Diversity and distribution of termite assemblages in montane forests in the Knuckles Region, Sri Lanka

Abstract

This study was conducted in the Knuckles Forest Region in central Sri Lanka, and investigated how termite species richness, abundance and functional group diversity vary in different montane forest types and identified the likely causes of this pattern. Termite diversity declined with increased elevation, with upper montane forests recording a single endemic species, Postelectrotermes militaris Desneux. Transect sampling in lower montane forests yielded 26 species, with a higher number from dry forests (22 species) than from wet forests (15 species). Species specificity also was high in dry forests (11 species) compared with wet forests (four species). Termite abundance did not show a distinct trend in dry and wet forests. Live-wood termites were present only in upper montane and high-altitude lower montane dry forests. Wet forests had a higher relative abundance (78%) but not species richness (40%) of soil and soil–wood interface feeders. In dry forests, both species richness (82%) and abundance (88%) of fungus-growing wood feeders were higher. The study suggests that key drivers of the species distribution pattern are low temperature and differing forest floor conditions. In the upper montane forest floor where earthworms dominate, wet soil and damp, woody litter riddled with beetles are not favourable for termites. In lower montane wet forests, moist, thick decomposing leaf litter and in dry forests, drier, relatively undecomposed leaf litter with many dry sticks and branches support species with specific food habits.

Full text

Diversity and distribution of termite
assemblages in montane forests in the
Knuckles Region, Sri Lanka
Iroshani I. Hemachandra
1,2
, Jayanthi P. Edirisinghe
1
*,
W.A. Inoka P. Karunaratne
1
, C.V. Savithri Gunatilleke
3
and R.H.S. Suranjan Fernando
3
1
Department of Zoology, Faculty of Science, University of Peradeniya,
Peradeniya, Sri Lanka;
2
Postgraduate Institute of Science (PGIS),
University of Peradeniya, Peradeniya, Sri Lanka;
3
Department of
Botany, University of Peradeniya, Peradeniya, Sri Lanka
(Accepted 28 November 2013)
Abstract. This study was conducted in the Knuckles Forest Region in central Sri Lanka,
and investigated how termite species richness, abundance and functional group diversity
vary in different montane forest types and identified the likely causes of this pattern.
Termite diversity declined with increased elevation, with upper montane forests recording
a single endemic species, Postelectrotermes militaris Desneux. Transect sampling in lower
montane forests yielded 26 species, with a higher number from dry forests (22 species)
than from wet forests (15 species). Species specificity also was high in dry forests
(11 species) compared with wet forests (four species). Termite abundance did not show a
distinct trend in dry and wet forests. Live-wood termites were present only in upper
montane and high-altitude lower montane dry forests. Wet forests had a higher relative
abundance (78%) but not species richness (40%) of soil and soil – wood interface feeders.
In dry forests, both species richness (82%) and abundance (88%) of fungus-growing wood
feeders were higher. The study suggests that key drivers of the species distribution pattern
are low temperature and differing forest floor conditions. In the upper montane forest
floor where earthworms dominate, wet soil and damp, woody litter riddled with beetles
are not favourable for termites. In lower montane wet forests, moist, thick decomposing
leaf litter and in dry forests, drier, relatively undecomposed leaf litter with many dry sticks
and branches support species with specific food habits.
Key words: abundance, altitude, forest fragmentation, functional groups, ground cover,
microhabitats
Introduction
The global distribution of termites (infraorder
Isoptera) is limited primarily by temperature and
moisture (Collins, 1989; Bignell et al., 2011). In the
tropics, termites are predominant at lower altitudes
and are scarce or absent at higher latitudes (Collins,
1983; Eggleton et al., 1994; Jones and Eggleton,
2011), occurring between latitudes of 30– 518N and
40–458S (Wood, 1979). Worldwide, the infraorder
Isoptera comprises more than 2958 described
species in 271 genera and seven families (Engel
et al., 2009). The 3105 living and fossil species are
classified into 12 families and 330 living and fossil
genera according to the recent Treatise on the
Isoptera of the World (Krishna et al., 2013).
*E-mail: jpediri@pdn.ac.lk; jpediri48@gmail.com
International Journal of Tropical Insect Science Vol. 34, No. 1, pp. 41–52, 2014 doi:10.1017/S174275841300043X
qicipe 2014

Many termite species still remain undescribed,
particularly in the tropical and subtropical regions
(Eggleton et al., 1996). In lowland tropical and
subtropical forest ecosystems, termites are of key
ecological importance as they mediate decompo-
sition processes and nutrient recycling, and thereby
exert a strong influence over soil functioning
(Lavelle et al., 1997). However, there are only a few
studies on altitudinal distribution of termites in
the tropics. Studies conducted on soil macrofauna
in Sarawak, northwestern Borneo (Collins, 1980),
have shown a significant negative correlation
between increasing altitude and the abundance
of soil termites. Based on a study in Sumatra,
Indonesia, Gathorne-Hardy et al. (2001) reported
that altitude has a significant effect on termite
species richness, which declined even within a
100 m increase in altitude. Detailed information on
montane termites is scarce (Jones and Eggleton,
2000). Studies conducted on species composition of
termites in Malawi in the African continent, over an
altitudinal gradient, have inferred that the structure
of the assemblages was clearly due to a mixture of
altitudinal and site history factors (Donovan and
Eggleton, 2002). A study by Palin et al. (2011) along
an Amazon –Andes elevation gradient in Peru
suggests that key drivers of the elevation pattern of
termite diversity are reduced temperature with alti-
tude and mid-elevation peaks in soil water content.
