these three classes. In
assessing compositional indicators, the main taxonomic
groups included in the project were spiders, hoverflies,
birds and plants. These were chosen on the basis that
they represented a range of functional groups whose
taxonomy and ecology were sufficiently well known to
facilitate their use as indicators. In all three sub-projects
interdisciplinarity was stressed, and wherever possible
the different groups were studied in the same study sites
and during the same periods. Studying different groups in
this manner gives better insight into the functioning of the
ecosystem, thereby shedding more light on possible
management methods and best practice.
This report is a synthesis of five technical reports
produced by the BIOFOREST Project (Gittings
et al
.,
2004; Smith
et al
., 2005, 2006; Wilson
et al
., 2005;
Iremonger
et al
., 2006). For more information on a
particular aspect of the BIOFOREST Project, the reader is
referred to these more detailed reports. All project outputs
(reports, papers, etc.) are listed in Appendix 1.
S. Iremonger et al., 2000-LS-3.1-M2
4
2 Methods
2.1 Measuring Biodiversity
Strictly speaking, biodiversity is an ecological concept and
does not equate with conservation value. For example,
the concept of biodiversity makes no distinction between
native biodiversity and artificial diversity in the form of
introduced species and altered ecosystems (Angermeier,
1994). However, the term ʼbiodiversityʼ arose in the
context of concerns about the destruction of natural
habitats and the extinction of species on local and global
scales (Gaston, 1996b). As such, use of the term in socio–
political contexts is inextricably linked with the value of the
natural world. It is this wider sense of the word
'biodiversity', incorporating both the variability of the
natural world and its value, that is employed in the
Forest
Biodiversity Guidelines
(Forest Service, 2000c).
Therefore, our use of the term in this report will mean both
the variability of species and ecosystems and their
conservation value, in accordance with how 'biodiversity'
is used in management contexts.
The most basic method of measuring biodiversity is to
report the total species richness of the taxonomic group
being considered (Magurran, 1988; Gaston, 1996a).
However, total species richness does not indicate
anything about the identity of the species involved.
Ubiquitous species generally require little effort to ensure
their conservation, but rare, threatened or specialised
species will probably require adoption of specific
conservation measures. In fact, total species richness can
be misleading, as in some habitats of biodiversity
conservation value (e.g. blanket bog) total species
richness can increase following anthropogenic
disturbance due to the invasion of widespread generalist
species, masking the effect of the loss of rare, threatened
and specialised species. To address this issue, we have
also analysed the species richness of various species
groupings that are subsets of the total biota in each of the
taxonomic groups: rarity/conservation status, forest use,
and functional or behavioural groups.
A second component of species-level biodiversity is the
evenness or the relative abundances of the species
(Begon
et al
., 1990; Gaston, 1996b). Sites dominated by
one or a small number of species are intuitively less
diverse than sites where species abundances are more
equably distributed. Traditionally, mathematical diversity
indices, such as Simpson's or Shannon's indices, have
been constructed to take into account both species
richness and evenness aspects of species diversity.
However, in situations where the species assemblage is
comprised of a disparate group of mainly non-interacting
species the ecological meaning of species evenness may
be unclear. As an example, consider two hypothetical
forest bird communities. One has two Nightjars and two
Wood Pigeons, the other has 20 Nightjars and 100 Wood
Pigeons. Because Wood Pigeons and Nightjars do not
interact, their relative abundances tell us nothing of
interest about the ecology of the assemblages. In fact, the
second community is clearly of greater biodiversity
conservation value due to its larger population of a
threatened bird species, although it has lower evenness
than the first community. Therefore, we have focused on
species richness rather than species diversity as our main
measure of biodiversity for animal groups.
2.2 Vegetation
2.2.1 Terrestrial vegetation sampling
The vegetation team sampled terrestrial vascular plants,
mosses, liverworts and lichens in all three projects.
Vegetation data were collected at three different scales:
the habitat scale, the 100 m2 scale and the 4 m2 scale. In
Project 3.1.1, vegetation was also collected at the site
scale. The number of plots at each scale in the different
sub-projects is given in Table 2.1.
At the habitat scale in Project 3.1.1, all habitats present on
site were mapped according to the Heritage Council
habitat classification scheme (Fossitt, 2000). Within each
habitat, plant species were recorded on the DAFOR
scale: D, dominant; A, abundant; F, frequent; O,
occasional; R, rare. In Project 3.1.3, a complete species
list was compiled for glades and for a 20 m long section of
rides and roads.
At the 100 m2 scale in Project 3.1.1, the presence of plant
species was recorded. In Project 3.1.2, species cover was
recorded to the nearest 5%. In all 4 m2 plots, the cover of
plant species was recorded to the nearest 5%.
Biodiversity in Irish plantation forests
5
Vegetation structure data were collected at different
scales, including average height and percentage cover of
vegetation in different strata, such as trees, saplings,
shrubs, brambles, forbs, graminoids and bryophytes/
lichens. Precise definitions of these vegetation layers
varied according to the aims of the different projects. Also
recorded were the percentage cover of bare soil, leaf litter,
coarse and fine woody debris and other non-vegetation
categories. In Project 3.1.2, percentage cover and volume
of woody debris were recorded in different size and decay
classes in each 100 m2 plot.
Environmental and management data were also
collected; the nature and scale of the data collected
depended on the aims of the project. Data recorded in all
projects included slope, aspect, elevation, soil type and
drainage, grazing intensity, and silvicultural or other land
management. Soil samples were collected in all projects,
and soil pH and organic content were determined. In
Projects 3.1.1 and 3.1.2, concentrations of soil nutrients,
such as P, N, K, Ca and Mg were determined. In Project
3.1.3, the light environment was measured using
hemispherical photography (Rich, 1990).
Nomenclature followed Stace (1997) for vascular plants,
Smith (2004) for mosses, Paton (1999) for liverworts and
Purvis
et al
. (1992) for lichens.
2.2.2 Epiphyte sampling
In Project 3.1.3, we studied the epiphytic flora associated
with forest open spaces. All epiphyte surveying took place
on the north side (i.e. south-facing side) of open spaces.
Epiphytes were studied on a pair of trees at each of 12
sites, one tree at the edge of an open space and one tree
in the forest interior. Study plots were located on the trunk
and branches at four different height zones in the tree:
tree base, lower, middle and upper. Trunk plots were
located on the side of the trunk facing the open space and
the opposite side (referred to as south and north sides,
respectively). Plots were 50 cm in height, and ranged from
a maximum width of 25 cm to that required to sample a
half cylinder of the trunk. The percentage cover of each
epiphyte species and total percentage cover of
bryophytes, lichens, vascular epiphytes, others (algae,
fungi, etc.), needle litter, and total percentage bare bark
were estimated.
In the middle and upper zones, a branch from the north
side and a branch from the south side were removed for
study on the ground. Three plots, 25 cm long by 50 cm
wide, were studied on each branch. The percentage of the
plot occupied by branches and needles was estimated
and the percentage cover of each epiphyte species and
total percentage cover of bryophytes, lichens, vascular
epiphytes, others (algae, fungi, etc.), and total percentage
bare bark were also estimated.
At each site, the slope and aspect of the site and the
orientation of the edge at which trees were studied were
recorded. Tree density and diameter at breast height
(DBH) were recorded from two 10 m × 10 m forest plots,
and used to calculate stand basal area. DBH, tree height,
heights to first live branch and base of live crown and the
distance of the tree from the open-space edge were
recorded for each tree sampled. The height above
ground, girth and inclination at the centre of each trunk
plot were recorded. For branches, the height above
ground (at insertion), inclination, total branch length and
the length of branch covered by foliage were recorded, as
well as the distance from the trunk and diameter of the
main axis at the centre of each plot.
2.2.3 Data analysis
Several biodiversity metrics were calculated from the
vegetation data in plots: species richness of plant groups,
including vascular plants, bryophytes and lichens,
Shannon's and Simpson's diversity indices and the
Berger–Parker index of evenness (Magurran, 2004).
Plant species were classified according to their woodland
affinity, soil moisture and pH preferences, and native/alien
Table 2.1. The number of sites and number of sampling units at three different scales (habitat, 100 m2 plot and
4m
2 plot) in the vegetation survey.
Project Sites No. sampling units
Habitat 100 m2 (per site) 4 m2 (per 100 m2)
3.1.1 48 All habitats on site 3 2
3.1.2 42 – 3 1
3.1.3 20 5 open spaces per site –2+*
*Per open space.
S. Iremonger et al., 2000-LS-3.1-M2
6
status. Vascular plants were also classified as
competitors, stress tolerators or ruderals, or combinations
of these categories, according to Grimeʼs CSR theory
(Grime
et al
., 1988). The species richness of plants in all
of these categories was calculated for each plot. To avoid
pseudo-replication, biodiversity metrics, plant
abundances and environmental data in smaller sample
units were frequently averaged or otherwise combined for
analyses focusing on larger scales. For example, species
abundances in the two 4 m2 plots in each 100 m2 plot in
Project 3.1.1 were averaged to produce a single
independent estimate of vegetation cover.
2.3 Spiders
2.3.1 Spider sampling
Spiders were sampled in plots established in areas of
homogenous vegetation cover representative of the site.
The number of plots used varied depending on the
particular objectives of the project. In Project 3.1.1,
spiders were also sampled in three supplementary plots
whose purpose was to sample other habitat features,
such as hedgerows, thought to be important to the siteʼs
biodiversity.
Each sampling plot comprised five pitfall traps, which
consisted of a plastic cup 7 cm in diameter by 9 cm depth.
Each trap had several drainage slits pierced
approximately 2 cm from the top of the cup and was filled
with antifreeze (ethylene glycol) to a depth of 1 cm to act
as a killing and preserving agent. The traps were placed
in holes so that the rim was flush with the ground surface.
The traps were active from May to July and were changed
three times during this period, approximately once every
3 weeks. Where large numbers of traps were lost through
disturbance, the sampling period was extended for
another three weeks. Plots from which fewer than 12 traps
were collected were excluded from analyses. Spiders
were sorted from the pitfall trap debris and stored in 70%
alcohol. Spiders were identified to species level,
excepting juveniles, which were excluded from analyses.
Nomenclature follows Roberts (1993).
The percentage cover of vegetation was recorded in a
1m
2 quadrat surrounding each pitfall trap. The vegetation
was classified into the following structural layers: ground
vegetation (0–10 cm), lower field layer (>10 cm to 50 cm)
and upper field layer (>50 cm to 200 cm), and cover of
dead wood, leaf litter, rocks and bare soil, and depth of
leaf litter, were also recorded. All cover values were
estimated using the Braun–Blanquet scale (Mueller-
Dombois and Ellenberg, 1974). The main vegetation
species present within each plot were also recorded. Two
soil samples from each plot, taken to a depth of 15 cm,
were analysed for organic content. Grazing intensity was
ranked from 0 to 3.
2.3.2 Data analysis
We analysed relative rather than absolute spider
abundances, as the efficiency of pitfall traps may have
been affected by variation in vegetation structure around
the traps. Species were categorised according to the
literature into the following habitat associations: general
habitat preference (open habitats, forested habitats or
generalists), moisture preference (wet habitats, dry
habitats or generalists) and vegetation preference
(ground layer, low vegetation, bushes and trees or
generalists).
2.4 Hoverflies
2.4.1 Hoverfly sampling
We used Malaise traps to sample hoverflies. In Project
3.1.1, we installed two traps within 50 m of each other
along linear features within each site. In Project 3.1.2, we
installed two traps in each site. Where possible, these
traps were at least 100 m apart and 100 m from the forest
edge. In Project 3.1.3, we installed four Malaise traps in
each site: two on forest roads, and two in glades. The
traps were located within 10 m of the edge of the open
space, so that they sampled both the open-space and the
forest fauna.
The Malaise traps were operated continuously from early
May to between mid-July and early September,
depending on the project, on whether a sampling period
was compromised by trap damage, and on whether
catches in the trap were unusually low. The contents of
the traps were collected approximately every 3 weeks.
Where farm livestock were present, we used temporary
electric fencing to protect traps. Sites where some of the
Malaise traps were damaged during more than one round
of sampling are excluded from analyses at the site scale,
but successful traps in these sites are included in the
analyses at the trap scale. All hoverflies caught in the
Malaise traps were identified to species.
We used a macrohabitat classification based upon the
CORINE classification (Commission of the European
Communities, 1991), but with modifications to reflect
Biodiversity in Irish plantation forests
7
habitat characteristics of importance to hoverflies
(Speight
et al
., 2004). We recorded the spatial extent of
each major macrohabitat supplementary habitat type in a
100 m radius around each Malaise trap. We recorded
habitat structure in this area, using categories based
largely on those defined by Speight (2000) and using the
DAFOR scale (see Section 2.2.1). Data were collected for
a selection of these categories, as appropriate to the
habitats under study, in each project. In Project 3.1.1, we
recorded frequency of the above parameters in discrete
lengths of hedges and treelines, and in discrete patches
of scrub. In unplanted sites, grazing intensity was
estimated from 1 to 3. In Project 3.1.2, we also estimated
canopy cover, frequency of clearings and abundance of
dead wood in several different categories.
2.4.2 Data analysis
We divided the recorded species into open-habitat
associated species and woody vegetation species. For
Project 3.1.3, we further subdivided these groupings into
forest species, open scrub species, small open-space
species and large open-space species. We also used
classifications, based upon microhabitat associations, to
define species groups that might be associated with trees
and shrubs and with wet habitat features. In each of the
projects, we also identified species of particular
conservation interest belonging to a selection of the
following groups: anthropophobic species (unable to
tolerate human activity), species associated with surface
water habitats, wetland specialists, wet grassland
specialists and scrub specialists.
Caution is required in interpreting abundance data from
Malaise trap catches. However, we considered that it was
appropriate to use abundance data when comparing
open-space types within sites in Project 3.1.1. For all
analyses in Projects 3.1.2 and 3.1.3, we used presence–
absence data. Analyses of Project 3.1.2 data were
restricted to species whose ecologies were associated
with macrohabitats present within the site.
2.5 Birds
Bird data were collected from each site over the course of
two visits, one in May/early June and one in June/early
July. Due to timing constraints, early visits to Project 3.1.2
sites in 2001 were missed, and a round of visits from early
July to August were made. All bird surveys were
conducted between 07:00 h and 18:00 h, and restricted to
relatively fine weather. Clusters of birds of the same
species were recorded as having a maximum number of
two individuals. Flying birds of species that typically
forage over wide, non-territorial areas and above the
forest canopy were excluded from the survey.
In all projects, bird assemblages were sampled using
point counts. Between four and 12 points were situated in
each site (depending on project and on site size) at a
minimum of 100 m apart, to cover as wide a range of
environmental variation relevant to the study as possible.
Points were located in the field using a Garmin GPS 12
and aerial photographs/1930 series six-inch (scale
1:4000) OS maps. Counts were conducted for 10 min,
during which time the identity and distance from the
observer of all birds detected were recorded. Point counts
were conducted between 07:00 h and 11:00 h and
between 13:00 h and 17:00 h (GMT). Each point was
visited once in the morning and once in the afternoon. The
following variables were estimated for an area 50 m
around the point: area of shrub cover, area of non-crop
tree cover, area of brash cover, total area of open space,
crop tree canopy cover and crop tree height.
Mapping surveys were conducted in unplanted Project
3.1.1 sites. During mapping surveys, all areas of a site
were approached to within 50 m, and areas of shrub and
tree cover to within 20 m. The species and position of all
birds seen or heard were recorded on a 1:4000 map of the
site. The same map was used to record the shape, size
and position of any substantial areas in the following
categories: hedges, treelines, semi-natural woodland,
shrub cover, pre-thicket and closed canopy forest
plantation, farmyards and gardens. For each hedge, all
woody plant species contributing to hedge structure were
identified to species or genus level. Hedges were scored
in the following categories: canopy height, width and
structure, number of mature and young standard trees,
percentage gaps, number of connections to other hedges
and woodland/forest, presence and size of hedge-bank
and ditch vegetation and presence of a grass verge.
In Project 3.1.3, approximately 1 km of road was
censused in each study site, between 08:00 h and 18:00
h. We recorded the species, position and distance from
the observer of all birds within 10 m of the road gap edge,
excluding birds flying over the forest canopy. The
following variables were estimated for homogenous
sections of road: shrub cover (woody vegetation 0.5–2 m
high), broadleaved tree cover (broadleaved vegetation >2
m high), brash cover, crop tree height, and road gap
S. Iremonger et al., 2000-LS-3.1-M2
8
width. Road section length was measured from aerial
photographs.
2.5.1 Data analysis
Densities of birds recorded from mapping surveys in
Project 3.1.1 were estimated as the mean number of birds
recorded from a site, divided by the site area. Numbers of
birds detected in each road section during the road survey
in Project 3.1.3 were treated as relative abundances. The
numbers of birds detected during point counts was
affected both by distance from the observer and by
environment around the point. For Projects 3.1.2 and
3.1.3, these numbers were converted to densities using
the computer programme Distance 4 (Smith
et al
., 2005;
Iremonger
et al
., 2006; Wilson
et al
., 2006).
For Project 3.1.3, analysis of bird point count data was
restricted to evaluating presence/absence data for each
species. Measures of bird species richness within 50 m
and 100 m were used to investigate relationships with
open space at the same scales. Species richness for all
bird species detected was used to investigate
relationships with open space within 200 m and 300 m of
the point count locations. Several bird species associated
with broadleaved woodland occurred too infrequently
along roads for their abundances to be evaluated
separately, so for analysis of the road survey data these
species were combined into a single group.
In Project 3.1.1, Arcview GIS 3.2 was used to calculate
lengths of hedges and areas of non-hedge features, and
to assign birds recorded during mapping surveys to
hedges (areas within 12 m of mapped hedges), non-
hedge features and areas of open land. Mapping data
were analysed at the scale of individual hedges, and at
the scale of the site. Point count data were used to
compare unplanted and planted sites. In order to
eliminate the effect of hedge length on bird species
richness and abundance, values of these variables were
standardised for length of hedge.
In Project 3.1.2, species were classified as forest
specialists if more or less restricted to forest habitat, forest
generalists if occurring in a wide variety of habitats with an
element of tree cover, and open species if requiring areas
with no forest cover.
2.6 General Data Analysis
Standard statistical techniques appropriate to ecological
data were used. Prior to parametric analyses, variables
were inspected for conformity to the assumptions of
parametric statistics. Variables were transformed, outliers
were removed and non-parametric statistics were used as
needed. Univariate analyses included correlation, linear
and non-linear regression for testing for relationships
between continuous variables. Analysis of variance
(ANOVA),
t
-tests and non-parametric equivalents were
used to test for differences among treatment groups.
Differences in frequency of qualitative variables, among
groups were tested using likelihood ratio χ2 tests (or G-
tests in Sokal and Rohlf, 1995). Multivariate statistical
analyses included ordination (e.g. non-metric
multidimensional scaling (NMS) and canonical correlation
analysis (CCA)), clustering (e.g. flexible-ß clustering) and
multivariate comparisons tests (e.g. multivariate analysis
of variance (MANOVA) and multi-response permutation
procedure (MRPP)). Univariate analyses were performed
with SPSS 11.0 (SPSS, 2001), and multivariate analyses
were conducted using SPSS or PC-Ord (McCune and
Mefford, 1997).
In Projects 3.1.1 and 3.1.2, indicators of biodiversity were
developed. These indicators were designed to be used by
non-specialists to identify sites of potentially high
biodiversity. Structural and functional indicators were
assigned if statistical analysis showed that they were
significantly associated with sites that supported species-
rich or otherwise important assemblages of plants or
animals. Bird species compositional indicators were
developed in the same way; Amber or Red-listed bird
species were considered
de facto
indicators of
biodiversity. Plant species compositional indicators were
assigned using the indicator species analysis method of
Dufrêne and Legendre (1997), which provides an
indicator value score based on the constancy and fidelity
of a species in a given assemblage.
