Grassland Specialist Species Research Articles

Variability in leaf traits reveals contrasting strategies between forest and grassland woody communities across southern Brazil

Forests and grasslands often form mosaics in subtropical regions such as in southern Brazil. Currently, we observe the processes of woody species encroachment and forest expansion over grasslands due to changes in climate conditions and disturbance regimes. Woody plants occurring across such mosaics can be specialists from one habitat type (forest or grassland) or a generalist species (those occurring in both of these contrasting habitats). Here, we explore if their occurrence in distinct habitats is coordinated by functional traits, considering both intra- and interspecific variability and phylogenetic relatedness between species, thereby assessing changes between habitats from the individual to the community scale. We surveyed forest and grassland vegetation forming mosaics in nine sites in southern Brazil. We found that grassland-forest communities do not differ in phylogenetic diversity, irrespective of considering or not the gymnosperms of the communities. Furthermore, forests presented lower diversity in leaf area than grasslands, with a predominance of large leaves but higher diversity of specific leaf area and leaf dry matter content, with leaves predominantly with an acquisitive resource strategy. When considering species with different habitat preferences, forest-specialist species showed traits related to resource acquisition, while grassland-specialist species showed trait values associated with resource conservation. Generalist species have trait values according to habitat occurrence, showing high intraspecific variability and trait plasticity to establish on both forest and grassland habitats. Assessing the trait variability from woody individuals is important to understanding the contrasting strategies used by different species in grassland-forest mosaics and can be essential to predict the dynamics of these ecosystems, given the changes in climate and disturbances regimes.

Preserving large tracts of natural grassland promotes mammal species richness and occurrence in afforested areas

The global loss of biodiversity paired with the shortcomings of protected areas highlights the need to improve the conservation potential of human-modified lands. Although often referred to as “ecological deserts”, large spatial scales and long rotation periods make tree plantations a relatively stable and permeable environment that could provide an important link between fragmented natural habitats. Different intensities of afforestation within the same geographic grassland region provide an opportunity to test how transformation by commercial plantations affects local biodiversity. We conducted camera trap surveys at two sites characterised by different degrees of afforestation. We demonstrate a higher mammalian diversity and a higher probability of habitat use in less transformed areas, suggesting that preserving large tracts of native vegetation is vital when offsetting biodiversity loss from timber plantations, especially regarding grassland-specialist species. Community-level habitat use increased in more rugged areas, while in the highly transformed site, habitat use increased closer to indigenous patches and roads. Our research highlights the importance of maintaining comprehensive networks of protected units as part of a broader landscape management approach and identifies a major challenge for the forestry industry moving forward, with plantation stands being dominated by species that threaten the long-term sustainability of the crop itself.

Species accumulation in novel grassland habitats is linked to land cover history

Novel grassland habitats along linear infrastructure have gained attention as potential supplementary or replacement habitats for species suffering from the widespread loss of traditionally managed semi‐natural grasslands. However, it can take time for species to colonise new habitats, and both the historical and the current landscape composition can affect colonisation rates, particularly for grassland specialist species. We investigated the influence of more than 100 years of landscape history on present‐day species richness of plants, butterflies and bumblebees in two types of linear infrastructure habitats: road verges and power line corridors. We analysed the effects of time since habitat establishment and the amount of surrounding grassland cover in different time periods on species richness of the three taxa. Our results suggest a long time lag in the establishment of plant species in novel grassland habitats, with richness of butterflies and bumblebees largely dependent on the richness of plant species. There was no direct relationship between habitat age and the richness of butterflies or bumblebees, but we found unexpected legacy effects of grassland area on present‐day species richness. Higher richness of bumblebee species in road verges located in landscapes with larger surrounding grassland cover in the past is most likely a consequence of those landscapes containing a mosaic of afforested and abandoned grassland habitats today. Furthermore, we found that power line corridors might be important replacement habitats for butterflies in landscapes with little other grassland area left. Provided that road verges and power‐line corridors are managed appropriately, our results show that their species richness can be expected to increase in the future.

