Article

The influence of field shape, area and surrounding landscape on plant species richness in grazed ex-fields

January 2008
Biological Conservation 141(1):126-135

January 2008
141(1):126-135

DOI:10.1016/j.biocon.2007.09.004

Authors:

Sara AO Cousins

Stockholm University

Elsa Aggemyr

Stockholm University

Over the past 100 years species-rich semi-natural grasslands have decreased dramatically in Western Europe, where former arable fields (ex-fields) are used instead as pasture. The disappearance of semi-natural grasslands has caused a threat to the biodiversity in agricultural landscapes. Many typical grassland plants are dispersal limited, thus grazed ex-fields can be used to investigate if species spontaneously colonise these new grassland habitats. We examined the relationship between surrounding landscape, field area, shape, distance between edge and centre, and plant species diversity in ex-fields that had been grazed for 15–18 years. The results showed that there were 35% more plant species in fields surrounded by commercial forestry production compared to those surrounded by open agricultural landscape. Area and shape did not influence species richness, although there was increasing number of species in the centre with decreasing distance from the edge. Twenty-five percent of the species where typical grassland species, and ex-fields surrounded by forest had 91% more grassland species compared to those in the open landscape. It is possible to increase grassland plant occurrences by grazing ex-fields surrounded by forest or other grassland remnant habitats, particularly in landscapes where grazed semi-natural grasslands are scarce.

Diversity patterns in high‐latitude grasslands

Article

Full-text available

Feb 2022

Aim Grasslands of varying land‐use intensity and history were studied to describe and test species richness and compositional patterns and their relationships with the physical environment, land cover of the surrounding landscape, patch geometry, and grazing. Location The mainland of Norway. Methods We utilized data from the Norwegian Monitoring Programme for Agricultural Landscapes, which recorded vascular plants from 569 plots, placed within 97 monitoring squares systematically distributed throughout agricultural land on the Norwegian mainland. We identified four grassland types: (i) moderately fertilized, moist meadows; (ii) overgrown agricultural land; (iii) cultivated pastures and disturbed ground; and (iv) natural/unfertilized and outfield pastures. Results Soil moisture and grazing measures were found to be important in explaining species compositional variation in all grassland types. Richness patterns were best explained by complex and differing combinations of environmental indicators. Nevertheless, negative (nitrogen and light level) or unimodal (pH) responses were similar across grassland types. Vegetation plots adjacent to areas historically and/or currently dominated by mires, forests, or pastures, as well as abandoned and overgrown grasslands, had a slightly higher species richness. Larger grasslands surrounding the vegetation plots had slightly less species than smaller grasslands. Conclusions This study demonstrates that data from a national monitoring programme on agricultural grasslands can be used for plant ecological research. The results indicate that climate‐change‐related shifts along moisture and nutrient gradients (increases) may alter both species composition and species richness in the studied grasslands. It is likely that large and contiguous managed (grass)land might affect areas perceived as remnants, probably caused by the transformation to homogeneous (agri)cultural landscapes reducing edge zones, which in turn may threaten the species pool and richness. The importance of land use and land‐cover composition should be considered when planning management actions in extensively used high‐latitude grasslands.

Effects of landscape composition, species pool and time on grassland specialists in restored semi-natural grasslands

Article

Oct 2017
BIOL CONSERV

Habitat restoration is an important complement to protecting habitat for the conservation of biodiversity. Semi-natural grasslands are target habitats for ecological restoration in temperate Europe. Restoration of abandoned semi-natural grasslands often relies on spontaneous colonisation of plant species from the soil seed bank or the surrounding landscape. Although many studies show that the regional species pool is important for upholding local diversity, its effect on restoration outcome in semi-natural grasslands is poorly known. In this multi-landscape study, we examined grassland specialist species occurring in restored grasslands and the effect of specialist species pool, landscape composition and local temporal factors. We found that specialist richness and frequency was positively affected by specialist richness and frequency in the surrounding landscape. Specialist richness in the restored grasslands also increased with time since restoration. Moreover, specialist frequency in the restored grassland increased with the proportion of semi-natural and remnant grassland habitats in the landscape. We also found a positive relationship between the proportion of species occurring in both the restored grassland and its surrounding landscape and time since restoration, in landscapes with high proportions of semi-natural grasslands. This suggests that both temporal factors, as well as the landscape composition and species pool, affect plant recolonisation in restored semi-natural grasslands.

DOSTÁLOVÁ, A. 2010: Secondary succession toward woodland: Changes in the herb layer species composition [Změny bylinného patra v průběhu sekundární sukcese lesa] – 245p., University of South Bohemia, Faculty of Sciences, České Budějovice, Czech republic

Thesis

Full-text available

Jan 2010

Alena Dostalova

ANNOTATION: This dissertation focus on spontaneously developed forests (SDFs) on mesic stands. The present tree layer was described and the possible changes in the tree layer was estimated. Influence of site- and context-dependent factors on the species composition and general character of the herb layer was studied in detail. An experiment was established to study seed and safe-site limitation of nine forest herb species. Summary The study area was situated into the southern part of the Czech Republic (40°35-38´ N, 14°11-17´ E), altitude 665-940 m (Fig. 1). Climatic conditions moderately oceanic between the warm and cold type (climatic regions MT 3 – Ch 7), average year temperature 6.8°C and average year precipitation 718-1 003 mm. The SDFs on mesic stand (neither waterlogged nor desiccated, with vegetation neither ruderalised nor typical for poor soils) were studied. Forty eight plots (100 m2) were fixed in SDFs, which differed in age to cover up the chronosequence of successional sere directed toward forests in the study area. The species composition and the influence of the site- and context-dependent factors on the species composition and character of the herb layer were studied, and an estimation of the probable future development of the tree layer was calculated. The studied SDFs were on average 7.4 ha large (ranging from 0.08 to 22 ha), the shape differed much between the studied SDFs (an average relative length of the SDF border was found to be 3.1, ranging from 1.1 to 15.6), and the nearest distance to the border of the SDF was found to be not long (on average 22 m, ranging from 10 to 80 m). The SDFs were semi-open growths with an average relative irradiance of 20% of incoming radiation in the 120 cm above ground (ranging from 3 to 68%), with a relatively dense herb layer reducing the incoming radiation on average at 6% in the 5 cm above ground (ranging from 1 to 36%). Most of the SDF were on shallow soils (mean depth of the organic soil horizon was found to be 23 cm, ranging from 4 to 70 cm), with relatively high rock fragment content (mean value 42%, ranging from 6 to 86%). Several soil characteristics were found to be intermediate between the numbers typical for grassland and forest soils: soil reaction (mean value 4.3, ranging from 3.8 to 5.6), organic matter content (mean value 11%, ranging from 5 to 21%), basal respiration of the microbial community (mean value 2.7 g C CO2.g1.hod1, ranging from 0.7 to 5.8 g C CO2.g1.hod1). Most of the SDFs were surrounded by SDFs (on average 38%), grassland (31%), and forests (23%), while fields (6%) and “other” land cover (2%) were low abundant. The distance to the nearest grassland was only 45±60 m, while the nearest forest was found to be 111±152 m away and the nearest field 743±912 m. The average age of the tree layer was found to be 30 years (ranging from 10 to 46 years), but the age structure of the tree layer was not found to be homogeneous, because the maximum age of the tree layer was 46 years (ranging from 12 to 84 years). This finding corresponds with the data from the historical aerial photos: most of the SDFs were not covered by trees in 1952 (65% grasslands, 19% fields; 13% covered by scattered trees, and 4% by closed tree canopies), while half of the SDFs were covered by trees in 1966 (33% grassland, 13% fields, 25% scattered trees, 29% closed tree canopy) and most of the plots were covered by trees in 1983 (4% fields, 13% grassland, 23% scattered tree canopy, 60% closed tree canopy). The tree layer changes from the dense growth of young thin trees (up to 179 trees.are-1) to open canopies of adult trees (down to 2 trees.are-1). The age structure of the older tree layer is less age uniform than in the young SDFs. The tree layer was dominated by pioneer tree species. In total, 11 tree species were listed in the tree layer. The anemochorous species dominated the tree layer, but endozoochorous species were also able to colonise these growths. On average 2.6 species were found in a plot, and 83% of the trees were deciduous ones. The birch (Betula pendula Roth.) was found to be the most common and most abundant species (occupying 88% of plots, 60% of trees), but the European aspen (Populus tremula L.), Norway spruce (Picea abies (L.) Karsten), mountain ash (Sorbus aucuparia L.), and Scots pine (Pinus sylvestris L.) were able to dominate the tree layer as well. Of other species, the goat willow (Salix caprea L.) and common ash (Fraxinus excelsior L.) were more common incidental trees in these growths. The species composition of the tree-layer was related from the studied factor to the Ellenberg T indicator value and shape of the SDF (14% of the total variability in the data explained). The Norway spruce and Scots pine preferred colder stands, while the sycamore maple, cherry-tree and common ash preferred warmer stands. The birch occupied sites with more irregular shapes, unlike the European aspen which preferred less complicated shapes of the SDF (it may be a result of vegetative reproduction of this species). The growths dominated by the European aspen were found to be more occupied by the endozoochorous cherry tree and mountain ash, while in the SDFs dominated by birch the anemochorous goat willow was more common. More tree species were found to be at higher altitudes and/or at colder stands, in younger growths and in the SDFs with more complicated shapes. The abundance of the two most common species (birch and Norway spruce) were influenced mostly by the soil conditions, history, age and proportion of SDF, and forests in the 300 m surroundings. In total, fifteen tree-seedling species were listed. Most of the seedlings were 10-40 cm high. An average plot contained 145 seedlings of five species. The best colonisers were species non-specific to the stage of succession (59% of the seedlings, 96% of the plots), and anemochorous species (75% of the seedlings, 98% of the plots). Species typical for terminal stages of succession were able to colonise 65% of the plots, but they took only 4% of the total number of seedlings. Zoochorous species occupied 85% of the plots and took 25% of the seedlings. Species typical for the early stages of succession preferred plots more irradiated at the 20 cm above ground, lower altitudes, less productive sites, and sites near to the forest. Species typical for terminal stages of succession preferred lower altitudes, older growths, medium rich stands with more organic matter content, lower soil reaction, and sites near forests. Species non-specific to the stage of succession gained in medium-aged SDFs and under a dense tree layer. Anemochorous and zoochorous species were not found to be influenced by any studied factor. The sycamore maple (Acer pseudoplatanus L.) was the most common seedling species (60%), while the European aspen (10%), mountain ash (10%), Norway spruce (9%), cherry tree (5%), and common ash (3%) were also abundant. The altitude and soil reaction significantly influenced the tree-seedling species composition. Sycamore maple seedlings were more common in younger SDFs, which grew faster. Norway spruce seedlings were negatively influenced by relative irradiance at the 20 cm above ground. The number of birch seedlings was negatively influenced by the relative irradiance at the 20 cm above ground and/or by the abundance of typical grassland species. More cherry tree seedlings were found at plots in lower altitudes, near forests and in older stands. The mountain ash was more common in the plots where the herb layer was more similar to the herb layer of the forests. An estimation of the changes for the next generation of the trees was done. It was based on a comparison of the present and estimated species composition. The estimated tree layer species composition was derived from the number of tree seedlings according to their height. The estimation predicts big changes in the tree layer species composition. The estimated tree layer species composition was related to the time of succession, nutrients, and humidity (25% of the total variability explained). The shift was found to be directed toward the species composition typical for terminal stages of succession, but the species composition of the second generation of the tree layer was still estimated to be very different. The succession will probably be long, and several centuries can be expected to be necessary for the successional changes leading to the species composition near the natural species composition. Most of the species common in the present tree layer are supposed to change their abundance in the estimated tree layer. The most important finding is the estimated decrease of the pioneer species the birch, and the predicted increase of the ubiquitous species the Norway spruce and the sycamore maple and the ability of species typical for terminal stages of succession (beech, pedunculate oak) to establish themselves in the next tree generation. The sycamore maple, European beech, and pedunculate oak (Quercus petraea (Mattuschka) Liebl.) were found to be typical species in the estimated tree layer, although present common species (birch, European aspen, Norway spruce) will be more common. The results are relatively optimistic for the forest managers, because only 5% of the plots probably will not be colonised by species “valuable” for forest management, while 47% of plots will contain more than one of these species. Most of the plots (79%) exceeded 2,000 seedlings of “valuable” species per hectare, which is sufficient for natural regeneration. Almost half of the trees “valuable” for forest management were found to be deciduous. The general character of the herb layer of the SDFs in the first tree generation could be described as follows: grassland character prevails (average G = 20.5, Gw = 45.1), while woodland character plays a minor role (average W = 8.7, Ww = 18.0). Most of the species listed in the herb layer were related to the grassland vegetation (in total, 86 species, mean abundance 33%), followed by a group of species growing both in grassland and wood (30 species, 17%), woodland species (26 species, 10%), antropochorous and/or ruderal species (18 species, 3%), shrub species (10 species, 1%) and species typically growing at clearings (4 species, 2%). Most of the species related to the grassland vegetation were exozoochorous species (average Gw_Zex = 22.6) and species non-specific to the type of distribution (average Gw_Ns = 11.5), while most of the species related to the forest vegetation were anemochorous (average Ww_Wd = 6.5), endozoochorous species (average Ww_Zend = 5.6) or species non-specific to the type of distribution (average Ww_Ns = 4.5). Species grouped according to the biotope were in general more influenced by the context-dependent factors, especially by the historical vegetation cover and by the proportion of grassland and forests in the surroundings, while the proportion of “other” land cover and the character of the SDF (area, shape and position within the SDF) were of less importance. Of the site-dependent factors, the soil characteristics were more important for several groups of species, but the relationships were group dependent. General trend observed was the preference of grassland species to the soil conditions closer to the soil conditions typical for grassland soils (i.e., lower organic matter content, higher soil reaction). The most important finding was that the abundance of the woodland species increased with the age of the tree layer and with the duration of the tree layer. However, a decrease in grassland species was not observed. The increase in the woodland character of the herb layer with the duration of the tree layer (Aa, Amax, historical vegetation cover) was promoted using the (weighted) grasslandness and (weighted) woodlandness indeces. The relationships of the other factors were index dependent, and no general trend was observed, except for the woodlandness related to the soil conditions more similar to the forest soils (i.e., higher organic matter content, lower soil reaction and higher microbial respiration). Almost all of the groups of species according to the type of distribution related to the woodland were found to be more abundant in the SDFs with the tree layer developed for a longer time period (Aa, Amax, historical vegetation cover), but the decrease in groups of species related to grassland vegetation was not observed. Many of the site- and context-dependent factors significantly influenced the abundance of the groups of species, but the relationships were group dependent and no general pattern could be observed. In total, 161 vascular plant species were listed, on average 32±8.6 species per 100 m2. The herb layer of SDFs was found to be highly variable (23% of the species were found only at one plot, while only 18% were found at more than 33% of the plots). An average diversity value was found to be 2.6 (ranging from 0.4 to 3.5), measured as a Shannon Wiener index, which is relatively high. All the common species in this study were also common species in the study area and species widespread in Central Europe. The most common species were the following: Agrostis capillaris L., Galium mollugo agg. L., Holcus mollis L., Veronica chamaedrys L. (present at more than 80% plots), while the most abundant were the following species: Agrostis capillaris, Avenella flexuosa (L.) Drejer, Holcus mollis and Vaccinium myrtillus L. (more than 7% abundance per occupied plot). Most of the diagnostic and constant species were species related to the grassland vegetation (33 out of 161 species), especially of the Arrhenatherion elatioris, Polygono bistortae Trisetion flavescentis and Violion caninae alliance. Only ten species were related to the forest vegetation, i.e., of the Dentario enneaphylli Fagetum association, Luzulo Fagion and Quercion petreae alliance. Only several typical forest species were able to establish in the SDFs, and they were usually low abundant. Ferns and Vaccinium myrtillus were the only more abundant typical forest species, and of the Oxalis acetosella L. was relatively frequent. However, some forest species typical for oak-beech or beech forests were also listed in the herb layer, e.g., Asarum europaeum L., Geranium robertianum L., Mercurialis perennis L. and Mycelis muralis L. In general, the influence of the studied factors on the frequent species abundance was species specific, and only a few general trends could be observed. Both site- and context-dependent factors influenced the abundance of frequent species, and there was found to be no big difference or general trend true for these two types of factors. The seed and safe-site limitation of forest herbs was studied in a factorial designed experiment in a 12-year abandoned grassland (48°41.468´ N, 14°17.382´ E, altitude 700 m). The influence of disturbance and shading on species composition, general characteristics of the vegetation, and on species abundances was studied, and seedling establishment of forest species was monitored. In total, 16 treatments in six randomised blocks were fixed and the following manipulations were performed: i) shading at the 40% level of incoming PhAR, ii) shading at the 5% level of incoming PhAR, iii) removal of above-ground plant biomass, iv) disturbance of the turf, v) seed addition of typical forest species (Actaea spicata L., Carex sylvatica Huds., Dentaria enneaphyllos L., D. bulbifera L., Galium odoratum (L.) Scop., Maianthemum bifolium (L.) F.W. Schmidt, Mercurialis perennis, Oxalis acetosella, Paris quadrifolia L.). However, the between-year variability in species composition was higher than the changes in vegetation caused by disturbance (iii and iv) or shading treatments (i and ii), and the treatments were found to have had a significant effect. Disturbance treatments were found to be able to influence the species composition directly, and the changes in the species composition caused by the disturbance treatments were more quantitative than qualitative, unlike the shading treatments. Shading was found to slow down the changes in the species composition between years, and therefore this treatment was able to stabilise the species composition. However, the turf disturbance was the most radical treatment causing the biggest changes in the vegetation one year after the treatment practice, and the following year the vegetation was able to close again. The reduction at the 40% level of the incoming radiation treatment was not able to produce new gaps in the vegetation, but the shading at 5% of the incoming radiation was able to increase the abundance of gaps. The decrease in species diversity in control plots was observed, while the removal of above-ground vegetation was able to stabilise the diversity and the turf disturbance treatment increased the diversity, but only for a one-year period. The annuals, rosettes and small perennial herbs were more abundant in the plots with the turf disturbance treatment. Most of the forest species were not able to germinate, although the seed densities were high. The germination capacity in laboratory conditions was also found to be low for most of the species. Only forest species sown directly into the study site were found. This finding indicates the seed limitation of the forest species. All the recruited species were found the following year after sowing. Dentaria enneaphyllos was the only well establishing species, but it was not able to germinate in 56% of the plots and its survival was found to be on average 3% in the plots, where it was able to germinate. None of the seedlings was able to develop into a further stage than to the seedling with cotyledons. Shading treatment was able to enhance the seedling recruitment of D. enneaphyllos, and there was also a similar trend (however insignificant) for disturbance of the turf treatment. The numbers of Oxalis acetosella seedlings indicate a similar pattern, although there was found to be an insufficient number of O. acetosella for the statistical analysis. These findings indicate the possible safe-site limitation of the forest species at a relatively early stage of succession.

