Unimproved Grassland Research Articles

Scale‐dependent effects of landscape variables on gene flow and population structure in bats

AbstractAimA common pattern in biogeography is the scale‐dependent effect of environmental variables on the spatial distribution of species. We tested the role of climatic and land cover variables in structuring the distribution of genetic variation in the grey long‐eared bat, Plecotus austriacus, across spatial scales. Although landscape genetics has been widely used to describe spatial patterns of gene flow in a variety of taxa, volant animals have generally been neglected because of their perceived high dispersal potential.LocationEngland and Europe.MethodsWe used a multiscale integrated approach, combining population genetics with species distribution modelling and geographical information under a causal modelling framework, to identify landscape barriers to gene flow and their effect on population structure and conservation status. Genotyping involved 23 polymorphic microsatellites and 259 samples from across the species' range.ResultsWe identified distinct population structure shaped by geographical barriers and evidence of population fragmentation at the northern edge of the range. Habitat suitability (as captured by species distribution models, SDMs) was the most important landscape variable affecting genetic connectivity at the broad spatial scale, while at the fine scale, lowland unimproved grasslands, the main foraging habitat of P. austriacus, played a pivotal role in promoting genetic connectivity.Main conclusionsThe importance of lowland unimproved grasslands in determining the biogeography and genetic connectivity in P. austriacus highlights the importance of their conservation as part of a wider landscape management for fragmented edge populations. This study illustrates the value of using SDMs in landscape genetics and highlights the need for multiscale approaches when studying genetic connectivity in volant animals or taxa with similar dispersal abilities.

20% loss of unimproved farmland in 22 years in the Engadin, Swiss Alps

Agricultural intensification has reached mountain areas with retardation. This development is worrying as it targets some of the last remaining strongholds of traditionally farmed land in central Europe which are important hotspots of biodiversity. However, large-scale documentations of changes in agricultural habitats are rare, but are needed to guide agricultural policy for the conservation of biodiversity.We investigated vegetation changes of the agricultural landscape in a valley of the Alps (Engadin, a rather dry valley in Switzerland) between 1987/1988 and 2009/2010. In 58 plots (total area 1253ha) we recorded changes in vegetation types and the intensity of usage and we investigated correlations between these changes and site factors.By 2009/2010, all unimproved vegetation types have lost 20% of the area they covered in 1987/1988. The loss was greatest in areas where new agricultural infrastructure/reallocation projects (“ameliorations”) had been realized. This observation illustrates the potentially devastating effect of such projects for farmland biodiversity.Overall, intensively used fertile meadows (which are of limited nature value) have increased. The afflux came from the above mentioned unimproved grassland types, and not, as might be expected, from low-intensity fertile meadows (traditional hay meadows with a high nature value). In fact, the latter meadow type has seen a net gain from the intensively used fertile meadows (i.e. extensification). Both of these opposing processes (intensification and extensification) were subsidized by the government: money for infrastructure projects on the one hand and money for ecological compensation areas on the other hand.Abandonment of farmland, unlike in some other regions in the Alps, is not a general problem in the Engadin, but it did reduce the area of xerotherm grassland by 19% and of nutrient-poor meadows by 8%. Grazing, which could prevent abandonment, increased during our study period, but was mostly of high intensity, thus was not optimal from a conservation point of view. Recent contracts for nature conservation are likely to help maintain mowing and extensive grazing management on marginal land.The Engadin remains a biological hotspot and a beautiful landscape of high value for tourism. But these values are not secured as illustrated by the loss during the last 20 years. Thus, planers of irrigation and other infrastructure projects and decision-makers in general need to better incorporate both the extant nature values and their fragility into their planning.