Contrasting responses of vascular plants and bryophytes to present and past connectivity in unmanaged grasslands

The area of semi-natural grasslands has decreased dramatically causing many grassland specialist species to persist in small habitat fragments. Furthermore, ecological communities once shaped by disturbances related to traditional agriculture now face the impacts of modern agriculture and urbanization. Many of the species have become endangered due to the combined effects of habitat destruction and degradation. We studied the responses of vascular plants and bryophytes to present and past connectivity in semi-natural grasslands, while accounting for the effects of local environmental conditions. We conducted vegetation surveys in 33 fragmented, unmanaged dry grasslands in Southwest Finland. A total of 191 vascular plant species and 60 bryophyte species were recorded. Higher vascular plant diversity was associated with higher historical connectivity, whereas bryophyte diversity declined with increasing current connectivity. Edaphic conditions, microclimate and disturbances were found to structure both vascular plant and bryophyte communities, but the responses to individual environmental variables were very different. The contrasting responses could be explained by the differences between the typical life-history strategies in vascular plants and bryophytes as well as resource competition between the two groups. These results highlight the need to consider different species groups when planning conservation measures. Vascular plant richness may best be conserved in connected grasslands whereas bryophyte richness in isolated ones. The results also indicated that trampling by humans could result in positive disturbance and to some extent help maintain richness of grassland specialist species.

Grassland legacy remaining in vegetation and seedbank species diversity: Evaluation in abandoned grasslands and plantation forests

Species-rich semi-natural grasslands have been drastically transformed into agricultural areas, plantation forests, and abandoned grasslands worldwide. Grassland legacy—the impacts of a past grassland-use history on biological communities—is often detected in clear-cut forests that were formerly grasslands. This study assessed whether grassland plant species remain in the standing vegetation and soil seedbanks in transformed former grasslands. We surveyed standing vegetation and soil seedbanks in four land-use types with a grassland history (i.e., managed grassland, abandoned grassland, evergreen plantation, and deciduous plantation) and compared plant species richness and species composition among them. Grassland species remained but had lower species richness in abandoned grasslands and plantations, particularly of evergreen trees, than in standing vegetation in managed grasslands. The grassland species richness of seedbanks was significantly lower in abandoned grasslands than in managed grasslands. There were no differences in grassland species richness or the number of individuals in seedbanks among the other land-use types. The grassland species composition differed between standing vegetation and seedbanks regardless of land use, and the grassland species composition of standing vegetation in managed grasslands clearly differed from that of the other land-use types. Additionally, exotic species appeared in both the standing vegetation and seedbanks of managed and abandoned grasslands but not in those of plantations. Thus, our study detected grassland legacy in both standing vegetation and soil seedbanks, with variations depending on diversely transformed land uses, although the presence of grassland specialist species seemed to be limited. These results highlight the potential importance of plantation forest management for grassland restoration and the risk of exotic plant establishment associated with abandoned grassland restoration. • Grassland species were present but low species richness in standing vegetation of abandoned grasslands and plantation forests. • Grassland species richness declined in seedbanks of abandoned grasslands. • Grassland species’ seeds remained in soils of evergreen and deciduous plantations. • Forest management can help secure sites and seed sources for grassland restoration.

Temporal continuity and adjacent land use exert different effects on richness of grassland specialists and alien plants in semi‐natural grassland

