The potential conservation value of unmowed powerline strips for native bees

The land area covered by powerline easements in the United States exceeds the area of almost all national parks, including Yellowstone. In parts of Europe and the US, electric companies have altered their land management practices from periodic mowing to extraction of tall vegetation combined with the use of selective herbicides. To investigate whether this alternate management practice might produce higher quality habitat for native bees, we compared the bee fauna collected in unmowed powerline corridors and in nearby mowed grassy fields at the Patuxent Wildlife Research Center (MD). Powerline sites had more spatially and numerically rare species and a richer bee community than the grassy fields, although the difference was less pronounced than we expected. Powerline sites also had more parasitic species and more cavity-nesting bees. Bee communities changed progressively through the season, but differences between the site types were persistent. The surrounding, non-grassland landscape likely has a strong influence on the bee species collected at the grassland sites, as some bees may be foraging in the grasslands but nesting elsewhere. Improving habitat for native bees will help ameliorate the loss of pollination services caused by the collapse of wild and managed honeybee populations. This study suggests that powerline strips have the potential to provide five million acres of bee-friendly habitat in the US if utilities more generally adopt appropriate management practices.     

A comparison of green lanes and field margins as bumblebee habitat in an arable landscape

There have been major changes in agricultural practice over the past 50 years. The increasing efficiency of arable production has led to larger field sizes with the associated removal of many hedgerow field boundaries. This, together with high input farming practices, has had a deleterious effect on the quality of the rural landscape as a wildlife habitat. This study focuses on green lanes, that is, trackways bounded on both sides by hedgerows, and the adjacent field margins of arable crops and examines each habitat to determine their relative resource value to bumblebees. The vegetation communities within 15 green lane sites and those of the adjacent field margins were recorded, and subsequent analysis showed that species richness was significantly higher within the green lanes. Bee numbers were recorded at each site during 10 visits, both along the inside of green lane hedges and the outside of the opposite hedge on the field margins of the arable crops. At each visit the flower abundance of 10 plant groups was recorded for each habitat type. The results show that bumblebee abundance was significantly higher within the green lane habitat than on the field margins and that this difference was directly related to the abundance of flowers within the habitat.     

Predicted fates of ground-nesting bees in soil heated by wildfire: Thermal tolerances of life stages and a survey of nesting depths

Periodic wildfire defines plant community composition and dynamics in many of the world’s semi-arid biomes, whose climates and floras also favor wild bee diversity. Invasive flammable grasses, deforestation, historical fire suppression and human ignition are increasing fire frequency and intensifying its severity, as well as introducing fire to previously fireproof biomes. In many of these habitats, bees are key pollinators. Many, often most of the solitary bee species and individuals in these biomes nest underground (so-called “mining” bees). To evaluate their susceptibility to fire, we tested heat tolerances of bees’ four life stages using an experimental design that mimicked heat conduction dynamics of natural soils. All life stages survived heating of up to 45 °C for 27 min, but none survived heating at 54 °C for 9 min; the pupal stage survived best. At near-lethal temperatures, more prolonged heating caused more mortality. These data were related to published studies of heat penetration depths in soil during fire and an exhaustive compilation of published nesting depths reported for mining bees. We conclude that a small fraction (9%) of the shallowest-nesting mining bee species is likely to die from soil heating by wildfire. Among these, ground-nesting megachilids (Osmia, Megachile) will be most vulnerable, owing to their shallow horizontal nests. Because mining bees prevail in most biomes of the temperate zone, any vegetation rehabilitation efforts should therefore expect that bee communities will largely survive the immediate effects of wildfire, and therefore will need pollen and nectar resources in the year(s) after fire.     

