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1.
Although it is recognized that anthropogenic forest fragmentation affects habitat use by organisms across multiple spatial
scales, there is uncertainty about these effects. We used a hierarchical sampling design spanning three spatial scales of
habitat variability (landscape > patch > within-patch) and generalized mixed-effect models to assess the scale-dependent responses
of bird species to fragmentation in temperate forests of southern Chile. The abundances of nine of 20 bird species were affected
by interactions across spatial scales. These interactions resulted in a limited effect of within-patch habitat structure on
the abundance of birds in landscapes with low forest cover, suggesting that suitable local habitats, such as sites with dense
understory cover or large trees, are underutilized or remain unused in highly fragmented landscapes. Habitat specialists and
cavity-nesters, such as tree-trunk foragers and tapaculos, were most likely to exhibit interactions across spatial scales.
Because providing additional sites with dense understory vegetation or large habitat trees does not compensate the negative
effect of the loss of forest area on bird species, conservation strategies should ensure the retention of native forest patches
in the mixed-use landscapes. 相似文献
2.
ContextUrbanization has altered many landscapes around the world and created novel contexts and interactions, such as the rural–urban interface.ObjectivesWe sought to address how a forest patch’s location in the rural–urban interface influences which avian species choose to occur within the patch. We predicted a negative relationship between forest bird richness and urbanization surrounding the patch, but that it would be ameliorated by the area of tree cover in the patch and matrix, and that total tree-cover area would be more influential on forest bird species richness than area of tree cover in the focal patch alone.MethodsWe conducted bird surveys in 44 forest patches over 2 years in Southeast Michigan and evaluated bird presence and richness relative to patch and matrix tree cover and development density.ResultsWe observed 43 species, comprised of 21 Neotropical migrants, 19 residents, and three short-distance migrants. Focal-patch tree-cover area and the matrix tree-cover area were the predominant contributors to a site’s overall forest-bird species richness at the rural–urban interface, but the addition of percent of over-story vegetation and percentage of deciduous tree cover influenced the ability of the patches to support forest species, especially Neotropical migrants. Development intensity in the matrix was unrelated to species richness and only had an effect in four species models.ConclusionsAlthough small forest patches remain an important conservation strategy in developed environments, the influence of matrix tree cover suggests that landscape design decisions in surrounding matrix can contribute conservation value at the rural–urban interface. 相似文献
3.
ContextConservation for the Indiana bat (Myotis sodalis), a federally endangered species in the United States of America, is typically focused on local maternity sites; however, the species is a regional migrant, interacting with the environment at multiple spatial scales. Hierarchical levels of management may be necessary, but we have limited knowledge of landscape-level ecology, distribution, and connectivity of suitable areas in complex landscapes. ObjectivesWe sought to (1) identify factors influencing M. sodalis maternity colony distribution in a mosaic landscape, (2) map suitable maternity habitat, and (3) quantify connectivity importance of patches to direct conservation action. MethodsUsing 3 decades of occurrence data, we tested a priori, hypothesis-driven habitat suitability models. We mapped suitable areas and quantified connectivity importance of habitat patches with probabilistic habitat availability metrics. ResultsFactors improving landscape-scale suitability included limited agriculture, more forest cover, forest edge, proximity to medium-sized water bodies, lower elevations, and limited urban development. Areas closer to hibernacula and rivers were suitable. Binary maps showed that 30% of the study area was suitable for M. sodalis and 29% was important for connectivity. Most suitable patches were important for intra-patch connectivity and far fewer contributed to inter-patch connectivity. ConclusionsWhile simple models may be effective for small, homogenous landscapes, complex models are needed to explain habitat suitability in large, mixed landscapes. Suitability modeling identified factors that made sites attractive as maternity areas. Connectivity analysis improved our understanding of important areas for bats and prioritized areas to target for restoration. 相似文献
4.