This study was carried out in Sri Lanka, an island
in the Indian Ocean whose land area covers an
extent of 65,793.3 km
2
. About 23% of its land area is
under closed-canopy indigenous forests (MALF,
1995). Very little is known about the role of forest
termites of Sri Lanka despite its dwindling forest
cover. Apart from a few taxonomic studies reported
during the British period, later studies have
concentrated on termites of plantation crops, mainly
tea, coconut, rubber and sugarcane. Species so far
documented from Sri Lanka have been listed by
Hemachandra et al. (2012) and Krishna et al. (2013).
In view of forest fragmentation resulting from large-
scale forest clearances for development projects,
especially during the recent past, there is the need to
document forest termites. In Sri Lanka, of the five
major natural forest types recognized, tropical
montane forests in the highlands are unique in
having a rich biodiversity. Two types of montane
forests are recognized. Those above 1300 m are
referred to as upper montane forests, which cover
0.05% of the island’s total land area with an extent
of 3108 ha. These are found in the mountain tops,
such as Pidurutalagala, Hakgala, Peak Wilderness
and Knuckles. Those between 900 and 1300 m are
the lower montane forests, which are restricted to
1.04% of the island with an extent of 68,616 ha.
In this study, we surveyed termites in three
different montane forest types in the Knuckles
Forest Range (KFR), and assessed species richness,
abundance and functional group diversity in each
forest type. We hypothesized that species assem-
blages and functional groups of termites will differ
in the three montane forest types. This is to be
further confirmed in comparison with a high-
altitude forest in Hantane hills in central Sri Lanka
(Hemachandra et al., 2010).
Materials and methods
Study sites
Knuckles Forest Range
The Knuckles Conservation Forest of 17,500 ha lies
within the KFR in central Sri Lanka and is located at
900 –1852 m. It has been nominated for an Inter-
national Man and Biosphere Reserve, due to its
ecological and hydrological importance. The forests
therein are classified according to vegetation as
(i) upper montane forests (.1300 m), (ii) lower
montane forests (wet and dry, 600 –1300 m),
(iii) semi-evergreen forests (,600 m), (iv) patana
grasslands (,100 m), (v) savannah, (iv) riverine
forests (along the river banks) and (v) disturbed
habitats due to ‘chena’ (shifting) cultivation and
plantations of cardamom, Pinus and Eucalyptus
(Bambaradeniya and Ekanayake, 2003).
The Knuckles Forest receives monsoonal rain
from both southwest monsoon (May – September)
and northeast monsoon (December – February) (de
Rosayro, 1958), resulting in higher rainfall during
these periods. The location of the forest region has
resulted in a wide range of rainfall patterns in
different parts of the region.
The choice of forest sites for the study of termites
in the montane zone of the KFR was intended to
cover the variation in altitude, climate and
vegetation. A total of seven transects representing
three different montane forest types, namely the
upper montane forests and the lower montane
forests (wet and dry), were selected for the study.
Their distribution in the KFR is given in Fig. 1.
The upper montane (KUM) forests are the
climax vegetation above 1300 m. A dense fog layer
often covers the wet forests. Forests have a dense
canopy and a scanty to thick shrubby layer. Trees
are short and much branched, gnarled and the
stems are covered with lichens, mosses and ferns.
The highland area of the Knuckles Forest is
extremely wet throughout the year with an annual
average rainfall of 5000 mm. The upper montane
forest sites are accessible only by four-wheel drive
vehicles and then uphill by foot through tea
plantations or abandoned tea land. Three transects,
KUM1, KUM2 and KUM3, were laid in the upper
montane forests. The lower montane (KLM) forests
I.I. Hemachandra et al.42

represent a transition belt between the highland
and lowland forests and occur on the wet, western
and dry, eastern slopes of the KFR. The lower
western slopes are wet with an annual rainfall
of 3350 mm and the eastern slopes are much drier
with less than 2500 mm. Patches of wet KLM forests
and sclerophyllous dry KLM forests are found
between 700 and 1300 m (Bambaradeniya and
Ekanayake, 2003; Giragama and Wickramaratne,
2005; Ratnayake, 2005). The lower montane forest
sites were reached by road, from where footpaths
led to the relatively undisturbed interior forests.