Effects of livestock breed and rearing experience on foraging behaviour of yearling beef cattle grazing unimproved grasslands

AbstractThe relative importance of breed versus rearing experience on the grazing behaviour and diet selection of beef cattle when grazing unimproved grassland was examined over 4 years. Suckler‐reared calves of a traditional (T) breed (North Devon) or a commercial (C) breed (Simmental × Hereford Friesian) were cross‐fostered and then reared either extensively (E) on unimproved grassland or intensively (I) on agriculturally improved fertilized grassland. As yearlings, the four groups of calves (Traditional breed + Extensive rearing (TE); Traditional breed + Intensive rearing (TI); Commercial breed + Extensive rearing (CE) and Commercial breed + Intensive rearing (CI)) grazed unimproved grassland dominated by Molinia caerulea, for 2 months, and foraging behaviour was studied in a test phase. There was a breed effect on total (bites + chews; TJM) jaw movement rate (T, 78·2 vs. C, 76·5 min−1; F prob. = 0·041) during grazing and on the proportion of bites taken from plant communities with sward height ≥6 cm (T, 0·83 vs. C, 0·76; F prob. = 0·018). Rearing experience affected TJM rate in the first year in July (E, 80·0 vs. I, 76·8 min−1; F prob. = 0·015) and August (E, 78·5 vs. I, 75·5 min−1; F prob. = 0·046). The intensively reared animals grew less well on average during the test phase than those that had previous experience of the unimproved grassland as calves with their mothers (E, 0·16 vs. I, 0·09 kg day−1; F prob. = 0·033). Our findings indicate that the rearing experience of livestock appears to be as important as the breed when designing grazing managements for nature conservation areas.

Rhinanthus minor population genetic structure and subspecies: Potential seed sources of a keystone species in grassland restoration projects

Abstract In the last few decades unimproved semi-natural grasslands have been affected by intensification of land use and habitat fragmentation. Because of their biodiversity these species-rich grasslands are of high conservation importance and efforts are under way to restore such habitats. Detailed knowledge of within species diversity will aid deciding on the optimal seed source for such restoration projects, e.g. local genotypes or ecotypes. Rhinanthus minor is a species that is typically found in semi-natural grasslands and is commonly used in grassland restoration projects. This is because R. minor is a hemiparasitic plant that takes minerals and nutrients from its host, which in turn decreases the host's biomass and leads to opportunities for less competitive species in the vegetation. Here, we investigate genetic diversity within and between R. minor populations. This allowed us to test whether the six different subspecies of R. minor that have been described in the UK, based on their morphology, flowering time, and habitat, can be differentiated using molecular markers. We identified moderate levels of genetic differentiation between R. minor populations within the UK. In addition, R. minor individuals from the UK appear to be distinct from R. minor and Rhinanthus angustifolius individuals from other European countries based on microsatellite genotyping and DNA sequencing of cpDNA and rDNA ITS. The molecular markers used in the current study did not separate populations of R. minor based on either their subspecies or habitat. The implication for the use of R. minor in grassland restoration projects seems to be that it is not necessary to use local seeds or seeds from the same subspecies.

Home range use and habitat selection by barbastelle bats (Barbastella barbastellus): implications for conservation

We studied foraging behavior and habitat selection of barbastelle bats (Barbastella barbastellus) at two breeding colonies in southern England. In total, 28 adult female bats were radiotracked to determine home range use, habitat preferences, and patterns of nocturnal activity. Individual home ranges varied considerably, with bats traveling between 1 and 20 km to reach foraging areas (¯ X ¼ 6.8 km 6 4.8 SD). Nonreproductive females foraged at greater distances than reproductive females, providing evidence of state-dependent foraging behavior. Commutes were typically rapid and direct and bats moved freely across large open areas. Individual bats foraged independently from one another and were highly faithful to their respective core foraging areas, which formed just a small fraction of home ranges. Riparian zones and broad-leaved woodland were habitats most strongly selected for foraging. Unimproved grassland and field margins were also important components of the foraging environment. Bats night-roosted only occasionally and for short periods. Conservation efforts for B. barbastellus should target the protection and enhancement of preferred foraging habitats within 7 km of roost sites. Linear landscape elements such as tree lines and hedgerows should be managed to improve their value to foraging bats and to enhance connectivity with roost sites.