乡土野花组合在农业景观中的应用

乡土野花组合是筛选以乡土野花为主体的,并通过混合播种建立群落的一种景观植被建植模式,是欧美国家近年来较为流行的一种农业景观恢复与建设的技术措施。已有的研究发现乡土野花组合能够改善景观结构与生境质量,吸引传粉生物和自然天敌,从而起到增强农业景观的传粉及害虫控制功能,并改善农作物品质、提高农作物产量;与此同时,乡土野花组合也具有较好的文化功能。乡土野花组合的设计对建植效果具有重要作用,其物种筛选、配比、播种方式及布局是设计中需要主要解决的问题。本文在总结欧美国家乡土野花组合设计模式与生态监测结果的基础上,提出乡土野花组合物种筛选的3原则：乡土性、功能多样性与包含特定关键物种;并对其生长周期、物种数、播量、播种面积与空间布局等技术细节进行了讨论,以促进乡土野花组合的本土化、区域化发展。欧美国家提出了一系列推动产业发展及农户补贴的有关政策,其中美国主要以推动基础研究与产业发展政策为主,注重限制植物材料本土化;欧洲国家通过多项立法及农业环境管护政策为农户提供多样化的生态补贴,以促进农户充分参与乡土野花组合栽植过程。在我国,尚缺乏成熟的乡土野花组合应用案例。中国的乡土野花组合需充分发掘种质资源并进行生态、栽培与景观特性评估,以实现本土化的乡土野花组合。本文最后提出,通过多学科合作实现乡土野花组合的设计与推广,政府、产业、科研机构与农民共同参与乡土野花组合的设计过程,并提出市场化的生态补贴政策,以推动乡土野花组合在我国农业景观的应用,为改善我国农业生态环境做出应有贡献。     

Quantitative pollen requirements of solitary bees: Implications for bee conservation and the evolution of bee–flower relationships

Knowledge about the quantitative pollen requirements of solitary bees is crucial for the preservation of endangered bee species and the understanding of the evolution of bee–flower relationships. We estimate the number of flowers required to rear a single larva for 41 European bee species (i) by comparing the pollen content of brood cells with the pollen quantity contained in the flowers of the bees’ host plants and (ii) by deducing the pollen requirements from a regression model describing the relationship between the average bee dry body mass and the average brood cell pollen content. The flower requirements of the bee species examined vary by three orders of magnitude. Depending on both bee species and host plant, from seven to 1100 flowers or from 0.9 to 4.5 flower heads are needed to rear a single larva. As only about 40% of the pollen contained in a flower was found to be available to a single female bee, these minimal figures have to be multiplied by a factor of approximately 2.5 to obtain a realistic estimate of bee flower requirements. The amount of pollen lost from flowers for bee nutrition is surprisingly high. We hypothesize that the recent decline of many bee species may have its main cause in a food shortage provoked by a decrease in flower diversity and quantity following habitat destruction and modern agricultural practices. The substantial pollen losses to bees as documented in this study support earlier findings on floral adaptations against excessive pollen harvesting by bees.     

Assessing threats to pool-breeding amphibian habitat in an urbanizing landscape

Geographically-based threat assessments are important for identifying natural resources at risk, yet have rarely been applied to identify habitat conservation priorities for imperiled organisms at a local scale. Pool-breeding amphibians have complex life cycles that place them at risk from habitat loss and fragmentation both in wetlands and in adjacent uplands. Because the most rapidly growing cause of habitat degradation in North America has been urbanization, a threat analysis of pool-breeding amphibian habitat should both be dynamic, i.e., sensitive to land-use change, and comprehensive, recognizing traditional protected area networks as well as less formal conservation assets (e.g., land-use regulations). To assess threats to wood frogs (Rana sylvatica) and spotted salamanders (Ambystoma maculatum) in a rapidly urbanizing, forested region of New England (USA) we examined gaps in the current protection network, as well as changing human settlement patterns. We found that greater than 50% of 542 potential breeding pools delineated using low-level infra-red aerial photography (median area 379.5 m²) were not represented on National Wetland Inventory (U.S.FWS) maps, and thus de facto at risk. Most importantly, conservation lands and regulatory protections failed to protect 46% of potential breeding pools and 80% of adjacent non-breeding habitat. While an assessment of human settlement patterns projected that only 5% of the region contained high quality amphibian habitat under acute development pressure, nearly half of the region (44.7%) had attained a moderate threat level, highlighting the importance of conservation planning during early stages of urbanization. We conclude by illustrating the role for multiple conservation strategies when protecting functional landscapes for pool-breeding amphibians.     

Soil-living parasitic Hymenoptera: comparison between a forest and an open landscape habitat

Community structures and local diversity patterns of parasitic Hymenoptera with soil and leaf litter hosts were studied in a German beech forest and a meadow. Hymenoptera appeared to be one of the most species-rich taxa associated with the soil. Eighty-eight species were found in the meadow (total density of 128 ind. m⁻² yr⁻¹) and 188 species (149 ind. m⁻² yr⁻¹) in the forest. The mean parasitism rates were above 60% for parasitoids of mycetophagous Diptera and between 7% and 26% for parasitoids of saprophagous Diptera. Species overlap between both habitats was higher than expected from a random sample model. Species common to both habitats were primarily parasitoids of predatory Coleoptera. High mean densities of these species support the hypothesis of a positive correlation between local abundance and range size.     