Two transects were laid in each of the lower
montane wet forests (KLM4 and KLM5) and the
lower montane dry forests (KLM6 and KLM7).
Hantane Forest Range
The Knuckles termite assemblages were compared
with two lower montane (HLM) forest sites in
Fig. 1. Montane transects (seven species) located within the conservation area of the Knuckles Forest Range in Sri Lanka
(inset). KUM, Knuckles upper montane; KLM, Knuckles lower montane.
Termite distribution in montane forests of Sri Lanka 43

Hantane hills. It is a relatively small, isolated, forest
range in the wet zone of central Sri Lanka (78170N
and 808360E, 518 –1110 m elevation). One (HLM)
forest site is a primary forest at 900 m and the
other is an Albizia-dominant secondary forest at
1000 m. The phytosociological features and the
vegetation types therein are given in Greller et al.
(1980) and Ratnayake (2001). The high-altitude
lower montane forest sites in Hantane Hills where
transects (HLM2 and HLM3) were laid are also
accessible only by foot.
The standard belt transect method had already
been used there, and the findings have been
reported in Hemachandra et al. (2010). Location
and altitude of forest sites in the KFR and Hantane
hills where transect sampling was carried out and
the ambient temperature and relative humidity at
the time of sampling are given in Table 1. The
ground cover in the different transects was closely
examined at the time of sampling, and a descriptive
record made.
Sampling of termites
The standard belt transect method of Jones and
Eggleton (2000) was used for sampling. Each
transect (100 £2 m) was divided into 20 contiguous
sections, and each section was sampled for 30 min
by two people. Within each transect, the following
microhabitats were searched for termites: surface
soil (12 samples, each 12 £12 cm, to 10 cm depth);
leaf litter on surface soil, tree buttresses; dead tree
stumps, logs, branches and twigs; runways on trees
and arboreal nests up to 2 m height. Soldier and
worker termites were collected into vials containing
80% isopropyl alcohol and labelled with the section
and transect number. The number of encounters
with each species in a transect was used as a
measure of relative abundance of that species in the
transect. An encounter is all the species collected
from one point of excavation (Davies et al., 2003). As
no termites were collected from transect sampling
in the KUM, it was supplemented with casual
searching, spending roughly equal time and effort
in each of the KUM sites where the known
microhabitats of termites were searched.
Identification of termites and their feeding habits
Termites found in each point of excavation (hit)
in a transect section were collected separately into
80% isopropyl alcohol, and identified to possible
taxa using keys and descriptions of Roonwal and
Chhotani (1989) and Chhotani (1997). The wet
collection was stored in the Entomology laboratory,
and the voucher collection is held in the Peradeniya
University Museum Insect collection.
Feeding habits of termites were deduced from
generic identity and feeding group classification of
Donovan et al. (2001). In addition, slide-mounted
mandibles of worker termites of recorded species
were examined for molar plate ridges in the right
mandibles for confirmation of feeding groups.
Accordingly, species were assigned to the following
four feeding groups and five feeding habits: group I
(W), live-wood-feeding lower termites; group II
(WF), fungus-growing wood feeders; group II (NF),
non-fungus-growing wood feeders; group III (I),
soil– wood interface feeders; group IV (S), true soil
feeders.
Data analysis
We followed the general pattern shown in Jones
(2000) for examining and interpreting the data
on montane termites. Similarity in termite species
composition among transects in the KUM and KLM
forest sites of the KFR, and the two HLM transects
Table 1. Locations and environmental conditions of montane forest sites in the Knuckles
Region and Hantane, Sri Lanka, where transects were laid
Position
Transect code N E Elevation (m) Temperature (8C) RH (%)
KUM1 7831028.1900 80843056.6800 1347 20.6 90.5
KUM2 7821035.4200 8085005.5700 1330 19.7 92.7
KUM3 7823039.5900 80842040.6800 1389 20.2 91.25
Wet KLM4 7822037.4900 8084303.4600 1065 24.0 81.1
Wet KLM5 7831031.2800 80844016.7000 1085 25.6 73.2
Dry KLM6 7832049.7800 80844056.1800 900 24.8 65.4
Dry KLM7 7820026.5500 80851031.5100 1094 26.8 66.8
HLM2 7817046.2800 80838031.4200 900 – –
HLM3 781504.7500 80837025.3900 1000 – –
RH, relative humidity; KUM, Knuckles upper montane; KLM, Knuckles lower montane;
HLM, Hantane lower montane.
I.I. Hemachandra et al.44

in Hantane was examined by cluster analysis.
Bray–Curtis ordination (similarity index) was
carried out on square root-transformed abundance
data using the computer software package PRIMER
(Clarke and Warwick, 2001), and the classification
was displayed as a dendrogram. Transect variables
(elevation, temperature and humidity) were corre-
lated with each other using Pearson’s correlation.