Organic Farming and Landscape Structure: Effects on Insect-Pollinated Plant Diversity in Intensively Managed Grasslands

Parallel declines in insect-pollinated plants and their pollinators have been reported as a result of agricultural intensification. Intensive arable plant communities have previously been shown to contain higher proportions of self-pollinated plants compared to natural or semi-natural plant communities. Though intensive grasslands are widespread, it is not known whether they show similar patterns to arable systems nor whether local and/or landscape factors are influential. We investigated plant community composition in 10 pairs of organic and conventional dairy farms across Ireland in relation to the local and landscape context. Relationships between plant groups and local factors (farming system, position in field and soil parameters) and landscape factors (e.g. landscape complexity) were investigated. The percentage cover of unimproved grassland was used as an inverse predictor of landscape complexity, as it was negatively correlated with habitat-type diversity. Intensive grasslands (organic and conventional) contained more insect-pollinated forbs than non-insect pollinated forbs. Organic field centres contained more insect-pollinated forbs than conventional field centres. Insect-pollinated forb richness in field edges (but not field centres) increased with increasing landscape complexity (% unimproved grassland) within 1, 3, 4 and 5km radii around sites, whereas non-insect pollinated forb richness was unrelated to landscape complexity. Pollination systems within intensive grassland communities may be different from those in arable systems. Our results indicate that organic management increases plant richness in field centres, but that landscape complexity exerts strong influences in both organic and conventional field edges. Insect-pollinated forb richness, unlike that for non-insect pollinated forbs, showed positive relationships to landscape complexity reflecting what has been documented for bees and other pollinators. The insect-pollinated forbs, their pollinators and landscape context are clearly linked. This needs to be taken into account when managing and conserving insect-pollinated plant and pollinator communities.

Habitat associations of Eurasian Skylarks Alauda arvensis breeding on Irish farmland and implications for agri-environment planning

Capsule Skylarks breeding in Ireland prefer extensive grassland habitats and almost completely avoid tillage habitats.Aims To describe the distribution and habitat use of breeding Skylarks in Ireland, particularly in lowland agricultural habitats, and to use this information to inform conservation measures for this species.Methods Countryside Bird Survey (CBS) and Farmland Bird Project (FBP) data were examined to determine large-scale (national) distribution and habitat selection, in addition to smaller-scale (farm- and field-level) habitat use. The CBS is a national breeding bird monitoring scheme involving 397 1-km squares. The FBP collected detailed bird and habitat data from 122 farms.Results CBS and FBP data both showed significant regional differences in breeding Skylark densities, with the highest relative abundances in the northwest and west. Dry grassland/grass moor habitats supported the highest densities of breeding Skylarks in the CBS, which were significantly higher than in improved grassland or tillage. At the farm-level, Skylark numbers were positively related to wetland habitats but negatively associated with trees in field boundaries, dense ground vegetation and overall density of farm boundaries. At the field-scale, larger fields and unimproved grasslands were preferred.Conclusion Agri-environment measures tailored to region-specific requirements and to the relatively local habitat preferences of target species are required if population declines of species of conservation concern, including Skylarks, are to be reversed.

Using multi-scale modelling to predict habitat suitability for species of conservation concern: The grey long-eared bat as a case study

Although spatial scale is important for understanding ecological processes and guiding conservation planning, studies combining a range of scales are rare. Habitat suitability modelling has been used traditionally to study broad-scale patterns of species distribution but can also be applied to address conservation needs at finer scales. We studied the ability of presence-only species distribution modelling to predict patterns of habitat selection at broad and fine spatial scales for one of the rarest mammals in the UK, the grey long-eared bat (Plecotus austriacus). Models were constructed with Maxent using broad-scale distribution data from across the UK (excluding Northern Ireland) and fine-scale radio-tracking data from bats at one colony. Fine-scale model predictions were evaluated with radio-tracking locations from bats from a distant colony, and compared with results of traditional radio-tracking data analysis methods (compositional analysis of habitat selection). Broad-scale models indicated that winter temperature, summer precipitation and land cover were the most important variables limiting the distribution of the grey long-eared bat in the UK. Fine-scale models predicted that proximity to unimproved grasslands and distance to suburban areas determine foraging habitat suitability around maternity colonies, while compositional analysis also identified unimproved grasslands as the most preferred foraging habitat type. This strong association with unimproved lowland grasslands highlights the potential importance of changes in agricultural practices in the past century for wildlife conservation. Hence, multi-scale models offer an important tool for identifying conservation requirements at the fine landscape level that can guide national-level conservation management practices.