Landscape structure and land use history influence changes in island plant composition after 100 years

Article

Sep 2012
J BIOGEOGR

Aim We investigated how current and historical land use and landscape structure affect species richness and the processes of extinction, immigration and species turnover. Location The northern part of the Stockholm archipelago, Baltic Sea, Sweden. We resurveyed 27 islands ranging from 0.3 to 33 ha in area. Methods We compared current plant survey data, cadastral maps and aerial photographs with records obtained from a survey in 1908, using databases and a digital elevation model to examine changes in plant community dynamics in space and time. We examined the effects of local and landscape structure and land use changes on plant species dynamics by using stepwise regression in relation to eight local and three landscape variables. The eight local variables were area, relative age, shape, soil heterogeneity, bedrock ratio, number of houses, forest cover change, and grazing 100 years ago. The three landscape variables were distance to mainland, distance to closest island with a farm 100 years ago, and structural connectivity. Hanski’s connectivity measure was modified to incorporate both connectivity and fragmentation. Results The investigated islands have undergone drastic changes, with increasing forest cover, habitation, and abandonment of grassland management. Although the total species richness increased by 31% and mean island area by 23%, we found no significant increase in species richness per unit area. Local variables explain past species richness (100 years ago), whereas both local and landscape variables explain current species richness, extinctions, immigrations and species turnover. Grazing that occurred 100 years ago still influences species richness, even though grazing management was abandoned several decades ago. The evidence clearly shows an increase in nitrophilous plant species, particularly among immigrant species. Main conclusions This study highlights the importance of including land use history when interpreting current patterns of species richness. Furthermore, local environment and landscape patterns affect important ecological processes such as immigration, extinction and species turnover, and hence should be included when assessing the impact of habitat fragmentation and land use change. We suggest that our modified structural connectivity measure can be applied to other types of landscapes to investigate the effects of fragmentation and habitat loss.

Small-scale plant species richness and evenness in semi-natural grasslands respond differently to habitat fragmentation

Article

Mar 2009
BIOL CONSERV

The study explores whether small-scale species diversity, species evenness and species richness in semi-natural grassland communities are similarly associated with present management regime and/or present and historical landscape context (percentage of differ-ent land-cover types in the surroundings). Species diversity, evenness and richness were recorded within 441 50 · 50 cm grassland plots in a 4.5 · 4.5 km agricultural landscape on land, Sweden. Recent and historical land-cover maps (years 2004, 1959, 1938, 1835, and 1800) were used to characterize the present and past landscape context of the sampled veg-etation plots. Partial regression and simultaneous autoregressive models were used to explore the relationships between species diversity measures (Shannon diversity, richness and evenness) and different explanatory variables while accounting for spatial autocorre-lation in the data. The results indicated that species richness was relatively sensitive to grassland isolation, while the response of species evenness to isolation was characterized by a degree of inertia. Because the richness and evenness components of species diversity may respond differently to habitat fragmentation, we suggest that monitoring projects and empirical studies that focus on changes in biodiversity in semi-natural grasslands should include the assessment of species evenness – as a complement to the assessment of spe-cies richness. In addition, our results indicated that the development and persistence of a species-rich and even grassland vegetation was favoured in areas that have historically (in the 19th century) been surrounded by grasslands. Information on landscape history should, whenever possible, be incorporated into the planning of strategies for grassland conservation.

Abandonment or biomass production? Phytodiversity responses to land-use changes of semi-natural grasslands in northern Europe

Article

Jun 2024
BIOL CONSERV

Are historical land use patterns and chemical soil characteristics complementary for assessing the restoration potential of Nardus grassland?

Article

Full-text available

Aug 2022

Aims: Historical land use legacies and chemical soil characteristics both explain either directly or indirectly the habitat quality of Nardus grassland, which is protected under the European habitat directive. Yet the relative importance and complementarity of both sets of variables are generally unknown. This knowledge is also relevant for practical reasons, as historical land use variables can be used in desktop spatial analyses, whereas soil characteristics require field surveys to collect samples for laboratory analyses. To this end, we aim to disentangle the relative importance of historical land use legacies and soil chemistry for the Nardus grassland quality, and determine the potential of habitat suitability mapping for predicting potential restoration areas. Location: Natura 2000 grasslands in Flanders (northern Belgium) Methods: We compared the model performance of three generalized additive models (GAM), using either land use history metrics, soil chemistry, or both as explanatory variables, with the Nardus grassland indicator species count as response. Results: All three models were able to predict areas suitable for at least 3 Nardus grassland indicator species with high sensitivity and specificity. However, minimum 4 indicator species are required for a favorable conservation status of Natura 2000 Nardus grasslands in Flanders. Using this threshold to detect high priority zones, the model based on historical land use variables resulted in a lower sensitivity than models which included soil chemistry. Conclusions: We suggest a two‐step approach, with an a priori desktop spatial analysis based on historical land use variables subdivided in a high priority zone and lower priority zone. If the targeted area for restoration or conservation can be found within the high priority zone, additional soil analysis are only required to help guide conservation and restoration measures. If additional sites are considered within the lower priority zone, a field survey to collect additional soil data is recommended.

Do Geographically Isolated Grasslands Follow the Principle of Island Biogeography in a Landscape Scale? Taking Poyang Lake Grassland as an Example

Article

Full-text available

Oct 2022

As one of the basic theories of biodiversity conservation, island biogeography has been widely accepted in the past decades. Originally, island biogeography was put forward and applied in oceanic environments. But later on, it was found out that the application was not only limited to oceanic islands, but also in terrestrial environments with relatively isolated conditions. In terms of biodiversity level, island biogeography generally focuses on a small scale, such as species diversity and genetic diversity. The studies of biodiversity on a large-scale based on island biogeography, such as ecosystem and landscape scales, were seldomly conducted. Taking Poyang Lake, the largest fresh water lake in China as case study area, 30 grasslands were randomly selected to study whether island biogeography can be applied to grasslands at a landscape level from three island attributes (area, distance and shape), and the most important ecological variable (flooding) in Poyang Lake. The results showed that in general, grasslands have the property of an island, and follow the basic principle of island biogeography. We found the area and flooding duration were the two most important determinants of landscape diversity. There was a significant positive correlation between the grassland area and the landscape diversity, which could be well expressed by logarithmic function model (R2 = 0.73). There was a negative correlation between flooding duration and landscape diversity, which could be described by an inverse model (R2 = 0.206). The distance to mainland and the shape of grassland were correlated with landscape diversity, but the fitting result of the models was not as good as expected. The possible reason could be that Poyang Lake is a seasonal lake, the water level varies with hydrological conditions, so that the grasslands are not strongly isolated and their shape is not stable enough required by island biogeography. Furthermore, it indicates that besides area, distance and shape attributes, flooding strongly affects the biodiversity of grassland vegetation, and should not be ignored when applying island biogeography theory to Poyang Lake. This study is expected to be a supplement for island biogeography in terrestrial environments, and the results are expected to benefit for the biodiversity conservation in Poyang Lake.

Patch three-dimensional effect for plant species diversity of urban remnant mountain in multi-mountain city

Article

Full-text available

Jul 2022
ECOL INDIC

In some karst mountainous areas, with the urban expansion driven by rapid urbanization, a large number of natural mountains that were not suitable for development and construction were embedded into the urban built environment, forming urban remnant mountains(URMs). In this study, we conducted a indicator system to explore the relationship between morphological characteristics of URM and its plant species diversity. The results showed that: (i) The two boundary plane morphological indicators of URMs were significantly associated with its plant species α and β diversity; among the overall morphological indicators, mountain form factor (MFF) was significantly associated with plant species α and β diversity, mountain size coefficient (MSC) was negatively related to Margalef (R) index, and mountain volume density (MVD) had no significant relationship with plant diversity. Additionally, surface morphological indicators were significantly negatively correlated with the Pielou (Jgi) index, and positively correlated with Jaccard (Cj) and Sorenson (Cs) indices. (ii) There were also differences in the influence of morphological characteristic indicators of URMs on the plant species diversity of its different slope position and slope direction. Mountain shape index (MSI), mountain fractal dimension (MFD) and MFF had significant influence on plant species α and β diversity indices of different slope position and slope direction; All surface indicators of URMs morphological characteristics were significantly associated with plant species α and β diversity indices on the southern slope of URMs. (iii) The effects of URMs morphological indicators on plant diversity of different life forms were different, and the influence of herb plant diversity was more significant. (iiii) The multiple regression analysis showed that the URM morphological characteristic indicators could explain the difference of plant species α diversity among different URMs, while the interpretation of plant species β diversity among URMs was poor. In general, the three-dimensional characteristics of the URM are complex and particularity, and the quantitative indicators of different dimensions all showed the impact on the plant species diversity of the URMs. This study demonstrated that the ecological processes of the URM habitats have more complex patch effects in response to interference as compared to the general remnant habitat.

Ecosystems and their functions Ecosystems and their functions Ecosystems and their functions

Conference Paper

Full-text available

Oct 2012

The importance of traditional agricultural landscapes for preventing species extinctions

Article

Full-text available

Apr 2021
BIODIVERS CONSERV

Ove Eriksson

The main paradigm for protection of biodiversity, focusing on maintaining or restoring conditions where humans leave no or little impact, risks overlooking anthropogenic landscapes harboring a rich native biodiversity. An example is northern European agricultural landscapes with traditionally managed semi-natural grasslands harboring an exceptional local richness of many taxa, such as plants, fungi and insects. During the last century these grasslands have declined by more than 95%, i.e. in the same magnitude as other, internationally more recognized declines of natural habitats. In this study, data from the Swedish Red List was used to calculate tentative extinction rates for vascular plants, insects (Lepidoptera, Coleoptera, Hymenoptera) and fungi, given a scenario where such landscapes would vanish. Conservative estimates suggest that abandonment of traditional management in these landscapes would result in elevated extinction rates in all these taxa, between two and three orders of magnitude higher than global background extinction rates. It is suggested that the species richness in these landscapes reflects a species pool from Pleistocene herbivore-structured environments, which, after the extinction of the Pleistocene megafauna, was rescued by the introduction of pre-historic agriculture. Maintaining traditionally managed agricultural landscapes is of paramount importance to prevent species loss. There is no inherent conflict between preservation of anthropogenic landscapes and remaining ‘wild’ areas, but valuating also anthropogenic landscapes is essential for biodiversity conservation.

Ecosystems and their functions Ecosystems and their functions Ecosystems and their functions

Book

Full-text available

Oct 2012

Foreword As grassland represents a very important ecosystem in the world it is not surprising that a lot of research activities are focused on this. Many scientists from all over the world have been included in many major international ecological projects. These studies have resulted in many interesting results and a better understanding of the grassland ecosystem. In the last two decades the topic of grassland ecology research has changed. Many projects are now dealing with such aspects as the impact of global changes in the atmosphere on grassland and the influence of some of the negative factors on plants or communities. Grassland studies were typically on integration of grassland, managed or not managed by man. After a few decades studying high levels of grassland utilisation (high fertilizer levels, very intensive grazing, overgrazing, etc.) nowadays much more attention is being paid, and this will increase in the future, to keeping a high level of biodiversity and to analysing grassland without utilisation. In these proceedings we hope to give a picture of the ecological study of grassland, not only in our country but also in surrounding states. Our institute welcomes you all here to study this future with us. We are much obliged to all the participants who were kind enough to submit papers for publication in the proceedings and giving us all a better overview of grassland research in other countries.

The long-term legacy of historical land cover changes

Thesis

Jan 2019

Jens Kolk

Over the last years there is an increasing awareness that historical land cover changes and associated land use legacies may be important drivers for present-day species richness and biodiversity due to time-delayed extinctions or colonizations in response to historical environmental changes. Historically altered habitat patches may therefore exhibit an extinction debt or colonization credit and can be expected to lose or gain species in the future. However, extinction debts and colonization credits are difficult to detect and their actual magnitudes or payments have rarely been quantified because species richness patterns and dynamics are also shaped by recent environmental conditions and recent environmental changes. In this thesis we aimed to determine patterns of herb-layer species richness and recent species richness dynamics of forest herb layer plants and link those patterns and dynamics to historical land cover changes and associated land use legacies. The study was conducted in the Prignitz, NE-Germany, where the forest distribution remained stable for the last ca. 100 years but where a) the deciduous forest area had declined by more than 90 per cent (leaving only remnants of "ancient forests"), b) small new forests had been established on former agricultural land ("post-agricultural forests"). Here, we analyzed the relative importance of land use history and associated historical land cover changes for herb layer species richness compared to recent environmental factors and determined magnitudes of extinction debt and colonization credit and their payment in ancient and post-agricultural forests, respectively. We showed that present-day species richness patterns were still shaped by historical land cover changes that ranged back to more than a century. Although recent environmental conditions were largely comparable we found significantly more forest specialists, species with short-distance dispersal capabilities and clonals in ancient forests than in post-agricultural forests. Those species richness differences were largely contingent to a colonization credit in post-agricultural forests that ranged up to 9 species (average 4.7), while the extinction debt in ancient forests had almost completely been paid. Environmental legacies from historical agricultural land use played a minor role for species richness differences. Instead, patch connectivity was most important. Species richness in ancient forests was still dependent on historical connectivity, indicating a last glimpse of an extinction debt, and the colonization credit was highest in isolated post-agricultural forests. In post-agricultural forests that were better connected or directly adjacent to ancient forest patches the colonization credit was way smaller and we were able to verify a gradual payment of the colonization credit from 2.7 species to 1.5 species over the last six decades.

Land-use history influence the vegetation in coniferous production forests in southern Sweden

Article

May 2019
FOREST ECOL MANAG

During the last centuries, land use in Europe intensified, which has led to a drastic decrease in the cover of semi-natural grasslands. In Sweden, much of the lost grasslands was turned into forest. This study investigated if species typical of managed grasslands could be found in coniferous production forests more than 80 years after grassland management ceased. Species and trait composition for plants was investigated in two types of forest differing in land use history (meadow in the 1870s or continuous coniferous forest), and in reference grasslands. The average plant species richness as well as the richness of grassland indicator species were 30% higher in forests with a history as meadow compared to in forests with a history as forest, hence clear signs of historical grassland management in today’s forests. Compared with forests with continuous coniferous history, vegetation in forests with a meadow history tended to be more similar to reference grassland regarding both plant species and especially plant trait composition. The study provides proof of remnant grassland populations in coniferous production as the source for the biodiversity of clearcuts, rather than seed dispersal or seed bank survival. The result highlights the importance of land use for biodiversity of clearcuts, and points to the potential value of forests with a history of meadow in grassland conservation and restoration.

Land-use history influence the vegetation in coniferous production forests in southern Sweden

Article

Mar 2019
FOREST ECOL MANAG

Per Milberg

During the last centuries, land use in Europe intensified, which has led to a drastic decrease in the cover of semi-natural grasslands. In Sweden, much of the lost grasslands was turned into forest. This study investigated if species typical of managed grasslands could be found in coniferous production forests more than 80 years after grassland management ceased. Species and trait composition for plants was investigated in two types of forest differing in land use history (meadow in the 1870s or continuous coniferous forest), and in reference grasslands. The average plant species richness as well as the richness of grassland indicator species were 30% higher in forests with a history as meadow compared to in forests with a history as forest, hence clear signs of historical grassland management in today's forests. Compared with forests with continuous coniferous history, vegetation in forests with a meadow history tended to be more similar to reference grassland regarding both plant species and especially plant trait composition. The study provides proof of remnant grassland populations in coniferous production as the source for the biodiversity of clearcuts, rather than seed dispersal or seed bank survival. The result highlights the importance of land use for biodiversity of clearcuts, and points to the potential value of forests with a history of meadow in grassland conservation and restoration.