Ecological theory predicting the impact of fire on ecological communities is typically focused on post-disturbance recovery processes or on disturbance-diversity dynamics. Yet the established relationship between vegetation structure and animal diversity could provide a foundation to predict the short-term effects of fire on biodiversity, but has rarely been explored. We tested the hypothesis that fire effects on bird assemblages would be moderated by increasing vegetation structure. We examined bird assemblages in burnt and unburnt sites at 1 and 6 years after a wildfire, and compared richness and composition responses among and within three structurally distinct vegetation types in the same landscape: heath, woodland and forest. We found that short-term changes in bird assemblage composition were largest in simple heath vegetation and smallest in complex forest vegetation. The short-term change in species richness was larger in forest than in heath. We also found that among-site assemblage variability was greater shortly after fire in heath and woodland vegetation compared with forest vegetation. Our results indicate that complexity in vegetation structure, particularly overstorey cover, can act as an important moderator of fire effects on bird assemblages. Mechanisms for this response include a greater loss of structure in vegetation characterised by a single low stratum, and a proportionally greater change in bird species composition despite a smaller absolute change in species richness. We discuss our results in the context of a new conceptual model that predicts contrasting richness and composition responses of bird assemblages following disturbance along a gradient of increasing vegetation structure. This model brings a different perspective to current theories of disturbance, and has implications for understanding and managing the effects of fire on biodiversity in heterogeneous landscapes. 相似文献
5.
ContextAs agricultural demands for land continues to expand, strategies are urgently needed to balance agricultural production with biodiversity conservation and ecosystem service provision in agricultural landscapes. ObjectivesWe used a factorial landscape design to assess the relative contributions of forest proximity and local forest cover to bee diversity and the provision of coffee pollination services. MethodsWe quantified bee diversity and fruit set in 24 sun-grown coffee fields in Southeast Region of Brazil that were selected following a factorial sampling design to test the independent effects of local forest cover (in a radius of 400 m) and proximity to forest fragments. To assess the impact of landscape simplification, we also evaluated local coffee cover. ResultsBee richness and abundance were higher in the proximity of forest fragments, but only bee abundance decreased when the coffee cover dominated the surrounding landscapes. Coffee fruit set was 16% higher overall with bee visitations compared with bee exclusion and increased to 20% when coffee bushes were near forest fragments, and the coffee cover was low. Surprisingly, local forest cover did not affect the bee community or coffee fruit set. ConclusionOur results provide clear evidence that the proximity of coffee crops to forest fragments can affect the abundance and richness of bees visiting the coffee flowers and thereby facilitate the provision of pollination services. The positive association between forest proximity and fruit set reinforces the importance of natural vegetation in enhancing bee diversity and, therefore, in the provision of pollination services. The negative effect of coffee cover on fruit set at the local scale suggests that the service demand can surpass the capacity of pollinators to provide it. These effects were independent of the local forest cover, although all studied landscapes had more than 20% remaining forest cover (within a 2 km radius), which is considered the extinction threshold for Atlantic Forest species. Interspersion of forest fragments and coffee plantations in regions with more than 20% of forest cover left could thus be a useful landscape management target for facilitating pollinator flows to coffee crops and thus for increasing coffee yields. 相似文献
6.
We surveyed birds in patches of native eucalypt forest and in surrounding exotic matrix (Radiata pine forests) in south-eastern
Australia. Our objectives were: (1) to examine the influence of the width of native forest patches and the age of surrounding
pine forests on bird occurrence in patches of native forest; and (2) to verify the relationship between the use of the surrounding
pine matrix and bird species response to variation in width of patches of native forests. A total of 32 study sites (boundaries
between eucalypt and pine forests) were surveyed. Birds were counted by the area search method within 0.5-ha quadrats. Data
were analysed using generalised linear models. Wide patches of eucalypt forest supported higher species richness and greater
numbers of birds, such as foliage searchers and nectarivores, than narrow patches. Matrix age also influenced the occurrence
of some species in native patches. The abundance of species in wide and narrow patches of native forest was related to their
use of the matrix. This was true for native forests surrounded by old but not by young pine forests. We suggest that management
in wood production landscapes take into account both characteristics of native patches and the surrounding matrix. Negative
impacts of fragmentation in managed landscapes might be reduced by promoting matrix types that are suitable for bird species. 相似文献
7.