A rapid ecological network assessment tool and its use in locating habitat extension areas in a changing landscape

An understanding of the ecological systems which dictate landscape form and function must be achieved in order to objectively view development led landscape ecological change. Habitat fragmentation, loss and isolation of habitat patches and reduced connectivity are having a significant detrimental effect on the way our landscapes function. A conservation planning tool which considers these issues in tandem with planned landscape level change, whilst incorporating species and habitat specific details, is necessary if we are to ameliorate the ecological impact of built development. A landscape scale modelling approach was developed for a case study area in the South Midlands of the UK to investigate spatial targeting of habitat extension areas. Habitat extension opportunities currently arise as a consequence of existing planning regulations and conditions and are likely to increase as the concept of habitat “banking” is embraced. Ecological networks and ecoprofiles were employed to guide the location of these extension areas via an examination of the landscape ecology effects of area composition, size and location. The ability of extension areas to contribute to landscape functionality was determined spatially. Habitat extension areas identified by the approach increased the existing ecological network size by a factor of over 2.7:1 and were able to deliver the majority of habitat creation targets set out in regional Biodiversity Action Plans (BAPs). 100% of wetland, unimproved grassland and broadleaf and mixed woodland creation targets were met, whilst 75% of the lowland heath target could be achieved. Semi-natural habitat mosaic areas of over 3700 ha which incorporated habitat of more than one type were identified, with such areas determined to be of importance in achieving landscape improvements for a wide range of species. We conclude that rapid assessment tools such as that employed in this research will have increased utility in conservation planning as the British landscape continues to experience both sustained and elevated levels of built development pressure.

A comparative study of the molecular composition of a grassland soil with adjacent unforested and afforested moorland ecosystems

On-line thermally assisted hydrolysis and methylation (THM) in the presence of both unlabelled and 13C-labelled tetramethylammonium hydroxide (TMAH) was used to assess the relative contributions of phenolics (lignin, demethylated lignin and non-lignin phenolics) in a peaty gley soil profile beneath an unimproved grassland (LL), from a study site located at Harwood (Northumberland, northeast England, UK). This site also includes an unforested moorland (ML) and a second rotation Sitka spruce stand (SS). The common lignin proxies have been corrected for contributions of non-lignin phenols and demethylated lignin in the LL ecosystem and then compared with those from the ML and SS ecosystems. The phenolic compositions from the contributory vegetation inputs (i.e. grasses, heather and Sitka spruce) to all three soils (LL, ML and SS) were also analysed. By using 13C-labelled TMAH it was possible to show that the chemical composition of soil organic matter (SOM) reflected the different vegetation inputs in each of the L/F layers but these characteristics were lost from the deeper organic and mineral layers. Similar changes in the yield of lignin monomers ( Λ) with increasing soil depth were displayed in the LL soil profile as reported previously in the ML soil in that no maxima were observed in these amount-depth profiles. The tannin input to the LL soil is low and as a consequence, unlike the ML and SS soils, there is no progressive decrease in the amounts of these non-lignin phenolics with increasing depth. Finally the methylated carbohydrate derivatives (MC) become more abundant relative to the phenolics with increasing soil depth in all three ecosystems (LL, ML and SS).

Butterflies on the brink: habitat requirements for declining populations of the marsh fritillary (Euphydryas aurinia) in SW England

1. The marsh fritillary Euphydryas aurinia is one of our most endangered butterflies, and the only to be protected under European legislation as well as British. It persists in fragile subpopulations threatened by habitat fragmentation and degradation. 2. A combination of swaling and cattle grazing are accepted to be best practice for managing wet, unimproved grasslands—the favoured habitat for E. aurinia in Cornwall. These two well-endorsed methods of management were used to increase and improve the quality of habitat for E. aurinia over a 5 years period, 2004–2008, at a stronghold network of habitat patches in mid Cornwall, south-west England. 3. Analyses of adult and larval densities over 5 years in fifty-four transects across nine sites found E. aurinia to favour habitat patches with higher densities of the larval food plant (Devil’s-bit scabious Succisa pratensis), higher sward height in autumn, and intermediate optimum levels of stock grazing. 4. Main findings indicated most sites experienced significant declines in numbers. Unfavourable weather in the last 2 years of monitoring was likely to have had a significant impact on the response of individual subpopulations to habitat management though poor recovery rates may also reflect a time-lag in colonisation events after habitat improvement has occurred. 5. Habitat management produced an improvement, albeit an inconsistent improvement in habitat variables across patches—S. pratensis shows a clear recovery at some sites. Autumn sward height increased significantly at one site, and a quadratic relationship between stock grazing and important habitat variables has been found which will aid further improvement over all sites for the long term persistence of E. aurinia.