A comparison of constructed and natural habitat for frog conservation in an Australian agricultural landscape

Constructed ponds are an important consideration in the conservation of wetland biota in agricultural landscapes. Twenty-two natural ponds and 22 adjacent constructed ponds (farm dams) were surveyed on the Southern Tablelands of New South Wales to compare patterns of use by frogs and develop frog conservation recommendations. Farm dams supported similar numbers of frog species to natural ponds, although differences in frog assemblage were observed between the pond types. Limnodynastes tasmaniensis and Uperolia laevigata were significantly more likely to occur at farm dams while L. peronii was more likely to occur at natural ponds. Results suggest waterbodies with high levels of emergent vegetation cover that lack fish are likely to support a high number of frog species, regardless of origin (i.e. natural or constructed). However, it is important for landholders to conserve natural waterbodies as these environments appear likely to support frog species that do not use farm dams.     

Bats in a fragmented landscape: Species composition, diversity and habitat interactions in savannas of Santarém, Central Amazonia, Brazil

Species response to forest fragmentation may strongly vary according to ecological requirements, shape, spatial configuration and connectivity of fragments, and the structure of the surrounding matrix. Bats are natural candidates for studies on forest fragmentation. However, the conclusions of such studies are often contradictory. We present the results of a study on the effects of forest fragmentation on bat communities in Alter do Chão, Santarém area, in Central Amazonia, Brazil, an area composed by forests and fragments surrounded by savanna-like vegetation. We compared the species composition between habitats, tested the effect of size, shape and density of trees of forested areas on the presence species and their relative frequency of captures, and investigated the savannas as an ecological barrier for the dispersion of bats. With an effort of 5678 mistnet-hours, we captured 3740 bats (64 species). Multidimensional Scaling indicated no strong separation between the habitats sampled, however, savanna sites were grouped distinctly of fragments and forest sites. Multiple linear regressions indicated no significant correlation between the number of bat species recorded and the size, shape or tree density in forest sites and fragments. There was a significant correlation between the number of captures and the variables tested, explained by the shape of the sites, but not by size or tree density. In general, sites with bigger shape indices had fewer captures. Ten of the 20 most captured species showed no significant difference between the three habitats. The bat communities in Alter do Chão were not strongly affected by forest fragmentation, and the savannas did not appear to act as an ecological barrier to bats.     

The value of forest strips for understorey birds in an Amazonian plantation landscape

Remnant forest strips are frequently proposed as valuable conservation tools in fragmented tropical landscapes, yet we currently lack evidence to evaluate their potential conservation value for native biota. We examined the potential value for understorey forest birds of 30-year-old riparian and terra firme (unflooded) primary forest strips within a large silvicultural landscape in the north-east Brazilian Amazon, where the matrix is dominated by Eucalyptus plantations. We conducted mist-netting in eight forest strips connected to continuous forest (four of each forest type), with a total of 24 replicate sampling sites located near to (<1 km), far from (2.5-9 km), and within undisturbed forest controls (i.e. 16 samples within the strips, and 8 in controls). Bird communities in both strip types changed with increasing distance along forest remnants into the plantation matrix. Matrix-embedded samples were characterised by a higher representation of birds typical of secondary growth forest but not those typical of the Eucalyptus-dominated matrix. While the long-term viability of the bird populations in these remnants remains unclear, our data demonstrate that forest strips can provide important habitat for many bird species that are otherwise rarely found outside primary forest. Forest strips therefore provide an important tool to enhance biodiversity conservation in plantation landscapes. The relative practical ease with which these areas can be selected and maintained means that the protection of forest strips as part of a wider conservation strategy is likely to have particular appeal to policy makers and landscape managers working in the human-dominated tropics.     