Biodiversity in Irish plantation forests
9
3 Project 3.1.1: Biodiversity of Afforestation Sites
3.1 Introduction
The objectives of this project were to:
• Assess the biodiversity of frequently afforested
habitats
• Develop methodologies for biodiversity assessment
and identify indicator species in these habitats
• Assess the efficacy of the
Forest Biodiversity
Guidelines
(Forest Service, 2000c) and recommend
improvements.
The sections below summarise the complete technical
report for this project (Smith
et al
., 2006). All data are
incorporated into the BIOFOREST Database.
The work included two reviews:
1.
Biodiversity Assessment in Preparation for
Afforestation: A Review of Existing Practice in
Ireland and Best Practice Overseas,
produced as a
stand-alone report (Gittings
et al
., 2004)
2.
Review of the Biodiversity of Habitat Types Used for
Afforestation in Ireland
, incorporated into the final
project technical report (Smith
et al
., 2006).
3.2 Review of Methods of Biodiversity
Assessment
3.2.1 Introduction
The objective of this study was to review different pre-
planting habitat biodiversity assessment methods used
overseas and to highlight those that would be most
suitable for integrating into the methodologies used in
Ireland. The review focused on the assessment of
terrestrial and wetland biodiversity (i.e. largely excluding
aquatic biodiversity). There is no standardised protocol for
the assessment of biodiversity in afforestation sites, but
methods include assessment of species biodiversity using
traditional inventory and biota analysis and landscape-
scale assessment of biodiversity using remote sensing
and GIS.
3.2.2 Methods
Information on existing practice in Ireland was collated
from a variety of published policy documents, guidelines
and reports, and by consultation with personnel in the
relevant agencies. In addition, the biodiversity
assessments contained in the nine afforestation
Environmental Impact Statements (EISs) that had been
carried out in Ireland were reviewed. Existing practice was
regarded as deficient where it was considered likely to fail
to identify sites of high biodiversity importance, resulting in
the risk of damage to such sites.
Information on existing practice overseas was obtained by
literature searches, a questionnaire survey and web
searches. The United Kingdom was the only country
where we found evidence of a significant body of relevant
information, so we focused a more detailed information
search on the United Kingdom. This included a review of
a sample of Scottish afforestation environmental
statements. Examples of best practice were identified as
those that were most likely to identify sites of high
biodiversity importance, thereby having greatest potential
for prevention of damage to the site biodiversity.
3.2.3 Irish practice
The recent introduction of statutory consent procedures
for all afforestation, and new procedures for
Environmental Impact Assessment (EIA) of afforestation
have addressed the major deficiencies that previously
existed in the legislative control of afforestation in Ireland.
However, with the exception of criteria relating to
designated sites, the legislative procedures for screening
for sub-threshold EIAs are not very specific. Local
authorities, which should be equipped with strategic
overviews of their constituencies, are not required to carry
out strategic assessments for forestry. In the few cases
where strategic assessments have been prepared,
minimal attention is given to potential biodiversity
constraints outside designated areas.
The personnel involved in biodiversity assessment for
afforestation do not currently receive adequate training or
other guidance (e.g. in the Forest Service publication the
Forest Biodiversity Guidelines
) for the identification of
habitats and fauna and flora of biodiversity importance.
S. Iremonger et al., 2000-LS-3.1-M2
10
The employment of an ecologist by the Forest Service
was a welcome development, although more than one
ecologist is needed. The official guidance on conducting
EIAs, published by the EPA, does not deal with issues
such as scope, survey methods and evaluation in
sufficient detail. None of the EISs reviewed contained
adequate assessments of overall biodiversity. The main
deficiencies were insufficient scoping, non-standardised
habitat/vegetation classifications, reliance on incomplete
lists of species with little or no information on abundance
or distribution within the site, and little or no evaluation of
the conservation importance of the site. The fact that six
of the nine afforestation projects for which an EIS was
submitted were approved indicates that assessment by
the local authorities was deficient. Despite lacking in-
house expertise in biodiversity assessment, the Forest
Service and local authorities are responsible for
assessing the biodiversity impacts of all afforestation
proposals. The state nature conservation agency (NPWS)
is only consulted about proposed afforestation located in
or near designated areas.
In conclusion, lack of adequate strategic assessment,
failure of regulations to require biodiversity assessment
for the vast majority of afforestation proposals, and
serious deficiencies in those biodiversity assessments
that are carried out mean that sites of high biodiversity
importance are currently at risk of being damaged by
afforestation.
3.2.4 United Kingdom practice
The low area thresholds for an EIA of afforestation
projects and the provisions for a sub-threshold EIA
appear to provide an effective framework for identifying
afforestation projects for which an EIA should be carried
out. Local biodiversity action plans provide a coherent
method of identifying priority habitats and species.
Strategic assessments often include information on
biodiversity constraints outside designated sites, with
countywide Phase 1 habitat surveys providing a valuable
resource.
The low area thresholds and provisions for the sub-
threshold requirement of an EIA make this the principal
method used for biodiversity assessment. Other specific
procedures for biodiversity assessment have also been
developed for special grant schemes and private forestry
companies. Preliminary surveys and consultations during
the scoping process for an EIA enable identification of
those aspects of the siteʼs ecology that require more
detailed investigation. Standardised survey
methodologies are used, and the survey effort and
methods are clearly stated in the environmental
statement. Data are also taken from previous surveys and
consultations. Where there is a significant nature
conservation interest, the findings of the environmental
statement are reviewed by the statutory nature
conservation agency.
In conclusion, the ecological information that is available
through strategic assessments, conservation
designations and consultation with both statutory and
non-statutory conservation organisations means that, for
most forestry proposals, the Forestry Commission is able
to make well-informed decisions about whether an
environmental assessment is necessary and what its
scope should be. Where best practice is achieved,
environmental assessments are successful in identifying
much of the biodiversity held by a site, either through field
surveys or through reviews of existing knowledge.
Generally, assessment procedures are such that the risk
of new afforestation resulting in significant damage to
conservation interests in the UK is low.
3.3 Habitats Review
A core principle of SFM is that forestry does not impact
detrimentally on unforested habitats. Therefore,
information on the biodiversity of habitats that are
frequently subject to afforestation is required if Irelandʼs
forests are to be managed sustainably. We reviewed the
biodiversity of three types of habitats that are commonly
afforested in Ireland: improved grasslands, wet
grasslands and peatlands, and identified potential
indicators of biodiversity to be tested using field data.
The Irish habitat classification scheme developed by the
Heritage Council (Fossitt, 2000) provides the most current
and widely used broad classification of habitats in Ireland.
This level of classification is adequate for use when
studying mobile, wide-ranging taxa, such as birds.
However, the broad habitat types defined by Fossitt
(2000) frequently combine distinctive plant communities
that differ in ecology and biodiversity. The Braun-Blanquet
system of phytosociology has often been used in the past
by researchers in Ireland, and provides a more fine-scale
system of classification. Another advantage of this
system, from our point of view, is the use of character
species to define and distinguish phytosociological
associations with other levels (syntaxa) in the
Biodiversity in Irish plantation forests
11
classification hierarchy. Character species of syntaxa of
high biodiversity interest are well suited to be potential
indicators of biodiversity.
Climate, soils and human management determine the
composition and abundance of species in grasslands. In
general, the more intensive the management, the lower
the biodiversity. Small pockets of semi-natural grassland
are often found in a matrix of more intensive land use, and
are vulnerable to loss through agricultural intensification,
dereliction or conversion to a different land use, such as
forestry. Various attempts have been made to estimate
the cover of different grassland types in Ireland, but these
are generally either inaccurate, out of date, or localised.
Irish grasslands are divided into three phytosociological
classes comprising lowland pastures, upland acid
grasslands and dry limestone grasslands. Lowland
pastures are further subdivided into a group of dry semi-
natural grasslands, improved grasslands and
intermediates, and a group of oligotrophic and base-rich
wet grasslands. Improved grasslands are heavily grazed,
frequently cut for silage, usually receive high fertiliser and
herbicide applications and are often reseeded. Such
grasslands are generally species-poor and are dominated
by
Lolium perenne
and
Trifolium repens
, together with a
limited number of agricultural weeds. With the exception
of field-margin hedgerows, improved grasslands usually
also support a poor bird fauna. In contrast, wet grasslands
can be some of the most species-rich grassland
communities in Ireland. Both oligotrophic and base-rich
wet grasslands are frequently dominated by rush (
Juncus
)
species and often support a diverse assemblage of
broadleaved herbs. However, species-poor intermediates
between improved and wet grasslands can also be
dominated by rushes and superficially resemble more
high biodiversity types. Wet grasslands such as the
Shannon callows can be important feeding and breeding
grounds for wildfowl and waders.
Peatlands in Ireland include bogs, fens and wet heaths. Of
these, the peatlands that appear to be most frequently
afforested in Ireland are blanket bogs and wet heaths.
Wet heaths occur on shallow peats or peaty podzols and
are generally dominated by dwarf shrub vegetation,
especially
Calluna vulgaris
and
Erica tetralix
. Wet heaths
frequently occur in intimate mosaics with blanket bog.
Blanket bogs can be divided into two types: lowland
blanket bog, which occurs in oceanic climates in the west
at elevations below about 150 m , and upland blanket bog,
which occurs in hilly or mountainous terrain throughout
the country. Upland blanket bogs are characterised by an
abundance of
Sphagnum
mosses,
Eriophorum
species
and dwarf shrubs, including
Calluna vulgaris, Erica tetralix
and
Vaccinium myrtillus
. In contrast, lowland blanket bogs
are more grassy in appearance, with
Schoenus nigricans
and
Molinia caerulea
as among the most prominent
species, and lower
Sphagnum
cover than in upland
blanket bogs. Lowland blanket bogs also frequently
include a variety of hydrological features, such as flushes,
pools, streams and swallow holes; these can also be
found in upland bogs, but are much less common. Blanket
bogs and wet heaths support a number of birds of
conservation concern, including Red Grouse, Lapwing,
Golden Plover, Curlew and Greenland White-fronted
Geese. Blanket bogs and wet heaths are important Irish
habitats at national and international levels. Active (i.e.
peat-forming) blanket bogs are priority habitats for
conservation under the EU Habitats Directive, and wet
heath is also a designated, though non-priority, habitat for
conservation. Ireland contains approximately 8% of the
worldʼs blanket bogs, and therefore has an important
international role in conserving these habitats.
3.4 Biodiversity Survey
3.4.1 Study design and site selection
We identified three broad habitat types that are among
those typically used for afforestation in Ireland: peatlands,
improved grassland, and wet grassland. Ideally, the
biodiversity of these habitats and the initial effects of
afforestation on this biodiversity would be investigated by
surveying sites before they were planted, and tracking
them over the course of the forest cycle. However, for a
number of reasons this approach was not practical, and
instead we paired unplanted study sites of the relevant
habitat type with 5-year-old, first-rotation plantations.
Planted and unplanted sites were chosen to be closely
matched in terms of relevant environmental conditions
such as soil type, drainage, slope, altitude, and proximity
of other types of habitats such as forests and rivers.
Where possible, the paired sites were adjacent to each
other, although three of the pairs were separated by 1–5
km. Sitka spruce (
Picea sitchensis
) was the main tree
species in the planted sites.
We initially identified candidate pairs of sites from the
Forest Inventory and Planning System (FIPS), and refined
this selection using aerial photographs. We identified
other candidate sites by making enquiries of local and
regional forest managers and forestry contractors. We
S. Iremonger et al., 2000-LS-3.1-M2
12
ground-truthed nearly 100 sites, of which we selected 24
pairs of planted and unplanted for this study (eight within
each habitat type) (Fig. 3.1). We surveyed eight pairs of
sites (four peatland and two each of improved and wet
grassland) and the three unpaired sites in 2002. We
surveyed the remaining 16 pairs of sites in 2004. In
addition to these paired sites, we also surveyed an
additional three unplanted sites (one improved grassland
and two wet grassland) in 2002, which were afforested
less than a year later.
3.4.2 Vegetation
3.4.2.1 Diversity in unforested habitats
We recorded 531 taxa of vascular plants, bryophytes and
lichens in 133 habitats in the 51 sites. Vascular plant
species richness was higher in unplanted wet grasslands
than in unplanted improved grasslands or peatlands.
Bryophyte and lichen species richness was highest in
peatlands and lowest in improved grasslands. Total
species richness, Simpsonʼs diversity and Berger–Parker
evenness were significantly lower in improved grasslands
than in wet grasslands or peatlands.
Most of the plant species in improved grasslands
preferred mesic conditions, whereas species preferring
damp conditions were the most common moisture group
in wet grasslands, and species preferring wet habitats
were the most common group in peatlands. Typical
woodland plants made up less than 2% of the flora in any
group. Species often found in both wooded and
unwooded habitats formed a lower proportion of the flora
in improved grasslands than in wet grasslands or
peatlands. Competitors comprised a relatively low
proportion of peatland species, while improved
grasslands supported a relatively low proportion of stress
tolerators, with the majority of the species employing
ruderal strategies.
Cluster analysis of the habitat data confirmed the pre-
established habitat groups, and further subdivided
improved grasslands and peatlands into subtypes. We
also found that supplementary and marginal habitats can
contribute substantially to the biodiversity of a site,
through provision of habitats for species that would
otherwise not occur in the main habitat matrix. Additional
cluster analyses were carried out on 100 m2 and 4 m2 plot
data. Although there was substantial variation among
sampling scales in the assignment of sample units to
clusters, certain patterns emerged from the data. In
peatlands, the more intact lowland blanket bogs were
distinguished at the larger scales from the remainder of
the wet heaths and upland blanket bogs, which were on
the whole more disturbed and of less biodiversity interest.
Grasslands were generally divided into improved
grasslands, semi-improved grasslands, oligotrophic wet
grasslands and base-rich wet grasslands. The latter two
groups were recognised as potentially being of high
biodiversity interest, although their value will depend to a
great extent on the landscape context. A given semi-
natural wet grassland may be of ecological importance in
Figure 3.1. Locations of all paired sites in Project 3.1.1.
Biodiversity in Irish plantation forests
13
an agriculturally intensive landscape, whereas the same
wet grassland may be of little particular interest in
landscapes where communities of similar or higher quality
are abundant. For indicators of plant diversity see Section
3.4.6.
3.4.2.2 Effects of afforestation
Vascular plant species richness at the 4 m2 plot scale (but
not larger scales) was significantly higher in unplanted
sites in all habitat groups. Bryophyte and lichen species
richness in 100 m2 plots was significantly higher in planted
improved grasslands and peatlands than in unplanted
sites, as a result of the provision of new microhabitats by
forestry drains. Simpsonʼs diversity was lower in planted
wet grassland and peatland 4 m2 plots.
Compared with planted plots, unplanted plots contained a
higher proportion of species associated with open
habitats and a lower proportion of species occurring
commonly in both open and wooded habitats. In
peatlands and improved grasslands, a higher percentage
of vascular plant species had competitor strategies in
planted than in unplanted sites. In grasslands, plants with
ruderal strategies comprised a higher proportion of the
species in unplanted than in planted sites. Stress
tolerators and species preferring wet conditions were
proportionately more abundant in unplanted than in
planted peatlands. Acidophilic and non-ruderal plants
made up significantly more of the flora in planted than in
unplanted improved grasslands.
There were significant differences in species composition
and abundance between planted and unplanted sites
within each of the three habitat groups. These differences
were large in improved grasslands (due to substantial
increases in competitive grass species, principally at the
expense of
Lolium perenne
) and peatlands (where
Molinia caerulea
often becomes dominant). The
difference between planted and unplanted wet grasslands
was not as large, varying with wet grassland type. Tests
of the 100 m2 plot presence/absence data also detected
significant differences between planted and unplanted
sites within the habitat groups. Differences were more
pronounced at the 4 m2 scale than at the 100 m2.
Hedgerows, treelines and associated streams did not
differ in composition between planted and unplanted
sites.
3.4.3 Hoverflies
We recorded a total of 98 species of hoverflies, of which
63 are associated with open habitats and 50 are
associated with woody vegetation habitats. Four of these
are considered to be threatened and another five species
are considered to be decreasing.
3.4.3.1 Diversity in unforested habitats
Open hoverfly assemblages in the three unplanted
habitats were generally distinct from one another, in
peatlands more than in the other two habitats. The
number of open-habitat associated, wet grassland
specialist and woody vegetation species was significantly
higher in wet grassland sites than in peatland sites.
However, peatland sites had the highest numbers of
open-habitat associated anthropophobic species. The
proportion of the Irish hoverfly fauna in different
characteristic open-habitat groupings represented in the
unplanted sites was never more than 50% (and often
much lower), with the exception of some of the more
species-poor faunal groups.
In both peatland and grassland habitats, sites where total
hoverfly catches were very low (i.e. less than 100) tended
to be widely scattered in ordination space, indicating
insufficient sampling to characterise the hoverfly
assemblages of these sites. There was no relationship
between species richness (of all hoverflies, or of wetland
specialist species) and wet habitat parameters. However,
a small group of wet grasslands identified by cluster
analysis of grassland sites was typified by species
associated with surface water and/or oligotrophic habitats
and had higher species richness than the other site
clusters. Sites with low grazing intensity had significantly
higher numbers of grazing-sensitive species, and
numbers of wet grassland specialists were positively
correlated with the frequency of tussocks. Numbers of
woody-vegetation associated species were correlated
with an index of broadleaved woody vegetation cover.
The residuals from the regression of woody vegetation
species richness against this index were positively
correlated with occurrence of understorey vegetation.
3.4.3.2 Effects of afforestation
The ordination of the open-habitat associated species
does not show any separation between the planted and
unplanted peatland sites. The ordinations of the open-
habitat associated and woody-vegetation associated
species in the improved and wet grassland sites show a
broad separation between the planted and unplanted
S. Iremonger et al., 2000-LS-3.1-M2
14
sites. There were more woody vegetation and tree/tall
shrub species in planted than in unplanted grassland
sites. There were no other significant differences in
species richness between the planted and unplanted
sites.
In the planted grassland sites, numbers of woody-
vegetation and tree/tall-shrub associated species were
positively related to the length of hedges and treelines and
the weighted cover of other broadleaved woody
vegetation. The differences in numbers of woody-
vegetation and tree/tall-shrub associated species
between the paired planted and unplanted sites were
correlated with the differences in the indices of woody
vegetation cover. The growth stage of the planted conifers
was not correlated with the species richness of these
species groups. Nine species were more abundant in
planted sites than in unplanted sites, and ten species
showed the opposite pattern. Wetland specialists were
significantly more abundant in unplanted sites, but open-
habitat, surface water, woody-vegetation and tree/tall-
shrub associated species did not differ significantly
between planted and unplanted sites.
3.4.4 Spiders
3.4.4.1 Diversity of unforested habitats
Of 33,157 individuals caught, 3,448 were juveniles and
189 species were identified from the remainder. The
majority of species sampled were typical ground-layer
species, but 30 species were associated with low
vegetation and six species with trees and shrubs. Across
habitat types, species richness was lowest in the
improved grasslands. Spider abundance in
supplementary plots (see Section 2.3.1) was greater than
in the main habitat type in improved grasslands and
peatlands and less in wet grasslands.
More open-habitat associated species, fewer forest-
associated species and more wetland-associated species
were found in standard plots than in supplementary plots,
especially in grassland sites. The number of open- or
forested-habitat species did not differ between the habitat
types. The number of ground-layer spider species was
highest in improved grassland and lowest in peatland
sites, but did not differ between the standard and
supplementary plots. The number of low-vegetation
species did not differ between habitat or plot type. Several
rare or notable species were sampled within the peatland
and wet grassland habitats (for further details, see
Oxbrough
et al.
, 2005). No rare species were found within
the improved grasslands
.
For indicators of spider
diversity, see Section 3.4.6. (For further details, see
Oxbrough
et al.
, 2007.)
NMS ordinations of grassland plots revealed much
greater variation in assemblage structure among
supplementary plots than among standard plots. Among
peatland plots, spider species assemblages in
supplementary plots differed from those in standard plots.