We examine the influence of both local habitat and landscape variables on avian species abundance at forested study sites situated within fragmented and contiguous landscapes. The study was conducted over a six year period (1991–1996) at 10 study sites equally divided between the heavily forested Missouri Ozarks and forest fragments in central Missouri. We found greater species richness and diversity in the fragments, but there was a higher percentage of Neotropical migrants in the Ozarks. We found significant differences in the mean number of birds detected between the central Missouri fragments and the unfragmented Ozarks for 15 (63%) of 24 focal species. We used stepwise regression to determine which of 12 local vegetation variables and 4 landscape variables (forest cover, core area, edge density, and mean patch size) accounted for the greatest amount of variation in abundance for 24 bird species. Seven species (29%) were most sensitive to local vegetation variables, while 16 species (67%) responded most strongly to one of four landscape variables. Landscape variables are significant predictors of abundance for many bird species; resource managers should consider multiple measures of landscape sensitivity when making bird population management decisions.Order of first two authors decided by coin toss 相似文献
8.
Habitat area and isolation have been useful predictors of species occupancy and turnover in highly fragmented systems. However,
habitat quality also can influence occupancy dynamics, especially in patchy systems where habitat selection can be as important
as stochastic demographic processes. We studied the spatial population dynamics of Chrysemys picta (painted turtle) in a network of 90 wetlands in Illinois, USA from 2007 to 2009. We first evaluated the relative influence
of metapopulation factors (area, isolation) and habitat quality of focal patches on occupancy and turnover. Next, we tested
the effect of habitat quality of source patches on occupancy and turnover at focal patches. Turnover was common with colonizations
( n = 16) outnumbering extinctions ( n = 10) between the first 2 years, and extinctions ( n = 16) outnumbering colonizations ( n = 3) between the second 2 years. Both metapopulation and habitat quality factors influenced C. picta occupancy dynamics. Colonization probability was related positively to spatial connectivity, wetland area, and habitat quality
(wetland inundation, emergent vegetation cover). Extinction probability was related negatively to wetland area and emergent
vegetation cover. Habitat quality of source patches strongly influenced initial occupancy but not turnover patterns. Because
habitat quality for freshwater turtles is related to wetland hydrology, a change from drought to wet conditions during our
study likely influenced distributional shifts. Thus, effects of habitat quality of source and focal patches on occupancy can
vary in space and time. Both metapopulation and habitat quality factors may be needed to understand occupancy dynamics, even
for species exhibiting patchy population structures. 相似文献
9.
ContextInsectivorous birds are sensitive to forest disturbances that may limit the availability of food consisting mainly of invertebrates. However, birds and invertebrates may be differently affected by forest disturbances while invertebrates may interact with disturbances. ObjectivesWe aim to determine: (i) the effects of forest degradation on invertebrates and insectivorous birds; (ii) the effect of the availability of invertebrates as a food source on birds; (iii) interactions between food availability and forest degradation. MethodsWe selected 34 1-km radius landscape units, where the abundance of birds and invertebrates was sampled in the canopy and understory. Bird density as well as the abundance and richness of invertebrates were considered as dependent variables and analysed using Generalized Linear Mixed Model and Structural Equation Models. Remote-sensing indices of forest degradation were included as predictors. ResultsEight indices of forest degradation affected canopy and understory invertebrates differently. Unlike invertebrates, bird abundance was affected by a smaller number of degradation indices, forest amounts as well as the cover of understory and canopy. Only two forest degradation indices had a comparable effect on bird abundance and invertebrates. We found causal relationships between understory invertebrates and the abundance of understory birds (all species and the small-sized ones), but also invertebrate abundance × forest cover interactions affected the abundance of a bird species. ConclusionsOur results indicate that birds and invertebrates respond differently to forest degradation, but also provide evidence for bottom-up control by forest degradation and suggest food limitation varies with forest amounts. 相似文献
10.