Urban drainage systems: An undervalued habitat for aquatic macroinvertebrates

Knowledge about the ecology of urban water systems is very scarce. We assessed the conservation value of urban drainage systems in lowland areas and compared these with similar watercourses in rural areas. A total of 36 water bodies in urban areas were selected to investigate the macroinvertebrate biodiversity in relation to environmental variables. Multivariate analysis of aquatic macroinvertebrate assemblages was used to distinguish urban water types and to link these types to key environmental variables. Several biodiversity indices for urban water systems were compared with those for other drainage systems in The Netherlands. Four types of macroinvertebrate assemblages were distinguished in the urban water systems, differing in environmental conditions and values of ecological indicators. The variation in macroinvertebrate assemblages was significantly explained by nitrate, pH, grain size (sediment composition), transparency, nymphaeid and submerged vegetation. Urban drainage systems can sustain a macroinvertebrate biodiversity comparable to that of drainage systems in rural areas (ditches and canals) and (semi)natural watercourses (lotic waters such as small streams and rivulets) and can even be a habitat for red list species. To optimize biodiversity values, urban water management should aim at lowering nutrient levels, stimulating vegetation (diversity of habitat structure) and increasing transparency, which are key factors for macroinvertebrate diversity. We show the potential conservation benefits of water systems in urban areas, but further studies are needed to investigate the optimal design of cities to include biodiversity as an integrated part of the urban environment, thereby sustaining a higher biodiversity in an increasingly urbanizing world.     

Using habitat models to determine conservation priorities for pond-breeding amphibians in a privately-owned landscape of northern Idaho, USA

As rural landscapes experience increasing levels of residential development, the persistence of species that rely on them will depend on informed planning and management decisions. An understanding of habitat requirements is essential for setting priorities and developing landscape-level plans for the survival of these species. In many temperate rural landscapes, artificially created ponds may be the only wetlands available for aquatic reproduction by amphibians. The introduction of non-native fish into these ponds reduces survival and prohibits successful reproduction of many native pond-breeding amphibians. We surveyed 105 randomly selected wetlands in a primarily privately-owned, rural landscape in north Idaho, USA, for pond-breeding amphibian larvae in 2004 and 2005. We used an information theoretic multimodel inference and an algorithmic (random forests) approach to model habitat for each species based on local and landscape characteristics. We also used a mail survey to quantify how landowners value fish in their wetlands and their plans for future wetland development and fish stocking. Sixty-seven percent of pond owners reported that fishing in their pond was at least slightly important to them and 36% of owners indicated that they were at least 50% likely to add fish to their ponds in the next 5-10 years. Landscape change predictions for this area indicate that forests will become more open due to thinning; habitat models indicated that this is likely to be detrimental to long-toed salamanders and beneficial to Pacific treefrogs. Habitat models also indicate that Columbia spotted frog breeding sites consist of wetlands on flat ground with high solar insolation and that this species is sensitive to nearby development, indicating that as this landscape becomes further developed, this species may require habitat protection for persistence.     

Hunting habitat selection by hen harriers on moorland: Implications for conservation management

We examine habitat use by hunting hen harriers Circus cyaneus at three study sites in Scotland to evaluate whether foraging patterns differ between sexes, sites, and stages of the breeding period. We modelled time spent hunting in focal plots as a function of habitat and nest proximity. Male hunting intensity (time spent hunting per hour of observation and km²) varied between sites and breeding periods, being lower during the nestling than the incubation period. Habitat use patterns were mostly consistent among study sites, which is important for developing species management recommendations applicable over the species’ range. Males avoided improved grassland, and selected areas of mixed heather and rough grass (with an optimum at ca. 50% heather cover). The effect of nest proximity was small. In contrast, females hunted mainly within 300-500 m of the nest, with a small additive effect of vegetation cover, areas of fragmented heather being preferred. Habitat management to benefit foraging harriers will involve creating (or maintaining) mosaics of heather/grassland around nest areas. Additionally, it might be possible to manipulate habitat to reduce conflict in areas where harrier predation on red grouse is important by segregating areas holding highest grouse densities (with high heather cover) from those favoured for harrier foraging (heather-grass mosaics). However, it would be necessary to test whether these manipulations might also influence harrier nest distribution, an effect which could negate any benefits from this strategy.     