Peatland spider species assemblages were also broadly
distinguished by habitat type and, among supplementary
plots, by the presence or absence of upper field-layer
vegetation. Spider assemblages of upland blanket bogs,
wet heaths and to a lesser extent lowland blanket bogs
were distinguished from those of cutover bogs. Ground
vegetation cover was associated with wet heath and
upland blanket bogs, whereas lower field-layer cover was
associated with cutover bogs and stream edges.
Cluster analysis revealed four main groups of spider
assemblages:
1. the Peatland-Open Group comprised the majority of
standard peatland plots and some standard wet
grassland plots
2. the Improved Grassland-Open Group comprised
most of the standard improved grassland plots
3. the Wet Grassland Group mostly comprised
supplementary and standard wet grassland plots
4. the Linear Group comprised supplementary plots
from all three habitat types.
3.4.4.2 Effects of afforestation
Total species richness did not differ between unplanted
and planted peatland and wet grassland sites, but was
significantly greater in planted than unplanted in the
improved grassland. Across all sites, total abundance and
the number of open-habitat associated and wet-habitat
associated species was greater in unplanted sites, and
the number of species associated with forested habitats
was higher in planted sites. Numbers of ground-layer and
low-vegetation species did not differ between the
unplanted and planted peatlands and wet grasslands, but
were significantly greater in planted than unplanted
improved grasslands. In supplementary peatland plots,
the number of wet habitat species was lower in planted
sites than in unplanted sites. Measures of species
Biodiversity in Irish plantation forests
15
diversity in supplementary plots did not differ between
planted and unplanted grassland sites.
Grassland spider assemblages differed between
unplanted and planted plots in improved grassland, but
not in wet grassland. Spider assemblages from planted
improved and wet grasslands are less distinct than those
from unplanted improved and wet grasslands. Spider
assemblages of unplanted peatland flushes were distinct
from those of equivalent planted habitats in poor fen and
upland blanket bog, but not in lowland blanket bog and
wet heath. Upper and lower field-layer cover was greater,
and ground vegetation cover less in planted than in
unplanted peatland plots.
3.4.5 Birds
3.4.5.1 Diversity of unforested habitats
A total of 46 bird species were recorded during mapping
surveys. Cluster analysis of hedge-plant species data
identified four distinct clusters of hedges. Both within and
between clusters, high bird species richness and
abundance were associated with tall, wide hedges, with
many mature standard trees, low percentage of gaps,
high plant species richness and presence of ivy in the
hedge canopy.
NMS ordination of bird density data separated sites
according to two axes. Axis 1 values were strongly and
positively correlated with species richness, and tended to
be highest in improved grassland and lowest in peatland
sites with values for wet grassland sites intermediate
between these two. Axis 2 values were strongly and
negatively correlated with total bird abundance, and
tended to be lowest in sites with high shrub and tree
cover. Cluster analysis separated sites into three
grassland clusters (an improved grassland cluster, a wet
grassland cluster and a mixed cluster) and two peatland
clusters. Eight woodland-associated bird species were
typical of the wet grassland cluster, and two open-habitat
bird species were typical of the largest peatland cluster.
No species were identified as being typical of the other
clusters, but the absence of two open-habitat species was
typical of the improved grassland cluster.
The proportions of open land, land within 12 m of large,
medium and small hedges, and land under other
categories of tree and shrub cover, are given in Fig. 3.2.
Species richness in the grassland clusters was much
higher than in the peatland clusters. Total bird abundance
and densities of birds in open land were highest in the wet
grassland cluster and lowest in improved grassland and
peatland clusters; the latter were much lower than
densities in the vicinity of hedge, tree or shrub cover.
Among the grassland clusters, bird densities within 12 m
of hedges were highest in the wet grassland cluster and
lowest in the improved grassland cluster. Densities of
birds in other tree and shrub cover were highest in the
improved grassland cluster, but had little influence on bird
assemblages in this cluster as it covered an average of
less than 1% of sites. Measures of bird diversity were
positively correlated with total length of large and medium
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
12345
Cluster
Percentage of site
open land
non-hedge
cover
large
hedges
medium
hedges
small
hedges
Figure 3.2. Proportions of cover types in the five bird species clusters. The values for hedge cover shown are the
proportions of sites in each cluster within 10 m of each of the three hedge categories.
S. Iremonger et al., 2000-LS-3.1-M2
16
(but not small) hedges, area of treelines, and area of
semi-natural woodland. Neither bird species richness nor
abundance derived from mapping data were correlated
with non-hedge shrub cover. However, several elements
of shrub and tree-layer cover are positively correlated with
point-count derived abundances of 14 bird species
associated with woodland and scrub habitats, and
negatively correlated with abundances of four species
(Meadow Pipit, Redpoll, Skylark, and Stonechat) of open
habitats. Abundances of 11 forest and scrub species
(Blackbird, Blue Tit, Chiffchaff, Chaffinch, Coal Tit,
Dunnock, Goldcrest, Robin, Song Thrush, Wren and
Willow Warbler) were positively correlated with overall
bird abundance and/or species richness. Abundance of
skylark, an open-habitat species, was strongly negatively
correlated with bird species richness.
3.4.5.2 Effects of afforestation
Estimates of species richness from point counts were
consistently lower than those derived from mapping
surveys, but density estimates from point-count data
tended to be higher than those derived from mapping
surveys. Relative to estimates of density derived from
mapping surveys, estimates derived from point counts
tended to be highest in improved grassland sites and
lowest in peatland sites.
Total shrub cover, bird species richness, total abundance
of birds, and ordination Axis 2 scores were greater in
planted sites than in their unplanted pairs. Ten bird
species were more abundant, in contrast with just one bird
species (Skylark) that was less abundant, in afforested
than in open sites. The five species that show the greatest
proportional difference in abundance between planted
and unplanted sites (Grasshopper Warbler, Reed
Bunting, Sedge Warbler, Whitethroat and Willow Warbler)
are all ground-nesting birds. The increase in abundance
of these species in planted relative to unplanted sites is
greater in Clusters 1 and 3 than in Cluster 2 or Clusters 4
and 5 combined. This difference between clusters
appears to be related to availability of bramble cover,
which tends to be low in all unplanted sites apart from
those in Cluster 2, and relatively high in all planted sites
apart from those in Clusters 4 and 5 (Fig. 3.2).
3.4.6 Indicators
We identified several biodiversity indicators for peatlands
and grasslands. These are associated with semi-natural
or natural plant communities that have experienced little
human modification and the invertebrate and bird
assemblages of these habitats. We have also identified
several bird species of conservation concern as
de facto
indicators of biodiversity: these species are themselves of
conservation interest. Many of these bird species are
easy to detect and to identify, and so are therefore well
suited for use in pre-afforestation biodiversity
assessment. Red Data Book or legally protected plant
species may also be considered
de facto
indicators of
biodiversity, although we did not encounter any in our
survey.
We divide the indicators into three types, compositional,
structural and functional, and into two quality levels, firm
and potential. Firm indicators (Table 3.1) include those
that have been pre-identified or supported by previous
research, and that have been tested and confirmed by the
present study, and also birds of conservation concern.
Firm indicators are not infallible, they simply have been
independently identified by more than one source.
Potential indicators (Table 3.2) are new indicators that
have emerged from analysis of field data from the present
study, and indicators that would otherwise qualify as firm
indicators, but about which we have reservations as to
their ability to discriminate between high and low
biodiversity sites. Potential indicators need to be verified
using independent data before their status is confirmed.
Also presented are landscape-scale indicators of
biodiversity for hoverflies and birds (Table 3.3). These are
features that, if present within a landscape, indicate that
landscape-scale biodiversity of one or more species
groups is likely to be high.
Indicators should be assessed during the habitat mapping
required for the site development assessment (Forest
Service, 2000a), and through discussion with the
landowner or inspection of existing maps and records.
Plant species compositional indicators should occur
frequently in order to qualify as ʻpresentʼ for biodiversity
indicator purposes. A site containing one or more
landscape biodiversity indicators can be afforested
without much risk if the features in question are left
undisturbed and the plantation is set back an appropriate
distance from them. However, caution should be
exercised in the case of multiple afforestation projects
over time in a single landscape.
In addition to these positive indicators, there are some
negative
indicators of biodiversity. These indicate low
biodiversity (though their absence does not necessarily
indicate high biodiversity), and are all associated with
Biodiversity in Irish plantation forests
17
Table 3.1. Firm indicators of biodiversity.
Compositional l Structural Functional
Grasslands
Agrostis canina s.l.
Bryophyte cover >5% Low grazing intensity6
Carex echinata
Forb2 cover >25%
Carex nigra
Graminoid cover <75%
Carex panicea
Shrub3 cover >5%
Carex viridula
Cirsium dissectum
Danthonia decumbens
Festuca pratensis
Juncus conglomeratus
Molinia caerulea
Potentilla erecta
Prunella vulgaris
Pseudoscleropodium purum
Ranunculus flammula
Senecio aquaticus
Succisa pratensis
Thuidium tamariscinum
Locustella naevia
Grasshopper Warbler4
Emberiza schoeniclus
Reed Bunting4
Acrocephalus schoenobaenus
Sedge Warbler4
Sylvia communis
Whitethroat4
Vanellus vanellus
Lapwing5
Tringa totanus
Redshank5
Numenius arquata
Curlew5
Gallinago gallinago
Snipe4
Alauda arvensis
Skylark4
Peatlands
Pluvialis apricaria
Golden Plover5Extensive flushes
Calidris alpina
Dunlin5Extensive fen habitat
Numenius arquata
Curlew5Presence of pools
Gallinago gallinago
Snipe4Presence of swallow holes
Falco columbarius
Merlin3Low grazing intensity
Circus cyaneus
Hen Harrier4Little or no peat cutting
Lagopus lagopus
Red Grouse5Absence of erosion or fire
Alauda arvensis
Skylark4Absence of drains
Saxicola rubetra
Whinchat4Total P <100 mg/l
1High frequency (see text) of any plant species listed is a compositional indicator of biodiversity.
2Broadleaf herbaceous plants including ferns, but not grasses, sedges or rushes.
3Not including gorse.
4The breeding presence of any of these bird species is a potential indicator of biodiversity, but site quality and habitat
availability in the surrounding landscape should also be taken into account.
5The breeding presence of any of these bird species indicates that a site is important for birds.
6Grazing intensity should be assessed over several years.
S. Iremonger et al., 2000-LS-3.1-M2
18
improved grassland. These include two firm negative
indicators (high cover of
Lolium perenne
and recent
reseeding of pasture), and five provisional negative
indicators (
Poa annua, Urtica dioica, Stellaria media,
Plantago major
and
Cirsium vulgare
).
3.5 Conclusions
The initial effect of afforestation on plant and animal
communities is to change the relative abundances of
species, rather than causing a radical shift in species
compositions. These effects are largely the result of three
factors: exclusion of grazing livestock, forestry drainage
and changes in nutrient management. They are likely to
be to the detriment of some groups of species (e.g. stress-
tolerant and ruderal plants, specialist ground-dwelling
spiders and open-habitat specialist birds), and benefit
others (e.g. competitive plant species, generalist spiders
and ground-nesting birds). However, these benefits will
be temporary, not lasting beyond canopy closure except
in unplanted areas of open habitat.
Forest drains may provide a temporary habitat for less
competitive plant species, but the overall effect of
drainage is to reduce the diversity of species dependent
on wet conditions. Wet habitat features such as flushes,
streams and swamps can substantially add to the plant,
spider and hoverfly diversity of a site, particularly in
peatland habitats. Results from all taxa indicate that other
marginal and supplementary habitats, such as treelines,
hedgerows, scrub, stone walls and earth banks, can also
increase the biodiversity of afforestation sites, by
supporting species that would not otherwise persist in the
farmland matrix. Promoting broadleaved woody
vegetation in young conifer plantations by retaining
existing vegetation and by planting and regeneration of
Table 3.2. New potential indicators of biodiversity.
Compositional Structural Functional
Grasslands
Carex hirta
High frequency of tussocks Total K <5,000 mg/l
Centaurea nigra
High cover of bramble
Hypericum tetrapterum
High cover of hawthorn
Iris pseudacorus
Juncus bulbosus
Lathyrus pratensis
Leontodon autumnalis
Mentha aquatica
Pellia epiphylla
1
Stellaria graminea
Peatlands
Campylopus atrovirens
Drosera rotundifolia
Pleurozia purpurea
Racomitrium lanuginosum
Rhynchospora alba
Schoenus nigricans
Sphagnum cuspidatum
1Can be easily confused with other
Pellia
species, but they are much less common, except in wet calcareous
sites, and are not likely to indicate low biodiversity habitats.
Table 3.3. Landscape-scale structural indicators of biodiversity.
Salix
swamp Treelines with over-mature trees
Scrub Surface water features (e.g. ponds, streams)
Well-developed hedgerows Semi-natural woodland1
1Including very small pockets.
Biodiversity in Irish plantation forests
19
broadleaved trees will enhance hoverfly and bird diversity.
However, all areas of retained habitat will require
sufficient space if they are to remain unshaded and persist
after the forest canopy closes. Also, if left ungrazed, many
unplanted habitats will eventually undergo succession to
scrub and native woodland and end up under a closed
canopy unsuitable for open-habitat specialists. Such
areas may need to have grazing continued at low
intensity, in order to allow the persistence of open habitats
and the species they support.
In general, afforestation sites held few species that were
rare on a national or regional scale. However, biodiversity
tended to be higher in wet grasslands and peatlands than
in improved grasslands. Studies of all taxa agree that
afforestation of semi-natural habitats would result in a net
loss of biodiversity, but that the effect of afforestation on
improved and semi-improved grasslands will generally be
neutral or positive, particularly in landscapes that contain
little semi-natural woodland habitat. The biodiversity value
of semi-natural habitats, especially grassland
communities, is dependent on landscape context: a
particular habitat may be of significant biodiversity interest
in intensive agricultural landscapes, but of less value in
landscapes where similar areas of habitat are abundant.
The steps that should comprise an effective biodiversity
assessment prior to afforestation are outlined in Fig. 3.3.
Figure 3.3. Flow chart outlining the stages in biodiversity assessment prior to afforestation.
*Assuming that other criteria (e.g. landscape, water quality) have been met. **Sites with no biodiversity
indicators present may still have high biodiversity and should be properly assessed before any decision to
afforest is taken. ***Some habitat types (e.g. intact blanket bog) should never be planted.
S. Iremonger et al., 2000-LS-3.1-M2
20
Biodiversity assessment should always begin with a
habitat survey, which should serve two functions: to
determine whether or not a site or part of a site should be
afforested on biodiversity grounds, and to identify habitats
to be incorporated into the Area for Biodiversity
Enhancement (ABE), as defined in the
Forest Biodiversity
Guidelines
(Forest Service, 2000c). The survey should
quickly reveal if the site is obviously of low biodiversity
value, in which case it can be afforested with little
likelihood of biodiversity loss. If the site is not clearly of low
biodiversity value, then the indicators above should help
decide whether or not it is of potentially high biodiversity.
The indicators should be used in conjunction with each
other: it would be misleading to characterise a site as
having high biodiversity (or not) on the basis of just one or
two indicators. We recommend as a general guideline the
presence of at least four or more indicators in two or more
groups (compositional, structural and functional) or four
plant species indicators as a guideline for designating
sites or parts of sites as potentially having high
biodiversity. Unless similar habitats of comparable or
higher biodiversity are abundant in the landscape, the site
should not be afforested without a more detailed
ecological assessment (not necessarily an EIA) and
approval by a certified ecologist (Gittings
et al
., 2004). In
landscapes dominated by improved grassland, tillage,
commercial forestry or other intensive land uses, sites
with two or more indicators present should also be
referred to an ecologist for assessment prior to
afforestation. The guidelines for the best number and
combination of indicators in different situations should be
tested by independent research using a different set of
sites (see Section 6.5).
Although the biodiversity indicators we have proposed
represent a tool that can be easily applied by non-
specialists, they are not infallible. Furthermore, they are
only applicable to peatlands, improved grasslands and
wet grasslands. Further biodiversity indicators should be
developed for other habitat types. If a site is suspected to
be of biodiversity value, despite the absence of indicators,
it should be referred to an ecologist for a more detailed
assessment. If more than 15% of a site consists of semi-
natural habitats, the decision of whether or not to afforest
should be carefully considered in the context of the
surrounding landscape matrix.
Biodiversity in Irish plantation forests
21
4 Project 3.1.2: Assessment of Biodiversity at Different
Stages of the Forest Cycle
4.1 Introduction
The strategic plan for the forestry sector calls for
20,000 ha to be planted every year until 2030 (DAFF,
1996). To date, very little research has been carried out
on the biodiversity of forest plantations and how it
changes through different stages of the forest cycle.
Given the proposed scale of planting, there is a need for
investigation into the biodiversity supported by Sitka
spruce (
Picea sitchensis
) plantations, which will account
for at least 60% of the forest cover in Ireland up to 2030
(DAFF, 1996). With greater encouragement for the
planting of broadleaves, research on the biodiversity of
broadleaf plantations is also necessary.
This project addresses the current lack of information on
biodiversity in Irish plantation forestry. The overall aim of
the project was to obtain a comprehensive understanding
of the biodiversity of conifer and broadleaf forest
plantations at different stages of development, and to
develop indicators of biodiversity as tools for monitoring
and management. We evaluated current forest practices
in the light of our findings, and recommended changes to
these practices that could enhance the biodiversity of
Irelandʼs plantation forests.
The main objectives of this project were to:
• Assess the range of biodiversity in representative
forests at key stages of the forest cycle
• Review possibilities for enhancement of biodiversity
in plantation forests and make recommendations
• Assess the effectiveness of the
Forest Biodiversity
Guidelines
in light of the results of this study.
The following sections summarise the complete technical
report for this project (Smith
et al
., 2005), which is
available from COFORD. All data are incorporated into
the BIOFOREST Database.
4.2 Study Design and Site Selection
Recent planting trends showed that Sitka spruce was the
dominant species being planted, and that ash (
Fraxinus
excelsior
) was the dominant broadleaved species. In
suitable sites, applications for afforestation grants on
enclosed land must contain a minimum of 10%
broadleaves, and the
Forest Biodiversity Guidelines
recommend that these should be planted “
in swathes and
not as single stems within the canopy
”. Based upon these
considerations, we designed our survey around three
forest types (pure Sitka spruce, pure ash and Sitka
spruce–ash non-intimate mixes) and five age classes,
which represent the major structural changes that take
place in forest development over the course of a
commercial rotation. A definition of each age class and
the number of sites we surveyed in each forest type–age
class combination are given in Table 4.1. Site locations
are shown in Fig. 4.1.
In order to compare sites that differed in the relevant
features (e.g. species composition and growth stage), but
that were otherwise similar, we selected sites in the
following clusters or pairs that were matched for
geographical location, soil type, drainage and altitude:
• Four clusters, each consisting of three pure spruce
sites of age classes 2–4 and a spruce–ash mix site of
age class 2
• Four pairs, each consisting of a pure spruce site and
a spruce–ash mix site of age class 1
• Four pairs, each consisting of a pure spruce site and
a spruce–ash mix site of age class 4.
We found very few pure ash sites of suitable size and
configuration for the purposes of our survey, so pure ash
sites were not selected to geographically or
environmentally match any of the other sites in our survey.
We initially identified potential sites from the Coillte
inventory database that, as well as meeting the
requirements for site type and cluster, conformed to the
following additional criteria: minimum dimensions of 4 ha
in area and 100 m in width, to accommodate bird point
counts; first rotation on previously unforested land; and no
forestry operations planned that might interfere with our
surveys.
S. Iremonger et al., 2000-LS-3.1-M2
22
We conducted field visits to confirm the suitability of these
potential sites. On these field visits, we checked the
structural development of the forest (age class 1 Sitka
spruce sites with a closed canopy, Sitka spruce of age
class 2 with an open canopy, and poorly developed Sitka
spruce of age classes 3 and 4 were excluded), soil type
and drainage, to confirm that they matched the
classification in the Coillte database.