ContextThe downlisting of giant panda (Ailuropoda melanoleuca) from Endangered to Vulnerable in IUCN Red List confirms the effectiveness of current conservation practices. However, future survival of giant panda is still in jeopardy due to habitat fragmentation and climate change. Maintaining movement corridors between habitat patches in the newly established Giant Panda National Park (GPNP) is the key for the long-term sustainability of the species. ObjectivesWe evaluated the impacts of conversion from natural forest to plantation on giant panda habitat connectivity, which is permitted within collective forests and encouraged by the policies for the economic benefits of local communities. We modeled distribution of giant panda habitat in Minshan Mountains which harbors its largest population, and delineated movement corridors between core habitat patches under management scenarios of different forest conversion proportions. MethodsWe applied an integrated species distribution model based on inhomogeneous Poisson point process to combine presence-only data and site occupancy data, and least-cost models to identify potential movement corridors between core habitat patches. ResultsWe found that current distribution of plantation has not damaged connectivity between core habitat patches of giant panda. However, it could be severely degraded if mass conversion occurred. Since the GPNP incorporates all the core habitats identified from our model, controlling natural forest conversion inside GPNP would maintain the movement corridors for giant panda. ConclusionsWe recommend no expansion of plantations inside the GPNP, and improving collective forest management for expansion of ecological forest in adjoining habitat patches. 相似文献
11.
The purpose of our study was to compare the number, proportion, and species composition of introduced plant species in forest
patches situated within predominantly forested, agricultural, and urban landscapes. A previous study suggested that agricultural
landscape context does not have a large effect on the proportion of introduced species in forest patches. Therefore, our main
goal was to test the hypothesis that forest patches in an urban landscape context contain larger numbers and proportions of
non-native plant species. We surveyed the vegetation in 44 small remnant forest fragments (3–7.5 ha) in the Ottawa region;
15 were situated within forested landscapes, 18 within agricultural landscapes, and 11 within urban landscapes. Forest fragments
in urban landscapes had about 40% more introduced plant species and a 50% greater proportion of introduced plant species than
fragments found in the other two types of landscape. There was no significant difference in the number or proportion of introduced
species in forest fragments within forested vs. agricultural landscapes. However, the species composition of introduced species
differed among the forest patches in the three landscape types. Our results support the hypothesis that urban and suburban
areas are important foci for spread of introduced plant species. 相似文献
12.
ContextAfrican production landscapes are diverse, with multiple cassava cultivars grown in small patches amongst a diversity of other crops. Studies on how diverse smallholder landscapes impact herbivore pest outbreak risk have not been carried out in sub-Saharan Africa. ObjectivesBemisia tabaci is a cryptic pest species complex that cause damage to cassava through feeding and vectoring plant-virus diseases and are known to reach very high densities in certain contexts. However, the factors driving this phenomenon are unclear. MethodsBemisia density data in cassava across a large number of sites representing a geographic gradient across Uganda, Tanzania and Malawi were collected. We tested whether in-field or landscape factors associated with land-use patterns underpinned Bemisia density variability and parasitism. ResultsWe found the B. tabaci SSA1 species dominated our study sites, although other species were also common in some cassava fields. Factors associated with the surrounding landscape were unimportant for explaining variability in adult density, but the in-field variables of cassava age and cultivar were very important. The density of nymphs and the parasitism of nymphs was heavily influenced by a diversity of landscape factors surrounding the field, including the size of focal cassava field, and area of cassava in the landscape. However, unlike the trend from many other studies on drivers of natural enemy populations, this pattern was not solely related to the amount of non-crop vegetation, or the diversity of crops grown in the landscape. ConclusionsOur findings provide management options to reduce whitefly abundance, including describing the characteristics of landscapes with high parasitism. The choice of cassava cultivar by the farmer is critical to reduce whitefly outbreak risk at the landscape-scale. 相似文献
13.
ContextAlthough the edge effect is known to be an important factor influencing the recruitment of trees in temperate forests, little is known of its synergistic relationships with landscape and fragment attributes. ObjectivesWe investigated how the edge effect on regeneration of oaks (Quercus spp.) varies with respect to fragment geometry, connectivity and landscape composition. MethodsWe recorded oak sapling density along edge-interior gradients in 29 forest fragments at the periphery of Mexico City and examined the data with Generalized Additive Models. ResultsA nonlinear and landscape-mediated edge effect was supported by data, including the interactions of the edge distance with patch connectivity, shape and size. Saplings were more abundant at a distance of ca. 50 m from the edge of small, large and connected patches, but large patches also exhibited reduced recruitment towards the interior of the patch. Conversely, sapling density in simple-shaped or connected patches was lower at the edge, exhibiting linear and concave-down increase trends towards the interior of patches, respectively. ConclusionsBoundary conditions could be interacting with interior forest conditions, making regeneration more frequent at 50 m from the edge. Shady and cooler sites in large patches may be inhibiting oak regeneration. The activity of acorn-dispersing animals and oak predators may increase in unconnected patches, thus increasing the likelihood of edge effects. These results provide insights into the restoration of temperate forest patches in heterogeneous fragmented landscapes. 相似文献
14.