AbstractAimsGrassland plant species diversity is affected by local, temporal and landscape environmental factors, but what is the relative importance of those factors? Understanding this is crucial for the effective conservation of grassland vegetation. We analyzed the factors affecting species richness to contribute to native species conservation and alien species management in grassland vegetation.LocationSemi‐natural grasslands in Shiroi City, Chiba Prefecture, Japan.MethodsThe species composition in 36 grasslands was surveyed in 2014. Plants were classified as native grassland specialist, other native or alien species. Generalized Linear Models (GLM) were developed, with the number of species in each plant type as the response variable and local (habitat area, use of mowing management), landscape (adjacent land use, connectivity to other grassland habitats) and temporal (period for which the grassland has been preserved from development, i.e., temporal continuity) factors as explanatory variables. Other GLM were developed with the presence/absence of each species as a response variable and three factors as explanatory variables.ResultsHabitat area, use of mowing management and temporal continuity were most important in explaining the number of grassland specialist species and had significant positive effects on their richness. Species‐based analysis identified a significant positive effect of temporal continuity on grassland specialist species. By contrast, habitat area and adjacent land use were most related to alien species richness. The number of alien species was high in grasslands adjacent to farmlands or roads.ConclusionsThe relative importance of temporal and spatial factors differs between native grassland specialists and alien species. Mowing is effective for the conservation of grassland specialists’ species diversity, particularly in historically old grasslands. However, it is necessary to pay attention to the invasion of alien species from adjacent residential or agricultural areas.

Powerline Corridors Can Add Ecological Value to Suburban Landscapes When Not Maintained as Lawn

Electric powerline corridors are informal green spaces that encompass large areas of land and have the potential to support biodiversity in urban and suburban landscapes. However, the extent to which these corridors provide novel habitats compared to the surrounding landscape is unclear. Biodiversity in corridors is often compared to that of “natural” habitats despite the fact that the corridors are subject to frequent vegetation management. In urban and suburban landscapes, residential yards may provide a more appropriate comparison because they are a dominant type of green space and are also characterized by frequent vegetation management. We conducted a study of the biodiversity in suburban powerline corridors in northern Illinois, USA, and compared it to the biodiversity found in nearby residential yards. Our goal was to determine whether powerline corridors added ecological value to these suburban landscapes. We included three different management styles of powerline corridors: (1) frequently mowed and kept as lawn, (2) brush mowed on a five-year cycle (“old-field”), and (3) restored and/or maintained as native prairie. We measured the species richness and composition of plants, birds, and insect pollinators in corridors and yards. The corridor management types and comparison yards differed significantly in the richness of all three taxa, with old-field and/or prairie sites having greater species richness than mown corridors and/or comparison yards. Community composition also differed by management category. While the species richness of old-field sites tended to be high, prairie sites generally had more species of conservation interest. Our study shows that both old-field- and prairie-managed powerline corridors add habitat value to Midwestern U.S. suburban landscapes by providing alternative habitat types that support many species. Nonetheless, we suggest that managers looking to specifically support native and/or grassland specialist species in this region should manage sites as prairies when possible.

Different-aged Pinus afforestation does not support typical Atlantic Forest fruit-feeding butterfly assemblages

The Atlantic Forest of the southern Brazilian highlands is a biocultural mosaic of Araucaria Forest and grasslands. Despite adverse impacts on biodiversity, extensive areas are being afforested with non-native pine (Pinus spp.), triggering forest succession on areas that were previously native grasslands. The long-term effects of afforestation with these non-native trees for biodiversity conservation are still unknown. Here, we assess this issue by comparing the fruit-feeding butterfly assemblages in young (20 year) and old (70 year) pine plots with nearby native Araucaria Forest. Abundance and richness of butterflies were positively correlated with temperature and mean humidity only in the native forest. Abiotic conditions differed between vegetation types: there was more sunlight, and was warmer and drier in the pine afforestation plots than in the Araucaria Forest. Butterfly species composition was similar between young and old pine plots, but distinct from the native Araucaria Forest. Butterfly species abundances in native forests were more evenly distributed than in afforestation sites. In these pine sites, assemblages were dominated by small, grass-feeding satyrines, whereas old pine sites had more liana-feeding biblidines, and the Araucaria Forest had more large-sized bamboo-feeding species. Our results indicate that even after 70 years of succession a non-native pine afforestation cannot support a butterfly assemblage as that found in the neighboring preserved forest. Moreover, threatened grassland specialist species have been locally extinct after only 20 years of pine afforestation. The evidence gathered here points against the use of silviculture with non-native trees in these biocultural mosaic landscapes.