Is Pollination at Risk? Current Threats to and Conservation of Bees

Insect pollination is an ecosystem service with high economic value that is mainly provided by bees. However, feral bees and managed honeybees are threatened globally by several anthropogenic factors such as changes in agricultural practices, loss of unimproved grasslands, urbanization, and spread of pathogens. These factors have led to the extinction of many native bees, to a reduction in the number of managed honeybee colonies, and put the nutritional bases for bees at risk. Chronic exposure to insecticides, even when they are appropriately used, may affect the foraging behavior of honeybees, which in turn weakens a colony and makes it more susceptible for diseases. Honeybees suffer from parasites like the Varroa mite, and from several viral and bacterial pathogens, which need to be controlled with great efforts. Climate changes represent future threats that will probably impact native bee populations as well as apicultural practices. Coordinated actions are needed to prevent the global loss of large pollinator populations. Especially the maintenance of plant and bee diversity is very important – as well as basic research on the causes for honeybee colony losses. Together, policy, science, and economy should have a crucial interest in conserving the global pollination service of bees.

Habitat does not influence breeding performance in a long‐term Barn Owl Tyto alba study

Capsule This study examines the relationship between habitat variables and various aspects of breeding and foraging performance for 257 Barn Owl breeding attempts involving both released and wild birds, at 86 different nest‐sites over a 14‐year period. Aims The study aimed to: (1) provide evidence for or against the importance of foraging habitat in Barn Owl breeding performance; (2) enable identification of areas which can, and those which cannot, be expected to sustain Barn Owl populations; (3) inform the compilation of any future guidelines such that Barn Owl release schemes are more likely to succeed; and (4) allow the revision of untested concerns in terms of the likely survival or otherwise of Barn Owls in a given area. Methods Three data sources are used to assess the proportions of various habitat types and lengths of linear features in the vicinity of each nest: (1) The Centre for Ecology and Hydrology Land Cover Map; (2) Ordnance Survey Strategi dataset; and (3) Agricultural Census data. These are linked to various aspects of breeding performance. Results Despite the size of the dataset, the number of significant correlations between habitat type and aspects of Barn Owl breeding success was similar to that expected by chance. Sites with more unimproved grassland within 1 km of the nest did not differ from those with less, except by a significant advancement of first‐egg date. Conclusion The paucity of significant results may be evidence that Barn Owls are in fact rather catholic and adaptable in their habitat requirements, and not as dependent upon large areas of Field Vole (or other) habitat as has often been stated.

Phosphate Addition and Plant Species Alters Microbial Community Structure in Acidic Upland Grassland Soil

Agricultural improvement (addition of fertilizers, liming) of seminatural acidic grasslands across Ireland and the UK has resulted in significant shifts in floristic composition, soil chemistry, and microbial community structure. Although several factors have been proposed as responsible for driving shifts in microbial communities, the exact causes of such changes are not well defined. Phosphate was added to grassland microcosms to investigate the effect on fungal and bacterial communities. Plant species typical of unimproved grasslands (Agrostis capillaris, Festuca ovina) and agriculturally improved grasslands (Lolium perenne) were grown, and phosphate was added 25 days after seed germination, with harvesting after a further 50 days. Phosphate addition significantly increased root biomass (p < 0.001) and shoot biomass (p < 0.05), soil pH (by 0.1 U), and microbial activity (by 5.33 mg triphenylformazan [TPF] g(-1) soil; p < 0.001). A slight decrease (by 0.257 mg biomass-C g(-1) soil; p < 0.05) in microbial biomass after phosphate addition was found. The presence of plant species significantly decreased soil pH (p < 0.05; by up to 0.2 U) and increased microbial activity (by up to 6.02 mg TPF g(-1) soil) but had no significant effect on microbial biomass. Microbial communities were profiled using automated ribosomal intergenic spacer analysis. Multidimensional scaling plots and canonical correspondence analysis revealed that phosphate addition and its interactions with upland grassland plant species resulted in considerable changes in the fungal and bacterial communities of upland soil. The fungal community structure was significantly affected by both phosphate (R = 0.948) and plant species (R = 0.857), and the bacterial community structure was also significantly affected by phosphate (R = 0.758) and plant species (R = 0.753). Differences in microbial community structure following P addition were also revealed by similarity percentage analysis. These data suggest that phosphate application may be an important contributor to microbial community structural change during agricultural management of upland grasslands.