Forbs Rather Than Grasses as Key Factors Affecting Succession of Abandoned Fields - A Case Study from a Subalpine Region of the Eastern Tibet Plateau

Article

Full-text available

Sep 2017

Jin-Hua Li

Plant species richness decreased in semi-natural grasslands in the Biosphere Reserve Wienerwald, Austria, over the past two decades, despite agri-environmental measures

Article

Jun 2017
AGR ECOSYST ENVIRON

Both, agricultural intensification and abandonment caused a strong decline in plant species richness in semi-natural grasslands in Central Europe within the last decades. At a global scale, the Convention on Biological Diversity targeted at halting the decline of biodiversity by the end of 2010. Agri-environmental schemes (AES) have been developed at the national level to reach this biodiversity target in agricultural areas. We evaluated the effectiveness of Austrian agro-environmental schemes on species-rich grasslands within the UNESCO Biosphere Reserve Wienerwald. We found a general decrease of vascular plant species richness at 95 sites, from an average of 43 species in 1990/92 to 31 species in 2011. The average decrease of species classified as threatened according to the national Red List from 12 to 7 and the parallel increase of widespread, nitrophilous species indicates a reduced conservation value of observed meadows. Species losses did not differ between mesic meadows of the Arrhenatherion type (EU habitat type 6510) and more nutrient-poor, semi-dry Brometalia grasslands (EU habitat type 6210), indicating the sensitivity to changes in agricultural management regimes even for more intensively used grassland types. AES decelerated this overall trend but could not stop biodiversity losses over the past two decades. Although the maintenance of grassland management through AES prevented biodiversity loss in areas which otherwise would have been abandoned, adaptations of the Austrian AES are desirable to effectively conserve biodiversity at agricultural sites.

Patch isolation and shape predict plant functional diversity in a naturally fragmented forest

Article

Jan 2017

Aims It is known that taxonomic diversity can be predicted by the spatial configuration of the habitat, in particular by its area and degree of isolation. However, taxonomic diversity is a poor predictor of ecosystem functioning. While functional diversity is strongly linked to the functionality and stability of ecosystems, little is known about how changes in the spatial configuration of the habitat affect functional diversity. In this study, we evaluated whether the spatial configuration of forest patches predicts the functional diversity of plants in a fragmented forest. Methods Five functional leaf traits (leaf dry matter content, leaf punch force, specific leaf area, leaf size and leaf thickness) were measured for 23 dominant plant species in 20 forest patches in a naturally fragmented forest on the Yucatan Peninsula. Abundance-weighted multivariate and individual trait metrics of functional diversity were calculated and correlated with size, degree of isolation and the shape of forest patches. Important Findings Patch shape was negatively correlated with multivariate and individual trait (leaf dry matter content and leaf size) metrics of functional diversity. Patch isolation measures were also negatively correlated with individual trait (leaf dry matter content, leaf punch force and leaf size) metrics of functional diversity. In other words, greater patch shape irregularity and isolation degree impoverish plant functional variability. This is the first report of the negative effects of patch shape irregularity and isolation on the functional diversity of plant communities in a forest that has been fragmented for a long time.

Long-Term Ecological Research Between Theory and Application

Book

Jan 2010

Ecosystems change on a multitude of spatial and temporal scales. While analyses of ecosystem dynamics in short timespans have received much attention, the impacts of changes in the long term have, to a great extent, been neglected, provoking a lack of information and methodological know-how in this area. This book fills this gap by focusing on studies dealing with the investigation of complex, long-term ecological processes with regard to global change, the development of early warning systems, and the acquisition of a scientific basis for strategic conservation management and the sustainable use of ecosystems. Theoretical ecological questions of long-term processes, as well as an international dimension of long-term monitoring, observations and research are brought together. The outcome is an overview on different aspects of long-term ecological research. Concepts and results of case studies in both aquatic and terrestrial ecosystems are discussed. The different time dimensions, as well as scales from the community and ecosystems up to the landscape scale are included. Finally, research is linked with application in different fields of ecology, and urgent future infrastructural, methodological and research demands and challenges are described. This book will be of interest not only to ecologists, conservation biologists, biodiversity scientists and environmentalists, but also to administrators of protected areas and natural resource managers.

Profitability of the production of energy grasses on marginal agricultural land in Sweden

Article

Dec 2015
BIOMASS BIOENERG

The objective of this study was to analyse the economic profitability of producing energy-grass fuels on marginal agricultural land in Sweden. Small and irregular-shaped fields, fields with less fertile soils, headlands and border strips were included, all located in four different regions representing different cultivation conditions. The grasses studied were reed canary grass (RCG) and ley, which were to be used as a solid fuel and biogas substrate, respectively. The economic profitability of these grasses was compared with the profitability of fallow land and the cultivation of winter wheat and spring barley. The results showed that all the alternatives studied, except winter wheat in southern Sweden, had a negative economic net gain (no subsidies included). Generally, the economic losses were greatest for small and irregular-shaped fields. Fallow had a higher economic competitiveness than RCG and ley for all marginal field categories and locations. RCG used as a solid fuel in boilers generally had a higher competitiveness than ley for biogas. However, when ley was used fresh without storage, its competitiveness improved considerably. Taking the direct payment subsidies and the economic value of reduced nutrient leakage into account, the economic net gain improved considerably. Nevertheless, fallow land still had a somewhat higher net gain than RCG for all field categories. Further cost reductions and higher revenues, including possible agro-environmental economic compensation, are required if RCG and ley are to be able to compete with fallow land.

Historical and recent fragmentation of temperate floodplain grasslands: Do patch size and distance affect the richness of characteristic wet meadow plant species?

Article

Sep 2015

Patch size and isolation are thought to have a large influence on the extinction risk of specialist plant species in grassland fragments in the modern agricultural landscape. We combined a re-sampling study in semi-permanent floodplain grassland plots with a GIS-based analysis of historical (1950s/1960s) and recent landscape patterns. Based on historical and recent vegetation maps and relevés from six study areas (plus a protected reference area) covering 50–60 years of vegetation change following agricultural intensification, we aimed at analysing the importance of fragmentation on the diversity of potentially sensitive specialist species of wet floodplain meadows in northern Germany. On the plot scale, we found 30–66 % reductions in species richness of these characteristic wet meadow plant species over time and an associated increase in the fragmentation of grassland habitats. Distance to the nearest suitable habitat had a modest negative effect on modern plot-scale richness, while the other tested landscape metrics (total meadow area, mean patch size and landscape proximity index distribution) had no significant influence. There was also no evidence for a legacy of historical landscape structure on current richness of specialist species. Instead, management intensity and its change over the past decades, as indicated by altered Ellenberg indicator values for nutrients and moisture, had a strong influence on plot-scale diversity. The results suggest that fragmentation is not the proximate cause of impoverishment and point to habitat deterioration as a main driver. We conclude that conservation measures in Central-European floodplain meadows should not only focus on large continuous grassland areas, but should also consider small meadow patches if they remained species-rich. © 2015, Institute of Botany, Academy of Sciences of the Czech Republic.

2010 Forest EcolMgt Gonzalez

Data

Full-text available

Sep 2015

The role of past and present management in the seed dispersal of grassland plants in the rural landscape

Article

Jan 2010

Alistair G Auffret

Effect of mining landscape history on local species diversity: a case study of the Yimin open-pit coal mine in Inner Mongolia

Article

Full-text available

Mar 2014

The exploration and utilization of mineral resources accelerates local economic and social development and simultaneously exacerbates the effects of climate and landscape changes, resulting in landscape fragmentation. Landscape change is widely considered as a major threat to species loss at a regional and global scale. However, how species diversity responds to landscape changes on a temporal scale has usually been ignored. In this study, we explored relationships between landscape and biodiversity (species level and functional group level) during different years (1975, 1990, 2000 and 2010) at the Yimin open-pit coal mine, a mine that has been exploited for more than 30 years and that has produced obvious fragmentation effects on the landscape in Hulunbuir City. The ongoing patterns of transformation of the landscape were measured using the landscape dominance index, the habitat integral index of connectivity (IIC), and the habitat probability of connectivity (PC) at seven different spatial scales. The main results were as follows: The present species diversity is significantly correlated with the landscape pattern indices of previous and earlier mining at a medium-sized spatial scale (4–8 km buffers). Different plant functional groups responded in various ways to changing landscape patterns. The species richness of perennial rhizome grasses was significantly correlated with the present small-scale landscape pattern (1–3 km), and the species richness of perennial forbs was significantly correlated with the previous and earlier mining large-scale landscape patterns (4–10 km). Perennial bunchgrasses were not significantly correlated with landscape patterns. We concluded that the time lag expressed by changes in plant species diversity occurred in response to changing patterns of construction and configurations of habitats in the landscape. The regional species pool determined the local species diversity. The connected habitat patches within a 4–8 km buffer region represented the principal species pool. The propagation strategies and dispersal traits of various functional groups were important mechanisms maintaining species diversity in a fragmented area.

Tidsåtgång för maskinarbeten på små fält - en simuleringsstudie Time demand for machine operations in small fields – a simulation study

Technical Report

Full-text available

Nov 2014

The machinery costs have an important impact on the economic profitability of crop production in small and irregular-shaped fields. In most cost calculations, the capacity of machinery operations in agriculture is given as a single value, which is assumed to be valid for all types of fields independent of field area, field shape, the presence of field obstacles, etc. This may result in misleading cost calculations for different crops and thus incorrect decision bases for the farmers. The main purpose of this study was to analyze the time demand for different machinery operations in small and irregular-shaped fields with the help of computer simulations. The objective was to get more field-specific capacity data that can be used for calculations of machinery costs. More precise basic data will give the farmers a better basis for decision when choosing crops in such fields. What is meant by the term a ‘small’ field is subjective and dependent on where the field is located. In a flat country with large-scale agriculture, a field of 5 ha may be regarded as ‘small’, whereas this area may be regarded as ‘large’ in forested areas. Of the four Swedish municipalities investigated in this study (Svalöv, Ronneby, Vingåker and Skellefteå), the average lot area was largest in Svalöv (6.7 ha) and smallest in Ronneby (1.9 ha). Furthermore, there is no unambiguous definition of what an ‘irregular-shaped’ field is. Often, however, the term is used to describe a field with several corners, narrow tips and ‘islands’ with un-cultivable land. It is often regarded that the more ‘irregular-shaped’ the field is, the more difficult (or costly) it is to cultivate. A comparison of the so-called shape index between the municipalities studied, indicated that fields in municipalities with a higher variability in topography and geographical structure (Ronneby and Vingåker) are more irregular-shaped. The time demand for machinery operations in rectangular fields was simulated using machinery work width, optimal (max) driving speed, field area and field shape as independent input variables. In the simulations, the time needed for turnings, curve driving (limited speed), acceleration/retardation, adjustments, stochastic stoppages, etc. were considered. The results showed, for example, that the time demand for a machine with a working width of 4.0 m, a driving speed of 8.0 km/h and working in a rectangular field with the shape 2:1 (length: width), was 36 min/ha when the field area was 1.0 ha, 26 min/ha when the field area was 5.0 ha and 24 min/ha when the field area was 15.0 ha. Thus, it was concluded that the field area was important to consider also for ‘regular-shaped’ rectangular fields. Simulations were also carried out for elongated rectangular fields (e.g. headlands and border strips). The results showed that the time for non-productive work (e.g. for in-field transports) can be considerable if the machinery work width is not well-adapted to the field width. The time demand for the mowing of grass (machinery width 2.25 m, driving speed 10.0 km/h, field area 1.0 ha) was compared for different ’irregular-shaped’ fields. Using a rectangular 2:1-field as a reference, the time needed varied from -4% (trapezium-shaped field) to +16% (a polygonal field with a circular impediment). The number of turnings (machine not in work) had a crucial impact on the results, but the extent to which the machine was driving in curves (machine in work but with a limited driving speed) was also an important factor. In the project, a simple method for calculating transport distances has been developed. The method was based on the fields’ block numbers.

Both local and landscape factors determine plant and Orthoptera diversity in the semi-natural grasslands of Transylvania, Romania

Article

Full-text available

Oct 2014

Semi-natural grassland supports a large proportion of biodiversity and ecosystem services in Europe, however, it is continuing to be destroyed or degraded. In addition to the clear role of local management in these processes, there is increasing evidence for wider landscape-scale effects on species richness and community composition of plants and animals. Most of this evidence comes from studies in highly altered western European landscapes with only fragments of remaining semi-natural grassland. In contrast, Eastern European countries such as Romania still contain large areas of semi-natural grassland, but this habitat is threatened by agricultural intensification and homogenization. We analyzed vascular plant and Orthoptera communities from species-rich pastures in Southern Transylvania, Romania, against a range of local and landscape factors. Species richness of plants had a highly significant positive relationship with landscape heterogeneity. Orthoptera species richness and abundance were negatively correlated with plant species richness, and increased with proportion of grassland in the landscape and local vegetation height. The results suggest that large and species-rich grassland communities can be significantly affected by both local and landscape scale land use changes, but effects can vary within and between taxonomic groups. Conservation measures such as agri-environment schemes should therefore seek to address landscape scale processes better, promoting a range of low-intensity land use practices in order to support a variety of landscape types.

Contingencies during the ecological restoration of semi-natural grasslands and their effects on plant species, functional traits and genetic diversity

Thesis

Full-text available

Oct 2013

Kenny Helsen

In an attempt to halt species and habitat loss across the continent, many restoration projects have been established across Europe. However, clear scientific insight in the processes governing the success of these restoration projects is currently limited, as traditional ecological restoration research mainly focuses on the species level and the effects of site-level conditions on assembly outcome. In this study, we evaluated several underexplored aspects of community assembly following restoration within several restored calcareous grasslands in the Viroin valley in southern Belgium. In an attempt to contribute to a better understanding of how different processes shape species colonization and community assembly following restoration, we examined the effects of the landscape configuration and contingencies on community assembly at different levels of diversity organization. More specifically, we looked at the species and functional trait level assembly of the above ground vegetation and the soil seed bank, on the one hand, and the population gene level during colonization of the long-lived grassland species, Origanum vulgare, on the other. Progressing assembly of the above ground vegetation was found to consist of a sequential replacement of generalist species with specialist species, which was reflected by a directional assembly at the functional trait level. Landscape configuration significantly affected this assembly, as grassland isolation slowed down assembly at both the species and the trait level. More interestingly, spatial isolation was found to act as a trait filter, independent of assembly age. We found a proportionally higher occurrence of species with light seeds and a high seed attachment potential in more isolated restoration patches, which could indicate that dispersal is likely more limited in isolated grasslands. Furthermore, we compared differentiation among these restored grasslands based on the species and functional trait composition. These analyses showed that trait similarity among grasslands clearly increased with the amount of time since restoration, indicating trait convergence through time. At the species level, we found no evidence of convergence through time, with even a trend towards divergence. These results support the idea that only limited niches occur, which are only filled by species that have the appropriate functional traits, resulting in clear deterministic assembly at the trait level. Species identity, on the contrary, has no role in this niche filling. The first appropriate species to reach a restoration site will be the ones that get established, resulting in divergence of the species composition among restored grasslands. When comparing the genetic diversity of recent populations and old, putative source populations of Origanum vulgare, we did not observe decreased genetic diversity in recent populations, nor inflated genetic differentiation among them. Nevertheless, a significantly higher inbreeding coefficient was observed in recent populations, although this was not associated with negative effects on two measured proxies related to reproductive success. Our analyses indicated that colonization occurred from several source populations, with sufficient gene flow overcoming any large genetic founder effects, which likely increased the overall metapopulation viability of O. vulgare. Gene flow was nonetheless affected by the spatial configuration of the grasslands as gene flow into the recent populations mainly originated from nearby source populations. Comparing the soil seed bank composition of restored and ancient grassland, we observed that the species richness decreased through time. This was reflected at the trait level by a replacement of traits associated with generalist therophytes by traits typical for chamaephytes and grassland specialists. While species differentiation remained relatively constant, trait differentiation was observed to decrease through time. Only the species composition of ancient grasslands was affected by spatial isolation. The seed bank composition of ancient grasslands was furthermore observed to be a nested subset of that of young grasslands. These results suggest that community disassembly occurs in the seed bank. This implicates that directly following restoration, a large and diverse seed bank is formed, followed by a gradual net loss of species. Although theory predicts this species loss to be driven by seed persistence traits, we found that this was not the case in our system, but that species loss was likely governed by functional changes in the above ground community. This disassembly process results in one deterministic end state at the trait level, but not at the species level. Our results suggest that several parallels in assembly patterns exist among the different organizational levels of diversity, most notably among both the species and functional trait level of the above ground community and the soil seed bank. Nevertheless, clear differences among the different organizational levels also remain, illustrating the importance of a multi-level approach to gain in-depth insight in community assembly following restoration. More specifically, restoration monitoring should evaluate the genetic viability of colonizing species in parallel with community assembly since colonization itself is not a guarantee for successful establishment. The soil seed bank can furthermore significantly affect above ground assembly and should for this reason be taken into account. Finally, we observed that the spatial configuration of the study area and priority effects significantly affect assembly patterns, and should therefore be included when designing restoration projects.

Colonization credit of post-agricultural forest patches in NE Germany remains 130–230 years after reforestation

Article

Full-text available

Feb 2015
BIOL CONSERV

In many temperate regions worldwide, a large portion of deciduous forest grows on former agricultural land, while a smaller portion is ‘ancient’ forest on sites with no historical record of agricultural land use. The differences in species diversity between ancient and post-agricultural forests have been well documented. However, in regions where forest fragmentation occurred only a few centuries ago, it remains unclear whether these differences are due to an extinction debt in ancient forests (i.e., a delay in local species extinction), a colonization credit in post-agricultural forests (i.e., species are yet to colonize a patch), or both. Additionally, our knowledge on how soil conditions and landscape configuration interact with species’ traits to determine the colonization credit is limited. Here, we surveyed ancient and post-agricultural forest patches in NE Germany to quantify the magnitude of the colonization credit and identify its determinants. The colonization credit in an average forest patch amounted to 4.7 forest specialist species and ranged up to 9 species in highly isolated patches. In contrast, we found more species than predicted in patches better connected to ancient forests. The colonization credit was not smaller in older patches than it was in younger ones. Species with a low dispersal potential and a low seed output contributed most to the colonization credit. Our study demonstrates that in a landscape where the extinction debt has already been paid and only a small fraction of ancient forest is left, the recovery of forest specialist diversity in post-agricultural forests may take several centuries.