Grassland management and land use history shape species composition and diversity in Transylvanian semi‐natural grasslands

AbstractAimsSemi‐natural grasslands are among the most biodiverse habitats in Europe, and they are of great conservation and agricultural value. However, changes in land use like grazing intensification and the cessation of traditional management have dramatic effects on the extent and biodiversity of these ecosystems. In this study we investigated how current management practices and land use history shape species composition and diversity patterns in semi‐natural grasslands of the Eastern hills of the Cluj region.LocationEastern hills of Cluj (“Dealurile Clujului de Est” ‐ ROSCI0295) Natura 2000 conservation site and close surroundings, Transylvania, Romania.MethodsWe surveyed plots in extensively and intensively grazed grasslands, grasslands mown by hand or heavy machinery, and abandoned grasslands. To quantify grassland continuity, we analysed a series of historical cadastral and more current maps ranging from the 18th to the 21st century.ResultsSpecies composition was significantly influenced by current management, grassland continuity and environmental factors. Mown and extensively grazed grasslands had more grassland and forest edge specialists than abandoned and intensively grazed grasslands. In addition, there was a positive relationship between the number of grassland specialists, forest edge species and grassland continuity, while the number of ruderal species related negatively to grassland continuity. The highest diversity values were recorded in traditionally mown grasslands. However, diversity‐related variables were poorly reflected by grassland continuity.ConclusionsThis study provides evidence that short‐term abandonment may not be as detrimental for grasslands as often suggested, and intensive grazing results in the greatest loss in species diversity. Grassland continuity tightly influences the persistence of grassland specialist species. Thus, we recommend land use history to be included in the selection and identification of high‐nature‐value grasslands by prioritizing conservation efforts for older grasslands.

Functional rather than structural connectivity explains grassland plant diversity patterns following landscape scale habitat loss

ContextFunctional connectivity is vital for plant species dispersal, but little is known about how habitat loss and the presence of green infrastructure interact to affect both functional and structural connectivity, and the impacts of each on species groups.ObjectivesWe investigate how changes in the spatial configuration of species-rich grasslands and related green infrastructure such as road verges, hedgerows and forest borders in three European countries have influenced landscape connectivity, and the effects on grassland plant biodiversity.MethodsWe mapped past and present land use for 36 landscapes in Belgium, Germany and Sweden, to estimate connectivity based on simple habitat spatial configuration (structural connectivity) and accounting for effective dispersal and establishment (functional connectivity) around focal grasslands. We used the resulting measures of landscape change to interpret patterns in plant communities.ResultsIncreased presence of landscape connecting elements could not compensate for large scale losses of grassland area resulting in substantial declines in structural and functional connectivity. Generalist species were negatively affected by connectivity, and responded most strongly to structural connectivity, while functional connectivity determined the occurrence of grassland specialists in focal grasslands. Restored patches had more generalist species, and a lower density of grassland specialist species than ancient patches.ConclusionsProtecting both species rich grasslands and dispersal pathways within landscapes is essential for maintaining grassland biodiversity. Our results show that increases in green infrastructure have not been sufficient to offset loss of semi-natural habitat, and that landscape links must be functionally effective in order to contribute to grassland diversity.

Roadside diversity in relation to age and surrounding source habitat: evidence for long time lags in valuable green infrastructure

Abstract1. The severe and ongoing decline in semi‐natural grassland habitat during the past two centuries means that it is important to consider how other, marginal grassland habitat elements can contribute to landscape‐level biodiversity, and under what circumstances.2. To examine how habitat age and the amount of core grassland habitat in the surrounding landscape affect diversity in green infrastructure, we carried out inventories of 36 rural road verges that were either historical (pre‐1901) or modern (established post‐1901 and before 1975), and were surrounded by relatively high (>15%) or low (<5%) levels of grassland habitat. We recorded the number of plant species, grassland specialists, grassland conservation species and the fraction of the landscape's species and specialists found in the road verge.3. Road verge communities were characterised by high levels of grassland specialist species (35% of the 161 species recorded), with road verge sites supporting 15–20% of the specialist species found in the surrounding 25 km2 landscape.4. Richness of species and specialists were more closely related to road age than to the amount of surrounding habitat. Higher diversity in historical roads, despite the majority of modern roads being at least 60 years old, suggests a long time lag in the establishment of grassland communities in marginal grassland habitats. We identified no effect of historical surrounding land use on present day diversity in road verges.5. Road verge richness was not affected by the amount of surrounding grassland. This could be due to the relatively low amounts of grassland remaining in all landscapes, together with dispersal limitation commonly found in grassland plant communities contributing to a potential time lag.6. We identified road verges as potentially very important habitats for grassland communities. Because of the high levels of grassland specialists present, these and other marginal grasslands and grassland green infrastructure should be explicitly considered in landscape‐scale conservation management. Practitioners looking to identify the most species‐rich road verges should aim to find the oldest possible, while long time lags in community assembly suggests that seed sowing could be appropriate to enhance roadside diversity, even in decades‐old road verges.