The objective of this paper is to present an approach that addresses competing land uses in the reserve site selection problem. This approach is implemented in a spatial optimization model for conservation planning in human-dominated landscapes: MENTOR. This model allocates new sites as stepping stones between existing sites. We illustrated the model by a case with competition for space between wildlife habitat and agriculture as it occurs in the Netherlands. We focused on deciduous forests with the European nuthatch Sitta europaea as an umbrella species for forest birds. Suitability maps for deciduous forests and for agriculture were applied as input for the allocation model.Effects on the landscape pattern, nuthatch populations, bird species richness and dairy farming were described. We can conclude that the application of MENTOR leads to an effective reserve network in De Leijen concerning the suitability of the land for dairy farming. The results show a doubling of the average proportion of occupied habitat, an increase in colonization probability of patches, a decrease in extinction probability of local populations, and an increase in bird species richness per patch. Whereas it results in a relatively small reduction in land currently used by agriculture. 相似文献
15.
ContextClimate and land-use change have led to disturbance regimes in many ecosystems without a historical analog, leading to uncertainty about how species adapted to past conditions will respond to novel post-disturbance landscapes. ObjectivesWe examined habitat selection by spotted owls in a post-fire landscape. We tested whether selection or avoidance of severely burned areas could be explained by patch size or configuration, and whether variation in selection among individuals could be explained by differences in habitat availability. MethodsWe applied mixed-effects models to GPS data from 20 spotted owls in the Sierra Nevada, California, USA, with individual owls occupying home ranges spanning a broad range of post-fire conditions after the 2014 King Fire. ResultsIndividual spotted owls whose home ranges experienced less severe fire (<?5% of home range severely burned) tended to select severely burned forest, but owls avoided severely burned forest when more of their home range was affected (~ 5–40%). Owls also tended to select severe fire patches that were smaller in size and more complex in shape, and rarely traveled?>?100-m into severe fire patches. Spotted owls avoided areas that had experienced post-fire salvage logging but the interpretation of this effect was nuanced. Owls also avoided areas that were classified as open and/or young forest prior to the fire. ConclusionsOur results support the hypothesis that spotted owls are adapted to historical fire regimes characterized by small severe fire patches in this region. Shifts in disturbance regimes that produce novel landscape patterns characterized by large, homogeneous patches of high-severity fire may negatively affect this species. 相似文献
16.
Although landscape ecology emphasizes the effects of spatial pattern on ecological processes, most neutral models of species–habitat relationships have treated habitat as a static constraint. Do the working hypotheses derived from these models extend to real landscapes where disturbances create a shifting mosaic? A spatial landscape simulator incorporating vegetation dynamics and a metapopulation model was used to compare species in static and dynamic landscapes with identical habitat amounts and spatial patterns. The main drivers of vegetation dynamics were stand-replacing disturbances, followed by gradual change from early-successional to old-growth habitats. Species dynamics were based on a simple occupancy model, with dispersal simulated as a random walk. As the proportion of available habitat ( p) decreased from 1.0, species occupancy generally declined more rapidly and reached extinction at higher habitat levels in dynamic than in static landscapes. However, habitat occupancy was sometimes actually higher in dynamic landscapes than in static landscapes with similar habitat amounts and patterns. This effect was most pronounced at intermediate amounts of habitat ( p = 0.3?0.6) for mobile species that had high colonization rates, but were unable to cross non-habitat patches. Differences between static and dynamic landscapes were contingent upon the initial metapopulation size and the shapes of disturbances and the resulting habitat patterns. Overall, the results demonstrate that dispersal-limited species exhibit more pronounced critical behavior in dynamic landscapes than is predicted by simple neutral models based on static landscapes. Thus, caution should be exercised in extending generalizations derived from static landscape models to disturbance-driven landscape mosaics. 相似文献
17.