Historical Landscape Perspectives on Grasslands in Sweden and the Baltic Region

Article

Full-text available

Mar 2014

A landscape perspective is generally recognized as essential for conservation biology. The main underlying reason is that species respond to features of the landscape at various spatial scales, for example habitat area, connectivity, and matrix habitats. However, there is also an “historical” component of a landscape perspective, which has not received similar attention. The underlying reasons for historical effects are that humans have influenced landscapes during several millennia and that species and communities may respond slowly to land use change. An historical perspective on landscapes also relates to how we perceive “natural” vs. “cultural” landscapes, and thus how conservation actions are motivated and valuated. We review studies from Sweden and the Baltic region in the context of an historical landscape perspective, focusing on semi-natural grasslands, i.e., grasslands formed by long-term human management for grazing and hay-making. Semi-natural grasslands are today a high concern for conservation. Historical effects are ubiquitous on species distributions and patterns of species richness, and have important implications for developing informed conservation programs in semi-natural grasslands, particularly with regard to assumptions of historical baselines, the choice of conservation targets, and insights on time-lags in the response of species to current landscape change.

Vegetation in clear-cuts depends on previous land use: A century-old grassland legacy

Article

Full-text available

Oct 2014

Plant species richness in central and northern European seminatural grasslands is often more closely linked to past than present habitat configuration, which is indicative of an extinction debt. In this study, we investigate whether signs of historical grassland management can be found in clear-cuts after at least 80 years as coniferous production forest by comparing floras between clear-cuts with a history as meadow and as forest in the 1870s in Sweden. Study sites were selected using old land-use maps and data on present-day clear-cuts. Species traits reflecting high capacities for dispersal and persistence were used to explain any possible links between the plants and the historical land use. Clear-cuts that were formerly meadow had, on average, 36% higher species richness and 35% higher richness of grassland indicator species, as well as a larger over-all seed mass and lower anemochory, compared to clear-cuts with history as forest. We suggest that the plants in former meadows never disappeared after afforestation but survived as remnant populations. Many contemporary forests in Sweden were managed as grasslands in the 1800s. As conservation of remain-ing grassland fragments will not be enough to reduce the existing extinction debts of the flora, these young forests offer opportunities for grassland restora-tion at large scales. Our study supports the concept of remnant populations and highlights the importance of considering historical land use for under-standing the distribution of grassland plant species in fragmented landscapes, as well as for policy-making and conservation.

Plant diversity in heterogeneous landscapes: Implication of landscape context and management in grassland communities

Presentation

Aug 2011

Background/Question/Methods Plant diversity patterns are structured by ecological processes operating at multiple scales over space and time. Despite that the importance of dispersal and habitat heterogeneity in structuring and maintaining plant diversity is increasingly recognized, the effects of landscape context and habitat quality are seldom studied simultaneously. Most studies have focused on species diversity in a set of similar habitats, often depicting the landscape as a binary template and eluding the potential role of adjacent habitats on plant diversity. Yet, communities are open systems linked to surrounding communities through reciprocal dispersal likely to affect species’ extinction, colonization and coexistence at both local and regional scales. We investigate how changes in management and landscape context affect plant community structure in semi-natural pastures and adjacent forests. Using 25 island landscapes, we examine the effect of grazing management and the proportion of open land in the surrounding landscape on composition and diversity of species assemblage in plant communities. Specifically, we (1) investigate the effect of spatial proximity and habitat quality on species composition in grassland communities and (2) test hypothesized relationships between species assemblage structure and change in management and landscape context at both habitat and landscape scales. Results/Conclusions Our results highlight the importance of habitat quality and species sorting on species assemblage in heterogeneous landscapes, but also the role of dispersal between adjacent habitats in structuring and potentially promoting species coexistence in local communities. Structural equation models show clear difference in the response of grassland communities inhabiting contrasting habitats. While reduced area of open land and cessation of livestock grazing induce compositional shift without direct effect on species diversity in open pastures, we observe substantial change in spatial turnover, composition, and species diversity in adjacent forests. These results suggest that diversity, as well as its spatial structure, is influenced by inflow from adjacent habitats affecting species coexistence and communities’ capacity to track abiotic and biotic changes across space and time. In conclusion, our study highlights the influence of adjacent habitats on structuring local species assemblage and maintaining diversity at both local and regional scales through the interplay of species sorting, mass effect, and spatiotemporal storage. It especially stresses the importance to consider multiple scales when assessing and managing diversity in heterogeneous and dynamic landscapes.

Moving towards the edge: Matrix matters!

Article

Jan 2013

Sara AO Cousins

In this issue of the Journal of Vegetation Science, Chabrerie et al. use plant inventories and geographical data to investigate effects on species richness and turnover caused by management intensity in the surrounding matrix in new and old forest fragments. Although forest edge age was important, more intensive management of the matrix clearly sharpened the edge-interior gradient. In this issue of the Journal of Vegetation Science, Chabrerie et al. use plant inventories and geographical data to investigate effects on species richness and turnover caused by management intensity in the surrounding matrix in new and old forest fragments. Although forest-edge age was important, more intensive management of the matrix clearly sharpened the edge-interior gradient.

Plant community assembly in semi-natural grasslands and ex-arable fields: A trait-based approach

Article

Jan 2014

QuestionThe assembly of plants into communities is one of the central topics in plant community ecology. The objective of this study was to investigate how plant functional trait diversity and environmental factors influence community assembly in two different grassland communities, and if variation in these factors could explain the difference in species assembly between these communities. LocationSix grazed ex-arable fields and eight semi-natural grasslands in southeast Sweden. Methods We estimated species abundance and measured soil attributes at each site. For each species within each site we measured specific leaf area (SLA), leaf dry matter content (LDMC) and seed mass. We analysed the data both for abundance-weighted species values and species occurrence. ResultsTrait gradient analysis indicated random distribution of species among sites, while CCA analysis indicated that both soil phosphorus and moisture were related to species assembly at a site. Correlations and fourth-corner analysis also revealed a relationship between measured species traits and soil phosphorus and moisture. There was a lower average seed mass and higher SLA of species in ex-arable fields compared to species in semi-natural grasslands. Conclusions Even though trait gradient analysis indicated that plant community assembly in the studied grasslands was random, other results implied that species occurrence and abundance was influenced both by environmental factors and species traits. Higher species richness in semi-natural grasslands was associated with more large-seeded species found there compared to ex-arable fields, indicating that large-seeded species establish in grasslands later than small-seeded species.

At which spatial scale are plant species composition and diversity affected in beech forests?

Article

Full-text available

Dec 2011
ANN FOR SCI

• Context Landscape structure is crucial for forest conservation in regions where the natural forest is fragmented. Practical conservation is currently shifting from local stands to a landscape perspective, although few studies have tested the relative effects of different spatial scales on plant species composition and diversity in forests. • Methods We studied vascular plants and 17 predictor variables related to landscape (i.e. patch size or the surrounding landscape matrix) and stand conditions (i.e. soil pH and stand structure) in 50 semi-natural beech (Fagus sylvatica L.) forests in the northern Iberian Peninsula. • Aims We analysed the effect of landscape heterogeneity and stand-associated environmental conditions on plant species composition and diversity. Moreover, we studied the influence of these scales on the diversity of different life forms. • Results Plant species composition and diversity responded primarily to suitable habitat proportions in the surrounding landscape and secondarily to soil pH. The response to these factors differed among life forms. Species diversity, especially tree and shrub diversity, increased with increases in the proportion of ecologically similar habitat in the surrounding landscape (forests dominated by Quercus spp.). Species diversity (primarily herb diversity) also increased with increasing soil pH. • Conclusion Future landscape management should seek to produce a heterogeneous matrix comprising patches of natural, unmanaged and managed deciduous forest and including other traditional uses and forest plantations.

Local spatial context measurements used to explore the relationship between land cover and land use functions

Article

Aug 2013
INT J APPL EARTH OBS

Urban land use types contribute to grassland conservation: The example of Berlin

Article

May 2013

Urbanisation is an important driver of biodiversity loss, also contributing to habitat loss and fragmentation of grasslands at the urban-rural interface. While urban green spaces are known to include many grassland habitats, it is uncertain to what extent urban land use types harbour grasslands of special conservation interest and whether patch characteristics and connectivity of these differ from grasslands on agricultural land. By relating the city-wide biotope mapping to the land use mapping of Berlin, Germany, we assessed (1) to which specific urban land use types the major grassland biotope types belong, (2) differences in patch characteristics and connectivity, and (3) the conservation value of grassland patches at a typological level by means of their legal protection status. Grasslands cover 5% of Berlin's surface, and 43% of that area is assigned to legally protected grassland types. The majority of legally protected grassland (71%) lies on urban land opposed to 29% on agricultural land. Airports and historic parks, which only cover 2% of land in Berlin, contain one-third of all protected dry grasslands. Wet grassland is more confined to agricultural land. In airports and agricultural areas, grassland patches are larger but of a more complex shape than those in historic parks. In airports, grassland patches show greater connectivity as they are situated in grassland-dominated surroundings. Grassland in historic parks appears to be more vulnerable due to smaller patch sizes and higher fragmentation. The example of Berlin demonstrates that the urban green infrastructure can clearly contribute to grassland conservation and may thus partially compensate for the decline of traditional grasslands in cultural landscapes. It will be important to involve residents and landowners in urban grassland conservation and management because most grassland of special conservation interest (57%) was found outside of conservation areas.

Past and present management influences the seed bank and seed rain in a rural landscape mosaic

Article

Oct 2011
J APPL ECOL

1. Seed bank and seed rain represent dispersal in time and space. They can be important sources of diversity in the rural landscape, where fragmented habitats are linked by their histories. 2. Seed bank, seed rain and above-ground vegetation were sampled in four habitat types (abandoned semi-natural grassland (ABA), grazed former arable field (FAF), mid-field islet (MFI) and grazed semi-natural grassland (SNG)) in a rural landscape in southern Sweden, to examine whether community patterns can be distinguished at large spatial scales and whether seed bank and seed rain are best explained by current, past or intended future vegetation communities. 3. We counted 54 357 seedlings of 188 species from 1190 seed bank and 797 seed rain samples. Seed bank, seed rain and above-ground vegetation communities differed according to habitat. Several species characteristic of managed grassland vegetation were present in the seed bank, seed rain and vegetation of the other habitats. 4. The seed banks of SNGs and the seed rain of the FAFs were generally better predicted by the surrounding above-ground vegetation than were the other habitat types. The seed rain of the grazed communities was most similar to the vegetation in the FAFs, while the seed banks of the abandoned grasslands most resembled the vegetation in SNGs. 5. Gap availability and seed input could be limiting the colonisation of target species in FAFs, while remnant populations in the seed bank and the presence of grassland specialists in the above-ground vegetation indicate that abandoned grasslands and mid-field islets could be valuable sources of future diversity in the landscape after restoration. 6. Synthesis and applications. SNG communities are able to form seed banks which survive land-use change, but their seed rain does not reflect their above-ground communities. It is important that grassland plants set seed. By connecting existing grasslands with restoration targets, increased disturbance in the target habitats would allow for colonisation via the seed bank or seed rain, while decreased grazing intensity would benefit seed production in the source grasslands. Otherwise, landscape-wide propagule availability might increase with a more varied timing and intensity of management.

Biodiversity in Chestnut Woodlots: Management Regimen vs Woodlot Size

Data

Full-text available

Oct 2012

This paper analyzes the effect of woodlot size and land-use intensity on the species richness of vascular plants, birds, beetles, and ants in Castanea sativa (chestnut) woodlots of the northwestern Iberian Penin-sula included in the category "9260 Castanea sativa woodland", "Annex I, DC 92/43/European Commu-nity". The results show that the surface area of the woodlot did not affect the richness of vascular plants and ants but did affect birds and beetles. The level of abandonment of the woodlot affected only the rich-ness of vascular plants, while the use level had no significant impact on species richness of any of the groups. The degree of maturity of the woodlot, estimated by the tree-trunk circumference, determined only the richness of plants but not that of different groups of animals. In conclusion: 1) Plants and animals responded differently to woodlot size, abandonment, and the degree of maturity of the woodlots; 2) Tradi-tional agricultural practices do not negatively affect the biodiversity of the chestnut woodlots of the northwestern Iberian Peninsula or favor plant diversity; and 3) A traditional use of these woodlots may continue to play an important role in maintaining the diversity of plant species in the area.

Landscape care paradoxes: Swedish landscape in a European context

Article

Full-text available

Nov 2012
GEOFORUM

Contemporary European agriculture has a number of additional aims beside of food production, such as safeguarding environmental services and conservation values. Substantial efforts at official levels are aimed towards sustainable development but also towards maintaining values of what may be termed vanishing landscapes. Selected areas and landscape features are set aside for protection or restoration. Individual efforts of this type have a long history in Sweden, and the issue has recently received increased attention, primarily due to more ambitious government goals concerning biodiversity conservation and Sweden’s ratification of the European Landscape Convention. This has resulted in an increased scientific and official interest in vanishing values in the rural landscape, where parts of Eastern Europe, such as the Maramures district in Romania, have been used as model examples of land use regimes which in the past was common in Sweden. In this context, the dilemma of romanticizing peasants’ use of land is highlighted and discussed more than has hitherto been done. This paper sheds light on some paradoxes inherent in official policies in relation to land use practices concerning the management of rural landscapes in Sweden, and relates the Swedish situation to a contrasting example of landscape practice in Romania. We discuss the concept of landscape care in relation to the construction and perception of landscape values and valuable landscapes through the lenses of rural realities and official policies. When Swedish authorities engage in the promotion of landscape care, they tend to work with slices of land, specific predefined values and individual farmers, and they often disregard the need to treat the landscape as a socio-ecological complex dynamic in space and time. We discuss how environmental policy generally could be improved through the adoption of a more inclusive and flexible approach towards aiding the different aims inherent in multifunctional rural landscapes.

Regeneration of sandy old-fields in the forest steppe region of Hungary

Article

Full-text available

Sep 2011

Abandoned agricultural fields are potential sites for the regeneration of natural vegetation, and land abandonment is a widespread phenomenon in the developed world. We studied the vegetation of 161 old-fields in the Kiskunság, central Hungary. Old-fields were categorized into three age groups based on historical aerial photographs: fields abandoned 1–7, 8–20, and 21–57 years ago. Old-field vegetation was compared to potential target communities (open and closed grassland and forest) based on the richness and cover of predefined species groups (all species, neophytes, characteristic species of natural habitats). In general, the medium- and old-aged old-fields only slightly differed from each other, and were more similar to open natural grasslands than to closed ones, although they occupied environments that were intermediate between open and closed grasslands. Forest species establishment was limited in the old-fields; therefore, forest regeneration seems to be unlikely on old-fields at a decadal time scale. The dominance of alien species only slightly declined with old-field age and was much higher than in natural grasslands. The finding that open grassland communities recovered on these old-field sites, but were accompanied by stable alien components, suggests that these communities could be regarded as a new combination of species, or novel communities, with a considerably high conservation value.

Impact of Land Use Changes on the Diversity and Conservation Status of the Vegetation of Mountain Grasslands (Polish Carpathians)

Article

Full-text available

Feb 2022

In recent decades, in the Polish Carpathians, agriculture has undergone major changes. Our goal was to investigate whether the former management (plowing or mowing and grazing) had an impact on the current species composition, diversity and conservation status of the vegetation of grazing areas. We carried out vegetation studies on 45 grazing sites with traditional methods of grazing (transhumant pastoralism). The survey covered both old (continuous) grasslands and grasslands on former arable land. The most widespread were Cynosurion pastures and mesic Arrhenatherion grasslands. Wet Calthion meadows occurred at more than a half of grazing sites, while nutrient-poor Nardetalia grasslands were only recorded at several grazing sites. For each grazing site, we used soil maps from the 1960s to read land use in the past. We mapped present grassland and arable land area. Compared with the 1960s, there was a significant decrease in the area of arable land and an increase in grasslands. Species diversity was greater in grazing sites where grasslands developed on former arable land. However, this diversity was associated mainly with the occurrence of common grassland species. Cynosurion pastures and wet Calthion meadows had the best conservation status, while nutrient-poor Nardetalia grasslands were the worst preserved. We concluded that the conservation status of mesic grasslands and pastures is dependent on the present diversity of land use within a grazing site, rather than the land use history 60 years ago. This is the first study of the natural, not economic, value of pasture vegetation in the Polish part of the Carpathians.

The decline of Gentianella campestris : three decades of population development of an endangered grassland plant in Sweden

Article

Full-text available

Mar 2021

Species‐rich semi‐natural grasslands are declining all over northern Europe, and many plant species confined to such grasslands are currently under threat. We studied the development of populations of one such species, the field gentian Gentianella campestris, during three decades in the County of Södermanland, south of Stockholm, Sweden. Gentianella campestris is Red Listed as Endangered in Sweden. It is a strict biennial, and as far as known with only a transient seed bank. Large population fluctuations are a characteristic of this species, and its life history makes the species inherently sensitive to factors causing population reductions. We found that the number of sites with G. campestris has declined with over 60% in the last three decades. The total number of flowering individuals also show a strong decreasing trend, although there was an increase the last year (2020) at a few remaining sites. Cessation of grazing management is a major cause of the decline, but populations also disappeared from managed sites. It is possible that the management has been inappropriate, and circumstantial evidence suggests that summer drought might be an additional cause of population decline. Data from 2018, a year with an exceptional summer drought, supports this explanation. A sowing experiment indicated that recruitment of new populations is unlikely in the present‐day landscape where most vegetation is unsuitable for G. campestris. Due to the poor prospects for long‐term maintenance of grazing management in still remaining semi‐natural grasslands, and the decline even at sites with current management, G. campestris faces a risk of becoming regionally extinct within the coming decades.