Habitat Structure, Quality and Landscape Predict Species Richness and Communities of Collembola in Dry Grasslands in Austria.

We assessed the relationships between site size, habitat quality, landscape factors (fragmentation, landscape diversity) and species richness in communities of Collembola in 50 small dry grassland habitat patches in an agricultural landscape of eastern Austria. Grasslands in that region were once widespread and extensive, but have become increasingly fragmented and isolated. We hypothesized that dry grassland springtails species richness is significantly correlated with site variables (soil properties, habitat quality) and that the size of grassland sites is positively correlated with species richness. We used pitfall traps in 50 dry grasslands in differently structured agricultural landscapes and tested total abundance and three species richness measures: (1) the number of dry grassland specialist species; (2) total number of dry grassland species and (3) overall species richness. In the multivariate correlation models, we found that all species richness measures were significantly related to the plant species richness, a shape parameter of the sites, soil properties such as humus, temperature, sand and gravel content and the landscape variable reflecting isolation (distance to the nearest large dry grassland area). This landscape variable indicates that neighbouring grasslands are influencing the species richness of the sites. This may be a result of passive wind dispersal across the landscape or historic connection of the small sites with much larger dry grasslands. The size of the site did not show any significant correlation with total, dry grassland specialist, dry grassland generalist or generalist species richness. The small size of Collembola might explain these findings, because they have high population densities even in small patches.

Ecosystem engineering by foxes is mediated by the landscape context-A case study from steppic burial mounds.

In intensively used landscapes, remnant grassland fragments are often restricted to places unsuitable for agricultural cultivation. Such refuges are the ancient burial mounds called “kurgans,” which are typical landscape elements of the Eurasian steppe and forest steppe zone. Due to their hill‐like shape, loose soil structure and undisturbed status kurgans provide proper habitats for burrowing mammals. Accordingly, grassland vegetation on kurgans is often exposed to bioturbation, which can influence the habitat structure and plant species pool. In our study, we explored the effect of fox burrows and landscape context on the habitat properties and vegetation composition of small landscape elements, using kurgans as model habitats. We surveyed the vegetation of fox burrows and that of the surrounding grassland on five kurgans situated in cleared landscapes surrounded by arable lands and five kurgans in complex landscapes surrounded by grazed grasslands. We recorded the percentage cover of vascular plants, the amount of litter, and soil moisture content in twelve 0.5 m × 0.5 m plots per kurgan, in a total of 120 plots. We found that foxes considerably transformed habitat conditions and created microhabitats by changing the soil nutrient availability and reducing total vegetation cover and litter. Several grassland specialist species, mostly grasses (Agropyron cristatum, Elymus hispidus, and Stipa capillata) established in the newly created microhabitats, although the cover of noxious species was also considerable. We found that landscape context influenced the sort of species which could establish on kurgans by affecting the available species pool and soil moisture. Our results revealed that foxes act as ecosystem engineers on kurgans by transforming abiotic and biotic conditions by burrowing. Their engineering activity maintains disturbance‐dependent components of dry grasslands and increases local environmental heterogeneity.