Using a geographic information system (GIS), digital maps of environmental variables including geology, topography and calculated
clear-sky solar radiation, were weighted and overlaid to predict the distribution of coast live oak ( Ouercus agrifolia) forest in a 72 km 2 region near Lompoc, California. The predicted distribution of oak forest was overlaid on a map of actual oak forest distribution
produced from remotely sensed data, and residuals were analyzed to distinguish prediction errors due to alteration of the
vegetation cover from those due to defects of the statistical predictive model and due to cartographic errors.
Vegetation pattern in the study area was associated most strongly with geologic substrate. Vegetation pattern was also significantly
associated with slope, exposure and calculated monthlysolar radiation. The proportion of observed oak forest occurring on
predicted oak forest sites was 40% overall, but varied substantially between substrates and also depended strongly on forest
patch size, with a much higher rate of success for larger forest patches. Only 21% of predicted oak forest sites supported
oak forest, and proportions of observed vegetation on predicted oak forest sites varied significantly between substrates.
The non-random patterns of disagreement between maps of predicted and observed forest indicated additional variables that
could be included to improve the predictive model, as well as the possible magnitude of forest loss due to disturbances in
different parts of the landscape. 相似文献
18.
Landscape change is an ongoing process for even the most established landscapes, especially in context to urban intensification and growth. As urbanization increases over the next century, supporting bird species’ populations within urbanizing areas remains an important conservation challenge. Fundamental elements of the biophysical structure of urban environments in which bird species likely respond include tree cover and human infrastructure. We broadly examine how tree cover and urban development structure bird species distributions along the urban-rural gradient across multiple spatial scales. We established a regional sampling design within the Oak Openings Region of northwestern, Ohio, USA, to survey bird species distributions across an extensive urbanization gradient. Through occupancy modeling, we obtained standardized effects of bird species response to local and landscape-scale predictors and found that landscape tree cover influenced the most species, followed by landscape impervious surface, local building density, and local tree cover. We found that responses varied according to habitat affiliation and migratory distance of individual bird species. Distributions of short-distance, edge habitat species located towards the rural end of the gradient were explained primarily by low levels of urbanization and potential vegetative and supplemental resources associated with these areas, while forest species distributions were primarily related to increasing landscape tree cover. Our findings accentuate the importance of scale relative to urbanization and help target where potential actions may arise to benefit bird diversity. Management will likely need to be implemented by municipal governments and agencies to promote tree cover at landscape scale, followed by residential land management education for private landowners. These approaches will be vital in sustaining biodiversity in urbanizing landscapes as urban growth expands over the next century. 相似文献
19.
Habitat loss and associated fragmentation effects are well-recognised threats to biodiversity. Loss of functional connectivity (mobility, gene flow and demographic continuity) could result in population decline in altered habitat, because smaller, isolated populations are more vulnerable to extinction. We tested whether substantial habitat reduction plus fragmentation is associated with reduced gene flow in three ??decliner?? woodland-dependent bird species (eastern yellow robin , weebill and spotted pardalote) identified in earlier work to have declined disproportionately in heavily fragmented landscapes in the Box-Ironbark forest region in north-central Victoria, Australia. For these three decliners, and one ??tolerant?? species (striated pardalote) , we compared patterns of genetic diversity, relatedness, effective population size, sex-ratios and genic (allele frequency) differentiation among landscapes of different total tree cover, identified population subdivision at the regional scale, and explored fine-scale genotypic (individual-based genetic signature) structure. Unexpectedly high genetic connectivity across the study region was detected for ??decliner?? and ??tolerant?? species. Power analysis simulations suggest that moderate reductions in gene flow should have been detectable. However, there was evidence of local negative effects of reduced habitat extent and structural connectivity: slightly lower effective population sizes, lower genetic diversity, higher within-site relatedness and altered sex-ratios (for weebill and eastern yellow robin) in 10 × 10?km ??landscapes?? with low vegetation cover. We conclude that reduced structural connectivity in the Box-Ironbark ecosystem may still allow sufficient gene flow to avoid the harmful effects of inbreeding in our study species. Although there may still be negative consequences of fragmentation for demographic connectivity, the high genetic connectivity of mobile bird species in this system suggests that reconnecting isolated habitat patches may be less important than increasing habitat extent and/or quality if these need to be traded off. 相似文献
20.
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. 相似文献
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