Towns, Ecology, and the Land

Book

Feb 2019

Richard T. T. Forman

Towns and villages are sometimes viewed as minor, even quaint, spots, whereas this book boldly reconceptualizes these places as important dynamic environmental 'hotspots'. Multitudes of towns and villages with nearly half the world's population characterize perhaps half the global land surface. The book's pages feature ecological patterns, processes, and change, as well as human dimensions, both within towns and in strong connections and effects on surrounding agricultural land, forest land, and arid land. Towns, small to large, and villages are examined with spatial and cultural lenses. Ecological dimensions - water, soil and air systems, together with habitats, plants, wildlife and biodiversity - are highlighted. A concluding section presents concepts for making better towns and better land. From a pioneer in both landscape ecology and urban ecology, this highly international town ecology book opens an important frontier for researchers, students, professors, and professionals including environmental, town, and conservation planners.

Plant community assembly and biodiversity: a spatio-temporal perspective

Thesis

Full-text available

Nov 2011

Oliver Purschke

Biodiversity, the variety of life at all organisational levels from genes to ecosystems, affects ecosystem processes and therefore the goods and services ecosystems provide. More research is needed to provide new insights into biodiversity changes and the processes that drive these changes, in order to formulate effective policy and conservation measures to stop the ongoing biodiversity loss. In this thesis, I focus on spatial and temporal changes in different aspects of plant biodiversity and examine the driving forces that generate and maintain observed biodiversity patterns. Multiple facets of biodiversity (taxonomic, phylogenetic, functional) were characterized in semi-natural grasslands (in plots of 0.5 × 0.5 and 2 × 2 m, and whole grassland polygons). The extent to which the present-day and historical characteristics of the sites and their surrounding landscape explain the current diversity patterns was quantified. Temporal changes in the multiple facets of diversity, and assembly processes that drive these changes, were investigated along a more than 300 year long chronosequence representing an arable-to-semi-natural grassland succession. Both grassland plant species richness and functional trait diversity in grassland sites were to a large extent explained by the land use history of the sites and the availability of grassland habitat in the surrounding historical landscape. It appears that not only is there a delayed loss of species diversity in response to landscape fragmentation (“extinction debt”) but that there is also a delayed decline of functional diversity in response to ongoing habitat destruction (i.e. a “functioning debt”) that will potentially generate a time lag in the changes in ecosystem attributes. Quantification of the linkages between the distribution and diversity of dispersal and persistence traits and current and historical properties of the grassland sites and their surrounding landscape revealed that long-distance dispersal potential as well as the diversity of different dispersal and persistence strategies within present-day grassland communities was mainly determined by the local management history and landscape history. Long-distance dispersal by wind and animals no longer appears to be contributing to the colonization of the remaining fragments of habitat within the increasingly fragmented modern landscape, and long-term persistent species are likely to dominate the grassland communities in the future. Whereas many long-distance dispersed species can still persist locally in the presence of grazing disturbance, grazing management may also promote the diversity of different dispersal and persistence strategies, but only in sites that were well connected to grassland areas in the past. The extent to which grassland management strategies can maintain a high diversity of dispersal and persistence strategies, and thereby the capacity of a plant community to buffer environmental change, will depend on the context of the site within the historical surrounding landscape. Comparative analysis of taxonomic, phylogenetic and functional diversity at different stages of arable-to-semi-natural grassland succession demonstrated that community assembly during secondary grassland succession was deterministic with respect to species traits, suggesting that it may be possible to predict changes in biodiversity, and associated alterations in ecosystems functioning in future environments, on the basis of species functional traits. Taxonomic, phylogenetic and functional diversity showed contrasting patterns of change over time. Short-term grazing management (5-50 years) promoted species richness, but did not enhance phylogenetic or functional diversity. Only long-term grazing management, over more than 270 years, promoted phylogenetic and functional diversity without further increases in species richness. I conclude that (a) multiple facets of biodiversity should be considered in order to more realistically assess the full dimensions of biodiversity loss resulting from human-driven environmental changes, (b) history is a major determinant of biodiversity, and (c) the simultaneous consideration of multiple facets of biodiversity can provide new insights into the processes that shape communities.

Function of small habitat elements for enhancing plant diversity in different agricultural landscapes

Article

Full-text available

Jan 2014
BIOL CONSERV

The extensive transformation of agricultural landscapes worldwide has led to a decrease in grassland species related to traditional low-intensive farming. To properly manage and protect species, habitats and ecosystems in any of these landscapes requires a better understanding of direct and indirect effects of the processes driving biodiversity decline. In this study, we investigated how small habitat elements, represented by mid-field islets and road verges, in different types of agricultural landscapes can sustain a regional species pool for plant diversity otherwise associated to semi-natural grasslands. Although semi-natural grasslands had higher total and specialist richness, we found that small habitat elements harboured relatively high plant species richness, especially in a landscape with many semi-natural grasslands left. In the most intensively managed landscape, total richness declined as distance to the nearest semi-natural grassland increased. In contrast, β-diversity was highest in these landscapes indicating that small habitats are also negatively affected by distance to grassland. We found that species trait composition varied depending on habitat and landscape. The results confirm that fragmentation shape trait composition within plant communities, e.g. plant size, clonality, longevity, and dispersal traits. We conclude that small habitat elements increase the total area available to grassland species present in the landscape, boosting the spatio-temporal dynamics of grassland communities. Small habitat elements may hence function as refugia or stepping stone habitats, especially in intensively utilized agricultural landscapes, and should be regarded as a functional part of a semi-natural grassland network, analogous to a meta-population.

Double-loss-modulated q-switched and mode-locked Nd:Lu0.15Y0.85VO4 laser at 1.34 μm with single-walled carbon nanotube saturable absorber and AO modulator

Article

Nov 2011

A diode-pumped dual-loss-modulated Q-switched and mode-locked (QML) Nd:Lu0.15Y0.85VO4 laser at 1.34 μm with single-walled carbon nanotube saturable absorber (SWCNT-SA) and acousto-optic (AO) modulator is demonstrated. The modulation depth of the dual-loss-modulated QML laser reaches 90%, being deeper than 75% that obtained by the single passively QML laser. The stability of the hybrid QML laser is significantly improved if compared to that only with SWCNT-SA. The Q-switched pulse energy and the Q-switched pulse width of the QML laser with the dual-loss-modulation are 487 and 27% of those only with SWCNT-SA, respectively.

Modeling patch characteristics of farmland loss for site assessment in urban fringe of Beijing, China

Article

Jun 2013

Farmland protection and delimitation in the urban fringe considers not only natural factors but also the spatial characters and site factors. Taking Daxing District, Beijing in China as a case study, this paper used landscape ecology and power-law methods to analyze and evaluate farmland loss during the period of 2004–2007 based on the interpretation results of SPOT5 remote sensing images in 2004 and 2007. At the patch level, we selected four landscape indices, namely patch size, shape index, the nearest neighbor distance between farmland and construction land (including residential land and other construction land), and cropping type, to evaluate the risk of farmland loss and establish a farmland site analysis indicator system. The results showed that patch size and shape index have a significant positive correlation with farmland loss, whereas the distance to construction land has a clear negative correlation with farmland loss. As regards cropping type, fallow farmland is much easier for non-agricultural use than cultivated farmland. The relative transition ratio among vegetable land, fallow farmland and cultivated farmland is 1:5.6:1. The patch size of lost farmland follows a power-law distribution, indicating that not only small parcels but also large parcels can be lost. Patch size less than 4 ha or more than 15 ha is in high loss risk, between 4 ha and 10 ha in medium loss risk, and larger than 10 ha and less than 15 ha in low risk. Farmland with a more regular shape has a higher likelihood of loss. Patch shape index less than 2.0 is in high loss risk, between 2.0 and 3.0 in medium loss risk, and larger than 3.0 in low risk. Construction land has a varying impact on farmland loss, the residential land effected distance is 1000 m, and that of the other construction land is 2000 m. This analysis showed the relationships between site factors and farmland loss, and the analysis framework can provide support and reference for farmland protection and delimitation of prime farmland in China.

Colonization of central European abandoned fields by dry grassland species depends on the species richness of the source habitats: A new approach for measuring habitat isolation

Article

Full-text available

Nov 2011

Abandoned fields are perceived as potential habitats for species of threatened semi-natural dry grasslands. However, information is lacking regarding how the spontaneous colonization of abandoned fields depends on the broader spatial context. We recorded the occurrence of 87 target species in 46 abandoned fields and 339 dry grasslands. We tested the effect of the isolation of abandoned fields from source grasslands on the number of dry grassland species occurring in abandoned fields either with or without habitat characteristics being used as covariates. The isolation of the fields was calculated using the distance and area (I A ) or distance and species richness (I S ) of source habitats. I S always explained the number of grassland species in the abandoned fields better than I A . The effect of isolation became smaller or even non-significant with the inclusion of covariates; it also changed with the method used for measuring distance (edge-to-edge or center-to-center), and it was lower when other abandoned fields were considered as additional source habitats. The different performance of the two isolation measures can be explained by the weak species–area relationship in the grasslands, indicating differences in their habitat quality. Species richness is a better proxy of habitat importance in terms of propagule source than habitat area, and the new isolation measure is therefore suitable for studying the effects of landscape structure on species richness in landscapes presenting a weak species–area relationship, such as areas exhibiting pronounced effects of land-use history. Inclusion of habitat characteristics as covariates may considerably alter conclusions regarding the effect of isolation, which might actually be overestimated when assessed separately.

Impact of species migration from agrocenosis for natural and use value of meadow communities sward

Article

Full-text available

Jan 2013

The aim of this study was assessment of segetal and ruderal species occurrence on the ecological structure and natural value of selected plant communities . The research was carried out in 2011 and 2012 year by Braun-Blanquet’s method, in Alopecuretum pratensis, Arrhenatheretum elatioris, Lolio-Cynisuretum and with Deschampsia caespitosa communities, which was localized in Wielkopolska region . The occurrence of segetal and ruderal species in the buffer zone and homogeneous patches with characteristic composition of species for each syntaxon were analyzed . The synanthropisation degree, floristic diversity and class of natural value of communities were determinated . Moisture, nitrogen and soil reaction content by phytosociological method (Ellenberg’s method) were described . The result indicated on participation of segetal and ruderal species in sward communities in the vicinity management with a different way of farming . The abundance of the population ruderal and segetal species in plant communities were affected of habitat conditions and usage of the sward

Factors and processes affecting plant biodiversity in permanent grasslands. A review

Article

Full-text available

Jan 2012

Research has delivered convincing findings on the effect of biodiversity on ecosystem functioning and humankind. Indeed, ecosystems provide provisioning, regulating, supporting, and cultural services. The global value of annual ecosystem services of grasslands and rangelands is about US$ 232 ha−1 year−1. Nevertheless, the precise evaluation of biodiversity benefits remains challenging. This issue is due to valuation methods, subjective assumptions, and complexity of drivers of plant community dynamics. Here, we review the primary factors that influence plant diversity of permanent grasslands, and we describe underlying processes. These factors must indeed be identified to focus policies meant to preserve and restore plant diversity and to advise farmers about efficient decision rules. We show that plant dynamics of permanent grasslands cannot be explained simply by agricultural management rules, e.g., grazing, fertilization, and mowing, implemented at the field scale. The configuration of the surrounding landscape, e.g., landscape heterogeneity, habitat fragmentation, and connectivity, acts as a species filter that defines the regional species pool and controls seed flow. The regional species pool often contains higher species richness in a heterogeneous landscape, because of a higher diversity of suitable habitats. This regional pool could be a major species sources for permanent grasslands according to the seed flow. We discuss the need to consider all of these factors to understand plant species composition of permanent grasslands and the necessity to study plant communities using both taxonomic and functional approaches. In order to report this integrative approach, we propose a conceptual model based on three ecological challenges—dispersal, establishment, and persistence—that are considered to act as filters on plant diversity, and a graphical representation of the complexity of such studies due to the interaction effects between plant dispersal abilities, forage productivity, disturbances induced by farming practices, and landscape heterogeneity on plant diversity. Last, we discuss the ability of farmers to manage each factor and the necessity of such study in the improvement of the current agro-environment schemes efficiency for farmland biodiversity restoration or preservation.

Biodiversity, ecosystem function, and resilience: Ten guiding principles for commodity production landscapes

Article

Full-text available

Mar 2006

Biodiversity conservation in forestry and agricultural landscapes is important because (1) reserves alone will not protect biodiversity; (2) commodity production relies on vital services provided by biodiversity; and (3) biodiversity enhances resilience, or a system's capacity to recover from external pressures such as droughts or management mistakes. We suggest ten guiding principles to help maintain biodiversity, ecosystem function, and resilience in production landscapes. Landscapes should include structurally characteristic patches of native vegetation, corridors and stepping stones between them, a structurally complex matrix, and buffers around sensitive areas. Management should maintain a diversity of species within and across functional groups. Highly focused management actions may be required to maintain keystone species and threatened species, and to control invasive species. These guiding principles provide a scientifically defensible starting point for the integration of conservation and production, which is urgently required from both an ecological and a long-term economic perspective.

Ecological Determinants of Species Loss in Remnant Prairies

Article

Full-text available

Sep 1996
SCIENCE

Recensuses of 54 Wisconsin prairie remnants showed that 8 to 60 percent of the original plant species were lost from individual remnants over a 32- to 52-year period. The pattern of species loss was consistent with the proposed effects of fire suppression caused by landscape fragmentation. Short, small-seeded, or nitrogen-fixing plants showed the heaviest losses, as did species growing in the wettest, most productive environments. The interruption of landscape-scale processes (such as wildfire) by fragmentation is an often overlooked mechanism that may be eroding biodiversity in many habitats around the world.

The History (1620-2003) of Land Use, People and Livestock, and the Relationship to Present Plant Species Diversity in a Rural Landscape in Sweden

Article

Full-text available

May 2006

The traditional agriculture in Europe favoured numerous plant and animal species that are presently declining. Integrated studies based on various sources are needed in order to unravel the complex relationships between changing landscapes and biological diversity. The objectives of this study were to describe changes in land use during c. 350 years in a Swedish agricultural landscape in relation to changes in human population and livestock, and to analyse relationships between historical land use and present-day plant species diversity. There were only minor long-term changes in land use, population and livestock between 1640 and 1854 in the two studied hamlets, but detailed data 1620-41 showed a large short-term fluctuation in livestock numbers. After 1854 larger changes took place. Grasslands were cultivated and livestock composition changed. After 1932, livestock number decreased and most of the former grazed outland (areas located outside the fenced infields) turned into forest by natural succession. 7 per cent of the study area is still grazed semi-natural grassland. The highest plant species richness is today found on semi-natural grassland with a long continuity of grazing. The distribution of five target species suggests that previous land use still has an important effect today. The majority of their occurrences are remnant populations located in previous outland pastures which are today forests.

Biophysical and human influences on plant species richness in grasslands: Comparing variegated landscapes in subtropical and temperate regions

Article

Full-text available

Dec 2001
AUSTRAL ECOL

A survey of grassy woodlands in the Queensland subtropics was conducted, recording herbaceous species richness at 212 sites on three properties (2756 ha). A range of habitats typical of cattle grazing enterprises was sampled and site variables included lithology, slope position, tree density, soil disturbance, soil enrichment and grazing. Results were compared with a previously published survey of temperate grasslands. Lithology, slope position and tree density had relatively minor effects on plant species richness, although in both surveys there was some evidence of lower species richness on the more fertile substrates. Soil disturbance and soil enrichment significantly reduced the richness of native species in both surveys, while exotic species were insensitive (subtropics) or increased (temperate) with disturbance. Rare native species were highly sensitive to disturbances, including grazing, in the temperate study. Although some trends were similar for rare species in the subtropics, the results were not significant and there were complex interactions between grazing, lithology and slope position. Grazing did not have a negative effect on native species richness, except in the closely grazed patches within pastures, and then only on the most intensively developed property. At the scale recorded (30 m2), the native pastures, roadsides and stock routes sampled in the subtropics appear to be among the most species-rich grasslands ever reported, both nationally and globally. Native species richness was approximately 50% higher than the temperate survey figures across all the comparable habitats. While there are no clear reasons for this result, potential explanations are proposed.

Countryside Biogeography of Neotropical Mammals: Conservation Opportunities in Agricultural Landscapes of Costa Rica

Article

Full-text available

Dec 2003

The future of mammalian diversity in the tropics depends largely on the conservation value of human-dominated lands. We investigated the distribution of non-flying mammals in five habitats of southern Costa Rica: relatively extensive forest (227 ha), coffee plantation, pasture, coffee with adjacent forest remnant (<35 ha), and pasture with adjacent forest remnant (<35 ha). Of the 26 native species recorded in our study plots, 9 (35%) were restricted to forest habitat, 14 (54%) occurred in both forest and agricultural habitats, and 3 (11%) were found only in agricultural habitats. Species richness and composition varied significantly with habitat type but not with distance from the extensive forest. Interestingly, small forest remnants (<35 ha) contiguous with coffee plantations did not differ from more extensive forest in species richness and were richer than other agricultural habitat types. Small remnants contiguous with pasture were species-poor. When clearing started, the study region likely supported about 60 species. Since then, at least 6 species (10%), one family (4%), and one order (11%) have gone extinct locally. The species that disappeared were the largest in their families and included carnivorous (e.g., jaguar [Panthera onca]), herbivorous (e.g., Baird's tapir, [Tapirus bairdii]), and arboreal (e.g., mantled howler monkey [Alouatta palliata]) species. Although there is no substitute for native forest habitat, the majority of native, nonflying mammal species use countryside habitats. The populations of many persist even >5 km from relatively extensive forest, at least over the 40 years since forest clearance. Moreover, if hunting ceased, we expect that at least one of the locally extinct species could be reestablished in the existing landscape. Thus, there is an important opportunity to maintain and restore the diversity, abundance, and ecosystem roles of mammals in at least some human-dominated regions of the Neotropics.