Despite our pre-survey field visits, we found that stand
age was frequently not well correlated with stand
structure, due to differences in site fertility and
management. Therefore, cluster analysis was used to
separate study sites according to their stage of structural
development, using tree height, diameter, spacing and
canopy cover data from the field. Spruce sites clustered
into five structural types: pre-thicket, thicket, closed-
maturing, reopening and mature. As Sitka spruce stands
matured, canopy cover increased at first, and then
decreased with the commencement of thinning operations
(Table 4.2). Ash clustered into five structural types: pre-
thicket, pole, closed-maturing, semi-mature and mature.
Canopy cover in ash stands more or less levelled off at the
closed canopy stage, but did not reach the maximum
observed in Sitka spruce stands (Table 4.2). The term
ʻmatureʼ as used here does not equate with commercial
maturity. Ash plantations in the mature structural type may
not be ready for harvest for several years, whereas spruce
stands may reach commercial maturity by the reopening
stage or earlier.
4.3 Vegetation
Species composition and diversity of the understorey flora
in Sitka spruce and ash plantations were dependent on
forest type and structure, as well as on site fertility and
history. In pre-thicket sites, the tree crop had a negligible
influence on vegetation communities and species
indicative of the original habitat type remained abundant.
In more mature sites, the influence of the canopy and
differences between Sitka spruce and ash plantations
were more apparent. Over the Sitka spruce forest cycle,
vascular plant species richness initially decreased,
Figure 4.1. Locations of study sites for Project 3.1.2.
Table 4.1. Number of sites surveyed in each forest type–age class combination.
Age class Age range (years) Pure ash Pure spruce Spruce–ash mix
15 4 4 4
28–15 4 4 4
320–30 0 4 0
435–50 0 8 4
5>50 4 0 0
Biodiversity in Irish plantation forests
23
reaching a minimum in the closed-maturing stage, and
subsequently increased in the reopening and mature
stages. In ash forests, numbers of vascular plant species
also tracked canopy cover, decreasing from a high point
in the pre-thicket stage to lower numbers in the semi-
mature and mature stages. Overall, ash forests supported
more vascular plant species than Sitka spruce. On the
other hand, bryophyte species richness increased with
forest maturity in both forest types, and Sitka spruce
forests supported more bryophyte species on average
than ash. When total plant species richness was
compared, we found no significant differences between
Sitka spruce and ash forests when variation due to
structural stage was removed.
Species composition differed between Sitka spruce and
ash forests. The majority of ash stands were planted on
brown earth and gley soils, and the flora was dominated
by species that prefer a neutral substrate or are broadly
tolerant. In contrast, the vegetation communities in the
Sitka spruce stands were dominated by acidophilic
vascular plants and bryophytes. Although differences in
pre-planting soil type and chemistry certainly explain
some of these differences, the acidic nature of the spruce
litter and its accumulation to form a deep humus layer
probably also play a part.
In both the Sitka spruce and ash forests, the numbers of
species with a preference for woodland habitats
increased through the structural cycle. In addition to
structure, forest age was positively associated with
greater numbers of woodland species. Numbers of
woodland vascular plant species in plantations were also
positively associated with the area and proximity of old
woodland. The increased importance of woodland
species in mature sites reflected a decline in species
characteristic of the original unwooded habitat. The flora
of more mature ash plantations was similar to but more
species-poor than that of native woodlands where ash is
prominent, and the flora of the more mature Sitka spruce
stands had some affinities to native acidophilic oak
woodlands.
4.4 Spiders
One hundred and thirty-nine species of spider were found
during the study. Of these, 15 were classified as having a
preference for forest habitats and 19 for open areas. NMS
ordination of all sites separated pre-thicket Sitka spruce,
pre-thicket ash and mixed, and pole ash sites from the
more mature sites, placing approximately half of the
closed maturing ash sites with the younger ash and
spruce sites. Factors related to this separation included
those typical of open habitat, such as cover of lower and
upper field layers (which were highest in younger sites),
and forest-related factors such as twig cover, dead wood,
ground vegetation and litter depth (which were highest in
older sites). Semi-mature and mature ash sites were also
separated from closed-maturing Sitka spruce. Factors
related to this separation included most of the above
forest-associated factors (which were highest in ash
sites), but also needle litter cover and organic content
(which were highest in spruce sites).
In age class 2, the species assemblages in Sitka spruce
plots were more similar to each other than the
assemblages in ash plots. The overall mean species
richness of spiders was slightly higher in Sitka spruce than
in ash sites. In both spruce and ash stands, species
richness tended to decrease with structural maturity.
There were no significant differences in total species
richness either between the Sitka spruce and ash
components of mixed stands or between the mixed
stands and matching pure Sitka spruce stands. The
number of forest specialists and ground-layer species
tended to increase with structural maturity, and was
Table 4.2. Mean percentage canopy cover and tree height in the five structural stages in Sitka spruce and ash
stands.
Sitka spruce Ash
Structural stage Canopy cover
(%)
Height
(m)
Structural stage Canopy cover
(%)
Height
(m)
Pre-thicket 29.6 2.5 Pre-thicket 12.2 3.1
Thicket 80.3 5.9 Pole 57.8 4.4
Closed-maturing 86.9 12.7 Closed-maturing 77.1 9.0
Reopening 70.8 18.8 Semi-mature 75.6 18.8
Mature 54.7 21.1 Mature 72.2 21.6
S. Iremonger et al., 2000-LS-3.1-M2
24
higher in spruce than in ash sites. The number of open-
habitat specialists and low-vegetation species decreased
with maturity. Lower field-layer vegetation was positively
correlated with total spider species richness and open-
habitat specialist species richness whereas canopy
closure had a negative effect on these species variables.
Forest spider species were positively correlated with litter
cover, litter depth and twig cover.
4.5 Hoverflies
We recorded a total of 72 species, including 54 new
county records of 34 species. We recorded ten tree/shrub
specialists of which six were mainly saproxylic species
(forest specialists), and we recorded 19 anthropophobic
species.
The principal axis of separation generated by NMS
ordination separated the hoverfly assemblages of pre-
thicket sites from those of more mature sites, especially
from mature ash sites. In pre-thicket sites, hoverfly
assemblages appeared to be determined primarily by pre-
planting habitat type. The assemblages of most of the
thicket and drier mature spruce and most of the closed-
maturing, reopening and wetter mature spruce sites also
differed from one another. This separation was
associated with a more open canopy and increased cover
of tall shrubs and tussocks in the former group.
Measures of species richness were generally similar
between ash and Sitka spruce sites, and between the ash
and Sitka spruce components of the mixed sites. Overall
hoverfly species richness and numbers of wet substrate
species were highest in pre-thicket and closed-maturing
sites. Species richness of forest and tree/shrub specialists
and dead wood species increased between the pre-
thicket and closed-maturing stages, but did not change
with further structural development of the forest. Numbers
of canopy tolerant, anthropophobic, foliage species and
wet substrate species did not vary significantly between
structural groups. Numbers of herb layer, ground debris
and root zone species all showed a general trend of
decrease with increasing structural development. At the
level of the trap, species richness of several functional
groups of hoverflies tends to be positively associated with
clearing area (especially in more structurally developed
sites) and negatively associated with tree height.
Species richness of wet substrate species was positively
associated with diversity of wet habitats and absence of
drainage ditches. The species richness of dead wood
species in age classes 3 and 4 Sitka spruce was positively
correlated with the frequencies of standing dead wood
and fallen trees. However, within the groups of wet (where
these categories of dead wood were more abundant) and
dry sites, these relationships were no longer significant.
4.6 Birds
A total of 62 species were recorded, of which 15 were not
used in subsequent analyses because they were classed
as non-breeding over-flyers, or because they were not
recorded within 50 m of the observer. Fourteen species of
conservation concern were recorded, including two over-
flying hirundines (Swallow and Sand Martin), and two
birds of prey (Hen Harrier and Peregrine). The other
species were all typical of open or scrubland habitats, with
the exception of Crossbill, Redpoll and Spotted
Flycatcher. Unlike the other three species groups, birds
responded to forest structure at a coarser resolution, and
forests were therefore classed as Older, Intermediate and
Younger.
Species classified as typical forest species for the
purposes of the analysis appeared to prefer more mature
plantations. However, the only one of these that is a true
forest specialist, requiring large areas of interior forest, is
the crossbill, which was recorded in only three sites (all of
which were Older pure Sitka spruce sites). Of the nine
typical forest species recorded, four were species known
to actively prefer a coniferous forest habitat (Goldcrest,
Coal Tit, Crossbill and Siskin). Within the bird habitat
subgroup of Older sites, the number of forest species we
recorded did not respond to any of the measured
environmental variables. This suggests that the forest
species in question, beyond showing a preference for the
more mature forest stands, are quite generalist in their
forest habitat requirements within the stand or at the
landscape scale. With the exception of Crossbill, the only
true forest interior species occurring in Ireland (Redstart,
Pied Flycatcher and Wood Warbler) are restricted to semi-
natural oak woodlands and were absent from our sites.
The paucity of bird species of conservation importance at
later stages of the forest cycle can partly be attributed to
the extreme rarity of true forest specialists in Ireland.
However, the survey methods did not allow a thorough
investigation of the importance of spruce and ash
plantations for some nocturnal or poorly detectable forest
species (e.g. Nightjar or Long-Eared Owl).
Biodiversity in Irish plantation forests
25
The growth stage of the forest was the main determinant
of bird community composition and bird species richness.
Younger stages of the forest cycle were characterised by
the presence of a number of ground-nesting seed eaters,
some of which were Red/Amber species of conservation
concern. The presence of such species was probably
more influenced by the original habitat of the site than by
features of the young plantation. The birds of Intermediate
forest stages tended to be generalists such as Robin,
Wren and Dunnock. Stands of any age with high densities
of these species tended to support species-rich
assemblages. Older stages of the forest cycle supported
more forest species as defined for the purposes of this
study; however, the lack of any true forest specialist
species, requiring large expanses of interior forest habitat,
was marked. Such species are scarce in Ireland. Indeed,
the forest species we recorded showed a preference for
the forest edge and for well-developed shrub, herb and
moss layers. Older stands were typified by Goldcrests,
high densities of which were associated with species-poor
forest stands.
The influence of species of tree on bird assemblage
appeared to be negligible. However, the mature ash
stands included in the study all incorporated a conifer
element – pure stands could not be found for study.
Additionally, these are results from Sitka spruce and ash
alone so caution must be exercised in extrapolating these
results to any other forest types.
4.7 Indicators
The indicators we have proposed for identifying sites of
high biodiversity value for the four taxonomic groups
above are shown in Tables 4.3 and 4.4. Table 4.3 gives
the indicators we identified in thicket stage to mature
spruce sites, and Table 4.4 does the same for pole stage
to mature ash sites. Separate biodiversity indicators for
pre-thicket forests were developed by Smith
et al.
(2005),
but many of these have been superseded by Project 3.1.1
indicators for afforestation sites (Section 3.4.6). It should
be noted that the findings of this study relate only to the
taxonomic groups studied. The indicators given here will
not necessarily be successful in distinguishing habitats of
Table 4.3. Biodiversity indicators for thicket through mature Sitka spruce stands. The sign of the indicatorʼs
relationship with species richness for each taxonomic group is given in brackets.
CompositionalaStructural Functional
Vascular plants and bryophytes
Rubus fruticosus
agg.
Dryopteris dilatata
Agrostis capillaris
Thuidium tamariscinum
and
Plagiothecium undulatum
b
Hypnum jutlandicum
b
Dicranum scoparium
b
Eurhynchium praelongum
b
Canopy cover (–)
Forb cover >20% (+)
Bramble cover <30% (+)
Bryophyte cover >50% (+)
Needle/FWD cover (–)
CWD (+)b
Proximity to woodland (+)c
Thinning (+)
Available P (+)d
Spiders Canopy cover (–)
Cover of 10–50 cm tall vegetation (+)
Thinning (+)
Hoverflies CWD (+) Wet habitats (+)e
Birds Dunnock (+)
Robin (+)d
Blackbird (+)
Wren (+)d
Redpoll (+)f
Chaffinch (+)f
Willow Warbler (+)f
Blackcap (+)f
Long-tailed Tit (+)f
Distance from edge (–)
Shrub cover (+)
Age (–)f
Elevation (–)
aPlant species indicators should be used as the two sets shown. Bird species indicators are high abundances of the indicated species,
rather than simple presence.
bIndicators of bryophyte diversity only.
cIndicator of woodland vascular plant species richness.
dMature (or Old) stands only.
eNot including thicket stands.
fIntermediate stands only.
S. Iremonger et al., 2000-LS-3.1-M2
26
high biodiversity value for other groups, especially of
invertebrate fauna (including spider assemblages in
higher levels of the forest strata). Also, time-intensive
surveys are often required to locate and identify species
of special conservation value. There are no easily
surveyed indicators that can be relied on to give an
accurate assessment of all components of biodiversity in
afforested sites. For instance, measuring only vascular
species richness will distinguish between forests that are
species-poor and species-rich for vascular plants.
However, such an approach may overlook habitats that
are important for bryophyte diversity, and possibly for
other groups as well. Additionally, this approach would
give equal weighting to common plants and less frequent
plants of more importance for biodiversity. No one type of
indicator, including species indicators, should be used in
isolation when assessing the diversity of a Sitka spruce or
ash stand. Although we have developed these indicators
for use by non-specialists, some training will nevertheless
be required to use them effectively (see Recommendation
36 below).
When assessing the biota of a site, it is recommended that
the structural, environmental and management status
(e.g. thinning history, previous land use, location) of the
stand be studied in conjunction with species composition.
We include several such factors among the indicators
listed below, and others can be useful in interpreting floral
and faunal survey data.
These indicators can be used to assess the effect of site
management practices on biodiversity and/or to identify
sites that potentially are of high biodiversity value. If
indicators for particular subgroups of species, such as
forest specialist spiders, are desired, see the appropriate
chapter in Smith
et al.
(2005). These indicators of
biodiversity should be considered as provisional
indicators only, until they are verified using independent
data (Noss, 1999). In addition, the context in which they
have been identified, i.e. pure stands and non-intimate
mixes of Sitka spruce and ash, must be taken into
consideration prior to their application. Except for
indicators of bird diversity, the indicators in Tables 4.3 and
4.4 should be employed at the site or stand level, rather
than at the level of the whole plantation or landscape.
The various indicators should be used in conjunction; in
general, it is misleading to label a stand as ʻbiodiverseʼ (or
not) on the basis of just one or two indicators. We
recommend the presence of at least four indicators in two
or more groups (compositional, structural and functional)
as a general guideline for designating sites or stands as
Table 4.4. Biodiversity indicators for pole through mature ash stands. The sign of the indicatorʼs relationship
with species richness for each taxonomic group is given in brackets.
CompositionalaStructural Functional
Vascular plants and bryophytes
Agrostis stolonifera
(–)
Thamnobryum alopecurum
(+)b
Polystichum setiferum
(+)b
Hedera helix
(+)b
Primula vulgaris
(+)b
Proximity to woodland (+)bc
Spiders Cover of 10–50 cm tall vegetation (–)b
Soil cover (–)
Birds Dunnock (+)
Blackbird (+)
Wren (+)
Robin (+)d
Redpoll (+)e
Chaffinch (+)e
Willow Warbler (+)e
Blackcap (+)e
Long-tailed Tit (+)e
Distance from edge (–)
Shrub cover (+)
Age (–)e
Elevation (–)
aPlant species indicators should be used together as one set. Bird species indicators are high abundances of the indicated species,
rather than simple presence.
bIndicators of woodland species richness.
cVascular plant species richness only.
dMature (or Old) stands only.
eIntermediate stands only.
Biodiversity in Irish plantation forests
27
potentially having high biodiversity. The numbers and
types of indicators that should be present in order to
accurately categorise the biodiversity status of forest units
should be investigated during the process of indicator
verification. The indicators cannot substitute for thorough
floral and faunal surveys, particularly when sites of
potentially major biodiversity importance are involved, but
can be employed as a first step in biodiversity
management assessment or identifying sites of
biodiversity value. In sites where few indicators are
present, management practices can be reviewed and
improved. Forest stands or plantations identified as being
of potentially high biodiversity can be surveyed and
assessed more thoroughly and management for
biodiversity can be prioritised in forest planning and
operations.
4.8 Conclusions
Different forest types and stages of the forest cycle
support different biota. In the early stages of the forest
cycle, species from the original unwooded habitat persist.
Previous and adjacent land uses are important influences
on ground flora composition and diversity. Open habitats
of high biodiversity value should not be afforested, as
most or all of the biota associated with these habitats will
not persist long beyond canopy closure.
In contrast, the later stages support a more characteristic
woodland biota. The paucity of natural woodlands in
Ireland means that plantations have the potential to
provide important habitats for populations of some forest
species that would otherwise be scarce, especially in
intensively farmed landscapes. However, the rarity of true
forest specialist bird species in Ireland means that the
potential role of plantations for these species is currently
limited. Proximity and abundance of old semi-natural
woodland and scrub in the landscape increase the
species richness of typical woodland plants. In particular,
ash forests originating from or adjacent to old woodland or
scrub had developed a flora most similar to that of old
semi-natural woodland. Availability of shrub cover was
also important for bird diversity. The most important
habitat features for forest specialist hoverflies are wet
substrates and dead wood.
Sitka spruce plantations can have a negative impact on
understorey flora diversity, especially during periods of
canopy closure. However, if managed appropriately, Sitka
spruce forests can be more species-rich and aesthetically
pleasing. Of all stages in the Sitka spruce structural cycle,
the mature stands support the richest communities of both
vascular plants and bryophytes. It is important to note,
however, that not all spruce stands may reach the mature
structural stage, which is not equivalent to commercial
maturity. Sitka spruce forests are important habitats for
bryophyte diversity as they support more specialist
species than the ash stands.
Understorey flora diversity varies less in ash than in Sitka
spruce plantations; while the early stages of the ash
structural cycle support high numbers of vascular species,
the semi-mature and mature stages are more favourable
habitats for bryophyte diversity. At no stage in the forest
cycle are the vegetation communities beneath the
broadleaf canopy as species-impoverished as the
communities beneath the closed-maturing Sitka spruce
stands. In general, mature sites with a more open canopy
(such as that provided by ash plantations) will support a
greater number of spider species. Ash forests also appear
to support a greater number of saproxylic hoverfly species
than spruce forests.
We found no consistent effects of mixed plantations on
the biodiversity of either the Sitka spruce or the ash
components of these stands. However, the fact that
different species assemblages are supported by ash and
Sitka spruce means that adding ash to a Sitka spruce
plantation is likely to increase the biodiversity of plants
and spiders at the plantation scale. The same is also true
for hoverflies, especially if the ash component includes
grassy clearings. There was little separation between the
bird assemblages of ash and Sitka spruce. However, the
mature ash sites we studied all incorporated a conifer
element, and the bird assemblages we encountered may
be different from those supported by pure ash sites. The
biodiversity of pure or mixed plantations of other species
of broadleaves is worthy of further investigation.
Although not a substitute for thorough ecological surveys,
the presence of certain easily identified species or the
measurement of certain structural characteristics of a
forest may give an insight into the species richness of a
plantation.
S. Iremonger et al., 2000-LS-3.1-M2
28
5 Project 3.1.3: Investigation of Experimental Methods to
Enhance Biodiversity in Plantation Forests
5.1 Introduction
The objective of Project 3.1.3, as stated in the
COFORD/EPA scoping document, was:
To identify those forestry management practices (with the
possibility of using experimental plots) which are best
suited to maintaining and enhancing biodiversity in
plantation forests
.
The first task for the Research Group was to carry out a
review of methodologies used to enhance biodiversity in
plantation forests, to inform the further design of the field
phase of the project. The different options open to the
Group were discussed at a special session during the
conference
Opportunities for Enhancement of Biodiversity
in Plantation Forests
, 24 October 2002, Vienna Woods
Hotel, Cork. Contributors included members of the
BIOFOREST Steering Group and individuals from forest-
related institutions both inside and outside of Ireland. A
decision was made that this project should focus on the
use of open space in forests for biodiversity
enhancement. As there were only resources available to
study one forest type in this project, and for reasons laid
out by Smith
et al
. (2005), forests dominated by Sitka
spruce (
Picea sitchensis
) were chosen as the subject.