Species variables, richness and abundance were not
subjected to any analysis, as the three upper
montane transects failed to yield any termites.
Results
Species composition and richness
Overall, a total of 26 termite species in 12 genera
and three families were collected from transect
sampling in the dry and wet KLM sites, and none
from the three transects in the KUM sites (Table 2).
Casual searching in the KUM sites yielded a single,
live-wood lower termite species, Postelectrotermes
militaris (Kalotermitidae). Among the termites
recorded were six endemic species, a previously
unrecorded genus, Grallatotermes, and seven pre-
viously unrecorded species. The live-wood species
P. militaris was found in two live trees: under the
bark of a thunder struck Syzygium umbrosum Thw.
and a wind struck Litsea ovalifolia (Wight) Trimen. In
the KLM site at 1094 m, there were two other lower
termite species: Neotermes sp.1 (Kalotermitidae)
collected under the burnt bark of a live tree and
Termitogeton umbilicatus (Rhinotermitidae) collected
from a dead branch of a live tree. The dry KLM
transect at 1094 m yielded two previously unrec-
orded species, Ceylonitermes indicola and Nasuti-
termes kali, for Sri Lanka (Table 2). Termites
showed a restricted distribution in the different
montane sites. There were six species that were
encountered only once (and were unique to a
transect). The genus Odontotermes includes
the most number of species (10) followed by
Dicuspiditermes (5) (Table 2).
The KLM transects were more diverse with five
and 10 species in the two dry KLM transects; nine
and 14 species in the two wet KLM transects
(Table 2). The most striking feature in the taxonomic
composition of recorded termites is that the two
lower termite families, Kalotermitidae (dry wood
termites) and Rhinotermitidae, were restricted to
the two highest elevations (Table 2 and Fig. 2). All
the other species recorded belonged to the three
higher termite subfamilies, Termitinae, Nasutiter-
mitinae and Macrotermitinae (with 6, 7 and 11
species, respectively) of the family Termitidae. Of
these species, 11 were found only in one of the four
lower montane forest transects sampled, 10 others
in two of the transects and just one species in three
transects, indicating that most species are localized
to some degree among the different montane sites/
transects (Table 2 and Fig. 2).
Species abundance
Overall, the total number of termite encounters
varied greatly among the transects, with a total of 13
and 73 in the two wet KLM transects, and 25 and 50
in the two dry KLM transects (Table 2). The number
of encounters of the different termite species also
varied widely in the wet and dry KLM transects.
Dicuspiditermes sp.1 and Dicuspiditermes hutsoni in
particular had unusually high encounters with 26
and 22 hits, respectively, within one transect (wet
KLM5 at 1085 m). Most other species had fewer
encounters in their respective transects. Species
composition and abundance showed different
patterns in relation to altitude. The two KLM
transects at higher elevations (1094 and 1085 m)
recorded a higher number of species (14 and
10 species) and higher relative abundances (50 and
73 encounters), respectively, compared with the
corresponding values in the two lower elevation
transects (Table 2).
The transect site elevation in the different forests
correlated significantly with the physical variables:
temperature (P¼0.05) and humidity (P¼0.018).
Microhabitats
Apart from the three termite species collected
from damaged live trees (LT) in sites at higher
elevations (KUM and KLM at .1300 and 1094 m,
respectively), majority (24 species) were collected
from the forest floor (Table 2), and several from
more than one microhabitat, namely excavated soil
samples (S), dead plant material comprising
branches and sticks (BS), stumps and logs (SL),
leaf litter and humus (LH) and runways on live
trees (RT). Termites inhabiting these microhabitats
are largely foraging species (deadwood feeders and
soil feeders) that wander away from their nest sites.
The likelihood of the presence of more live-wood
species in transects and sites cannot be ruled out, as
live trees (with no symptoms of damage) were not
examined for termites by invasive methods,
because it required destructive sampling. Mounds
were not found in any transect or during casual
searching in the study sites. Certain termite genera
occurred in specific microhabitats: Odontotermes
were mostly confined to dead BS in the forest floor
and Dicuspiditermes to soil. A few species were
collected from leaf litter at different stages of
decomposition. Four of the five endemic species
recorded, except the live-wood species, were
present in soil (Table 2).