Assessing grassland restoration success: Relative roles of seed additions and native ungulate activities

Article

Full-text available

Aug 2006
J APPL ECOL

Grassland restorations often lack rare forb and grass species that are found in intact grasslands. The possible reasons for low diversity include seed limitation, microsite limitation and a combination of both. Native ungulates may create microsites for seedling establishment in tallgrass prairie restorations by grazing dominant species or through trampling activities, but this has never been tested in developing prairies. We experimentally tested for seed and microsite limitation in the largest tallgrass prairie restoration in the USA by adding rare forb and grass seeds in two trials inside and outside native ungulate exclosures. We measured seedling emergence because this stage is crucial in recruiting species into a community. We also measured light, water and standing crop biomass to test whether resource availability could help to explain seedling emergence rates. Ungulates increased light availability for each sampling time and also increased above‐ground net primary productivity (ANPP) during summer. Seedling emergence of rare prairie forbs and grasses was consistently greater when we added seeds. Seedling emergence was conditionally greater with a combination of seed additions and grazing, but grazing alone was unable to increase emergence. When ungulates increased seedling enhancement, the mechanism was partially associated with increased water and light availability. Exotic and cosmopolitan weed seedling emergence was not affected by grazing. Synthesis and applications. These results suggest that tallgrass prairie restorations are primarily seed limited and that grazing alone may not be able to increase seedling emergence of rare species without the addition of seeds. Therefore, adding seeds to grassland restorations may increase seedling emergence of rare species, and mimicking effects of grazing may increase emergence when seeds are added.

Land‐use history and fragmentation of traditionally managed grasslands in Scandinavia

Article

Full-text available

Oct 2002
J VEG SCI

Plants associated with traditional agricultural landscapes in northern Europe and Scandinavia are subjected to drastic habitat fragmentation. In this paper we discuss species response to fragmentation, against a background of vegetation and land-use history. Recent evidence suggests that grassland-forest mosaics have been prevalent long before the onset of human agriculture. We suggest that the creation of infield meadows and outland grazing (during the Iron Age) increased the amount and spatial predictability of grasslands, resulting in plant communities with exceptionally high species densities. Thus, distribution of plant species in the present-day landscape reflects historical land-use. This holds also when traditional management has ceased, due to a slow response by many species to abandonment and fragmentation. The distribution patterns are thus not in equilibrium with the present habitat distribution. Fragmentation influences remaining semi-natural grasslands such that species density is likely to decline as a result of local extinctions and invasion by habitat generalists. However, species that for a long time have been subjected to changing mosaic landscapes may be more resistant to fragmentation than is usually believed. Conservation should focus not only on ‘hot-spots’ with high species richness, but also consider species dynamics in a landscape context.

A Landscape Approach to Biodiversity Conservation of Sacred Groves in the Western Ghats of India

Article

Full-text available

Dec 2005
CONSERV BIOL

Although sacred groves arc, important for conservation in India, The landscape that surrounds them has a vital influence on biodiversity within them. Research has focused on tree diversity inside these forest patches. In a coffee-growing region of the Western Ghats, however landscape outside sacred groves is also tree covered because Planters have retained native trees to provide shade for coffee plants. We examined the diversity of trees, birds, and macrofungi at 58 sites-10 forest-reserve sites, 25 sacred groves, and 23 coffee plantations-in Kodagu district. We measured landscape composition and configuration around each site with a geographic information system. To identify factors associated with diversity we constructed multivariate models by using a decision-tree technique. The conventional measures of landscape such as patch size did not influence species richness. Distance of sacred groves front The forest reserve bad a weak influence. The measures of landscape structure (e.g., tree cover in the surroundings) and stand structure (e.g., variability in canopy height) contributed to The variation in species richness explained by multivariate models. We suggest that biodiversity present within sacred groves bets been influenced by native tree cover in the surrounding landscape. To conserve this biodiversity The integrity of the tree-covered landscape matrix will need to be conserved.

Seed and microsite limitation of recruitment in plant populations

Article

Full-text available

Sep 1992

Availability of seed and microsites, respectively, are two factors that potentially may limit recruitment in plant populations. Microsites are small-scale sites suitable for germination and survival of seedlings. We discuss this dichotomy of recruitment limitation both from a theoretical and empirical point of view. Investigations of recruitment in 14 woodland species showed that 3 species were seed limited, 6 species were limited by a combination of seed and microsite availability, and 5 species were found not to be seed limited, but the limiting factor was not identified. A combination of seed and microsite limitation implies that recruitment is promoted by increasing both seed and microsite availability. We suggest that the importance of seed limitation in plant populations has been underestimated, and that the operating limiting factors may be dependent on spatial and temporal scale. We expect that many species, if adequately studied, will turn out to be both seed and microsite limited. Experimental field studies that incorporate a range of seed and microsite densities in various spatial and temporal scales are needed to examine the extent to which plant populations are seed and microsite limited.

Plants, insects and birds in semi-natural pastures in relation to local habitat and landscape factors

Article

Full-text available

Nov 2001

The preservation of remaining semi-natural grasslands in Europe has a high conservation priority. Previously, the effects of artificial fertilisation and grazing intensity on grassland animal and plant taxa have been extensively investigated. In contrast, little is known of the effects of tree and shrub cover within semi-natural grasslands and composition of habitats in the surrounding landscape on grassland taxa. We evaluated the effect that each of these factors has on species richness and community structure of vascular plants, butterflies, bumble bees, ground beetles, dung beetles and birds surveyed simultaneously in 31 semi-natural pastures in a farmland landscape in south-central Sweden. Partial correlation analyses showed that increasing proportion of the pasture area covered by shrubs and trees had a positive effect on species richness on most taxa. Furthermore, species richness of nectar seeking butterflies and bumble bees were negatively associated with grazing intensity as reflected by grass height. At the landscape level, species richness of all taxa decreased (butterflies and birds significantly so) with increasing proportion of urban elements in a 1-km2 landscape area centred on each pasture, while the number of plant and bird species were lower in landscapes with large proportion of arable fields. Our results differed markedly depending on whether the focus was on species richness or community structure. Canonical correspondence analyses (CCA) showed that the abundance of most taxa was ordered along a gradient describing tree cover within pastures and proportion of arable fields in the landscape. However, subsets of grassland birds and vascular plants, respectively, showed markedly different distribution patterns along axis one of the CCA. In contrast to current conservation policy of semi-natural pastures in Sweden, our results strongly advise against using a single-taxon approach (i.e., grassland vascular plants) to design management and conservation actions in semi-natural pastures. Careful consideration of conservation values linked to the tree and shrub layers in grasslands should always precede decisions to remove trees and shrubs on the grounds of promoting richness of vascular plants confined to semi-natural grasslands. Finally, the importance of landscape composition for mobile organisms such as birds entails that management activities should focus on the wider countryside and not exclusively on single pastures.

Making the matrix matter: Challenges in Australian grazing landscapes

Article

Full-text available

Jan 2005

Many ecological theories are based on the concept of patches. Patches are a useful starting point for conservation efforts, but a focus on patches alone will not always achieve desired conservation outcomes. Conservation strategies in the grazing landscapes of southeastern Australia suggest that large patches of trees are widely regarded as habitat while other forms of habitat are largely ignored. We provide data on birds and reptiles from the Nanangroe grazing landscape that illustrate the potential habitat value of areas located between large patches of trees – that is, the matrix. Despite evidence on its potential value, present conservation strategies rarely consider the matrix. Possible reasons for this bias relate to the economics of farming and the history of land use, the current environmental law framework, and also the reluctance of ecologists to study the matrix. More scientific evidence on the role of the matrix will be crucial if conservation strategies are to consider not only patches, but entire landscapes. However, for science to be relevant to land management, there is a need for new research approaches. First, an increased consideration of environmental policy and law will increase the likelihood of scientific findings being adopted by policy makers. Second, at an applied level, more practical on-ground research into farming practices and clearer communication are necessary to achieve more sustainable matrix management in Australian grazing landscapes.

The influences of patch shape and boundary contrast on insect response to fragmentation in California grasslands

Article

Full-text available

Oct 2002

Landscape ecologists typically identify boundaries to demarcate habitatpatches. The boundary between two habitat types may be abrupt, such as thetransition between a grassland and a parking lot, or more gradual, such as theshift between successional forest stages. Two key aspects of landscapeboundaries, their shape and contrast, are predicted to influence movement ofmaterials, plants, and animals. Ecological theory suggests that a patchsperimeter-to-area ratio should strongly influence animal emigration when patchboundaries are relatively permeable, but not when boundaries are more severe.Weinvestigated the interactive effects of patch shape and boundary contrast onmovement of ground-dwelling beetles (Carabidae and Tenebrionidae) in nativegrassland habitat at Jepson Prairie, Solano County, California, USA. Weconducted a field experiment with two patch shape treatments, square andrectangle, that held patch area constant, and two boundary contrast treatmentscreated by mowing grass surrounding each plot at two different heights. Wemonitored the number of beetles leaving each patch over a three-week periodfollowing treatment establishment. We observed a significant effect of boundarycontrast on net movement of beetles, with low contrast boundaries exhibitingnetimmigration and high contrast boundaries experiencing net emigration. Moreover,the importance of patch shape appeared to be greater for low contrast versushigh contrast boundaries, consistent with theoretical expectations. Ourcombinedobservations indicate that these ground-dwelling beetles were more likely tomove into patches that were rectangular and surrounded by a low contrast matrixthan patches that were square or surrounded by a high contrast matrix. Weconclude that net movement of beetles across patch boundaries is stronglyinfluenced by boundary contrast and may be affected by patch shape whenboundarycontrast is low.

Effects of patch shape on the number of organisms

Article

Full-text available

Oct 1996

Toshihide Hamazaki

This study examined effects of habitat patch shape on the abundance of organisms. The effects of patch shape were considered in terms of (1) immigration and emigration of organisms. (2) the amount of available resources in a patch and (3) spatial and temporal heterogeneity of the organisms and environment. I hypothesized that (1) the number of organisms would increase as patch shape elongates because organisms are more likely to encounter an elongated patch, (2) the number of organisms in a patch would remain constant for all patch shapes where the number of organisms in a patch was limited by the amount of resources, because patch shape does not change the patch area that is directly associated with the amount of patch resources, and (3) spatial and temporal variation of the abundance of organisms would increase as patch shape elongates because an elongated patch is more likely to interact with the variable surrounding matrix. Common millipedes,Oxidus gracilis, and their habitat, plywood boards of five shapes (width:length ratio; 1∶1, 1∶4, 1∶9, 1∶36, 1∶144) with an area of 900 cm2 were placed in forest and old field and the number of millipedes appearing under the boards was monitored. Significantly higher mean number of millipedes under the boards was observed at a patch with an elongated shape in the forest and the old field. A significant positive correlation was observed between perimeter length of a patch and the number of millipedes in the old field. The temporal and spatial variation of the number of millipedes was high in the old field. The spatial and temporal variation was higher for boards with elongated shape.

Effects of area and isolation of woodland patches on herbaceous plant species richness across Great Britain

Article

Full-text available

Jul 2004

Richness of Ancient Woodland Indicator plant species was analysed in 308 woodland patches that were surveyed during the Countryside Survey of Great Britain carried out in 1998. The Countryside Survey recorded vegetation plots and landscape structure in 569 stratified 1 km sample squares and developed a remotely-sensed land cover map of the UK. Using these datasets, we tested the hypothesis that Ancient Woodland Indicator species richness in woodland fragments was limited by patch area, shape and spatial isolation and that woodland patches located in the lowland region of Great Britain would respond differently than those in the upland region. The variation in Ancient Woodland Indicator species richness in the British lowlands (n = 218) was mainly explained by patch area and two measures of connectivity, the length of hedgerows and lines of trees in the 1 km square and the area of woodland within 500 m of the vegetation plot. By contrast, variation in Ancient Woodland Indicator species richness in the British uplands (n = 90) was related to Ellenberg scores of the vegetation communities sampled – a surrogate for habitat quality – and no significant effect of spatial structure was detected. It therefore appears that the degree of fragmentation of woodland in the British lowlands limits the distribution of Ancient Woodland Indicator species, while in the uplands, failed colonisation is a matter of habitat quality rather than a result of landscape structure.

Effects of habitat area, isolation, and landscape diversity on plant species richness of calcareous grasslands

Article

Full-text available

Jul 2004

Calcareous grasslands harbour a high biodiversity, but are highly fragmented and endangered in central Europe. We tested the relative importance of habitat area, habitat isolation, and landscape diversity for species richness of vascular plants. Plants were recorded on 31 calcareous grasslands in the vicinity of the city of Gttingen (Germany) and were divided into habitat specialist and generalist species. We expected that habitat specialists were more affected by area and isolation, and habitat generalists more by landscape diversity. In multiple regression analysis, the species richness of habitat specialists (n = 66 species) and habitat generalists (n = 242) increased with habitat area, while habitat isolation or landscape diversity did not have significant effects. Contrary to predictions, habitat specialists were not more affected by reduced habitat area than generalists. This may have been caused by delayed extinction of long-living plant specialists in small grasslands. Additionally, non-specialists may profit more from high habitat heterogeneity in large grasslands compared to habitat specialists. Although habitat isolation and landscape diversity revealed no significant effect on local plant diversity, only an average of 54% of habitat specialists of the total species pool were found within one study site. In conclusion, habitat area was important for plant species conservation, but regional variation between habitats contributed also an important 46% of total species richness.

Effects of historical and present fragmentation on plant species diversity in semi-natural grasslands in Swedish rural landscapes

Article

Full-text available

Apr 2007

Habitat loss and fragmentation of natural and semi-natural habitats are considered as major threats to plant species richness. Recently several studies have pinpointed the need to analyse past landscape patterns to understand effects of fragmentation, as the response to landscape change may be slow in many organisms, plants in particular. We compared species richness in continuously grazed and abandoned grasslands in different commonplace rural landscapes in Sweden, and analysed effects of isolation and area in three time-steps (100 and 50years ago and today). Old cadastral maps and aerial photographs were used to analyse past and present landscape patterns in 25 sites. Two plant diversity measures were investigated; total species richness and species density. During the last 100years grassland area and connectivity have been reduced by about 90%. Present-day habitat area was positively related to total species richness in both habitats. There was also a relationship to habitat area 50years ago for continuously grazed grasslands. Only present management was related to species density: continuously grazed grasslands had the highest species density. There were no relationships between grassland connectivity, present or past, and any diversity measure. We conclude that landscape history is not directly important for present-day plant diversity patterns in ordinary landscapes, although past grassland management is a prerequisite for the grassland habitats that can be found there today. It is important that studies are conducted, not only in very diverse landscapes, but also in managed landscapes in order to assess the effects of fragmentation on species.

The restoration and re-creation of species-rich lowland grassland on land formerly managed for intensive agriculture in the UK

Article

Full-text available

Sep 2004
BIOL CONSERV

Intensive agriculture has resulted in the loss of biodiversity and the specialist flora and fauna associated with the semi-natural grasslands of low-intensity pastoral systems throughout northwest Europe. Techniques employed to restore and re-create these grasslands on agricultural land in the UK are reviewed. Extensive cutting and grazing management have been shown to diversify improved swards and facilitate re-colonisation on ex-arable soils, although rates of re-assembly of plant communities with affinity to existing semi-natural grasslands have generally been slow. On former agriculturally improved swards, nutrient depletion has accelerated this process, especially where “gaps” for establishment have been created. Similarly, on ex-arable soils “nutrient stripping” and sowing with diverse seed mixtures has led to the rapid development of species-rich swards. On free draining brown earths such an approach may be required to restore grassland communities where soil phosphorous concentrations exceed semi-natural levels by more than 10 mg/l (using Olsen's bicarbonate extractant). However, the appropriateness of this threshold for other soil types requires further sampling. Although restored grasslands are likely to contribute to national biodiversity targets success will ultimately depend on the reinstatement of the communities and ecological functions of semi-natural references. Although this is technically feasible for a few plant assemblages, less is known about the re-assembly of microbial and faunal communities, or the importance of trophic interactions during grassland succession. As a consequence, more research is required on the functional attributes of semi-natural grasslands, as well as the methods required to restore localised types, novel nutrient depletion techniques, the “phased” introduction of desirable but poor-performing species and the performance of different genotypes during grassland restoration.

Vegetation Dynamics in an Experimentally Fragmented Landscape

Article

Full-text available

Jul 1995

In spatially heterogeneous habitats, plant community change may reflect spatially localized population-level processes that are sensitive to the size of an average habitat patch. However, local species turnover can also be determined by initial conditions and large-scale processes, in which case patch size effects may be overridden. To examine the role of patch size in directing secondary succession, we subdivided a newly abandoned agricultural field into an array of experimental patches (32, 288, and 5000 m(2), grouped to sample equivalent portions of the field), and have thereafter censused the resident plant and animal communities at regular intervals. Here we report results from the first 6 yr of studies on the changing vascular plant community in an experimentally fragmented landscape. The general course of change in all patches followed a trajectory typical of old-field succession, toward increasing dominance by longer lived and larger plant species. The same group of species that dominated at th

Secondary succession in an experimentally fragmented landscape: Community patterns across space and time

Article

Full-text available

May 2005

Secondary succession reflects, at least in part, community assembly - - -the sequences of colonizations and extinctions. These processes in turn are expected to be sensitive to the size of the site undergoing assembly and its location relative to source pools. In this paper we describe patterns of succession over 18 years in an experimentally fragmented landscape created in eastern Kansas, USA, in 1984. The design of the experiment permits one to assess the influence of patch size and landscape position on successional dynamics. The general trajectory of succession follows that typical of succession in much of the eastern United States. In the initial years of the study, there was relatively little effect of patch size or distance to sources. Here we show that spatial effects in this system have become increasingly evident with time, as gauged both by repeated-measures ANOVA and ordination techniques. Woody plants have colonized more rapidly (per unit area) on large and nearby patches. Species richness at a local (within-quadrat) scale in general has increased, with slightly greater richness in large than in small patches later in the study. Temporal stability in community composition has generally been greater in large patches. Spatial heterogeneity in community composition has increased during succession, but with different patterns in large and small patches. This long-term experiment suggests that landscape structure influences many aspects of community structure and dynamics during succession, and that such effects become more pronounced with the passage of time.