This project comprised three main elements:
1. An extensive survey of forests with different
configurations of open space
2. The establishment of an experiment on the
manipulation of open space in the forest, focusing on
roads
3. A separate study on Hen Harrier habitat
requirements.
The following sections summarise the technical report for
this project (Iremonger
et al.
(2006)), which is available
from COFORD. All data are incorporated into the
BIOFOREST Database.
5.2 Extensive Survey
5.2.1 Introduction
Natural forests almost always contain some open,
treeless areas within them. These may be temporary
canopy gaps of varying sizes caused by disturbance
agents, such as windthrow, fire or insect attack. More or
less permanent open spaces can also be found in forests
in places that are not favourable to tree growth because
of waterlogged soils, rock outcrops or herbivory. Open
spaces within forests provide suitable sites for plant
species that cannot tolerate the shaded conditions of the
forest interior (Peterken and Francis, 1999). The
additional habitats and species supported within open
spaces serve to increase the biodiversity of the forest as
a whole.
The value of open spaces for forest biodiversity is
recognised by the Forest Service, which requires 5–10%
of open space to be created or maintained as part of the
Area for Biodiversity Enhancement (ABE) within new
forestry plantations in order to qualify for afforestation
grant aid (Forest Service, 2000c). Such open spaces can
include ridelines, firebreaks, forest roads and turning
bays, unplantable areas, areas left unplanted to facilitate
ESB power lines or other utilities, and buffer zones for
aquatic habitats and archaeological features. In essence,
these open space types can be simplified into three: linear
open spaces, non-linear open spaces (or glades) and
roads. Although roads are also linear features, their
management (e.g. surfacing with gravel) and the different
roadside habitats (e.g. road cutting banks, roadside
drains) provided make them qualitatively different from
other linear open spaces. A key aim of maintaining open
spaces as part of the ABE within plantation forests is to
“
conserve and enhance the biodiversity value throughout
the entire forest
” (Forest Service, 2000c). A secondary
benefit is the provision of semi-natural open habitats that
may be rare in intensively managed landscapes.
Biodiversity in Irish plantation forests
29
The objectives of this sub-project were:
• To assess the biodiversity of plants, spiders,
hoverflies and birds in open spaces in plantation
forests
• To investigate the major environmental and
management factors influencing biodiversity at the
plantation scale between open spaces and within the
open space
• To recommend measures that can enhance the
biodiversity of plantation forests through planning and
management of open space.
5.2.2 General methods
5.2.2.1 Study sites
We selected 12 sites in two geographic clusters referred
to as Cork (in Counties Cork, Kerry and Limerick) and
Wicklow (Counties Wicklow and Dublin) (Fig. 5.1). We
selected sites that had a wide range of configurations of
open spaces from a GIS forest inventory database. Within
each cluster, we standardised, as far as possible, soil type
and habitat/vegetation types of the open spaces. All sites
were plantation forests comprised primarily of Sitka
spruce, ranging in age from 26 to 47 years old, and at
least 80 ha in size. The sites in the Wicklow cluster were
on podsols with rock outcrops and with dry–humid acid
grassland/dry heath vegetation (as defined by Fossitt
(2000)) in the unplanted open spaces. The sites in the
Cork cluster were on deep blanket peats and peaty
podsols with modified blanket bog vegetation in the
unplanted open spaces.
5.2.2.2 Plantation-scale open-space metrics
We calculated the amount of habitat in each of nine
categories: broadleaf scrub, road, undeveloped
plantation, windthrow, clear-fell, young forestry, unplanted
open space within the plantation, external open space,
and the length of rides. The area in each of these
categories was calculated for within 50 m, 100 m, 200 m
and 500 m of each central vegetation plot; for within 50 m,
100 m, 200 m and 500 m of each tree sampled for
epiphytes; for within 100 m, 200 m and 300 m of each
spider plot; for within 100 m, 200 m and 300 m of each
Malaise trap; and for within 300 m of each bird point-count
location. The habitat categories were mapped using aerial
photographs, and the amounts of habitats within a
specified distance (radius) of an open-space centre were
calculated using ArcView GIS.
5.2.3 Terrestrial vegetation
5.2.3.1 Diversity at plantation scale
A total of 229 terrestrial plant species were recorded. The
mean site vascular plant species richness of 4 m2 plots
ranged from 5.4 to 10.7. There were no significant
relationships between biodiversity metrics calculated at
the open-space scale and the amount of non-forest
habitat in the nine categories referred to in Section 5.2.2.2
at any of the four scales we investigated.
5.2.3.2 Diversity between open spaces
Combining both geographical clusters, rides had lower
vascular plant species richness and higher bryophyte
species richness than glades and roads. Roads had
higher vascular plant species richness, numbers of
species associated with open habitats and Simpsonʼs
diversity than the other two open-space types. In roads,
pH was positively associated with vascular plant species
richness, Simpsonʼs diversity and vegetation evenness.
Road-verge plots adjacent to forest roads surfaced with
limestone gravel had higher vascular plant species
richness than roads surfaced with local sandstone or
mica-schist.
5.2.3.3 Diversity within open spaces
Total vascular plant species richness and open species
richness (including vascular, bryophyte and lichen, see
Section 2.2.3) were higher in roadside plots located on the
road verge or ditch than in plots on banks or road setback.
Figure 5.1. Locations of study sites for the extensive
survey of open spaces in Project 3.1.3.
S. Iremonger et al., 2000-LS-3.1-M2
30
In glades, centre plots had significantly lower bryophyte
and lichen species richness, Simpsonʼs diversity index
and vegetation evenness than edge plots. There were no
significant differences in open species richness between
plot locations in glades. Total vascular plant species
richness and open species richness in the ride centre plot
were significantly higher than in ride edge plots. Vascular
plant species richness in 4 m2 plots was positively
associated with transmitted direct and diffuse solar
radiation. In contrast, bryophyte species richness,
vegetation evenness and Simpsonʼs diversity index were
generally lower in plots receiving more sunlight.
Vascular plant species richness was positively correlated
with ride width. There was a weak negative association
between bryophyte and lichen species richness and ride
width. Open species richness, Simpsonʼs diversity index
and Berger–Parker evenness index were not well
predicted by ride width. The ratio of ride width to tree
height was no better predictor of biodiversity metrics than
ride width alone. Vascular and non-vascular plant species
richness were positively associated with glade area.
There was no clear relationship between glade area and
open species richness, Simpsonʼs diversity index or
Berger–Parker evenness. There were no meaningful
relationships between biodiversity metrics and any
measures of light intensity or road width in road plots.
Transmitted solar radiation at the centre of open spaces
was well predicted by width of linear open spaces, but less
well predicted by either the ratio of road/ride width, or by
the area of non-linear open spaces. However, tree height
explained a significant amount of the residual variation
from a regression of transmitted diffuse light on road/ride
width.
5.2.3.4 Vegetation structure
Cluster analysis produced five coherent groups of plots
that differed primarily in cover of Sitka spruce, graminoids
and bryophytes. Vascular plant species richness was
significantly lower in the group with highest Sitka spruce
cover, which was dominated by plots in rides, and plots at
the edges of open spaces. Bryophyte and lichen species
richness were lowest in the graminoid-dominated group,
which was dominated by plots in glades and plots in the
centre of open spaces. Simpsonʼs diversity index was
lower in groups dominated either by mosses or
graminoids than when neither was dominant. There were
no significant differences in open species richness
between groups.
5.2.4 Epiphytes
A total of 68 species of epiphytes were found on the 24
trees surveyed – 28 bryophyte, 39 lichen and one
vascular plant species. Two of the bryophyte species
recorded are likely to appear on the Irish Red Data List for
bryophytes, which is in the process of being compiled.
Only 16 species occurred in more than 5% of plots. Mean
species richness was 22.6 at the site level, and 16.3 at the
level of the individual tree. Bryophyte species richness
was significantly lower in the Wicklow sites than in Cork.
Bryophyte species richness was positively associated
with tree density and negatively associated with mean
diameter of trees in the immediate area; density and
diameter were also negatively correlated. Site elevation
was negatively associated with bryophyte species
richness in Wicklow sites and negatively associated with
lichen species richness in Cork sites. Species richness
was not significantly associated with age of the plantation,
site aspect, width of the open space, glade area or canopy
openness at the centre of the open space. Amount of
open space 50–500 m from the sampled trees had no
apparent effects on epiphyte biodiversity.
There were no significant differences between edge and
interior trees from each site in terms of Simpsonʼs
diversity, Berger–Parker evenness, epiphyte cover, or
total bryophyte and lichen species richness. Average
DBH and basal area were significantly greater in the edge
plots than the interior plots.
Bryophyte species richness decreased with height on the
tree while lichen species richness increased. Edge trees
showed more variation in species richness between trunk
plots than did interior trees. In particular, there was more
variation in species richness between north-facing and
south-facing plots at the same height. Bryophyte cover
was significantly higher on the south side of the edge
trees than on the south side of interior trees, and on the
south side of the edge trees compared to the north side of
the same trees.
5.2.5 Spiders
A total of 11,872 individual spiders (including 2,690
juveniles) were captured in 13 families and 122 species.
Twenty-four species were classified as being associated
with open habitats and 14 with forested habitats.
5.2.5.1 Trends along the open to forest transect
Across the transect from open-space centre to forest
interior, mean species richness and abundance
Biodiversity in Irish plantation forests
31
decreased. Richness and abundance of open-habitat
associated species were significantly greater in the open
space compared to the other points, whereas richness
and abundance of forest-associated species were
significantly lower. Fifty-two species in the centre of the
open space did not occur 5 m into the forest, whereas only
six species occurred in the forest but not in the centre of
the open space. Spider assemblages found at the edge of
the open space represent a transition of assemblages in
the centre of the open space to those within the forest.
Variability in species composition of spider assemblages
at the forest boundary and within the forest is relatively
low compared to those in the open-space centre and
edge. Spider assemblages appeared to be closely
associated with vegetation structure: high cover of field-
layer vegetation in the open space, cover of ground-layer
vegetation at the open-space edge and needle litter and
twig cover within the forest.
5.2.5.2 Influence of open-space type and size
Species richness and abundance of all spiders and of
open-habitat associated species were significantly
greater in glades than in rides or roads. Abundance (but
not species richness) of forest-associated species was
significantly lower in glades than in roads.
Roads and rides had similar spider assemblages.
Ride/road-verge width was positively related to
abundance of all spiders and open-habitat associated
spiders and to open-habitat associated species richness,
and negatively related to abundance of forest-associated
spiders. Glade area was positively related to abundance
of open-habitat associated species. Cluster analysis
separates roads and rides that are less than 15 m wide
from those that are wider than 15 m. The assemblages of
narrow roads and rides (<15 m wide) with cover of
vegetation 10–50 cm tall were distinct from those of wider
rides with similar vegetation structures. These
represented a transition between forest interior and open
habitats with high lower (10–50 cm) field-layer cover.
5.2.5.3 Large-scale influence of open space
The total number of species and individuals, as well as the
number of open-habitat associated species, were
positively correlated with the area of unplanted open
space within 200 m, and negatively correlated with ride
length. Forest-associated species abundance, however,
showed the opposite trend. However, it is likely that ride
area indirectly represents the amount of forested area
within 200 m of the sampling points, i.e. the greater the
amount of planted forest, the greater potential for more
rides. There were no significant relationships between the
species variables and the following open-space types:
road, outside, undeveloped, windthrow, clear-fell,
broadleaf, total unforested and total open space. Plots
which had >10% unplanted open space within 200 m were
significantly greater in mean species richness than those
with <5%. There was no significant difference between
forest-associated species richness or species abundance
and proportion of unplanted open space, or between the
other open-space categories and the species variables.
5.2.6 Hoverflies
We recorded a total of 75 species, of which 65 are
associated with closed canopy spruce forest, small open
spaces, large open spaces or scrub habitats, and five are
associated with miscellaneous macrohabitats that
occurred in, or adjacent to, particular sites. Therefore,
only five species were recorded whose occurrence could
not be related to macrohabitats in, or adjacent to, the
trapping locations. We recorded three species that are
listed as threatened. The majority (nearly 80%) of the
recorded species are associated with open-space
habitats rather than closed-canopy forest. Overall, more
of the recorded species are associated with large open
spaces than with small open spaces, but the mean
species richness per site was similar in these two
categories. The most common habitat association of the
recorded species was with humid grassland habitats, but
there were more anthropophobic species associated with
moorland and surface water habitats. In fact, most (73%)
of the anthropophobic species associated with humid
grassland and moorland are also associated with surface
water habitats. While the total and mean per-site species
richness of scrub-associated species was relatively high,
very few of these species are anthropophobic.
Assemblage structure was significantly different between
forest roads and glades. At Malaise traps in forest roads,
the numbers of species associated with small and large
open spaces were positively correlated with the average
road width. There were no significant relationships
between the richness of these species groups with forest
road width at the trap location, or between the richness of
other species groups and forest road width. There were
no significant relationships between any of the measures
of open-space area within 100–300 m of the traps and the
numbers of hoverfly species.
S. Iremonger et al., 2000-LS-3.1-M2
32
The numbers of tree/tall-shrub foliage species (including
anthropophilic and conifer-associated species) were
negatively correlated with a gradient from broadleaved
trees and shrubs to coniferous shrubs. The numbers of
species associated with submerged sediment, water-
saturated ground and surface water habitats were
positively correlated with a gradient of increasing
influence of most wet habitat features, except drainage
ditches.
5.2.7 Birds
5.2.7.1 Roads
A total of 31 bird species were recorded during road
transects. Mean bird species richness along roads was
slightly higher in Cork sites than in Wicklow sites. Sections
of Cork road had higher levels of shrub cover and
broadleaf cover. Bird species richness was positively
correlated with shrub cover and with broadleaved tree
cover. There was no significant relationship between
species richness along roads and road gap width, crop
height or brash cover. Shrub cover and broadleaf cover
were positively correlated with relative abundances of
species associated with broadleaved woodland. Road
sections of 15 m or wider had significantly higher cover of
shrubs and broadleaved trees than narrower road
sections.
5.2.7.2 Point counts
A total of 38 bird species were recorded during point
counts. The mean number of bird species detected during
point counts in Cork sites was not significantly different
from that in Wicklow sites. However, the areas around
Cork points had significantly higher cover of shrubs and
broadleaved trees than the areas around Wicklow points.
Bird species richness within 50 m was positively
correlated with shrub cover and broadleaved tree cover.
Species richness was not significantly correlated with
brash cover, crop tree canopy cover or total area of open
space. Of the open-space/forest-area variables estimated
from aerial photographs, broadleaved woodland area was
positively correlated with bird species richness at every
scale we investigated. Bird species richness was also
positively correlated with road area at a 50 m scale, and
with clear-fell area and total area of open space at the
300 m scale. No other open-space variables measured on
aerial photographs were significantly correlated with bird
species richness at any scale.
More bird species were detected in the three sites with an
element of broadleaved woodland area than in the nine
other sites. Within the three sites that had a woodland
element, more bird species were detected from points that
had greater than 0.5 ha of woodland within 200 m than
from other points. In all sites, woodland area within 300 m
was positively related to the occurrence of several species
associated with broadleaved tree cover. Areas outside the
forest and total open space within 300 m were positively
related to occurrence of Meadow Pipits and Skylarks.
5.2.8 Conclusions
A large component of Irish biodiversity is associated with
forest habitats, and much of this biodiversity is dependent
upon areas of closed-canopy tree cover. However,
another important component of biodiversity in forest
plantations is the flora and fauna associated with open-
space habitats within forests. Many coniferous plantation
forests in Ireland are generally darker than the natural
broadleaf forests and have been found to lack elements of
biodiversity associated with open spaces and less dense
canopies in natural forest. Many of the characteristic
forest species remaining in Ireland are, strictly speaking,
species of forest edges and glades, rather than forest
interior species. In intensively farmed landscapes, open
spaces within forests may provide a suitable habitat for
species characteristic of semi-natural open habitats,
which no longer occur within the surrounding landscape.
Glades, rides and roads in Irish plantation forests can
support reasonably diverse communities of plants and
animals. The main factors influencing epiphyte
biodiversity in this study were elevation and tree density.
The positive association of tree density with bryophyte
species richness highlights the adaptation of bryophytes
to low light levels and their low tolerance to desiccation.
The main effect of open spaces on epiphyte diversity was
related to the presence of live branches on edge trees,
which appeared to shade the trunk and increase humidity
levels. The results of this study suggest that stand
management in relation to tree density may be more
important for epiphyte diversity than open spaces within
the forestry plantation.
In contrast, although the primary causes of variation in
terrestrial vegetation composition and diversity were soil
and climate factors, light regime was also important, and
the vegetation of glades and wide rides was distinct from
that of narrow, more shaded rides. In general, vascular
plant species richness increased and bryophyte and
Biodiversity in Irish plantation forests
33
lichen species richness decreased with increasing solar
radiation. Measures of vegetation diversity were highest
in the forest open-space ecotone at the edges of glades,
and tended to be lower both in well-lit, grass-dominated
situations and in heavily shaded, bryophyte-dominated
conditions.
Invertebrate diversity was also positively affected by open
space. Fifty-two of the spider species we found were
restricted to open spaces, in contrast to just six species
that were only present in closed canopy areas, and
average spider species richness per plot was significantly
higher in open spaces than in forest plots. Nearly 80% of
the hoverfly fauna that we recorded was associated with
open-space habitats, and around one-third of these are
mainly associated with semi-natural habitats. However,
other invertebrate groups (including spiders and
hoverflies associated with higher vegetation layers than
were sampled during this study) might respond very
differently to open space in forests.
The absence of any relationship between open space at
the plantation scale and diversity of plants or hoverflies,
suggests that plantation-scale processes such as
dispersal have relatively little influence on the diversity of
these groups in open spaces. In contrast, the overall
amount of unplanted open space within a plantation was
positively related to both species richness and abundance
of spiders. The absence of a similar relationship at a
smaller scale suggests that, at the scale of the plantation,
increasing the availability of open space encourages the
movement of spiders between open spaces.
This study suggests that to benefit terrestrial flora or
spider fauna typical of open habitats, rides and roads
should be an absolute minimum of 15 m in width and, in
many cases, should be wider in order to support well-
developed open-space habitat in mature spruce forests.
For non-linear open space, a stratified sampling approach
that varies glade area may reveal a similar ʻthresholdʼ
size, above which open species are supported. Our
results suggest that, depending on local conditions, glade
areas of 625–900 m2 should be sufficient to have at least
part of the glade well lit.
The bird fauna does not follow the patterns described
above. Typical open-space specialists that are
widespread in habitats just outside the plantation are
largely absent from open spaces within forest plantations.
However, open spaces provide the main opportunity for
the development of broadleaved tree and shrub cover
within conifer plantations, and such vegetation is
associated with higher bird biodiversity. This is largely due
to a suite of relatively uncommon species that rely on
these elements of open-space vegetation for foraging
and/or nesting habitat.
Open-space habitats containing broadleaved trees and
shrubs can also be extremely valuable for hoverflies, as
can some wet habitat features, including small-scale
features such as wet flushes and temporary streams. In
general, selection of areas for open-space retention
should focus on areas of high biodiversity or
environmental heterogeneity. There is a need to examine
the biodiversity value of a range of habitat types that could
potentially be selected as retained habitat, specifically
with regard to whether the unique and rare species
associated with pre-planting habitat persist after
afforestation.
Where deer numbers are high, overgrazing of forest open
space is likely to have a negative impact on biodiversity.
Control of deer populations in these areas will be a
necessary precursor to the development of broadleaves
and shrubs within forest open spaces.
5.3 Experimental Manipulation
Strips of open spaces adjacent to forest roads can make
a significant contribution to the biodiversity of forestry
plantations. The extent of this contribution is partly
dependent on the width of these unplanted strips. The
possibility of using these strips as a focus for an
experimental manipulation to be set up during this project
was decided in consultation with the project Steering
Group (see Section 5.1).