Termite distribution in montane forests of Sri Lanka 45

Table 2. Species composition, abundance
1
, feeding habits
2
and microhabitats
3
of termites in montane forest transects in the Knuckles Forest Range, Sri Lanka
Termite taxa Feeding habit Microhabitat
KUM
(wet, .1300 m)
KLMW4
(wet, 1065 m)
KLMW5
(wet, 1085 m)
KLMD6
(dry, 900 m)
KLMD7
(dry, 1094 m)
Family Kalotermitidae
Neotermes sp. 1 I (W) LT 1
Postelectrotermes militaris
4
I(W) LT C
5
Family Rhinotermitidae
Subfamily Termitogetoninae
Termitogeton umbilicatus
4
I(W) LT 1
Family Termitidae
Subfamily Macrotermitinae
Odontotermes bellahunisensis
6
II (WF) BS 2 2
Odontotermes ceylonicus II (WF) BS, S 3 2
Odontotermes guptai
6
II (WF) BS, S 3 2
Odontotermes hainanensis
6
II (WF) BS 1
Odontotermes horni II (WF) BS 3 1
Odontotermes sp. 5 II (WF) BS, S 1 5
Odontotermes sp. 9 II (WF) BS, S, RT 3 3
Odontotermes sp. 12 II (WF) SL, S 4
Odontotermes sp. 13 II (WF) BS, S 1
Odontotermes sp. 14 II (WF) LH, S 2
Hypotermes xenotermitis
6
II (WF) LH 1
Subfamily Nasutitermitinae
Nasutitermes ceylonicus
4
II (W) BS, SL, RT, S 15
Nasutitermes kali
6
II (W) BS, RT, S 3 3 13
Nasutitermes sp. 1 II (W) SL 3
Ceylonitermellus hantanae
4
IV (S) S 5 1
Ceylonitermes indicola
6
II (W) BS 1
Bulbitermes sp. 1
6
II (W) S 2
Grallatotermes sp. 1
6
II (W) SL, LH 6
Subfamily Termitinae
Dicuspiditermes hutsoni
4
III (I) S 22 5
Dicuspiditermes incola III (I) S 8
Dicuspiditermes sp. 1 III (I) S 26 1
Dicuspiditermes sp. 2 III (I) S 1
Dicuspiditermes sp. 3 III (I) S 2 1
Pericapritermes ceylonicus
4
III (I) S 2
No. of species (27 spp.) 510 914
Abundance (no. of encounters) 13 73 25 50
1
No. of hits/encounters of a species per transect.
2
Feeding habits: wood feeders I (W), fungus-growing wood feeders II (WF), non-fungus-growing wood feeders II (W), soil– wood interface feeders III (I) and soil
feeders IV (S).
3
Microhabitats: dead branches and sticks (BS), dead stumps and logs (SL), in soil samples (S), leaf litter and humus (LH), runways on live trees (RT) and in live
trees (LT).
4
Endemic species.
5
Collections: C, casual collections in KUM.
6
New records for Sri Lanka.
I.I. Hemachandra et al.46

Ground cover
Ground cover in the upper montane transects
was most characteristically wet and covered mostly
with organic-rich topsoil with large earthworm
casts, a thin to sparse leaf litter layer with an
occasional damp and decaying dead branches
riddled with beetles and ants. Ground cover in the
wet KLM was moist with a thick layer of
decomposing leaf litter. In contrast, in the dry
KLM, soils were drier with a relatively undecom-
posed leaf litter layer and with a greater amount of
dry dead sticks and branches.
Functional group diversity of termites
Of the three species of live-wood-feeding lower
termites of group I (W) recorded during the study, P.
militaris was the only species recorded from the
KUM. It was collected from a live tree during casual
searching. The other two species, Neotermes sp. 1
(Kalotermitidae) and T. umbilicatus (Rhinotermiti-
dae), found in the highest elevation KLM transect
(1094 m), were also collected from live trees. The
termites of group I (W) were absent from all the
other transects at lower elevations. Thus, it is
clear that montane forest sites at a high altitude
are poor in termite abundance, except for a few
distinct lower termite species having a specific
feeding habit.
In comparison with KUM sites, KLM transects
were more diverse, having termites belonging to
almost all the feeding groups, but the relative
number of species belonging to a particular feeding
group differed according to elevation and forest
type, irrespective of the wet or dry KLM site. The
higher termite species (group II) that included 17
species of fungus-growing wood feeders [group II
(WF)] and eight non-fungus-growing wood feeders
[group II (W)] were present in all the transects, but
differed in the number of species in the different
transects (Table 3 and Fig. 3A and B). There were
more non-fungus-growing wood-feeding species
[group II (W)] in the two dry KLM transects (three
species in each) and fewer in the two wet KLM
transects (one species in each). The distribution of
soil– wood interface-feeding species was somewhat
similar in the dry and wet KLM transects, with the
two wet transects recording one and four species
and the dry transects one and three species. Overall,
the wet KLM transect at 1065 m recorded a lower
number of species (five species), representing the
different feeding groups, while the dry KLM
transect at the highest elevation of 1094 m recorded
a higher number of species (14 species), represent-
ing all the feeding groups. A distinct difference was
observed in the distribution of the soil-feeding
species, Ceylonitermellus hantanae. It was present
only in two transects: dry KLM transect at 1065 m
and wet KLM transect at 1094 m.