The Theory of Island Biogeography

Article

Jan 1967

Poschlod P, Bonn S. Changing dispersal processes in the central European landscape since the last ice age: An explanation for the actual decrease of plant species richness in different habitats? Acta Bot. Neerl.

Article

Mar 1998

During the evolution of the Central European landscape and especially since the settlement of man there has been a permanent change of processes affecting dispersability of plants. In a traditional man-made landscape there was the highest diversity of dispersal processes combined with a high diversity of land use practices. In the actual man-=made landscape most of these processes became lost or changed. Due to the rules of seed prescription many weeds became extinct, which were spread in former times with uncleaned seed. Traditional manure contained huge amounts of diaspores whereas today animal slurry with low contents of diaspores or mineral fertilizer are used. Changing harvest methods have selected the dominance of weeds which ripen later and have light diaspores. Herded and transhumant domestic livestock decreased or became locally extinct, which was probably the most important dispersal vector in the Central European man-made landscape. Artificial flooding practices favoured the migration of species in meadows of mountain and flooding practices favoured the migration of species in meadows of mountain and floodplain regions. Whereas in the traditional man-made landscape all habitats were more or less connected due to alternating management or grazing, today most habitats are isolated. With respect to restoration efforts in habitats dispersal processes or vectors should be included before planning. If there is no possibility of restoring traditional or similar dispersal processes, artificial reintroduction of species is the only option.

Land Mosaics: The Ecology of Landscapes and Regions.

Article

Oct 1996

Effects of Edge Type and Patch Shape on Avian Communities in a Mixed Conifer-Hardwood Forest

Article

Jul 1996

Gerald J. Niemi

Forest bird communities were sampled along line transects in northwestern Wisconsin during June of 1985 through 1992 to determine whether edge type and patch shape affect avian abundance. Landscape structural characteristics quantified along these transects included: (1) edges that defined the habitat patches they separated, (2) fractals to quantify patch shapes, and (3) areal extent of different patches. Three multiple-regression models were constructed for 10 bird species and the mean number of individuals and species using the following sets of independent variables: (1) edge variables and fractals, (2) area variables, and (3) the first six components from a principal components analysis based on all independent variables. Multiple-regression analysis indicated that edge variables and fractal dimension explained the most variation in abundance for Black-capped Chickadees (Parus atricapillus), Red-breasted Nuthatches (Sitta canadensis), Hermit Thrushes (Catharus guttatus), and American Robins (Turdus migratorius). In contrast, area variables explained the most variation in abundance for Red-eyed Vireos (Vireo olivaceus), Chestnut-sided Warblers (Dendroica pensylvanica), and Ovenbirds (Seiurus aurocapillus). Abundances of Yellow-bellied Flycatchers (Empidonax flaviventris), Common Yellowthroats (Geothlypis trichas), and White-throated Sparrows (Zonotrichia albicollis) were equally correlated with both edge and area variables. Results of our study show that, for selected species, forest management strategies must be developed that consider not only stand characteristics, but also the edges created between these stands.

Regional Dynamics of Plants: A Review of Evidence for Remnant, Source-Sink and Metapopulations

Article

Nov 1996

Ove Eriksson

Despite a long tradition in plant ecology of studies of patch dynamics, recent developments of models for large scale dynamics in source-sink and metapopulations have largely focused on animals. In contrast to mobile unitary animals, many plants resist extinction, even under conditions where only a part of the life cycle can be maintained. This model of remnant population dynamics adds to the two commonly recognized source-sink and metapopulations dynamics. A review of the literature suggests that all three types of dynamics are common in plants. Regional dynamics are related to life-cycle characteristics determining dispersal ability and longevity of life cycle stages. Short-lived or highly habitat specialized plants with good dispersal tend to build up metapopulations, i.e. systems of local populations and non-occupied but potentially suitable sites, interconnected with dispersal, and in a continuous flux of local colonization and extinction. At the other extreme, long-lived plants with clonal propagation, or plants with extensive seed banks, tend to build up remnant population systems, in which many local populations persist over periods long enough to bridge unfavourable phases of successional development, intervening periods of favourable conditions. Source-sink populations are a special case of metapopulations, in the sense that they comprise both persistent refuge populations and ephemeral populations maintained by dispersal. It is suggested that a concept of local population inertia in remnant population systems, scales to higher level phenomena of vegetation inertia, and to community stabilization (through enhanced recovery after perturbations). Such an inertia may contribute to explain cases of exceptionally high species diversity, and lack of pronounced mass extinctions of plants in the fossil record.

The conservation effects of meadow bird agreements on farmland in Zeeland, The Netherlands, in the period 1989–1995

Article

Jun 2004
BIOL CONSERV

Meadow bird agreements are the most important Dutch agri-environment schemes, both in terms of uptake and of aim. Meadow bird agreements postpone the first agricultural activities on grassland thus reducing egg and chick mortality due to mowing or grazing. We investigated the conservation effects of meadow bird agreements by analysing settlement densities of meadow birds on 34 fields in 1989, 1992 and 1995 in the province of Zeeland, The Netherlands. We compared territory numbers on fields with meadow bird agreements with paired nearby control fields that were conventionally managed. In 1995, the number of territories of black-tailed godwit (Limosa limosa), lapwing (Vanellus vanellus) and the total number of meadow birds were significantly higher on fields with conservation management. These differences were partly caused by the higher quality (i.e. higher groundwater level) of fields with meadow bird agreements. Population trends were similar on fields with and without meadow bird agreements and the observed difference in settlement density in 1995 was already present in 1989. Furthermore the effectiveness of the scheme did not increase with time. Thus we found no conclusive evidence that the conservation measures themselves did result in higher territory numbers. Currently, we do not have sufficient ecological and behavioural knowledge of meadow birds to explain why the higher reproductive success does not result in higher settlement densities.

Are Plant Populations Seed-Limited? A Review of Seed Sowing Experiments M INI- REVIE of seed sowing Are plant populations experiments

Article

Feb 2000
OIKOS

We define seed limitation to be an increase in population size following seed addition. Here, we briefly consider how theoretical models deal with seed limitation and how seed sowing experiments can be used to unravel the extent of seed limitation in natural systems. We review two types of seed addition experiments: seed augmentation studies where seeds are added to existing populations; and seed introductions where seeds are sown in unoccupied sites. Overall, approximately 50% of seed augmentation experiments show evidence of seed limitation. These studies show that seed limitation tends to occur more commonly in early successional habitats and in early successional species. Most of the studies have concentrated on simply categorising populations as seed‐ or microsite‐limited, but we believe that seed sowing experiments could be used to reveal much more about community structure, and we discuss possible future directions. In 53% of introduction studies (where seeds were sown at sites from which the species was known to be absent) the introduced species was recorded in at least one of the experimental sites following sowing. However, of the subset of studies where both seedlings and adult plants were recorded, 64% of sites contained seedlings while only 23% contained adults. This implies that, for many species, conditions for establishment are more stringent than conditions for germination. The successful establishment of plants in unoccupied patches indicates the potential for immigration to enhance local diversity (the spatial mass effect). Few studies continued monitoring for long enough to determine whether or not self‐sustaining populations were successfully established, and no study attempted to link introduction sites to a putative natural source of propagules, or considered the dynamics of the metapopulation as a whole.

Effects of restoration with cattle grazing on plant species composition and richness of semi-natural grasslands

Article

Nov 2003

Juha Pykälä

Restoration of semi-natural grasslands by cattle grazing is among the most practical options for reversing the decline of northern European floristic diversity, but no studies on this subject are available. In this work the success of restoration of abandoned, privately owned mesic semi-natural grasslands by farmers receiving support from the EU agri-environmental support scheme was studied in southwestern Finland. Three kinds of grasslands were compared: old (continuously cattle grazed), new (cattle grazing restarted 3–8 years ago) and abandoned pastures (grazing terminated >10 years ago). Plant species composition of the three pasture types was floristically different in multivariate analyses (non-metric multidimensional scaling). Total species richness, richness of grassland plants, indicator plants and rare plants were highest in old and lowest in abandoned pastures in all studied spatial scales (0.25–0.8 ha, 1 and 0.01 m2). The results were congruent with different scales and species list definitions, suggesting that species density scale (1 m2) can be used as a partial surrogate for large scale species richness. Species richness of new pastures was 20% higher on 0.25–0.8 ha, 40–50% higher on 1 m2 and 30% higher on the 0.01 m2 scale compared to abandoned grasslands. Rare species showed insignificant response to resumed grazing. Despite problems in management quality, this study showed promising results of restoration of abandoned grasslands by cattle grazing on private farms. However, populations of several rare grassland plants may not recover with present cattle grazing regimes. Management regulations in the agri-environmental support scheme need to be defined more precisely for successful restoration.

Species richness in calcareous grasslands is affected by disperability in space and time

Article

May 1998

Species richness in calcareous grassland is discussed against the background of historical dispersal processes associated with traditional land‐use management such as grazing, but also the artificial establishment by hayseed. Important vectors in the traditionally man‐made landscape were sheep and cattle or other livestock such as goats. Calcareous grasslands were not only connected to each other but also to other habitats such as villages, forests, arable fields and heathlands by these vectors which could cover large distances (e.g. transhumance shepherding), which is not the case in the current man‐made landscape. Species richness after restoration management of abandoned and afforested calcareous grasslands was predicted by using characters of dispersability in space and time. These were the persistence of the species in the vegetation and the diaspore bank after abandonment or afforestation and the dispersal capacity through wind and sheep. The results reveal that reintroduction of sheep grazing is necessary to reestablish the original species richness. The first validation of the prediction of the succession on clear‐cut sites and a comparison with data of species composition in abandoned quarries and the surroundings made it obvious that a species' own dispersal capacity in space is very low except for some well wind‐dispersed species. Therefore, it is recommended to include and to simulate dispersal processes in future management to be able to restore the original species richness.

The Trade-Off between Dispersability and Longevity: An Important Aspect of Plant Species Diversity

Article

May 1998

Local presence of plant species is determined by population colonizations and extinctions. All traits that influence the capacity of individuals to colonize patches and survive within patches, are therefore important for community diversity. Spatial models can explain the coexistence of species provided that the inferior competitor has a greater spatial mobility and thereby can avoid competition. We searched the literature for empirical evidence for such trade‐offs and included all available information on correlations between traits associated with the capacity to colonize and traits promoting the ability to survive. A lower reproductive effort of a species is associated with a longer life span and a higher competitive ability. Morphological adaptations for dispersal are less common in species which better tolerate stress, that are better competitors or possess seed dormancy. Such patterns suggest that species that are good survivors may have a limited ability to colonize new patches and vice versa. A negative correlation between dispersability and longevity has important effects on the regional dynamics of single species as well as on the coexistence of species. From a conservation perspective differences in the colonization capacity among species imply that restoration of plant biodiversity must not only focus on conditions within patches, but also consider the spatial arrangement of patches in order to enable plants to bridge gaps in time and space.

Dispersal Can Limit Local Plant Distribution

Article

Dec 1992
CONSERV BIOL

The ability of species to establish new populations at unoccupied sites is a critical feature in the maintenance of biological diversity, and it has taken on new importance as a result of global climate change and expected changes in species distribution. To examine the dispersal potential of plant species, seeds of four annual plant species were experimentally dispersed 40 to 600 m from existing populations in Massachusetts (U.S.A.) to 34 nearby unoccupied but apparently suitable sites. At three of these sites new populations were established that persisted for four generations and expanded slowly in area. At seven sites, a small initial population eventually died out. At the 24 other sites, new populations did not become established, indicating that the sites were in some way unsuitable, that not enough seeds arrived, or that conditions suitable for seed germination do not occur every year. These results suggest that some species may be unable to disperse naturally out of their existing ranges in response to global climate change, particularly if habitat fragmentation creates barriers to dispersal. These species may have to be assisted to reach suitable sites nearby to prevent their extinction in the wild.

Plant species richness in calcareous grasslands as affected by dispersability in space and time

Article

Jan 1998
APPL VEG SCI

Why are annual plants rarely spring ephemeral?

Article

Jul 2008
NEW PHYTOL

The period of active growth for spring ephemeral plants coincides with the period of high light, water and nutrient availability between snow melt and canopy closure in the understorey of deciduous forests in eastern North America. However, low temperatures prevail during this period and might restrict the performance of these plants. Remarkably, this peculiar phenology is extremely rare among annual plants. To understand better the role of light and water availability and of temperature in the phenology of spring ephemeral plants, we investigated the effects of two temperature regimes (low: 16/7 °C and high: 21/14 °C), three water availability levels (saturated, control and drought), and three photosynthetically active photon flux densities: low (85–100 μmol m−2 s−1); intermediate (182–196 μmol m−2 s−1); high (437–454 μmol m−2 s−1) on the growth and reproduction of the annual Floerkea proserpinacoides. Total biomass, total leaf area and flower and seed production increased with increasing temperature, water availability and light intensity. Total leaf area and total biomass were reduced in plants that were stressed under drought. However, at high temperatures, this reduction was less pronounced when droughted plants were partially shaded. At low temperatures, plants began to senesce after approximately 9 wk, whereas at higher temperatures, signs of senescence appeared after only 7 wk of growth. Despite shorter longevity, total biomass was approximately 1.5 times higher in the control water treatment at higher than at lower temperatures as a result of greater above-ground growth, and plants allocated a significantly greater proportion of mass gain to seed production. Although F. proserpinacoides can tolerate low temperatures such as those typical of early spring, higher temperatures such as those of late spring/early summer are more favorable for growth and reproduction as long as water and light are not limiting. Spring ephemeral annuals might be rare because low temperatures reduce growth rate and extend the life cycle. An annual plant might not have time to reproduce before resource availability deteriorates with canopy closure unless reproduction begins early in the life cycle of the species.

Facilitating grassland diversification using the hemiparasitic plant Rhinanthus Minor

Article

Sep 2004
J APPL ECOL

Species‐rich grasslands are of high conservation value because of the diverse floral and faunal assemblages they support. Intensive agriculture has resulted in the large‐scale loss and fragmentation of this habitat throughout the UK and Europe. Diversification of species‐poor grasslands has proved to be problematical due to seed limitation, lack of microsites for germination and competition from established species. Studies of semi‐natural grasslands in Britain and Europe suggest that the presence of hemiparasitic angiosperms of the genus Rhinanthus is correlated with local decreases in productivity and an associated increase in species richness. In 1998 a randomized block experiment was established to examine: (i) the practicality of introducing Rhinanthus minor into a productive grassland from seed; (ii) the rate of establishment and colonization of the introduced populations; and (iii) the relationship between the frequency of the parasite and the establishment and persistence of introduced forb species. Establishment of Rhinanthus was less likely at the lowest sowing rate (0·1 kg ha ⁻¹ ) and population growth was initially slow compared with the higher seed rates (0·5 and 2·5 kg ha ⁻¹ ). After the first year, populations grew rapidly and colonized the unsown plots, so that after 4 years there was little difference in Rhinanthus frequency between treatments. In October 2000, 2 years after sowing Rhinanthus , a native wildflower seed mixture was oversown into a number of the treatments at 5 kg ha ⁻¹ . The mixture comprised 10 forbs of which nine species were previously not present in the grassland. All forbs established with up to seven species m ⁻² . This resulted in an increase in mean richness of sown species of 0·8 to 2·2 m ⁻² and in a cumulative richness per plot of 1·4 to 5·8 m ⁻² . In both 2001 and 2002 there was a strong, inverse relationship between the frequency of Rhinanthus and sward height. In 2002, there was evidence of a threshold frequency of the hemiparasite above which there was a significant reduction in grassland productivity. The frequency of Rhinanthus in 2001 had a significant beneficial effect on the persistence of seven of the 10 sown forbs in the following year. This probably reflects a reduction in competition from the established grassland species at the vulnerable seedling stage, together with death of the hemiparasite leading to a higher number of gaps for colonization. Synthesis and applications. The introduction of R. minor is a practical management tool to facilitate the colonization of species‐poor, productive grasslands by desirable species. This is achieved by the hemiparasite modifying the competitive relationships between the component species, and increasing establishment and survival of introduced species. This species has a potentially central role in determining the structure and dynamics of grassland communities.

Restoration of species-rich grassland on arable land: Assessing the limiting processes using a multi-site experiment

Article

Apr 2002
J APPL ECOL

Agricultural intensification has resulted in the reduction and fragmentation of species‐rich grasslands across much of western Europe. We examined the key ecological processes that limit the creation of diverse grassland communities on ex‐arable land in a multi‐site experiment over a wide variety of soil types and locations throughout lowland Britain. The results showed it was possible to create and maintain these communities successfully under a hay‐cutting and grazing management regime. Furthermore, there was a high degree of repeatability of the treatment effects across the sites. Lack of seed of desirable species was the key factor limiting the assembly of diverse grassland communities. Sowing a species‐rich seed mixture of ecologically adapted grassland plants was an effective means of overcoming this limitation. Community assembly by natural colonization from the seed bank and seed rain was a slow and unreliable process. However, there was no evidence to suggest that sowing a species‐poor grass‐dominated seed mixture made the vegetation any less susceptible to colonization by desirable species than allowing natural regeneration to take place. Deep cultivation caused significant reductions in soil P and K concentrations across the sites. This had a significant beneficial effect on the establishment and persistence of sown forbs in all years. It also resulted in a significant reduction in the number of unsown weedy grasses. However, for both variables these differences were very small after 4 years. Sowing a nurse crop significantly reduced the number of unsown grass species, but had no beneficial effect on the establishment of desirable species. Treatments sown with the species‐rich seed mixture following deep cultivation corresponded most closely to the specified target communities defined by the UK National Vegetation Classification. Natural regeneration and treatments sown with the species‐poor seed mixture were much less similar to the target. The sites on circum‐neutral soils achieved the greatest degree of similarity to the target. Those on calcareous and acid soils failed to achieve their targets and most closely resembled the target for neutral soils. This reflected the poor performance of the sown preferential species for these communities.