The recommended between-trunk clearance across the
forest roads is currently 15 m, with approximately 5 m
being the road surface and the other 10 m being divided
between the two sides of the road, leaving an average of
5 m on each side (Ryan
et al
., 2004). On average,
branches directly shade at least half of this area. Taking
into account the shade from the maturing trees, there is
little undisturbed open space in road gaps that is
unshaded. The Research Group proposed to investigate
the effect of doubling the clearance on the biodiversity of
the area.
It is intended that this experiment will be maintained
beyond the life of the BIOFOREST Project and that the
S. Iremonger et al., 2000-LS-3.1-M2
34
sites will be re-surveyed periodically. As such, the
ownership of the sites was important, and therefore the
project was restricted to using sites owned by Coillte.
Study sites were chosen from several that were
scheduled to undergo re-establishment (planting after
harvesting) in 2004/2005 (Fig. 5.2). Plantations
dominated by Sitka spruce were the focus of the
experiment. In sections of forest road within these
plantations two treatments were established: in the
normal treatment, trees were planted on either side of the
road with a 15 m clearance across the road between
trunks; in the wide treatment, trees were planted with
double clearance, i.e. 30 m between trunks (Fig. 5.3).
Baseline surveys were carried out during the summer of
2005 on vegetation, spiders, birds and hoverflies. Sorting
and identification of specimens ensued, and the baseline
data are included in the BIOFOREST Database. See
Iremonger
et al
. (2006) for more detail on surveys.
5.4 Special Report on Hen Harriers
Hen Harriers
(Circus cyaneus)
are a protected bird
species under European law, and one of the birds of
greatest conservation concern in Ireland. In recent
decades, large tracts of Hen Harrier habitat in the Irish
uplands have been afforested. Hen Harriers nest and
forage in young plantations, but closed canopy forests are
not used extensively by this species. The suitability of Irish
plantation forests for Hen Harriers therefore depends on
their age structure.
Using the results of a recent national survey, the NPWS
has outlined ten Indicative Areas (IAs) for Hen Harriers.
These cover 3.4% of the area of the Republic of Ireland,
and at the time of the survey supported roughly 75% of the
Irish Hen Harrier population. In order to ensure that these
areas remain suitable for Hen Harriers, land-use policy
and practice within them need to be informed by the
habitat requirements of this species, even if these are not
fully understood at present.
This study had two aims:
1. To determine whether areas within the IAs with
breeding Hen Harriers could be distinguished from
areas where they did not occur, using a threshold
level of habitat cover suitable for Hen Harrier hunting
and nesting, and
2. To predict how changes in age structure of the
forests within the IAs will affect the suitability of IAs
for Hen Harriers by 2015.
It was found that areas with breeding Hen Harriers can be
distinguished on the basis of percentage cover of suitable
habitat: Hen Harriers were ten times less likely to occupy
ranges in the IAs with less than 30% suitable habitat cover
Figure 5.2. Study site locations for the road width
experimental manipulation in Project 3.1.3.
Figure 5.3. Diagram of standard and wide road width
experimental treatment.
Biodiversity in Irish plantation forests
35
(within 1 km of their nest sites), than they were to occupy
areas with more than 30% suitable habitat cover. Canopy
closure in upland forests reduces the level of suitable
habitat available to Hen Harriers. According to the 30%
habitat threshold identified, the proportion of the IAs that
is unsuitable for Hen Harriers will increase from about
30% (at the time of the Hen Harrier survey in 2002) to
about 50% by 2015. Further afforestation and agricultural
improvement in the uplands will have to be carefully
regulated if it is not to exacerbate this process. The
persistence of Hen Harriers in some areas may depend
critically on the value of young second-rotation forests,
relative to young first-rotation forests and open habitats
such as bog and heath. This is something about which, at
present, we know very little. When assessing the impact
of a proposed land-use change, it is important to take into
account changes in the value to Hen Harriers of habitats
in the affected area and in the surrounding landscape,
especially in areas with high levels of forest cover.
The results of this special study on Hen Harriers were
submitted to COFORD and the EPA as a stand-alone
report (Wilson
et al
., 2005). This report was also
incorporated into the final technical report for the project
(Iremonger
et al.
, 2006).
S. Iremonger et al., 2000-LS-3.1-M2
36
6 Recommendations for Policy and Practice
Forests tend to be rich in biodiversity because they are the
most structurally complex of ecosystems. However, even-
aged single-species plantations are highly simplified
ecosystems compared to natural forests, and their
biodiversity is in general reduced. In particular, the closed-
canopy phase in the forest cycle under Sitka spruce and
other heavily shading conifers is associated with an
extremely impoverished ground flora. Greater diversity in
tree species enhances diversity in other plant and animal
groups; this was demonstrated in our study by the
contribution of ash stands to overall diversity within Sitka
spruce dominated plantations.
As the forest stand matures, it acquires an increasing
component of woodland specialist species (as opposed to
generalist species that occur widely in both woodland and
non-woodland habitats). Older forest stands favour
increased diversity because of (i) greater length of time for
colonisation, (ii) increased light penetration to lower
strata, (iii) increased epiphyte biomass and diversity (with
ʻknock-onʼ increases in mass and diversity of other biota),
and (iv) increased amounts of standing and fallen dead
wood. Dead wood forms a major component of the
decomposer food chain, and its presence is vital for
saproxylic invertebrates and fungi, also for many
bryophyte and lichen species. Retention of old stands is
therefore a vital element in promoting diversity within the
forest as a whole.
Gaps and open areas within forests provide a haven for
light-demanding species, and may contain a major
component of the overall biodiversity within a forest area.
Appropriate management of open spaces is vital. For
instance, we found a clear positive relationship between
bird diversity along forest roads and the abundance of
shrubs and self-sown native tree species. The resulting
scrubby fringe provides enhanced diversity in the forestʼs
provision of fruits and seeds, nesting sites, epiphytes, and
invertebrate fauna.
Table 6.1 contains a summary of the management
recommendations that we have identified, lists the
taxonomic groups (where applicable) that each
recommendation arises from, and indicates whether
modifications to official documentation are required.
Recommendations specifically requiring action from one
or more areas of the forest sector are distinguished from
those with a more general remit that apply not only to
forestry, but also to other sectors, in particular to local and
national government, and to universities and others
engaged in biodiversity research. Although a given
recommendation may originate from the results of a
particular taxonomic group, implementation of the
recommendation will often benefit the biodiversity of other
groups. Recommendations are divided into five
categories: (i) those dealing with strategic forest planning,
(ii) those dealing with biodiversity assessments of areas
for which proposals have been made to plant new forests,
(iii) those dealing with planning, planting and
establishment of new forests, (iv) those dealing with
management in existing forests, and (v) those which
suggest future areas of research.
For practical management purposes, and for ease of
ensuring regulatory compliance it is desirable to have
simple criteria, such as requirements for fixed
percentages of open space. However, in the application of
ecological management principles, there will always be
exceptions to simple rules. Where our recommendations
include specific criteria, these should be interpreted as
general principles, and provision should be made for
exceptions. In particular, priority should usually be given
to existing features of biodiversity importance.
We make the following recommendations subject to the
limitations of this project. Like any biodiversity study we
had to be selective about the taxonomic groups that we
studied. Other taxa, including arboreal spiders, host-
specific phytophagous invertebrates and fungi, could
show other effects of forest type and management. The
plantations we studied were composed of a limited range
of tree species and environmental situations. Caution
should be applied when extrapolating our results and
recommendations to other forest and habitat types. Our
study of open space focused on sections of forest roads
and rides that were predominantly orientated east–west,
so the precise quantitative form of the relationships we
found may not apply to sections of forest roads and rides
that are orientated generally north–south. Some of the
forest planning recommendations may apply to
Biodiversity in Irish plantation forests
37
Table 6.1. Summary of management recommendations. Recommendations are further explained in Sections 6.1–
6.5. The source and, where applicable, the number of each recommendation in the source report is given as
follows: R, recommendation from review of pre-afforestation biodiversity assessment procedure (Gittings
et al
.,
2004); O, objective from review of pre-afforestation biodiversity assessment procedure (Gittings
et al
., 2004); A,
biodiversity assessment of afforestation sites (Smith
et al
., 2006); B, assessment of biodiversity at different
stages of the forest cycle (Smith
et al
., 2005); C, investigation of experimental methods to enhance biodiversity
(Iremonger
et al
., 2006); and H, the distribution of Hen Harriers in Ireland in relation to land-use cover (Wilson
et
al
., 2005). Where applicable, the taxa on which each recommendation is based are given as V, vegetation; S,
spiders; H, hoverflies; and B, birds. The remit of each recommendation is classed as applying principally to the
forest industry (F) or more generally, including to governmental or other non-forestry groups (G).
Recommendations requiring modification to specific documentation are indicated as follows: E, EIA
Advice
Notes
; F,
Forest Biodiversity Guidelines
.
Recommendation Source Taxa Remit Modify
Strategic forest planning
1 Require all non-urban local authorities to prepare Indicative Forestry Strategies R2 G
2 Compile specialist reports identifying biodiversity constraints outside designated sites R3 G
3 Complete countywide habitat surveys and biodiversity action plans and establish a
biological records centre
O1 G
4 Survey invertebrate biodiversity in semi-natural habitats of conservation importance O2 G
5 Establish ecological advisory units in each local authority O3 G
6 Establish a system of professional accreditation for ecological consultants in Ireland O4 G
7 Incorporate requirements for biodiversity assessment (in 21, below) in Environmental
Impact Assessment (EIA)
Advice Notes
O5 G E
8 Develop guidelines for the choice of invertebrate taxa for EIAs O6 G E
9 Develop a more thorough classification of vegetation communities in Ireland O7 G
10 Afforestation and agricultural improvement should be regulated in areas with Hen Harriers H1 BF, G
11 Develop a mosaic of different stand age classes in heavily afforested areas occupied by
Hen Harriers
H3 B F
Pre-afforestation site assessment
12 Develop screening criteria to identify afforestation projects requiring a sub-threshold EIA R1 F F
13 Forest Service should employ ecologists R4 F
14 Pre-afforestation site surveys should map habitats using a standard classification and
note the presence of indicators and other biodiversity features
R5, A1, A3 F F
15 Consider site biodiversity in context of the surrounding landscape prior to afforestation A3 F F
16 Foresters submitting grant applications should have completed accredited ecological
training courses or employ qualified ecologists
R6 F F
17 A sample of grant applications from each self-assessment company to be inspected by a
Forest Service ecologist
R7 F F
18 More comprehensive consultation procedures for grant applications R8 G F
19 Local authorities to comment on conservation issues pertaining to grant applications R9 G F
20 Refer applications where biodiversity concerns have been raised to a Forest Service
ecologist to determine whether a more thorough assessment is required
R10 F F
21 Biodiversity assessments in afforestation Environmental Impact Statement (EISs) must
conform to specified standards
R11 F E
22 Biodiversity assessments contained in EISs to be reviewed by a Forest Service ecologist,
or an accredited external ecologist
R12 F E
23 Proposed changes in land use should be regarded as being potentially damaging to Hen
Harriers if they decrease the proportion of suitable habitat to below 30%
H2, H4 B G
S. Iremonger et al., 2000-LS-3.1-M2
38
Table 6.1.
Contd
.
Recommendation Source Taxa Remit Modify
Forest establishment
24 Semi-natural habitats should not be afforested, unless there are mitigating circumstances B1, A2, A3 V, H , B F F
25 Establish plantations in close proximity to semi-natural woodland B2 V F F
26 Create a mosaic of stands of different age and structure at the landscape scale B3 V, S, H, B F
27 Include a mixture of canopy species when planting B4 V, S , H F
28 Review the adequacy of the existing requirement for 5–10% open space in the
Forest
Biodiversity Guidelines
C S F F
29 Stipulate a minimum width of 15 m for linear open-space features included in the ABE C, A4, A6 V, H F F
30 Leave small unplanted areas to maintain gaps through the forest cycle B5 V, S, H, B F F
31 Leave small areas of wet habitat and avoid drainage where possible B6, A4, C H F F
32 Include open space within broadleaved component of plantation B7 H F F
33 Retain scrub, hedgerows and other marginal and additional habitats and allow for
adequate buffer zones
B8, A4 B F
34 Design complex edges to plantations to increase proportion of edge habitat B9 B F F
35 Leave boundaries unplanted to allow development of complex edge structure B10 B F F
Forest management
36 Provide guidelines to help foresters to identify potentially important habitats for ground
flora, spider and hoverfly diversity
B11 V, S, H F F
37 Rigorously thin Sitka spruce forests to prevent canopy closure B12 V, S, H F F
38 Promote broadleaved woody vegetation in young conifer plantations B13, A5, C H, B F F
39 Ensure grazing pressure is low enough to allow broadleaved tree and shrub vegetation to
develop
CV, H , B F
40 Retain mature Sitka spruce stands, where there is no risk of damage to adjoining semi-
natural habitats
B14 V, S F F
41 Retain large diameter dead wood B15 V, H F F
Future research
42 Test and refine the indicators identified in this project A7, B16 G
43 Conduct a comprehensive national survey and classification of grasslands A8, B17 G
44 Investigate forestry and biodiversity at whole-farm and landscape scales A9 G
45 Investigate the implications for biodiversity of different tree species mixtures B18, C G
46 Investigate the biodiversity of open spaces in plantations in agricultural lowland
landscapes
C G
47 An investigation of the biodiversity of over-mature commercial plantations B19 G
48 A study of the biodiversity of second-rotation forests B20 G
49 A study of the biodiversity in forests under continuous cover management B21 G
50 Monitor forest biodiversity in permanent plots B22 G
51 Investigate the inclusion of native woodland elements into commercial plantations B23 G
52 Further investigate the biodiversity of different open-space habitats within forests C G
53 Determine the influence of grazing pressure on broadleaved tree and shrub vegetation in
open spaces
C G
54 Investigate the biodiversity of other taxa found in Irish forests and afforested habitats C G
55 Develop a custom-designed GIS for analysis of habitat in areas with Hen Harriers H6 B G
56 Collect more detailed habitat data from the areas with Hen Harriers H7 B G
57 Improve our understanding of Hen Harrier habitat requirements H8 B G
Biodiversity in Irish plantation forests
39
reforestation projects as well as afforestation, but it should
be recognised that these recommendations are based
exclusively on data from first-rotation forests.
For the remainder of this chapter, the term ʻ
Guidelines
ʼ
refers to the
Forest Biodiversity Guidelines
(Forest
Service, 2000c).
6.1 Strategic Forest Planning
1. Require all non-urban local authorities to
prepare Indicative Forestry Strategies. See
below.
2. Compile specialist reports identifying
biodiversity constraints outside designated sites
as part of the preparation of Indicative Forestry
Strategies. See below.
3. Complete countywide habitat surveys and
biodiversity action plans and establish a
biological records centre.1See below.
The above three recommendations are aimed at
improving the background information on biodiversity
available to people assessing whether or not a site should
be planted. There are currently almost no data available
for evaluation of biodiversity importance outside of
designated sites. For most sites with semi-natural habitat,
these recommendations would mean that some
evaluation of their biodiversity importance would be
possible.
4. Survey invertebrate biodiversity in semi-natural
habitats of conservation importance. The current
lack of information on Irelandʼs invertebrate fauna
makes it hard to decide what taxa should be
focussed on by any pre-afforestation assessment,
and almost impossible to interpret the findings of
many such assessments, in terms of a siteʼs
biodiversity value, especially at regional and local
scales.
5. Establish ecological advisory units in each local
authority. So far, Heritage Officers with ecological
experience have been appointed to some local
authorities. However, many other local authorities
remain without any in-house ecological expertise. At
present, local authorities are not encouraged to
comment on afforestation grant applications, but in
the event that this changes (see Recommendation
19, below), such expertise will enable local
authorities to make invaluable contributions during
the consultation phase of assessments.
6. Establish a system of professional accreditation
for ecological consultants in Ireland, with the
ecological components of all Environmental Impact
Assessments carried out only by professionally
accredited consultants.
7. Incorporate requirements for biodiversity
assessment contained (in 21, below) in
Environmental Impact Assessment (EIA)
Advice
Notes
.See Recommendation 21, below.
8. Develop guidelines for the choice of invertebrate
taxa for EIAs. At present, choice of taxa for pre-
afforestation assessments is made almost solely on
the basis of logistical considerations such as
timescale, costs and available expertise. However,
only taxa that are able to distinguish sites of high
biodiversity importance should be considered
suitable for such assessments. As such, appropriate
taxa may well depend on the habitat type of the
proposed afforestation site. Variation in species
assemblages within and between habitats is poorly
known for most invertebrate taxa in Ireland, so the
development of guidelines may need to be preceded
by thorough, habitat-stratified surveys.
9. Develop a more thorough classification of
vegetation communities in Ireland, perhaps along
the same lines as the UK National Vegetation
Classification.
10. Afforestation and agricultural improvement
should be regulated in areas with Hen Harriers, to
minimise further decreases in their carrying capacity
for this species. Wherever possible, afforestation in
these areas should target improved agricultural land,
rather than areas of bog and rough pasture, which
are used by Hen Harriers for foraging. The level of
afforestation which is acceptable from a Hen Harrier
point of view depends on the value to Hen Harriers of
the remaining unforested habitat and, critically, on
the value of young second-rotation forests (see
1. The Irish National Biodiversity Data Centre was officially
opened in January 2007 on the Carriganore Campus of the
Waterford Institute of Technology. The Centreʼs duties cover
the collection of records from public bodies and private
collectors, their validation, collation, classification and
digitisation plus education, research and training in
biodiversity.
S. Iremonger et al., 2000-LS-3.1-M2
40
Recommendation 57, below).
11. Develop a mosaic of different stand age classes
in heavily afforested areas occupied by Hen
Harriers. Though more research is needed to
confirm this, current indications are that young
second-rotation forests can provide valuable nesting
and foraging habitat. If this is the case, then
minimising the proportion of forest that is under
closed canopy at any one time will maximise the
long-term carrying capacity of an area for Hen
Harriers, by avoiding ʻbottleneckʼ periods during
which availability of young second-rotation forest is
particularly low.
6.2 Pre-Afforestation Site Assessment
12. Develop specific screening criteria to identify
afforestation projects requiring a sub-threshold
EIA. The general absence of background
information on biodiversity in Ireland, and the
relatively high threshold for EIA, mean that it is
imperative that afforestation projects in sites of
potentially high biodiversity importance are flagged
for more detailed scrutiny.
13. Forest Service should employ ecologists. The
recent employment of an ecologist by the Forest
Service was a welcome development. However,
more than one ecologist would be needed to
adequately cope with the remit of Recommendations
17, 20 and 22, below.
14. Pre-afforestation site surveys should map
habitats using a standard classification and note
the presence of indicators and other biodiversity
features. The
Guidelines
should be revised to
contain precise definitions, based upon the Heritage
Council classification (Fossitt, 2000), of the habitats
which are required to be mapped. However, as this
classification scheme does not discriminate well
between some habitat sub-types that differ in
biodiversity, the development of an in-house
modification of the classification for use by foresters
should be considered. Also, the total extent of these
habitats within a site should be mapped (not just the
15% ABE), and the fauna necessary to record should
also be specified.
15. Consider site biodiversity in context of the
surrounding landscape prior to afforestation. In
general, areas of semi-natural habitats in areas of
intensive agriculture, forestry or other highly altered
landscapes should not be afforested. On the other
hand, where a particular semi-natural habitat is
abundant, afforestation of this habitat will not
generally have significant negative impacts on local
biodiversity. However, foresters and forestry
inspectors should be aware of the cumulative effects
of individual afforestation projects on landscape
biodiversity.
16. Foresters submitting grant applications should
have completed accredited ecological training
courses or qualified ecologists should complete the
relevant sections of the applications. This would
greatly increase the quality of information submitted
to the Forest Service by the Competent Foresters
who collect this information, addressing one of the
main deficiencies in biodiversity assessment for
afforestation projects in Ireland.