When soil-feeding and soil – wood interface-
feeding species (soil-associated feeders) were
grouped together (groups III and IV combined,
Table 3), a distinct difference in their distribution
and abundance was observed; the wet KLM
transects harboured a higher relative abundance,
though not a higher number, of such species that
fed on soil and extremely decayed soil-like wood
compared with their representation in the dry KLM
transects. The wet KLM5 transect at 1085 m was
distinct in having the highest relative abundance
0
2
4
6
8
10
12
14
16
KUM
KLMW4
KLMW5
KLMD6
KLMD7
HLM2
HLM3
Collection sites
No. of species
Termitinae
Nasutitermitinae
Macrotermitinae
Rhinotermitidae
Kalotermitidae
Fig. 2. Taxonomic composition of termites from transects
and casual collections in upper montane (KUM) and dry
and wet lower montane forest (KLM) sites.
Table 3. Distribution and abundance of termite species belonging to different feeding groups in the wet and dry lower
montane (KLM) forest transects of the Knuckles Forest Range
þ
Feeding groups
Groups I and II
(wood-associated feeders)
Groups III and IV
(soil-associated feeders) Total
Lower montane
forest type
No. and
percentage of species Abundance
No. and
percentage of species Abundance
No. of
species (genera) Abundance
Wet KLM 09 (60%) 19 (22%) 06 (40%) 67 (78%) 15 (6) 86
Dry KLM 18 (82%) 66 (88%) 04 (18%) 9 (12%) 22 (9) 75
Total 19 (76%) 85 (53%) 10 (40%) 76 (47%) 25 (11) 161
þ
Percentage refers to the number of species or abundance in relation to the total in that forest type.
Termite distribution in montane forests of Sri Lanka 47

(58 encounters) of soil – wood interface-feeding
species (Fig. 3B). Similarly, when both non-fungus
and fungus-growing wood-feeding species were
grouped together (groups I and II combined, wood-
associated feeders), a distinct difference in their
distribution was also observed. The dry KLM
transects had a greater richness and a higher
relative abundance of species that fed on wood and
wood-associated fungi, compared with species in
the wet KLM transects (Table 3). The dry KLM7
transect at the highest elevation of 1094 m had the
highest relative abundance (29 encounters) of non-
fungus-growing wood-feeding species (Fig. 3B).
Overall, the dry KLM transects were distinct
in having a greater species richness and abundance
(encounters) of wood and wood-associated non-
fungus-growing species, while the wet KLM
transects were distinct in having a greater species
richness and abundance of termite species that
fed on soil and decayed soil-like wood. When
soil-feeding termites were grouped together with
soil–wood interface species (groups I and II
combined), it was clear that the two dry KLM
transects had a higher species composition and
abundance of species that fed on wood and wood-
associated fungi compared with the two wet KLM
sites that had a greater richness and abundance
of species that fed on soil and extremely decayed
soil-like wood (Table 3).
Comparison of montane sites in the Knuckles Region
with Hantane sites
The Hantane transect at a high elevation (HLM3,
1000 m) recorded only a single species, the soil-
feeding C. hantanae (with 20 encounters), while that
at a low elevation (HLM2, 900 m) recorded a total
of four species, namely C. hantanae (15 encounters),
Dicuspiditermes incola (soil– wood interface feeder
with six encounters), Dicuspiditermes sp. 1 (soil –
wood interface feeder with four encounters) and
Dicuspiditermes sp. 2 (soil– wood interface feeder
with one encounter) (Hemachandra et al., 2010).
Wood feeders (groups I and II) were totally
absent in the Hantane transects, whereas the
Knuckles transects yielded 20 such species. The
Hantane transects included only soil (one species)
and soil– wood interface feeders (three species)
(groups II and IV), but the Knuckles transects
yielded seven such species. Endemic C. hantanae
was common to the high-altitude Hantane transect
where it occurred in high abundance (20 encoun-
ters), and to the KLM transects where it occurred in
lower abundance (KLM5: five encounters; KLM7:
one encounter). The three species of soil – wood
interface feeders (Dicuspiditermes sp. 1 and 2 and D.
incola) were also common to both Hantane hills and
KFR. The higher relative abundances of Dicuspidi-
termes sp. 1 (26 encounters) and D. hutsoni (22
encounters) in one and the same transect (KLM5), in
contrast to all the other termite species recorded
during the study, are of interest.