基于主观偏好和景观空间指标的农业景观特征偏好模型: 以北京市11个农业景观特征区域为例

本研究以北京市11个农业景观特征区域的真实照片为评价资料,通过对46位环境相关专业大学生进行的平衡非完全区组排序评判测试得到他们对不同景观照片的偏好数值。以250m为边长的正三角形在2006年110000土地利用图上截取出照片所对应的数据,根据这些数据计算了反映该照片景观特征的空间格局指数。利用多元逐步回归,以相对应的空间格局指数以及主观判断得到的绿色覆盖度和管理水平等共11个指标,分别针对不同景观特征区域构建景观偏好模型。研究表明,除各指标在权重上的差异外,有些指标在不同特征区域内,甚至在对景观偏好影响的方向上都有所差异:绿色覆盖度、管理水平、斑块黏合度、斑块聚合程度、分维度指数均体现出对景观可视偏好的正向影响,开阔地比例在可视范围体现了对景观偏好的逆向影响,而斑块数量、蔓延度、最大斑块指数、干扰比例和林地比例在不同景观特征分区内则表现不同的影响趋向。     

Spatial analysis of habitat quality in a fragmented population of little bustard (Tetrax tetrax): Implications for conservation

Little bustard populations have suffered reduction and isolation as a consequence of landscape transformations resulting from changes in traditional agricultural systems. Consequently, the species survives within reduced and fragmentary habitats, like islands isolated in a modified matrix. In this paper, we analyze the spatial variations in male density and habitat quality in a fragmented population located at the limit of the species’ Iberian range, which is affected by agricultural intensification, using a regional modelling approach. Habitat quality (quantified according to the species perception) and bird density decreased along the intensification gradient. However, in the most intensive agricultural zone, the quality of habitats selected by little bustard males increased, while density decreased, against the expected. In possible explanation, we suggest: (1) density is not necessarily a good indicator of habitat quality, (2) population could be under-saturated in this zone, (3) interannual variations in species distribution, or (4) other relevant variables related to the agricultural intensification process not included in this analysis, such as small-scale disturbances. Analysis of population distribution pattern showed a spatial configuration in which the most densely populated squares were located at the core of the biggest population patches, in contact with mid-density squares, and all surrounded by low-density squares. Fragmentation negatively affected habitat quality and male density. Largest population patches, containing higher density values, were located at the beginning of the intensification gradient. Preservation of little bustard densities is related to an adequate management of the farming system. Habitat fragmentation requires an urgent conservation strategy to prevent local and regional scale habitat deterioration, by reducing patch isolation to maintain genetic diversification and functional connectivity.     

Habitat and flower resource partitioning by an exotic and three native bumble bees in central Hokkaido, Japan

Studies of the interspecific relationships between alien and native pollinator species can help forecast the success of alien species as well as assess the extent of disturbance to native plant-pollinator interactions. We examined the habitat and flower resource occupancy by the invasive introduced bumble bee Bombus terrestris and three dominant native bumble bees in central Hokkaido, northern Japan, in relation to a landscape factor (forest cover ratio) and flower morphology with respect to the proboscis length of bees. Three years of monitoring the invasive boundary of B. terrestris indicated that this species, which dominates open agricultural areas, probably will not invade the forests in which the native species dominate. This habitat partitioning likely followed the displacement of the natives by the invader in open agricultural lands. In forested areas, the native species partitioned flower resources on the basis of the relationship between proboscis length and the lengths of the corolla tubes of flowers. However, in open agricultural areas, both the long- and short-tubed flowers were primarily visited by the exotic short-tongued B. terrestris, which foraged illegitimately (by nectar robbing) on long-tubed flowers (Trifolium pratense L.) and legitimately on short-tubed flowers (T. repens L. and Lavandula angustifolia Mill.). The invasion of B. terrestris into open natural vegetation, in addition to open agricultural areas, has recently been reported in Hokkaido. Even though the exotic and dominant native bumble bees partition their habitat according to landscape factors, the invasive bee has the potential to alter the overall interactions within plant-pollinator systems in the regions of open vegetation on Hokkaido Island.     

Amphibian distribution in a traditionally managed rural landscape of Eastern Europe: Probing the effect of landscape composition

A massive decline of biodiversity is caused by land-use changes. Efforts must therefore be made to better understand the factors that govern organismal distribution, especially for countries where traditional management is about to be intensified such as in Romania. We here document the spatial distribution of amphibians from a Romanian rural landscape where land-use is still largely traditional. We related the occurrence of nine amphibian species and species richness to measures of composition and configuration of the landscape surrounding 54 ponds at three spatial scales: circular areas of 400, 600 and 800 m radii. Busy roads most severely impacted single species and amphibian richness whereas landscape composition measures, such as cover of urban areas, agricultural areas, pastures, forests and wetlands were of little importance. We suggest that the relative unimportance of landscape compositional measures on amphibians is a consequence of the traditional management of these landscapes that keep the environmental conditions favorable for most species.     