17. A sample of grant applications from each self-
assessment company to be inspected by a
Forest Service ecologist. Self-assessment could
be a very effective way for the Forest Service to save
on limited time and human resources, while ensuring
a high standard of ecological assessment. However,
in order for this to be the case, self-assessment
companies must be monitored to ensure that the
quality of their ecological assessments is
acceptable.
18. More comprehensive consultation procedures
for grant applications. Some biodiversity features
such as rare plants or invertebrates will not easily be
picked up by initial site surveys. Many sites
containing such features will already be known to
members of the public, to NGOs and to locally based
branches of statutory bodies. Consultation
procedures for grant applications should be
amended to include posting of fuller details of
applications on the Forest Service website,
circulation of weekly lists of applications to local
authorities, NPWS and any other bodies on request,
and availability of full details of each application for
inspection in the local Forest Service office.
19. Local authorities to comment on conservation
issues pertaining to grant applications. In the
past, local authorities have not had in-house
technical expertise available, but the appointments
Biodiversity in Irish plantation forests
41
of Heritage Officers have begun to remedy this
deficiency. In conjunction with the previous
recommendation, and Recommendation 5, above,
this recommendation will help to close the
consultation gap that currently exists in relation to
non-designated sites.
20. Refer applications where biodiversity concerns
have been raised to a Forest Service ecologist to
determine whether a more thorough assessment
is required. Only 15% of afforestation sites are
designated as ABEs, so the decision as to whether
or not to afforest a site where more than 15%
consists of habitats of high biodiversity value should
be carefully considered in the context of the
habitat(s) involved, and the surrounding landscape
matrix. Regardless of how abundant it is in the
landscape, certain habitat types should never be
afforested, such as priority habitats listed in the EU
Habitats Directive
21. Biodiversity assessments in afforestation
Environmental Impact Statement (EISs) must
conform to specified standards. Surveys should
include adequate scoping and description of the
scoping process. All available background
information should be used, and advice sought from
a wide range of consultees. Surveys should be
focused on taxa relevant to biodiversity issues
associated with afforestation, and consideration
given to the trade-off between completeness of
species list and assessment of abundances.
Standard habitat classifications and survey
methodologies should be used, and full
documentation of methodologies and effort included
in ecological reports.
22. Biodiversity assessments contained in EISs to
be reviewed by a Forest Service ecologist, or an
accredited external ecologist. Even for someone
with a high level of ecological knowledge, it can be
hard to accurately assess the standard of a
biodiversity assessment from a report. For someone
with a non-ecological background, it is unreasonable
to expect that they will be able to discriminate
between assessments that will be successful in
identifying sites of high biodiversity, and those that
will not.
23. Proposed changes in land use should be
regarded as being potentially damaging to Hen
Harriers if they decrease the proportion of
suitable habitat in areas with Hen Harriers to
below 30%. The results of our study suggest that 3
km2 may be an appropriate scale at which to
evaluate habitat composition within these areas.
Until our understanding of the value of second-
rotation forests for foraging and nesting is improved,
a combined limit of substantially less than 70%
should apply to improved agricultural land and
plantation forestry in areas with Hen Harriers.
6.3 Forest Establishment
24. Semi-natural habitats should not be afforested,
unless there are mitigating circumstances. The
Guidelines
recommend that “
local biodiversity
factors (including habitats and species of particular
interest)
” should be identified and incorporated into
the site development plan, but do not explicitly
consider the choice of sites for afforestation.
Therefore, the
Guidelines
should recommend that,
where possible, improved grassland or arable land
should be used for afforestation instead of semi-
natural habitats, particularly in landscapes
dominated by intensive farming. Priority habitats
listed in the EU Habitats Directive (European
Commission, 1999) should not be afforested,
regardless of whether they are part of a designated
site, or how common they are in the surrounding
landscape.
25. Establish plantations in close proximity to semi-
natural woodland. We recommend that plantations
be established in close proximity to semi-natural
woodland, in order to facilitate the establishment in
plantations of woodland plants and other taxonomic
groups with poor dispersal abilities. New plantations
close to semi-natural woodland should preferably be
established and managed under the
Native
Woodland Scheme
(Forest Service, 2001) or be
comprised of species already occurring in the
existing woodland. Plantations comprised of tree
species that are potentially invasive in semi-natural
woodland should not be located near one.
26. Create a mosaic of stands of different age and
structure at the landscape scale. The
recommendation in the
Guidelines
to promote age
and structural diversity at the landscape scale is
supported by the results from all taxonomic groups.
S. Iremonger et al., 2000-LS-3.1-M2
42
A diverse forest structure should be implemented at
the planning stage of afforestation. Planning a
mosaic of stands of different ages and structural
stages may be difficult in some landscapes where
forest parcels have several different owners.
27. Include a mixture of canopy species when
planting. The recommendation in the
Guidelines
for
diversity of canopy species within a forest is
supported by the results of this research. Only non-
intimately mixed forests (i.e. adjacent single-species
blocks) were studied, however, and therefore we can
make no conclusions or recommendations on
intimate mixtures of tree species (see
Recommendation 45 below).
28. Review the adequacy of the existing requirement
for 5–10% open space in the
Forest Biodiversity
Guidelines.
Plantations are required to contain 5–
10% open space, except in plantations of less than
10 ha in size. In some plantations, larger amounts of
open space should be considered. However, the
contribution of the open-space habitat within forest
plantations to biodiversity at the landscape level
must be considered, and a universal prescription for
total amount of open space at the plantation scale
may not be appropriate.
29. Stipulate a minimum width of 15 m for linear
open-space features included in the Area for
Biodiversity Enhancement. The typical width of
forest ridelines is only 6 m (Forest Service, 2003)
and forest drains are normally associated with little or
no increase in tree spacing. Such gaps are too
narrow to be treated as open space from a
biodiversity perspective. Forest road widths of
greater than 15 m would enhance biodiversity for
some groups (e.g. flora and invertebrates) but such
widths are generally avoided because wide verges
are difficult for machinery to cross during harvesting.
A compromise could be to develop forest roads with
wide scallops, i.e. alternating sections of road of
standard and wide widths. This could also benefit
biodiversity by reducing wind-tunnel effects and by
increasing the length of forest edge habitat.
30. Leave small unplanted areas to maintain gaps
through the forest cycle. Although there is no
minimum size for ABEs, in practice this requirement
is interpreted through the retention of one or a few
discrete patches of habitat that, for ease of mapping,
are usually a minimum of 0.16 ha. However, even
very small areas of open space (e.g. less than 400
m2) may promote biodiversity, especially at the
thicket stage. Such open spaces should be widely
scattered through the forest and should be
incorporated into plantations less than 10 ha in size.
31. Leave small areas of wet habitat unplanted and
avoid drainage where possible. Small, wet habitat
features can support hoverflies as well as other
invertebrate and plant species. Ground preparation
and other types of drainage should be avoided in or
near small wet areas. Planting should be set back so
that these habitats are not shaded out by the trees as
they mature. If the biota they support is not
dependent on open conditions, wet habitat features
may be planted (without ground preparation) with
suitable native tree species to create a wet
woodland.
32. Include open space within broadleaved
component of plantation. Where ash is the 10%
broadleaved component of a conifer plantation, the
inclusion of an area of open space large enough to
allow the development of grassy clearings can
provide habitat for some hoverfly species that do not
normally occur in conifer plantations. Therefore, the
Guidelines
should recommend that at least some of
the open space and broadleaf components be
placed together, where possible.
33. Retain scrub, hedgerows and other marginal and
additional habitats and allow for adequate buffer
zones. Our research has demonstrated the
biodiversity value at the site and landscape scales of
marginal and additional habitats, such as
hedgerows, scrub, streams, ponds, stone walls,
earthbanks and others. These and other semi-
natural habitats described in Fossitt (2000) should
also be given specific mention in the
Guidelines
.
Scrub should not be removed or planted and should
be included as a retained habitat in ABEs. Planting
should be set back so that these habitats are not
shaded out by the trees as they mature. Where the
area of marginal and additional habitats plus buffers
exceeds the required 15% ABE area, the decision of
whether or not to plant should be carefully
reconsidered.
34. Design complex edges to plantations to increase
proportion of edge habitat. See below.
Biodiversity in Irish plantation forests
43
35. Leave boundaries unplanted to allow
development of complex edge structure. See
below.
The quantity and quality of edge habitat for birds would be
improved by establishing irregular external and internal
forest edges (e.g. along roads and rides), encouraging
heterogeneity of structure and species composition and
leaving a wide, unplanted margin between the forest edge
and the forest boundary or fence. These
recommendations are also included in the
Forestry and
Bird Diversity in Ireland
guide (OʼHalloran
et al
., 2002),
and are in broad agreement with existing
recommendations of the
Forestry and the Landscape
Guidelines
(Forest Service, 2000d).
6.4 Forest Management
36. Provide guidelines to help foresters to identify
potentially important habitats for ground flora,
spider and hoverfly diversity. At present, the
Guidelines
only contain guidance on identifying
important habitats at the pre-planting stage, and
even this guidance is problematic (Gittings
et al
.,
2004). For SFM, it is important for foresters to be
able to identify potentially important habitats and
indicators within established forests that need
special consideration. In order to able to do this,
foresters should be given adequate guidance and,
where necessary, training.
37. Rigorous thinning of Sitka spruce forests to
prevent canopy closure. Early and frequent
thinning of Sitka spruce forests to prevent complete
canopy closure would promote ground flora diversity
and create a habitat for spiders and hoverflies.
However, this is contrary to what is considered to be
silvicultural best practice. Such a thinning regime
may be applied to parts of larger forests or to the
whole of particular forests, such as those with good
biodiversity potential or those receiving significant
amenity use, and avoided in areas with significant
windthrow risk.
38. Promote broadleaved woody vegetation in
young conifer plantations. Broadleaved shrubs
and trees make important contributions to forest
biodiversity. The
Guidelines
should include more
specific guidelines on how to encourage shrub and
non-crop tree patches/stands in plantations. Pre-
existing shrubs (including bramble) and saplings
should be retained within conifer plantations, and
natural regeneration should be encouraged,
providing open spaces nearby existing broadleaved
seed sources. Clearance or damage of scrub along
roadsides and during thinning should be avoided
where possible, in which case mechanical clearance
methods should be used in preference to herbicides.
39. Ensure grazing pressure is low enough to allow
broadleaved tree and shrub vegetation to
develop. Our study was not designed to investigate
the effect of grazing on forest biodiversity. However,
levels of grazing differed markedly among our study
sites, and may have been responsible for some of
the differences we observed in the plant species
assemblages, vegetation structure and hoverfly and
bird diversity. More research needs to be done to
determine the optimal grazing regimes for
biodiversity in forest open spaces.
40. Retain mature Sitka spruce stands, where there
is no risk of damage to adjoining semi-natural
habitats. Structurally mature plantations are
particularly important for vascular plants, bryophytes
and spiders with strong woodland affinities. The
Guidelines
should encourage the retention of some
mature stands or even small groups of trees beyond
the normal felling age, except where there is a risk of
exotic tree regeneration in adjacent semi-natural
habitats such as woodlands, bogs and heathlands.
Ideally, plantations selected for retention should
have indicators associated with high botanical and
spider biodiversity, and should harbour large
diameter dead wood.
41. Retain large diameter dead wood. Although the
Guidelines
recognise the importance of retaining
dead wood, they do not specify the type(s) of dead
wood that should be retained. Our results indicate
that, in Sitka spruce stands, large diameter dead
wood supports more and rarer species of saproxylic
hoverfly and bryophytes than small diameter dead
wood. The
Guidelines
should require that the
specified volumes of dead wood retained after
thinning and felling be comprised of trees and
branches greater than 7 cm diameter and preferably
greater than 20 cm diameter.
6.5 Further Research
42. Test and refine the indicators identified in this
S. Iremonger et al., 2000-LS-3.1-M2
44
project. Further trials using independent data are
needed to determine how many indicators in which
categories best discriminate between high and low
biodiversity sites. More indicators are needed for
ecological situations not included in this study, such
as in open habitats like dry-humid acid grassland and
dry heath, in forests composed of species other than
Sitka spruce and ash, and in second-rotation forests.
43. Conduct a comprehensive national survey and
classification of grasslands. The classification of
grasslands in the Irish scheme (Fossitt, 2000) is
inadequate to describe the biodiversity of semi-
natural grasslands, making it hard or impossible to
identify grasslands of conservation value that should
not be subject to afforestation. We therefore
recommend that a comprehensive national survey,
analysis and classification of semi-natural
grasslands be undertaken, and that indicators be
developed to enable non-specialists to identify
grasslands of potential conservation value.
44. Investigate forestry and biodiversity at whole-
farm and landscape scales. Important research
questions include but are not limited to the following.
What are the effects of afforestation in landscapes of
varying forest cover? What are the effects of different
age and species compositions of forest on
biodiversity at the farm and landscape scales? Can
forests act as corridors between habitats of
conservation importance? What factors influence the
immigration of species into plantations from the
wider landscape?
45. Investigate the implications for biodiversity of
different tree species mixtures. In this study, we
were constrained by time and resources to
investigate only non-intimate mixtures of Sitka
spruce and ash. The biodiversity of mixed stands
may be different, especially with regard to canopy
cover. We recommend that a study on the
biodiversity of popular conifer species mixes and
conifer–broadleaf mixes be researched. Comparison
should be made between single-species stands,
intimate mixtures and intermediate situations.
46. Investigate the biodiversity of open spaces in
plantations in agricultural lowland landscapes.
Our study was restricted to plantations in upland
landscapes, but a large proportion of future
afforestation is likely to take place in more-or-less
intensively farmed lowland landscapes. We should
therefore conduct research to generate
management guidelines to realise the potential of
such forests. Such research should take into account
the open habitats present in the landscape outside
the forest boundary and differing agricultural
management regimes (e.g. REPS and non-REPS
farms).
47. An investigation of the biodiversity of over-
mature commercial plantations. The biodiversity
of over-mature commercial forests should be
investigated, in order to determine how long such
stands should be left to enhance the biodiversity
value of the forest. The role of over-mature
plantations as a species source for colonisation of
adjacent reforestation areas should also be studied.
48. A study of the biodiversity of second-rotation
forests. Though many commercial forests in Ireland
are now in their second rotation, we know almost
nothing about how the biodiversity of second-rotation
forests compares to that of first-rotation forests. It is
vital to know how biodiversity changes with each
felling cycle, and how it is affected by aspects of
second-rotation management such as ground
preparation, brash management, dead wood
retention and proximity to retained first-rotation
stands.
49. A study of the biodiversity in forests under
continuous cover management. Clear-fell
represents the predominant management type in
Irish forestry. Some research on silvicultural aspects
of continuous cover systems is being carried out in
Ireland, but the biodiversity implications of such
management are not known. Research on the
biodiversity of forests under different continuous
cover systems should be carried out, perhaps using
silvicultural forest plots already in existence if these
are suitable.
50. Monitor forest biodiversity in permanent plots.
This study examined biodiversity over the forest
cycle by substituting sites in different stages of
maturity for time. However, a more powerful study
would investigate how forest biodiversity changes
over the life cycle of a particular forest. State-owned
biodiversity monitoring sites should be established to
this end, incorporating a representative range of
climate conditions, soil types and canopy species.
Biodiversity in Irish plantation forests
45
Appropriate project management and funding
structures should be put in place to ensure long-term
continuity of this research.
51. Investigate the inclusion of native woodland
elements into commercial plantations. One
method of enhancing the native biodiversity of
commercial forestry plantations could be the planting
of small areas of native woodland for long-term
retention within the plantation. These could support
woodland species that may not otherwise be able to
exist in plantations of non-native species. The effects
on forest biodiversity of distance from sources of
woodland species and location of copses within a
plantation should be studied.
52. Further investigate the biodiversity of different
open-space habitats within forests. The focus of
our project was on identifying relationships between
biodiversity and open-space amounts and
configuration. Therefore, to achieve adequate
replication, and to avoid confounding factors, we
focused on widespread and mundane open-space
habitats. Research into the biodiversity of more
interesting open-space habitats would help develop
guidelines for the management of important retained
habitats.
53. Determine the influence of grazing pressure on
broadleaved tree and shrub vegetation in open
spaces. See Recommendation 39, above.
54. Investigate the biodiversity of other taxa found in
Irish forests and afforested habitats. Research on
the biodiversity of other taxonomic and functional
groups that are likely to have different ecological
responses to the aspects of forest management
addressed by this project would be useful. These
could include: epiphytes on broadleaved trees and
shrubs, fungi, spider fauna in shrubs and trees,
moths and ground beetles. Moths and ground
beetles have already been extracted from our
Malaise trap and pitfall trap samples and could,
therefore, be investigated relatively easily.
The following three measures address two main aims
regarding future research on Hen Harriers – to generate
information needed to implement the management
prescriptions we have recommended, and to improve our
understanding of Hen Harrier habitat requirements,
particularly with respect to second-rotation forest. The
latter aim can be achieved both directly, through
increases in our understanding of Hen Harrier ecology,
through the provision of data that can be used to test and
refine the predictions of the Hen Harrier habitat
requirement models.
55. Develop a custom-designed GIS for analysis of
habitat in areas with Hen Harriers. This would
allow the effects of a proposed change in land use on
the proportion of existing and future suitable habitat
cover in the surrounding area to be easily evaluated
in the context of existing land uses.
56. Collect more detailed habitat data from areas
with Hen Harriers. This should include an inventory
of all forests with planting species, planting year and
projected felling year, and more detailed and
accurate information on unplanted habitats than
were available for this study.
57. Improve our understanding of Hen Harrier
habitat requirements. This could be done through a
combined satellite- or radio-tracking study of
foraging adults, and monitoring of the fledging
success of Hen Harrier nests in different habitat
configurations.
S. Iremonger et al., 2000-LS-3.1-M2
46
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48
Appendix 1 Project Outputs
The three sub-projects described above generated a
huge amount of data, for which an interactive, GIS-based
database was custom-built. This will be restricted to use
by EPA- and COFORD-approved researchers for a year
from submission: after this time has expired it will be made
available to the general public through the EPA.
During the project a variety of outputs was generated.
Apart from the six-monthly Technical Reports required to
fulfil the contractual obligations, outputs were many in the
form of oral and written communications. These are listed
below under different category headings. In addition to
these the BIOFOREST Website was created and
maintained at http://bioforest.ucc.ie, and many of the
listed outputs are available on that.
Special Reports
Gittings, T., McKee, A.-M., OʼDonoghue, S., Pithon, J., Wilson,
M., Giller, P.S., Kelly, D.L., OʼHalloran, J., Mitchell, F.J.G.,
Iremonger, S., OʼSullivan, A. and Neville, P., 2004.
Biodiversity Assessment in Preparation for Afforestation: A
Review of Existing Practice in Ireland and Best Practice
Overseas.
Report prepared for COFORD and the EPA,
Dublin, Ireland.
Wilson, M., Gittings, T., O'Halloran, J., Kelly, T. and Pithon, J.,
2005.
The Distribution of Hen Harriers in Ireland in Relation
to Land-Use Cover in General and Forest Cover in
Particular.
Report prepared for COFORD and the EPA,
Dublin, Ireland.
End-of-Project Technical Reports
Iremonger, S., Gittings, T., Smith, G.F., Wilson, M.W., Oxbrough,
A., Coote, L., Pithon, J., O'Donoghue, S., McKee, A.-M.,
O'Halloran, J., Kelly, D.L., Giller, P.S., O'Sullivan, A., Neville,
P., Mitchell, F.J.G., O'Donnell, V., Kelly, T.C. and Dowding,
P., 2006.
Investigation of Experimental Methods to Enhance
Biodiversity in Plantation Forests
.
BIOFOREST Project 3.1.3
Final Report
. Report prepared for COFORD and the EPA.
Smith, G.F., Gittings, T., Wilson, M.W., French, L., Oxbrough, A.,
OʼDonoghue, S., Pithon, J., OʼDonnell, V., McKee, A.-M.,
Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell, F.J.G.,
Giller, P.S. and Kelly, T., 2005.
Assessment of Biodiversity at
Different Stages of the Forest Cycle. BIOFOREST Project
3.1.2 Final Report
. Report prepared for COFORD and the
EPA.