Cultural heritage and biodiversity conservation – plant introduction and practical restoration on ancient burial mounds

Linking the conservation of cultural heritage and natural values provides a unique opportunity for preserving traditional landscapes and receives an increased awareness from stakeholders and society. Ancient burial mounds are proper objects of such projects as they are iconic landscape elements of the Eurasian steppes and often act as refugia for grassland specialist species. The aim of this project was to reintroduce grassland plant species to burial mounds for representing them as cultural monuments with the associated biodiversity for the public. The effectiveness of seed sowing, transplanting greenhouse-grown plants and individuals from threatened populations on burial mounds in Hortobagy National Park, Hungary was tested. The following questions were answered: (1) which method is the most effective for species introduction? (2) which species can establish most successfully? (3) how does management affect the species establishment rates? It was found advisable to use a combination of seed sowing and transplanting greenhouse-grown plants. Sowing was found as a cost-effective method for introducing large-seeded species, whilst introduction of greenhouse-grown transplants warranted higher establishment rates for a larger set of species. Transplanting adult individuals was more reliable regardless of management regimes, however this method is labour-intensive and expensive. Intensive management, like mowing with heavy machinery and intensive grazing, should be avoided in the first few years after introduction. The authors highlighted the fact that introducing characteristic grassland species on cultural monuments offers a great opportunity to link issues of landscape and biodiversity conservation. This project demonstrated that, by the revitalisation of cultural monuments, cultural ecosystem services can also be restored.

Contrasting bird communities along production gradients of crops and livestock in French farmlands

Impacts on birds of intensive management practices and of landscape simplification have been widely studied, but there is a lack of knowledge about impacts on birds of landscapes associated with intensive livestock production. The objective of this work was to investigate changes in several bird community descriptors along different production gradients. Production of arable crops and from grazing livestock was computed over French agroecosystems and expressed in terms of edible energy. Using data from the French Breeding Bird Survey along with data from national agricultural statistics, we modeled the relationship between production and five bird community descriptors, namely, community trophic index, community specialization index, and three group-specific species richness indices. Bird communities were shaped by two production gradients. Along a gradient of increasing crop production, we observed a shift from locally species-diverse communities dominated by generalist or grassland specialist species towards species-poor communities dominated by granivorous species specialized in arable habitats (all p-values≤0.002). Second, we observed a shift towards homogenized communities dominated by generalists along a gradient of increasing livestock production (p-values≤0.001). Our research highlights the need to consider crop and livestock separately when investigating their impacts on biodiversity. It also hints towards the need for differentiated strategies to protect farmland birds in crop regions and in livestock regions.

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

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.

Island biogeography theory outweighs habitat amount hypothesis in predicting plant species richness in small grassland remnants

ContextThe habitat amount hypothesis has rarely been tested on plant communities. It remains unclear how habitat amount affect species richness in habitat fragments compared to island effects such as isolation and patch size.ObjectivesHow do patch size and spatial distribution compared to habitat amount predict plant species richness and grassland specialist plant species in small grassland remnants? How does sampling area affect the prediction of spatial variables on species richness?MethodsWe recorded plant species density and richness on 131 midfield islets (small remnants of semi-natural grassland) situated in 27 landscapes in Sweden. Further, we tested how habitat amount, compared to focal patch size and distance to nearest neighbor predicted species density and richness of plants and of grassland specialists.ResultsA total of 381 plant species were recorded (including 85 grassland specialist species). A combination of patch size and isolation was better in predicting both density and richness of species compared to habitat amount. Almost 45% of species richness and 23% of specialist species were explained by island biogeography parameters compared to 19 and 11% by the amount of habitat. A scaled sampling method increased the explanation level of island biogeography parameters and habitat amount.ConclusionsHabitat amount as a concept is not as good as island biogeography to predict species richness in small habitats. Priority in landscape planning should be on larger patches rather than several small, even if they are close together. We recommend a sampling area scaled to patch size in small habitats.