Remnant grassland habitats as source communities for plant diversification in agricultural landscapes

Article

Jan 2008
BIOL CONSERV

Lately there has been a shift in Sweden from grazing species-rich semi-natural grasslands towards grazing ex-arable fields in the modern agricultural landscape. These fields normally contain a fraction of the plant species richness compared to semi-natural grasslands. However, small remnant habitats have been suggested as important for plant species diversity and conservation as they may function as refugia for grassland specialists in fragmented and highly modified agricultural landscapes. In this study, we examined whether plant communities on small remnant habitats, i.e. midfield islets, can function as sources for grassland species to disperse out into surrounding grazed ex-fields (former arable fields). We examined species richness and grassland specialists (species favoured by grazing) and their ability to colonize fields after 5 and 11 years of grazing. The fields that had been grazed for a shorter time were fairly species-poor with few grassland specialists. A longer period of grazing had a positive effect on total and small-scale species diversity in both islets and fields. Species composition became more similar with time, and the number of grassland specialists in both habitats increased. We found that grassland specialists dispersed step-wise into the fields, and the number of grassland specialists decreased with distance from the source. Our study suggests that remnant habitats, such as midfield islets, do function as a source community for grassland specialists and enhance diversification of grassland species when grazing is introduced. For long-term conservation of plant species, incorporating small refugia into larger grazing complexes may thus enhance species richness.

The effects of patch shape on Indigo Buntings: Evidence for an ecological trap

Article

Jan 1422

Habitat loss and fragmentation have led to a widespread increase in the proportion of edge habitat in the landscape. Disturbance-dependent bird species are widely assumed to benefit from these edges. However, anthropogenic edges may concentrate nest predators while retaining habitat cues that birds use to select breeding habitat. This may lead birds to mistakenly select dangerous habitat—a phenomenon known as an ''ecological trap.'' We experimentally demonstrated how habitat shape, and thus amount of edge, can adversely affect nest site selection and reproductive success of a disturbance-dependent bird species, the Indigo Bunting (Passerina cyanea). We did so within a landscape-scale experiment composed of equal-area habitat patches that differed in their amount of edge. Indigo Buntings preferentially selected edgy patches, which contained 50% more edge than more compact rectangular patches. Further, buntings fledged significantly fewer young per pair in edgy patches than in rectangular patches. These results provide the first experimental evidence that edges can function as ecological traps.

Successfully Recovered Grassland: A Promising Example from Romanian Old‐Fields

Article

Sep 2006
RESTOR ECOL

Eszter Ruprecht

In this study, I analyzed the natural recovery of grasslands on abandoned agricultural fields in the Transylvanian Lowland (Câmpia Transilvaniei), Romania. I examined fields that were abandoned 1–40 years ago and considered how successful they have been in recovering spontaneously as compared to reference grassland, especially in relation to species composition and dominance structure. Diverse, nondegraded seminatural grasslands from the surroundings were chosen as targets for the recovery. Five such grasslands were analyzed in order to have multiple references that accounted for site heterogeneity and different land use history. This study found that the number of natural and seminatural habitat species increased, whereas the number of weeds and aliens decreased with age. Old-fields had become very similar in species composition and dominance structure to reference grasslands over a 14- to 20-year time interval, with the only failure being the unsuccessful or slow colonization of a few grassland species. Because spontaneous succession is efficient, human interventions are not needed to restore target communities on the old-fields. Propagule pressure expressed by the area of potential seed source in a 500-m-radius buffer was found to have a strong influence on recovery success of old-fields. The success of grassland species in colonizing postagricultural fields was not affected by their dispersal mode but by their frequency in the landscape, this being another evidence for the importance of propagule availability in the course of recovery. In order to maintain the potential for recovery of this landscape, we need to protect those close to natural habitats that contain a high amount of native flora.

Recreating Grasslands in Swedish Rural Landscapes – Effects of Seed Sowing and Management History

Article

Mar 2006

Regina Lindborg

Recent loss of plant species richness in Swedish semi-natural grasslands has led to an increase in grassland recreation and restoration. To increase the establishment of declining species favoured by grazing and to re-establish original species richness, seed sowing has been discussed as a conservation tool. In this study, I examined to what extent seed sowing in former arable fields increases species richness and generates a species composition typical of semi-natural grasslands. Six grassland species favoured by grazing (target species) and six generalist species favoured by ceased grazing, were studied in a seed-addition experiment. Four different seed densities were used on four different grassland categories, two grazed former arable fields, one continuously grazed grassland and one abandoned grassland. Target and generalist species emerged in all grassland categories, but seedling emergence was higher in the grazed than in the abandoned grassland. Target species had higher emergence in the two grasslands with the longest grazing continuity. Seedling emergence and frequency of established plants of each target species were positively associated. The largest fraction of seeds germinated at an intermediate sowing density, 20–50seeds/dm2, suggesting that aggregation of seeds positively affects emergence up to a certain threshold. In conclusion, artificial seed sowing may induce the recreation of typical grassland communities on former arable fields, which may be an important contribution to increase the total grassland area and species richness in the landscape.

The influence of management history and habitat on plant species richness in a rural hemiboreal Sweden

Article

Jan 2002

We explored patterns of plant species richness at different spatialscales in 14 habitats in a Swedish rural landscape. Effects of physicalconditions, and relationships between species richness and management historyreaching back to the 17th century were examined, using old cadastralmaps andaerial photographs. The most species-rich habitats were dry open semi-naturalgrasslands, midfield islets and road verges. Alpha diversity (species richnesswithin sites) was highest in habitats on dry substrates (excluding bedrock withsparse pines) and beta diversity (species richness among sites) was highest inmoist to wet habitats. Alpha and beta components of species richness tended tobe inversely related among habitats with similar species richness. Managementhistory influenced diversity patterns. Areas managed as grasslands in the17th and 18th century harboured more species than areasoutside the villages. We also found significant relationships between speciesrichness and soil type. Silt proved to be the most species-rich topsoil(10–20 cm) in addition to thin soils top of on green- orlimestone bedrock. The variation in species richness due to local relief orform of thesite also showed significant relationships, where flat surfaces had the highestnumber of species. In contrast, no significant relationship was found betweenspecies richness and aspect. Our study suggests that present-day diversitypatterns are much influenced by management history, and that small habitat,e.g., road verges and midfield islets, are important for maintaining speciesrichness.

Plant species richness in midfield islets and road verges – The effect of landscape fragmentation

Article

Feb 2006
BIOL CONSERV

Sara AO Cousins

Small marginal habitats in the rural landscape may play an important role for plant species richness as refugias. Little is known how the surrounding landscape and landscape history influence these patterns. I analysed how plant species richness was affected by isolation, habitat area, past and present land use, and if landscape context matters. Plant species occurrence in two different types of small marginal habitats were analysed, road verges and midfield islets. The study was conducted in two different agricultural landscapes in Sweden; one open modern agricultural landscape and one traditional rural landscape, and the results compared. Present and past land use, and landscape change was analysed using aerial photographs and old maps. There was a large grassland reduction more than 50 years ago in the modern landscape, when there still were quite a lot of grasslands left in the traditional landscape. Area and connectivity were more important for plant incidence in small remnant habitats in the modern landscape, compared to the less fragmented, traditional rural landscape. On the other hand there were more grassland specialists, 23% in the traditional landscape compared to 16%. Species richness became higher on midfield islet if grazing was re-introduced. The legacy of surrounding landscape remains in the species pool for a long time, atleast 50 years, even in small grassland fragments. Although small grassland remnants are more sensitive to fragmentation effects compared to larger grasslands, they still encompass a substantial part of the grassland species pool and may be valuable for reconstructing grassland management at a landscape scale.

A method for the selection of relevant pattern indices for monitoring of spatial forest cover pattern at a regional scale

Article

Jun 2006
INT J APPL EARTH OBS

When signing Agenda 21, several countries agreed to monitor the status of forests to ensure their sustainable use. For reporting on the change in spatial forest cover pattern on a regional scale, pattern metrics are widely used. These indices are not often thoroughly evaluated as to their sensitivity to remote sensing data characteristics. Hence, one would not know whether the change in the metric values was due to actual landscape pattern changes or to characteristic variation of multitemporal remote sensing data.The objective of this study is to empirically test an array of pattern metrics for the monitoring of spatial forest cover. Different user requirements are used as point of departure. This proved to be a straightforward method for selecting relevant pattern indices. We strongly encourage the systematic screening of these indices prior to use in order to get a deeper understanding of the results obtained by them.

Using functional traits to assess the role of hedgerow corridors as environmental filters for forest herbs

Article

Jul 2006
BIOL CONSERV

Linear habitats such as hedgerows can constitute important refuges for native flora and fauna, possibly providing connectivity between landscape elements. The effectiveness of these functions, however, depends on the ability of linear habitats to benefit a significant proportion of the local species pool and their functional attributes. This study aims to identify life-history traits that appear to either limit or facilitate survival or colonization of forest herbs in hedgerows. The distribution patterns of 47 native forest herbaceous species and their associated traits were compared in a system of hedgerows and attached forest patches of southern Quebec. Although 83% of the species surveyed in forest patches were present in hedgerows, significant differences in abundance suggest the existence of a selective pressure on forest species in linear habitats. Early spring flowering was negatively associated with hedgerows, possibly because of unfavourable microclimatic conditions. Seed dispersal phenology partly mirrors results for flowering phenology with early summer dispersal and late fall dispersal being less common in hedgerows than in forests. Slow dispersal mainly through myrmecochory was also less common in hedgerows compared to forest sites, suggesting a selective pressure on slow dispersers in linear habitats. The capacity for vegetative propagation was positively associated with hedgerows, possibly because it provides an alternative strategy to survive and expand when conditions are less favourable for sexual reproduction. Our approach highlights traits that can help determine the vulnerability of native forest species in linear habitats or their likelihood to benefit from the maintenance of wooded corridors in an inhospitable matrix.

Conservation of lowland semi-natural grasslands in the UK: A review of botanical monitoring results from agri-environment schemes

Article

Feb 2004
BIOL CONSERV

Agri-environment schemes are one of the main policy initiatives for delivering biodiversity objectives for lowland grasslands in the UK. Farmers entering into scheme agreements must adopt environmentally beneficial management practices. Results of botanical monitoring programmes, of duration up to 8 years for schemes in the four UK countries, are reviewed in the context of the UK Biodiversity Action Plan (BAP). No change was detected in 22 out of 38 samples (sets of quadrats or plots) of semi-natural grassland, implying maintenance of quality; some rehabilitation (improvement in condition) occurred in nine samples, but seven deteriorated. Some signs of reversion to grassland of biodiversity value (restoration) were detected in 9 out of 30 samples of agriculturally improved or semi-improved grassland. Rehabilitation or restoration usually coincided with low fertiliser input or changes in grazing intensity, and often occurred in western locations or the upland fringe. Deterioration was mostly due to inappropriate grazing intensity or altered hydrological regime. Greater use of site-specific targets and prescriptions would enhance future scheme performance and monitoring.

Assessment of long-term tallgrass prairie restoration in Manitoba, Canada

Article

Jul 2005
BIOL CONSERV

Ecological restoration is important in mitigating degradation and habitat loss of tallgrass prairie in North America. In 2002, we assessed the progress of a long-term tallgrass prairie restoration initiated in 1987 in southern Manitoba (Canada). Nine restoration and three reference sites were examined, as was a neighbouring site of future restoration that is now used for agriculture. Vegetation diversity, species composition, and associated soil properties were compared among restoration and reference sites, and changes associated with restoration identified. Restoration had a substantial effect on diversity and species composition, although restoration sites had significantly lower native and higher exotic diversity than reference sites. Overall and native diversity decreased over time, as both exotic and seeded native species were lost from the restoration sites. Particularly vulnerable were native forb species, which represent much of the diversity of prairie habitats. Forb presence was negatively associated with that of warm season native grasses, especially Andropogon gerardii (big bluestem). Similarity of restoration and reference vegetation increased over time, particularly for seeded native graminoids. When species that had been seeded elsewhere and had colonized restorations were examined, similarity between restoration and reference also increased with time, suggesting that older sites may be self-propagating. No significant differences in soil properties variables were observed among restoration sites, indicating that changes in these factors are slow relative to vegetation changes. Although time-since-restoration had a substantial impact on diversity and species composition, this habitat will require ongoing restoration.

Landscape perspectives on agricultural intensification and biodiversity—ecosystem service management. Ecol Lett 8:857-874

Article

Aug 2005
ECOL LETT

Abstract Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local high-intensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.

Integrating the statistical analysis of spatial data in ecology

Article

Oct 2002

Gurevitch Liebhold

In many areas of ecology there is an increasing emphasis on spatial relationships. Often ecologists are interested in new ways of analyzing data with the objective of quantifying spatial patterns, and in designing surveys and experiments in light of the recognition that there may be underlying spatial pattern in biotic responses. In doing so, ecologists have adopted a number of widely different techniques and approaches derived from different schools of thought, and from other scientific disciplines. While the adaptation of a diverse array of statistical approaches and methodologies for the analysis of spatial data has yielded considerable insight into various ecological problems, this diversity of approaches has sometimes impeded communication and retarded more rapid progress in this emergent area. Many of these different statistical methods provide similar information about spatial characteristics, but the differences among these methods make it difficult to compare the results of studies that employ contrasting approaches. The papers in this mini-series explore possible areas of agreement and synthesis between a diversity of approaches to spatial analysis in ecology.

Land Mosaic: The Ecology of Landscapes and Regions

Article

Jan 1995

R.T.T. Forman

Mosaic pattern is the central feature of land, and ecological structure, function, and change of the mosaic is the central focus of this book. Spatial arrangement is the structure of a landscape or region. It determines the movements and flows between local ecosystems, and across the mosaic. It changes in form over time. Spatial arrangement is also a useful handle for decision-makers in planning, conservation, design, management, and policy.

Environmental, historical, and contextual determinants of vegetation cover: A landscape perspective

Article

Jul 2001

We formulated and tested models of relationships among determinants of vegetation cover in two agroforested landscapes of eastern North America (Haut Saint-Laurent, Quebec, Canada) that differed by the spatial arrangement of their geomorphic features and intensity of agricultural activities. Our landscape model compared the woody plots of each landscape in terms of the relative influence of environmental attributes, land use history (1958 – 1997), and spatial context (i.e., proximity of similar or contrasting land cover). Our vegetation model evaluated the relative contribution of the same sets of variables to the distributions of herbs, trees, and shrubs. Relationships were assessed using partial Mantel tests and path analyses. Significant environmental and contextual differences were found between the vegetation plots of the two landscapes, but disturbance history was similar. Our vegetation model confirms the dominant effect of historical factors on vegetation patterns.Whereas land-use history overrides environmental and contextual control for trees, herbaceous and shrub species are more sensitive to environmental conditions. Context is determinant only for understory species in older, less-disturbed plots. Results are discussed in relevance to vegetation dynamics in a landscape perspective that integrates interactions between environmental and human influences.

Rethinking the Effectiveness of Public Protected Areas in Southwestern China

Article

Apr 2007

It is internationally recognized that conservation policies should respect indigenous cultures and consider the livelihoods of people affected by conservation restrictions. Countering this are concerns that human occupation and use of natural reserves is incompatible with conservation aims. But in China today the continued use and management of natural areas by local communities is likely to deliver better conservation outcomes than the current drive to establish public protected areas. The effectiveness of many protected areas in China is compromised by institutional conflicts, lack of ongoing financial and technical support, confusion between the objectives of generating revenue and conservation, dubious scientific definitions, lack of community trust in policies, and obscure user rights and land tenures. Southwestern China-one of the most biologically and ethnologically diverse areas on Earth-is a good illustration of a place where culture and biological diversity are closely linked. The indigenous people in this area have shown that local livelihood practices can be advantageous for the long-term maintenance of conservation goals. Rather than creating new protected areas, we argue that China is better advised to support ongoing sustainable use of natural areas by the people who have lived and nurtured these environments for generations.

What do conservation biologists publish? Biol Conserv

Article

Jul 2005
BIOL CONSERV

We provide an overview of publications from three prominent conservation journals (Biodiversity & Conservation, Biological Conservation and Conservation Biology) published in 2001 (n = 547 papers). We found a wide breadth of studies of different topics from different climates and habitats and across a range of spatial scales. Most studies were quantitative (89%) and used inferential statistics (63%). Research was biased towards vertebrates, forests, relatively pristine landscapes, and towards studies of single species and assemblages rather than communities or ecosystems. Despite assertions in the literature that conservation is synthetic, eclectic and multi-disciplinary, few studies were truly cross-disciplinary (13%). In addition, few studies investigated the loss of native vegetation (2%), or specifically studied introduced (4%) or non-threatened species (4%). 20% and 37% of studies had high relevance to policy and management, respectively. However, only 12.6% of studies actively went out to test or review conservation actions. Although many topics are covered in the literature, improvements are possible. We suggest: (1) broadening the number of habitats, taxonomic groups and scales studied and (2) providing closer and clearer links with other disciplines and research approaches, and with policy and management.

The influence of field shape, area and surrounding landscape on plant species richness in grazed ex-fields

Abstract

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