Drying and rewetting effects on soil microbial community composition and nutrient leaching

The effects of a dry-rewetting event (D/RW) on soil microbial properties and nutrient release by leaching from two soils taken from adjacent grasslands with different histories of management intensity were studied. These were a low-productivity grassland, with no history of fertilizer application and a high-productivity grassland with a history of high fertilizer application, referred to as unimproved and improved grassland, respectively. The use of phospholipid fatty acid analysis (PLFA) revealed that the soil of the unimproved grassland had a significantly greater microbial biomass, and a greater abundance of fungi relative to bacteria than did the improved grassland. Soils from both grasslands were maintained at 55% water holding capacity (WHC) or dried to 10% WHC and rewetted to 55% WHC, and then sampled on days 1, 3, 9, 16, 30 and 50 after rewetting. The D/RW stress significantly reduced microbial biomass carbon (C), fungal PLFA and the ratio of fungal-to-bacterial PLFA in both soils. In contrast, D/RW increased microbial activity, but had no effect on total PLFA and bacterial PLFA in either soil. Microbial biomass nitrogen (N) was reduced significantly by D/RW in both soils, but especially in those of the improved grassland. In terms of nutrient leaching, the D/RW stress significantly increased concentrations of dissolved organic C and dissolved organic N in leachates taken from the improved soil only. This treatment increased the concentration of dissolved inorganic N in leachate of both soils, but this effect was most pronounced in the improved soil. Overall, our data show that D/RW stress leads to greater nutrient leaching from improved than from unimproved grassland soils, which have a greater microbial biomass and abundance of fungi relative to bacteria. This finding supports the notion that soils with more fungal-rich communities are better able to retain nutrients under D/RW than are their intensively managed counterparts with lower fungal to bacterial ratios, and that D/RW can enhance nutrient leaching with potential implications for water quality.

Habitat use and diet of Common Snipe Gallinago gallinago breeding on moorland in northern England

Capsule Moorland breeding birds were associated with marshy grassland, acid flush and unimproved acid grassland, where their diet was dominated by earthworms and tipulid larvae. Aims To quantify breeding Snipe densities in upland habitats and to examine diet and the structural characteristics of feeding areas. Methods Snipe were surveyed on four areas (total 44 km2) near Otterburn, Northumberland in 2000 and 2002. The use of seven habitat types was assessed from estimates of relative density from a generalized linear model. Five variables were measured at Snipe flushing locations and compared with measurements made at random points. Diet composition and seasonal changes were determined from faecal samples collected during April, May and June. Results Mean breeding Snipe density was 2.28 ± 0.25 birds/km2 (approximately 1.14–1.34 pair/km2). Snipe densities on marshy grassland or acid flush were 3.4-times higher than on heath and heath/grass habitats. Densities on unimproved acid grass were 2.7-times higher than on improved grassland. Within habitats, Snipe were flushed from locations that were closer to ditches or pools and characterized by wetter soil and more uneven swards than randomly selected points. Snipe diet during April–June consisted mainly of earthworms and tipulid larvae, which accounted for 61 ± 7% and 24 ± 6% of the dry weight of prey items ingested, respectively. A wide variety of surface-active and aquatic prey were also taken, especially in April. Conclusion Snipe breeding on moorland in upland Britain depend on unimproved marginal grassland and wet habitats, owing to the species' specialized feeding requirements.

Spatial relationships between intensive land cover and residual plant species diversity in temperate farmed landscapes