Urban conservation hotspots: predation release allows the grassland-specialist burrowing owl to perform better in the city

Although habitat transformation is one of the main causes of biodiversity loss, there are many examples of species successfully occupying and even proliferating in highly human-modified habitats such are the cities. Thus, there is an increasing interest in understanding the drivers favoring urban life for some species. Here, we show how the low richness and abundance of predators in urban areas may explain changes in the habitat selection pattern of a grassland specialist species, the burrowing owl Athene cunicularia, toward urban habitats. Predation release improves the demographic parameters of urban individuals, thus favoring an increment in the breeding density of the species in urban areas that accounts for the apparent positive selection of this habitat in detriment of the more natural ones that are avoided. These results suggest that traditional habitat selection analyses do not necessarily describe habitat choice decisions actively taken by individuals but differences in their demographic prospects. Moreover, they also highlight that cites, as predator-free refuges, can become key conservation hotspots for some species dependent on threatened habitats such as the temperate grasslands of South America.

Interactive effects of land‐use change and distance‐to‐edge on the distribution of species in plant communities at the forest–grassland interface

AbstractQuestionsWhat are the patterns of plant communities in terms of richness and floristic composition along stable forest–grassland interfaces? Are there specific species at the edge and/or specialist species transgressions between adjacent habitats? How does edge displacement following land‐use change alter distance‐to‐edge plant diversity patterns? What are the relative influences of the edge effect and the edge displacement in forests and grasslands?LocationForests and grasslands in northeast France.MethodsFloristic surveys were conducted in three types of forest–grassland interface, which can be stable or the result of edge displacements due to afforestation or deforestation. The sample comprised a total of 132 plots in 22 forest–grassland interfaces. Point‐biserial correlation coefficients were used to classify the species into several groups in stable interfaces: forest, edge or grassland specialists and generalists. Using LMMs and Tukey's HSD tests, the total species richness and that of each species group were compared between the plot positions (i.e. distance‐to‐edge) and between the stable interfaces and cases of afforestation and deforestation. To evaluate the relative influence of the edge effect (plot position) and edge displacement (afforestation/deforestation) on plant community composition, CCAs and variation partitionings were performed.ResultsThe largest difference in both plant community richness and composition was found between the forest and grassland edges. The highest species richness was found at the grassland edges. In addition to a high number of generalist species, a mixture of forest and grassland specialist species were predominant at the edges, and the forest specialists were almost the only transgressive species. Afforestation interfaces showed an extinction debt of grassland and edge specialist species and a colonization credit of forest specialists in recent forests. The effects of edge displacement were larger than those of the edge effect in forests, and the opposite was observed in the grasslands.ConclusionsForest and grassland plant communities differ strongly even over very short distances. However, the edges host a large number of forest and grassland specialist species, which explain higher species richness than in adjacent habitats. This results from interactive effects of distance‐to‐edge and edge displacement following land‐use change.

Factors threatening grassland specialist plants - A multi-proxy study on the vegetation of isolated grasslands

Land use changes have resulted in the loss and isolation of semi-natural habitats worldwide. In intensively used agricultural landscapes the remnants of natural flora only persist in small habitat islands embedded in a hostile matrix. In the steppe zone burial mounds, so-called kurgans, have the potential to preserve the natural flora and act as local biodiversity hotspots. Exploration of the factors driving biodiversity in isolated habitat fragments is crucial for understanding the ecological processes shaping their vegetation and for designing effective strategies for their protection. We sampled the vegetation of 44 isolated kurgans in East-Hungary and studied the effects of habitat area, slope, recent disturbance, past destruction and the level of woody encroachment on the species richness and cover of grassland specialist and problem species (competitor weedy species). We used model selection techniques and linear models for testing relevant factors affecting specialist species in grassland fragments. We found that the biodiversity conservation potential of kurgans is supported by their steep slopes, which provide adequate habitat conditions and micro-climate for steppic specialist plant species. Specialist species are threatened both by recent disturbances and encroachment of alien woody species, especially black locust. Factors supporting specialist species suppressed problem species by providing unfavourable environmental conditions and putting them at a competitive disadvantage. We identified that woody encroachment and current disturbances affect the vast majority of kurgans, posing a serious threat to grassland specialist species. Thus, there is an urgent need to integrate active conservation measures into the current passive protection of kurgans.