Multi-scale effect of landscape processes and habitat quality on newt abundance: Implications for conservation

Recent studies in population dynamics suggest that landscape processes and habitat quality act at different scales on population abundances, but very few have modelled their simultaneous effects. However, at a time of large declines in natural populations, it is essential to understand such multivariate components. We tested the hypothesis that natural populations of palmate newts (Triturus helveticus) are affected on three scales: breeding patch (pond), habitat complementation (terrestrial cover), and metapopulation structure (density of ponds, surrounding populations). We conducted our survey in 130 ponds from southern France (Larzac) and analysed data with generalized additive models (GAM). Two main novel results emerge from these models: (1) the three landscape scales have significant effects on newt abundance, with more newts in deep, vegetated ponds, devoid of fish and surrounded by wooded areas and inhabited ponds; (2) the quality of the surrounding breeding patches is of primary importance in determining the abundance at core sites in a complex way: high abundances are associated positively with high densities of inhabited ponds, but negatively with the number of surrounding ponds. Deforestation, invasive species and abandonment of ponds all have negative impacts on the persistence of palmate newt populations. Future studies should encompass landscapes at different scales and incorporate the habitat quality in surrounding sites to better understand population dynamics and provide adequate conservation measures.     

Species diversity and habitat fragmentation: frogs in a tropical montane landscape in Mexico

We evaluate the alpha (within patch species richness), beta (spatial turnover among patches) and gamma (landscape) diversity of frogs in a tropical montane cloud forest (TMCF) in central Veracruz, Mexico in order to assess (1) the influence of forest fragmentation on frog assemblages, (2) the importance to diversity of the various elements of the landscape matrix, including the shaded coffee plantations and cattle pastures that surround TMCF and (3) to identify the frog guilds most affected by habitat transformation. We sampled ten sites between May 1998 and November 2000: five TMCF fragments and five anthropogenic habitats. For the entire landscape, we registered 21 species belonging to six families. 100% of these were found in the TMCF fragments and 62% in the surrounding mosaic of anthropogenic habitats. Gamma diversity (γ) is determined to a greater extent by species exchange (β) than by local species richness (α). Elevational variation, the degree of conservation of the vegetation canopy and fragment size appear to determine the species diversity of this landscape. Large species, terrestrial species, those whose eggs develop outside water, and those whose larvae develop in the water seemed to be most affected by habitat transformation. On its own, even the largest and most species-rich cloud forest fragment is not capable of preserving the current anuran diversity. Neither are the shaded coffee plantations that are interspersed among and link the patches of TMCF. However together they form a diverse system of habitats crucial to species conservation in this landscape.     

Body size, niche breadth, and ecologically scaled responses to habitat fragmentation: mammalian predators in an agricultural landscape

The ability to make a priori assessments of a species' response to fragmentation, based on its distribution in the landscape, would serve as a valuable conservation and management tool. During 1997-1999, we monitored 717 scent stations to examine seasonal use of forest patches, corridors, and crop fields by coyotes (Canis latrans), domestic cats (Felis catus), foxes (Vulpes vulpes and Urocyon cinereoargenteus), raccoons (Procyon lotor), striped skunks (Mephitis mephitis), opossums (Didelphis virginiana), and long-tailed weasels (Mustela frenata). For each species we developed landscape-based ecologically scaled landscape indices (ELSI), and we modeled species spatial distribution across three spatial scales (landscape-level, element-level, and local habitat-level). Our results suggest that these predators view landscape fragmentation at different spatial scales and demonstrate strong interspecific differences in their response to elements of the landscape. All species except coyotes and domestic cats avoided agricultural fields. In general, predator species that were more mobile (i.e. high ESLI for landscape connectivity; coyotes) were characterized by landscape- and element-based logistic models. In contrast, models including local habitat features generally were most appropriate for less mobile or more stenophagous predators (e.g. long-tailed weasels). Our analysis extends the application of the ESLI concept to species assemblages that do not appear to function as metapopulations, and it highlights the importance of examining spatial scale and species-specific responses to habitat fragmentation. We discuss the relevance of these findings for defining ecological landscapes, understanding predator-prey interactions at multiple spatial scales, and conserving predator and prey populations in fragmented landscapes.