Cluster analysis using Bray – Curtis ordination
(Fig. 4) showed that species composition of termites
in the wet KLM4 transect at 1065 m in the Knuckles
Region is similar to species in the Hantane transects
(HLM2 and HLM3). While species composition in
the other wet KLM5 transect at 1085 m is more
similar to the two dry transects (KLM7) at 1094 and
(KLM6) at 900 m elevations in the KFR (Fig. 4). The
first node separated the two groups at around 7%
similarity level, the Hantane sites and wet KLM
sites having more soil-associated feeders than the
dry KLM transects that were rich in wood-
associated feeders. Furthermore, N. kali, a new
record for Sri Lanka, was present in all the KLM
transects except KLM4. The second node in the
dendrogram separated the dry KLM7 transect at
1094 m from the wet KLM5 transect at 1085 m and
0
10
20
30
40
50
60
70
80
KLMW4
KLMW5
KLMD6
KLMD7
HLM2
HLM3
Transects
No. of encounters
0
2
4
6
8
10
12
14A
B
KUM
KLMW4
KLMW5
KLMD6
KLMD7
HLM2
HLM3
No. of species
IV (S)
III (I)
II (W)
II (WF)
I (W)
Fig. 3. (A) Number of termite species with different
feeding habits. (B) Abundance (no. of encounters) of
species with different feeding habits in the upper
montane (KUM) and lower montane (KLM) forests of
the Knuckles Region. I (W), live wood feeders; II (NF),
fungus growing wood feeders; II (W), non-fungus
growing wood feeders; III (I), soil-wood interface feeders;
IV (S), soil feeders.
I.I. Hemachandra et al.48

the dry KLM6 transect at 889 m at around 22%
similarity level. The preferentials included C.
hantanae, which is an endemic soil-feeding species
absent in the KLM5 and KLM6 transects. The third
node in the dendrogram separates the wet KLM4
transect at 1065 m in the KFR from the two transects
in Hantane (HLM2) at 1000 and (HLM3) 900 m,
and the preferential species reflect the differences
between the Hantane and KFR termite assemblages,
where wood feeders were absent in the Hantane
tansects.
The two Hantane transects (HLM2 and HLM3)
and the wet KLM4 transect at 1065 m had
predominantly more soil and soil – wood-feeding
preferential species (8:5) compared with the
remaining three transects (23:6) (Table 4). The ratio
of wood feeders in the Hantane transects and the
wet KLM transects at 1065 m was much smaller
(8:3) compared with that in the remaining three
transects (23:17).
Discussion
Further studies are needed to confirm the
finding that the upper montane sites are depaupe-
rate in termites compared with the lower montane
sites in other upper montane sites in the KFR and
elsewhere in Sri Lanka. Similar studies carried out
in upper montane tropical forests in Southeast
Asia have confirmed that upland forests are
relatively depauperate (Jones, 2000). It is of
significance that termite species at a high elevation
(i.e. KUM and KLM7 at .1300 and 1094 m) belong to
the lower termite families Kalotermitidae and
Rhinotermitidae. These species (P. militaris,T.
umbilicatus and Neotermes sp. 1) are non-foraging
live-wood feeders of group I (W) (Donovan et al.,
2001) that are one-piece nesters (Higashi et al., 1992).
Transform: Square root
Resembalance: S17 Bray–Curtis similarity
KLMW4
HLM2
HLM3
KLMD7
KLMW5
KLMD6
Transects
100 80 60 40 20 0
Similarit
y
Fig. 4. Bray–Curtis ordination dendrogram showing
the similarity of termite assemblages in montane forests
based on species composition recorded from casual
collections and transect sampling in the upper montane
(KUM) and lower montane wet (KLM4 and KLM5) and
dry (KLM6 and KLM7) forests of the Knuckles Region
and Hantane (HLM2 and HLM3).
Table 4. Species preferentials at each node in the Bray–Curtis ordination (see
Fig. 4)
þ
Node 1
HLM2 þHLM3 þKLM4 KLM5 þKLM6 þKLM7
Ceylonitermellus hantanae Nasutitermes kali
Total preferentials ¼8 spp. Total preferentials ¼23 spp.
W¼1, WF ¼2, S ¼1, SW ¼4W¼17, WF ¼10, S ¼1, SW ¼5
Node 2
KLM7 KLM5 þKLM6
Total preferentials ¼14 spp. Total preferentials ¼14 spp.
W¼5, WF ¼5, S ¼1, SW ¼3W¼3, WF ¼7, SW ¼4
Node 3
HLM2 þHLM3 KLM4
Dicuspiditermes incola Total preferentials ¼5 spp.
Total preferentials ¼4 spp. W ¼1, WF ¼2, S ¼1, SW ¼1
S¼1, SW ¼3
W, non-fungus-growing wood feeders; WF, fungus-growing wood feeders; S, soil
feeders; SW, soil –wood interface feeders.
þ
Only those preferential species occurring in all transects on the respective side of
the node are listed. The total number of preferential species in each feeding group
is provided.
Termite distribution in montane forests of Sri Lanka 49

Furthermore, the noteworthy absence of
ground-dwelling termites in KUM forests is most
probably due to the soil therein being very wet and
moist dominated by earthworms and hence would
not support soil termites. Similarly, the beetle-
infested damp and rotting wood from fallen parts of
trees would not favour wood-feeding termites. In
contrast, wet lower montane forests are distinct in
having a richer soil and soil-like wood-feeding
termite assemblage, while dry lower montane
forests are characterized by a greater number and
abundance of wood-feeding species. According
to Gathorne-Hardy et al. (2001), with an increase
of altitude, deadwood-feeding foraging termites of
group II (W) gradually diminish before soil feeders
(groups III and IV).