Smith, G.F., Gittings, T., Wilson, M.W., Oxbrough, A., Iremonger,
S., O'Donoghue, S., McKee, A.-M., O'Halloran, J., Kelly,
D.L., Pithon, J., O'Sullivan, A., Neville, P., Mitchell, F.J.G.,
Giller, P.S., O'Donnell, V. and Kelly, T.C., 2006.
Biodiversity
Assessment of Afforestation Sites. BIOFOREST Project
3.1.1 Final Report
. Report prepared for COFORD and the
EPA.
Database
OʼDonnell, V., Cummins, V., Wilson, M.W., Gittings, T.,
Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell, F.J.G.,
Giller, P.S., Smith, G., Oxbrough, A., Coote, L., French, L.,
OʼDonoghue, S., McKee, A.-M., Pithon, J., OʼSullivan, A.,
Neville, P., Kelly, T. and Dowding, P., 2006.
The
BIOFOREST Database
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the EPA.
PhD Theses
Coote, L., 2007.
Epiphyte Diversity in Irish Plantation Forests.
PhD Thesis, Trinity College, University of Dublin, Ireland.
French L., 2005.
Ground Flora Communities in Irelandʼs
Plantation Forests: their Diversity, Structure and
Composition
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MSc Theses
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Environmental Sciences degree thesis,
ETH, Zürich, Switzerland.
Buscardo, E., 2005.
The Effects of Afforestation on Biodiversity
of Grasslands in Ireland
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Portugal.
Tiernan, D., 2002.
Relationships between Sitka Spruce Forest
Flora and Surrounding Land Cover Patterns
. Environmental
Resource Management MSc degree thesis, University
College, Dublin, Ireland.
Publications
Coote, L., Smith, G.F., Kelly, D.L., O'Donoghue, S., Dowding, P.,
Iremonger, S. and Mitchell, F.G.J., 2007. Epiphytes of Sitka
spruce (
Picea sitchensis
) plantations in Ireland and the
effects of open spaces.
Biodiversity and Conservation
. In
press.
Gittings, T., Giller, P.S. and OʼHalloran, J., 2005. Notable
hoverfly (Diptera: Syrphidae) records, 2001–2002.
Irish
Naturalistsʼ Journal
28(3): 132–133.
Gittings, T., OʼHalloran, J., Kelly, T. and Giller, P.S., 2006. The
contribution of open spaces to the maintenance of hoverfly
(Diptera, Syrphidae) biodiversity in Irish plantation forests.
Forest Ecology and Management
237(1–3): 290–300.
Iremonger, S., Giller, P., OʼHalloran, J., Kelly, D. and Mitchell, F.,
2005. Biodiversity in temperate plantations. In: Mery, G.,
Alfaro, R., Kanninen, M. and Lobovikov, M. (eds)
Forests in
the Global Balance.
IUFRO World Series Volume 17.
Helsinki, Finland, pp. 132–133.
Biodiversity in Irish plantation forests
49
Oxbrough, A.G., Gittings, T., OʼHalloran, J. and Giller, P.S., 2005.
Structural indicators of spider assemblages across the forest
plantation cycle.
Forest Ecology and Management
212(1–
3): 171–183.
Oxbrough, A.G., Gittings, T., OʼHalloran, J., Giller, P.S. and Kelly,
T.C., 2006. The influence of open space on ground-dwelling
spider assemblages within plantation forests.
Forest
Ecology and Management
237(1–3): 404–417.
Oxbrough, A.G., Gittings, T., OʼHalloran, J., Giller, P.S. and Kelly,
T.C., 2006. The initial effects of afforestation on the ground-
dwelling spider fauna of Irish peatlands and grasslands.
Forest Ecology and Management
237(1–3): 478–491.
Oxbrough, A. (in review). Distribution records of some
uncommonly recorded spiders in Ireland including a new
Irish record:
Meioneta mollis
(O.P. Cambridge, 1871)
(Araneae: Linyphiidae).
Irish Naturalists Journal
.
Smith, G.F., Iremonger, S., Kelly, D.L., Mitchell, F.J.G. and
O'Donoghue, S., 2007. Enhancing vegetation diversity in
glades, rides and roads in plantation forests.
Biological
Conservation.
Wilson, M.W., Pithon, J., Gittings, T., Kelly, T.C, Giller, P.S. and
O'Halloran, J., 2006. The effects of growth stage and tree
species composition on breeding bird assemblages of
plantation forests.
Bird Study
53: 225–236.
Conference proceedings
OʼHalloran, J., Gittings, T., Smith, G., Wilson, M., Oxbrough, A.,
OʼDonoghue, S., French, L., Giller, P.S., Iremonger, S.,
Pithon, J., Kelly, D.L., Mitchell, F., Kelly, T., Dowding, P.,
OʼSullivan, A. and Neville, P., 2002.
Biodiversity of plantation
forests in Ireland – the BIOFOREST Project
. In:
Opportunities for Enhancement of Biodiversity in Plantation
Forests.
COFORD Seminar, 24 October, Cork.
Wilson, M.W., Gittings, T., OʼHalloran, J., Smith, G.F., Oxbrough,
A., OʼDonoghue, S., French, L., Giller, P.S., Iremonger, S.,
Pithon, J., Kelly, D.L., Mitchell, F.J.G., Kelly,T.C., Dowding,
P., OʼSullivan, A., Neville, P., McKee, A.-M. and Coote, L.,
2004.
Forestry and biodiversity in Ireland and a case study
of the Hen Harrier (
Circus cyaneus
): BIOFOREST Project.
In:
Forest Research and Development in Ireland 2004 –
Underpinning Industry Development
. Proceedings of the
conference held 20–21 September 2004, Tullamore, Ireland.
Published by COFORD, Dublin.
Presentations
Buscardo, E., Smith, G.F., Kelly, D.L. and Freitas, H., 2005.
The
effects of afforestation on biodiversity of grasslands in
Ireland
. Presentation at conference
Biodiversity and
Conservation Biology in Plantation Forests
, 27–29 April
2005, Bordeaux, France.
Coote, L., Kelly, D.L. and Dowding, P., 2004.
The relations
between epiphyte diversity and plantation forest structure
and composition.
Poster presented at the Irish Plant
Scientistsʼ Annual Meeting, Belfast, 2004.
Coote, L., Kelly, D.L. and Dowding, P., 2005. Epiphytes of Sitka
spruce (Picea sitchensis) in Irish plantation forests.
Presentation at conference
Biodiversity and Conservation
Biology in Plantation Forests
, 27–29 April 2005, Bordeaux,
France.
Coote, L., Kelly, D.L. and Dowding, P., 2005.
Irelandʼs high
frontier: Plants that grow on forest trees and what they tell us
about the environment.
Presentation at British Association
for the Advancement of Scienceʼs
Festival of Science
, Trinity
College, Dublin, September 2005.
Coote, L., Kelly, D.L., Dowding, P., Smith, G.F., OʼDonoghue, S.
and Iremonger, S., 2005.
Epiphytes in the forest – a little
studied species reserve.
Presentation at conference
Biodiversity in Irish Plantation Forests, Portlaoise, 26–27
Oct 2005.
French, L., Smith, G., OʼDonoghue, S., McKee, A.-M.,
Iremonger, S., Kelly, D.L. and Mitchell, F.J.G., 2004.
Biodiversity across the forest cycle in ash and Sitka spruce
plantations: Stand structure and vegetation change.
Paper
presented at the 14th Irish Environmental Researchersʼ
Colloquium (January 2004).
French, L., Smith, G.F., Kelly, D.L., Mitchell, F.J.G., OʼDonoghue,
S., McKee, A.-M., Iremonger, S. and Dowding, P., 2005.
Ground flora diversity over the forest cycle.
Presentation at
conference Biodiversity in Irish Plantation Forests,
Portlaoise, 26–27 Oct 2005.
Giller, P.S., Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell,
F.J.G., Kelly, T.C, Dowding, P., Smith, G.F., Gittings, T.,
Wilson, M.W., Oxbrough, A., French, L., Coote, L.,
OʼSullivan, A., Neville, P., OʼDonoghue, S. and McKee, A.-
M., 2005.
Introduction to the BIOFOREST project, its place
in Irish biodiversity research.
Presentation at conference
Biodiversity in Irish Plantation Forests, Portlaoise, 26–27
Oct 2005.
Gittings, T. Smith, G., Wilson, M.W., French, L., Oxbrough, A.,
OʼDonoghue, S., Pithon, J., OʼDonnell, V., McKee, A.-M.,
Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell, F.J.G. and
Giller, P.S., 2004.
Biodiversity across the forest cycle in ash
and Sitka spruce plantations: Comparison of trends between
taxonomic groups and management recommendations.
Paper presented at the 14th Irish Environmental
Researchersʼ Colloquium (January 2004).
Gittings, T., Oxbrough, A., Giller, P.S., OʼHalloran, J. and Kelly,
T.C., 2005.
Effects of afforestation on invertebrates.
Presentation at conference Biodiversity in Irish Plantation
Forests, Portlaoise, 26–27 Oct 2005.
Gittings, T., Wilson, M.W., OʼDonoghue, S., McKee, A.-M.,
Pithon, J., Iremonger, S., Giller, P.S., Kelly, D.L., J.
OʼHalloran and Mitchell, F.J.G., 2005.
Planning for
biodiversity in the afforestation process.
Presentation at
conference Biodiversity in Irish Plantation Forests,
Portlaoise, 26–27 Oct 2005.
Iremonger, S., Giller, P.S., OʼHalloran, J., Kelly, D.L., Mitchell,
F.J.G., Gittings, T., Wilson, M.W., Smith, G., Oxbrough, A.,
French, L., Coote, L., OʼSullivan, A., Neville, P.,
OʼDonoghue, S., Pithon, J., McKee, A.-M., Kelly, T.C,
Dowding, P., Cummins, V., V. OʼDonnell, V. and
OʼCallaghan, J., 2004.
BIOFOREST: Forestry and
biodiversity in Ireland.
Poster presented at European
Platform for Biodiversity Research meeting, 21–24 May,
Killarney, Ireland.
Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell, F.J.G., Giller,
P.S., Smith, G., Gittings, T., Wilson, M.W., Oxbrough, A.,
Coote, L., French, L., OʼDonoghue, S., McKee, A.-M.,
Pithon, J., OʼSullivan, A., Neville, P., OʼDonnell, V., Kelly, T.
S. Iremonger et al., 2000-LS-3.1-M2
50
and Dowding, P., 2006.
The BIOFOREST Project 2001–
2006. Implications of Results for Policy and Practice.
Presentation to the Irish Forest Service, Johnstown Castle,
Wexford.
Kelly, D.L., 2005.
Mind the GAP! Open spaces in forest and their
role as habitat for plants and animals.
Presentation at British
Association for the Advancement of Scienceʼs
Festival of
Science
, Trinity College, Dublin, September 2005.
Kelly, D.L., French, L., Smith, G.F., Mitchell, F.J.G., OʼDonoghue,
S., McKee, A.-M., Iremonger, S., Coote, L. and Dowding, P.,
2005.
A comparison between plantation forests and other
habitats, including semi-natural woodlands.
Presentation at
conference Biodiversity in Irish Plantation Forests,
Portlaoise, 26–27 Oct 2005.
Kelly, D.L., 2006.
Can Plantation Forests be Havens of
Biodiversity?
The Annual Augustine Henry Forestry Lecture
2006. Lecture to the Society of Irish Foresters, The Royal
Dublin Society, 9 March 2006.
OʼDonnell, V., 2005.
The BIOFOREST Database – innovative
and user-friendly.
Presentation at conference Biodiversity in
Irish Plantation Forests, Portlaoise, 26–27 Oct 2005.
OʼHalloran, J., Gittings, T., Smith, G., Wilson, M.W., Oxbrough,
A., OʼDonoghue, S., French, L., Giller, P.S., Iremonger, S.,
Pithon, J., Kelly, D.L., Mitchell, F., Kelly, T.C, Dowding, P.,
OʼSullivan, A. and Neville, P., 2002.
Biodiversity of plantation
forests in Ireland – The BIOFOREST Project
. Paper
presented at the COFORD conference
Opportunities for
enhancement of biodiversity in plantation forests,
24
October, Cork.
OʼHalloran, J., Iremonger, S., Kelly, D.L., Kelly, T.C, Wilson,
M.W., Smith, G.F., Gittings, T., Coote, L., Oxbrough, A.,
French, L., Mitchell, F.J.G., Giller, P.S., Dowding, P.,
OʼSullivan, A., Neville, P., OʼDonoghue, S. and McKee, A.-
M., 2005.
The burning questions – gaps in knowledge
illuminated by the research to date.
Presentation at
conference Biodiversity in Irish Plantation Forests,
Portlaoise, 26–27 Oct 2005.
Oxbrough, A. Gittings, T., Giller, P.S. and O'Halloran, J., 2004.
Biodiversity across the forest cycle in ash and Sitka spruce
plantations: Effects of Irish forestry on spider communities
.
Paper presented at the 14th Irish Environmental
Researchersʼ Colloquium (January 2004).
Oxbrough, A., Gittings, T., Giller, P.S. and OʼHalloran, J., 2004.
Spider communities as bioindicators in Irish plantation
forests
, Paper presented at the British Ecological Society
Annual meeting in Lancaster, 7–9 September 2004.
Oxbrough, A., Gittings, T., Giller, P.S., OʼHalloran, J. and Kelly,
T.C., 2005.
Effects of open spaces within forests on spider
and hoverfly diversity.
Presentation at conference
Biodiversity in Irish Plantation Forests, Portlaoise, 26–27
Oct 2005.
Smith, G. F., Gittings, T., Wilson, M.W., French, L., Oxbrough, A.,
OʼDonoghue, S., Pithon, J., OʼDonnell, V., McKee, A.-M.,
Iremonger, S., OʼHalloran, J., Kelly, D. L., Mitchell, F.J.G.,
Giller, P.S., OʼSullivan, A., Neville, P. and Kelly, T.C., 2005.
Biodiversity and management across the forest cycle in
even-aged sitka spruce and ash plantations in Ireland.
Presentation at conference
Biodiversity and Conservation
Biology in Plantation Forests
, 27–29 April 2005, Bordeaux,
France.
Smith, G.F., 2005.
Monotony or diversity? what niches do
plantations provide for flora and fauna and how do these
change as the trees mature?
Presentation at British
Association for the Advancement of Scienceʼs
Festival of
Science
, Trinity College, Dublin, September 2005.
Smith, G.F., Gittings, T., Wilson, M.W., French, L., Oxbrough, A.,
OʼDonoghue, S., Pithon, J., V. OʼDonnell, McKee, A.-M.,
Iremonger, S., OʼHalloran, J., Kelly, D.L., Mitchell, F.J.G.,
Giller, P.S., Kelly, T.C, P. Neville and OʼSullivan, A., 2005.
Enhancing biodiversity in plantation forests.
Presentation at
conference Biodiversity in Irish Plantation Forests,
Portlaoise, 26–27 Oct 2005.
Wilson, M.W., Pithon, J., Gittings, T., OʼHalloran, J., Giller, P.S.
and Kelly, T.C., 2004.
Biodiversity across the forest cycle in
ash and Sitka spruce plantations: Effects of Irish forestry on
bird diversity.
Paper presented at the 14th Irish
Environmental Researchersʼ Colloquium (January 2004).
Wilson, M.W., Gittings, T., McKee, A.-M., O'Donoghue, S.,
Pithon, J., Kelly, T.C, Giller, P.S., Norriss, D., Newton, S.,
Collins, K., Iremonger, S., Mitchell, F.J.G. and OʼHalloran, J.,
2005.
Forestry plantations in the landscape: the challenge
for biodiversity conservation.
Presentation at British
Association for the Advancement of Scienceʼs
Festival of
Science
, Trinity College, Dublin, September 2005.
Wilson, M.W., Smith, G.F., Gittings, T., Coote, L., Oxbrough, A.,
French, L., Iremonger, S., OʼHalloran, J., Kelly, D.L.,
Mitchell, F.J.G., Giller, P.S., Kelly, T.C, Dowding, P.,
OʼSullivan, A. and Neville, P., 2005.
Gaps in plantation
forests – a chance for enhancement of biodiversity in the
landscape.
Presentation at conference Biodiversity in Irish
Plantation Forests, Portlaoise, 26–27 Oct 2005.
Wilson, M.W., Gittings, T., Pithon, J., OʼHalloran, J., Giller, P.S.
and Kelly, T.C., 2005.
The Hen Harrier and Irish
FORESTRY.
Presentation at conference Biodiversity in Irish
Plantation Forests, Portlaoise, 26–27 Oct 2005.
Biodiversity in Irish plantation forests
51
Appendix 2 List of Staff
Individuals involved in the BIOFOREST Project met
periodically to plan and review. The following were the
main groups that met.
Research Group:
Department of Zoology, Ecology and Plant Science,
University College, Cork (UCC): Prof. Paul Giller, Prof.
John OʼHalloran, Dr Tom Kelly, Dr Tom Gittings, Dr Mark
Wilson, Dr Josephine Pithon, Dr Anne Oxbrough
Botany Department, Trinity College, Dublin (TCD): Dr
Daniel Kelly, Dr Fraser Mitchell, Dr Paul Dowding, Dr
George Smith, Dr Laura French, Dr Linda Coote, Dr
Susan Iremonger, Dr Anne-Marie McKee and Ms Saoirse
OʼDonoghue
Coillte Teoranta: Dr Aileen OʼSullivan, Mr Pat Neville, Dr
Alistair Pfeifer
Others joined this Research Group at different stages of
the project, in particular:
Coastal and Marine Resources Centre, University
College, Cork: Ms Vicki OʼDonnell, Ms Valerie Cummins
Temporary research students and associates:
Ms Erika Buscardo, Ms Jacqueline Bolli, Ms Julianna
OʼCallaghan
Management Group:
COFORD: Joe OʼCarroll, Dr Eugene Hendrick
EPA: Dr Helen Walsh, Dr Conor Clenaghan, Dr Garret
Kilroy, Dr Karl Richards
UCC: Prof. Paul Giller, Prof. John OʼHalloran, Dr Tom
Gittings
TCD: Dr Daniel Kelly, Dr George Smith
Coillte: Dr Aileen OʼSullivan
Project manager: Dr Susan Iremonger
Steering Group:
This group was composed of the other two groups, plus:
National Parks and Wildlife Service: Dr John Cross
Forest Service: Noel Foley
Forestry Commission (UK): Dr Jonathan Humphrey
University of Helsinki (Finland): Dr Jari Niemelä
European Environment Agency (Denmark): Dr Tor-
Björn Larsson
Centre for Ecology and Hydrology (UK): Dr Allan Watt
Environmental Research Technological Development
and Innovation (ERTDI) Programme 2000-2006
Environmental Protection Agency
Regional Inspectorate, McCumiskey House, Richview, Clonskeagh Road, Dublin 14, Ireland
Telephone: +353 (0)1 268 0100 Fax: +353 (0)1 268 0199 Website: www.epa.ie
Printed on recycled paper
ERTDI Report Series No. 51
BIODIVERSITY IN IRISH
PLANTATION FORESTS
Final Report
Environmental Research Technological Development and Innovation (ERTDI)
Programme 2000-2006
The Environmental Research Technological Development and Innovation
Programme was allocated €32 million by the Irish Government under the
National Development Plan 2000-2006. This funding is being invested in the
following research areas:
❚Environmentally Sustainable Resource Management
❚Sustainable Development
❚Cleaner Production
❚National Environmental Research Centre of Excellence
The Environmental Protection Agency is implementing this programme on
behalf of the Department of the Environment, Heritage and Local Government.
NATIONAL COUNCIL FOR FOREST RESEARCH & DEVELOPMENT
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N CHOMHAIRLE NÁISIÚNTA UM THAIGHDE AGUS FORBAIRT FORAOISE
BIODIVERSITY IN IRISH PLANTATION FORESTS -Final Report
NATIONAL COUNCIL FOR FOREST RESEARCH & DEVELOPMENT
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