Summary In temperate farmed landscapes conservation policies increasingly emphasize large‐scale reductions in land‐use intensity. Yet despite a managed reversion to more favourable abiotic conditions, depleted regional species pools may prevent the re‐assembly of target communities. Using national‐scale survey data recorded across Great Britain in 1998, we investigated the extent to which grassland indicator plant species persisted on potential refuge habitats across a spatial gradient of intensive land cover in lowland 1‐km squares. These habitats comprised road verges, field boundaries, watercourse banks and small biotope fragments. Intensive land cover comprised built land, arable and improved grassland. The rate of reduction in indicator species richness across the intensive land cover gradient was significantly lower in all potential refuge features than in surrounding fields and larger areas of habitat. The best refuge locations were watercourse banks and small biotopes. In both cases, indicator species richness was higher than adjacent fields at the lowest intensive land cover and stayed higher as intensive land cover increased. However, as intensive land cover increased, plant traits associated with higher nutrient availability were more prominently represented among indicator species. Although richer assemblages of indicator species persisted on refuge features, population sizes are likely to be small, because of species–area effects, and also vulnerable to nutrient surpluses and reduced or inappropriate disturbance. Synthesis and applications. Across the British lowlands, linear landscape features and small habitat fragments can provide limited safe havens for unimproved grassland plant species. However, the identity of refuge features and their species richness and composition are likely to vary with local conditions. Three activities are therefore paramount in assessing their role in larger scale extensification schemes: (i) development of rapid ways of assessing the plant diversity and distribution of refuge features in local areas; (ii) quantification of the risks posed to the viability of residual source populations through implementation of different options for incorporating them into extensification schemes; (iii) maximization of scheme performance by targeting landscapes with sufficient residual diversity to enable increases in population size of the target species in the medium term.

FLEXIBILITY OF HABITAT USE IN EPTESICUS NILSSONII: DOES THE SPECIES PROFIT FROM ANTHROPOGENICALLY ALTERED HABITATS?

In an environment subjected to rapid anthropogenic alterations, the distribution and abundance of mammalian species often reflect their flexibility in habitat use. The northern bat (Eptesicus nilssonii) is patchily distributed in Germany, where it is classified as a critically endangered species, but is abundant in Scandinavia. To assess its flexibility in habitat use, we radiotracked 10 females and 3 males captured at a maternity roost in Lower Saxony, Germany, during the summers 2002‐2003. These bats had access to a variety of habitats including pristine areas (unimproved grassland and forest) and anthropogenically altered habitats (pastures, euthrophic lakes, urban area). The widely overlapping home ranges had a median area of 524 ha. They extended asymmetrically around the maternity roost and reflected a preference for elevations around and below roost level, that is, 365 m elevation. Males traveled up to 70 km per night during exploring flights. E. nilssonii used forest habitats opportunistically before birth of the young and avoided them thereafter, whereas most bats preferred urban habitats and especially streetlamps after births. Intraspecific encounters were more frequent after births, particularly around streetlamps, suggesting an increased intraspecific competition at these sites. Interestingly, females spent 27% but males only 3% of their foraging time hunting with conspecifics. Thus, the species is a habitat generalist for which urban areas provide a supplementary seasonal habitat. However, because such habitats may not always remain profitable, natural habitats of forest and grassland will remain essential to the survival of this bat species in Germany.

The effect of pasture improvement and burning on Orthoptera populations of Culm grasslands in northwest Devon, UK

Very little research has been conducted into the impact of grassland management on insect populations of Culm grasslands located in northwest Devon, UK. This paper presents the effects of agricultural improvement and burning on Orthoptera populations of these wet, heathy pastures at Dunsdon National Nature Reserve. The results from this 2-year study should aid conservation management of this important UK habitat. Orthoptera populations and habitat variables of improved (drained and cropped from 1840-1875) and unimproved pastures, were monitored in 2002 and 2003. There was no significant difference in Orthoptera abundance between pasture cropped from 1840-1875 and unimproved grassland, suggesting that mobile grasshopper species such as the meadow grasshopper Chorthippus parallelus, recolonised the improved swards from surrounding pastures, after a lengthy period of arable cropping in the 1800s. Winter burning led to higher numbers of Orthoptera in the post-burn year, perhaps due to the reduced sward height and biomass on the burnt swards, making them more favorable for postdiapause development.

A field test of the relationship between habitat area and population size for five perennial plant species

Abstract. The population sizes of five perennial vascular plant species confined to old unimproved dry grasslands were assessed, viz. Anthericum ramosum, Filipendula vulgaris, Silene nutans, Thymus pulegioides, and Thymus serpyllum. All populations within the region were included. Only for Filipendula vulgaris and Thymus serpyllum, significant relationships between habitat area and population size were found. Thus, apparently perennial vascular plants have a limited ability to respond to large habitat areas by forming large populations. This puts a question mark on the use of incidence-function models for the study of plant metapopulations, because these models are based on an assumed positive relationship between habitat area and population size.