Postelectrotermes militaris, recorded only from
damaged living trees in KUM sites, is common in
living tea bushes at high elevations in the Central
Province and in the Ratnapura District (Green,
1913). It is a tea pest, mainly at 1066– 1372 m, and
hence commonly known as the ‘Up-country Tea
Termite’ (Ranaweera, 1962). It also occurs in live
trees such as Albizia falcataria,Crotalaria micans,
Erythrina subumbrans,Grevillea robusta,Neolitsea
cassia,Shorea zeylanica and Syzygium gardneri
(Wijeratne, 1999), which are grown as shade trees
in upcountry tea plantations.
The dry KLM transects are relatively species rich
and abundant in non-fungus-growing wood-feed-
ing species, while the lower wet KLM transects are
abundant in soil– wood interface-feeding species.
These differences may be attributed to the climate
and ground cover conditions in montane forest
types. A rich layer of decomposing leaf litter in the
forest floor of wet KLM is more suitable for humus
feeders. In dry KLM, dry dead sticks and branches
that are plentiful in the ground cover favour wood
feeders. The near absence of termites in KUM
forests may be attributed to (i) high altitude with
low temperatures, adverse for foraging termites,
(ii) wet and humid climate, lower stature and
almost closed canopy and earthworm dominance in
wet soil, adverse for soil-feeding termites, as well as
(iii) damp and decomposed wood riddled with
beetles and ants in the forest floor, adverse for
wood-feeding termites. It was evident that the role
of termites in KUM was taken over by soil-feeding
earthworms and wood-boring beetles, abundant in
KUM forest sites.
Small differences in altitude and temperature,
especially between the KUM and KLM sites, give
rise to very different climatic and microclimatic
conditions within these two forest types. Studies
carried out in Peninsular Malaysia identified forest
and soil type as the most important factor in
explaining the structure of termite assemblages
(Salick and Tho, 1984). Gathorne-Hardy et al. (2001)
considered altitude as having a significant effect on
the species composition and richness of termites
from a study in the Leuser Ecosystem in Sumatra,
Indonesia. Termites exhibit a wide range of feeding
habits with a high degree of resource specialization.
Hence, their distribution in forest ecosystems in
part will be determined by resource availability at
different altitudes (Eggleton et al., 1998). Consider-
ing all these factors and the absence of soil, soil –
wood interface and deadwood feeders in KUM, the
study indicates that termites have a reduced impact
on decomposition and recycling processes in KUM
forest types compared with those in KLM sites.
The location of KUM sites may be another
overriding factor that contributes to the distinctive-
ness in termite assemblages. Tea plantations were
established at high elevations in the distant past by
clearing much of the natural forest. Hence, it is
likely that P. militaris has moved in to living tea
bushes from nearby natural forests. As live trees
(with no external symptoms of damage) were not
examined for termites during this survey, their
increased occurrence cannot be ruled out. The ‘live
wood tea termites’, Glyptotermes dilatatus and
Neotermes greeni (family Kalotermitidae) (Rana-
weera, 1962) were not detected in montane forest
transects and could be attributed to live trees not
being subjected to invasive sampling.
Considering the limited termite fauna so far
recorded from the forests of Sri Lanka (Hemachandra
et al., 2012) in comparison with the fauna in
Southeast Asia (Gathorne-Hardy et al., 2001), it is
likely that further collecting efforts would certainly
lead to the documentation of other species
represented at least in the transition zones of
upper and lower montane forests. The present
findings and results of ongoing studies in other
forest types in the KFR when put together may shed
more light on factors influencing termite distri-
bution in the KFR.
Conclusion
Termite distribution in montane forests of the
KFR infers that altitude, temperature, moisture
levels (wet and dry forests) and forest floor litter
composition probably have an important effect on
termite species richness and functional group
diversity of termites. The total absence of soil-living
termites and deadwood feeders in the forest floor
litter in the upper montane forest sites in the KFR is
an important finding. For further confirmation,
a comparison with similar forests elsewhere in
Sri Lanka needs to be made. Dry montane forests
harbour a greater diversity of species and dead-
wood-feeding functional groups, inferring the role
of forest floor litter composition in determining the
species composition of termites.
I.I. Hemachandra et al.50

Acknowledgements
This work forms part of a larger study in the KFR
funded by the National Science Foundation of
Sri Lanka. We thank the several field assistants
for their help during sampling. We are indebted to
Mr A. Medawatta, formerly of the Department of
Botany, University of Peradeniya, for help with site
selection and for leading us through the difficult
forest terrain. Mr Malika Gunawardena formatted
the GPS data.
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