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1.
Mauricio Almeida-Gomes Jayme Augusto Prevedello Renato Crouzeilles 《Landscape Ecology》2016,31(4):711-719
Context
Native vegetation is often used as a proxy for habitat to estimate habitat availability in landscapes. This approach may lead to incorrect estimates of the impacts of habitat loss and fragmentation on species, which have not been thoroughly quantified so far.Objectives
We quantified to what extent the loss of native vegetation reflect actual habitat loss by native species in landscapes. We tested the hypothesis that habitat availability declines at greater rates than native vegetation and thus is overestimated when it is quantified on the basis of native vegetation.Methods
Using simulations, we quantified how the loss of native vegetation in artificial and real landscapes affects habitat availability for species with different habitat requirements. We contrasted a generalist species, which uses all native vegetation, with 10 habitat-specialist species classified into three categories (interior, patchy and riparian species).Results
Habitat availability generally declined at greater rates than native vegetation for all specialist species. This pattern was apparent for different specialist species in a broad range of landscape types. Interior species always lost habitat availability more rapidly than the generalist species. Most riparian species lost habitat availability more rapidly than the generalist species. Responses of patchy species were more complex, depending on their dispersal abilities and landscape structure.Conclusions
Habitat availability is likely to be overestimated when native vegetation is used as proxy for habitat, because habitat availability will generally decline at greater rates than native vegetation. Therefore, a species-centered approach should be adopted when estimating habitat availability in landscapes.2.
Ricardo Rocha Milou Groenenberg Paulo E. D. Bobrowiec Mar Cabeza Jorge M. Palmeirim Christoph F. J. Meyer 《Landscape Ecology》2017,32(1):31-45
Context
Habitat loss, fragmentation and degradation are widespread drivers of biodiversity decline. Understanding how habitat quality interacts with landscape context, and how they jointly affect species in human-modified landscapes, is of great importance for informing conservation and management.Objectives
We used a whole-ecosystem manipulation experiment in the Brazilian Amazon to investigate the relative roles of local and landscape attributes in affecting bat assemblages at an interior-edge-matrix disturbance gradient.Methods
We surveyed bats in 39 sites, comprising continuous forest (CF), fragments, forest edges and intervening secondary regrowth. For each site, we assessed vegetation structure (local-scale variable) and, for five focal scales, quantified habitat amount and four landscape configuration metrics.Results
Smaller fragments, edges and regrowth sites had fewer species and higher levels of dominance than CF. Regardless of the landscape scale analysed, species richness and evenness were mostly related to the amount of forest cover. Vegetation structure and configurational metrics were important predictors of abundance, whereby the magnitude and direction of response to configurational metrics were scale-dependent. Responses were ensemble-specific with local-scale vegetation structure being more important for frugivorous than for gleaning animalivorous bats.Conclusions
Our study indicates that scale-sensitive measures of landscape structure are needed for a more comprehensive understanding of the effects of fragmentation on tropical biota. Although forest fragments and regrowth habitats can be of conservation significance for tropical bats our results further emphasize that primary forest is of irreplaceable value, underlining that their conservation can only be achieved by the preservation of large expanses of pristine habitat.3.
Context
The habitat amount hypothesis has rarely been tested on plant communities. It remains unclear how habitat amount affect species richness in habitat fragments compared to island effects such as isolation and patch size.Objectives
How do patch size and spatial distribution compared to habitat amount predict plant species richness and grassland specialist plant species in small grassland remnants? How does sampling area affect the prediction of spatial variables on species richness?Methods
We recorded plant species density and richness on 131 midfield islets (small remnants of semi-natural grassland) situated in 27 landscapes in Sweden. Further, we tested how habitat amount, compared to focal patch size and distance to nearest neighbor predicted species density and richness of plants and of grassland specialists.Results
A total of 381 plant species were recorded (including 85 grassland specialist species). A combination of patch size and isolation was better in predicting both density and richness of species compared to habitat amount. Almost 45% of species richness and 23% of specialist species were explained by island biogeography parameters compared to 19 and 11% by the amount of habitat. A scaled sampling method increased the explanation level of island biogeography parameters and habitat amount.Conclusions
Habitat amount as a concept is not as good as island biogeography to predict species richness in small habitats. Priority in landscape planning should be on larger patches rather than several small, even if they are close together. We recommend a sampling area scaled to patch size in small habitats.4.
Context
North American grassland songbird populations have declined significantly due to habitat loss and fragmentation. Understanding the influence of the surrounding landscape on prairie fragment occupancy is vital for predicting the fate of grassland birds in these heavily altered landscapes.Objectives
We examined the relative importance of local and landscape variables on grassland bird occupancy of prairie fragments using a focal-patch study. We also investigated the spatial scale at which landscape variables were most influential.Methods
We surveyed birds on 29 unplowed prairie fragments in western Minnesota and eastern North and South Dakota. We quantified local habitat on the fragment using vegetation surveys and aerial photographs and the landscape surrounding the fragment out to 4 km using aerial photographs. We analyzed occupancy using multi-model approaches applied to multiple logistic regression.Results
Of 38 species encountered, nine were neither too rare nor too abundant to be analyzed. Predictors of patch occupancy were unique for each bird species, yet general patterns emerged. For eight species, landscape variables were more important than local variables. Mostly, those landscape variables measured configuration (e.g., edge density) and not composition (e.g., percent cover of a particular matrix element). Landscape effects were mostly from variables measured at the greatest extents from the prairie fragment.Conclusions
Using a focal-patch study design we demonstrated the importance of the surrounding landscape, often out to 4 km from the fragment edge, on prairie occupancy by grassland birds. Effective management of grassland songbirds will require attention to the landscape context of prairie fragments.5.
Context
Increased edge density is among the main negative effects of habitat loss and fragmentation. Roads are linear infrastructures that may promote barrier effects due to disturbance and mortality effects. We hypothesized that edges of habitat patches bordered by roads are less permeable than roadless edges.Objectives
We tested whether edge permeability and avoidance are influenced by the presence of paved and dirt roads bordering habitat patches, relatively to roadless edges.Methods
We translocated 55 montane akodonts (Akodon montensis) from the interior of vegetation remnants to their edges, and tracked fine-scale movements using spool-and-line devices. Edges were bordered by dirt roads (n = 12 mice), paved roads (n = 21) or were not bordered by roads (n = 22). We assessed edge permeability by comparing the number of tracks with crossings, and by comparing the empirical data to simulated correlated random walks. We also assessed edge avoidance by comparing the net direction travelled and net displacement from edge.Results
No edge crossings were recorded in roaded edges, whereas 36% of tracks in roadless edges crossed the edge at least once. Simulations indicated a significantly lower permeability of roaded edges, while the observed number of crossings in roadless edges was within the expected range. We found no evidence of higher avoidance of roaded edges, as both net direction travelled and displacement were similar across edge types.Conclusions
Roads decreased edge permeability for the montane akodont. This is likely to increase population isolation among vegetation remnants by reducing the structural connectivity in the already fragmented landscape.6.
Juan Luis H. Cardós Isabel Martínez Gregorio Aragón Christopher J. Ellis 《Landscape Ecology》2018,33(10):1757-1768
Context
The anthropocene is characterised by global landscape modification, and the structure of remnant habitats can explain different patterns of species richness. The most pervasive processes of degradation include habitat loss and fragmentation. However, a recovery of modified landscape is occurring in some areas.Objectives
The main goal is to know how lichen and bryophyte epiphytic richness growing on Mediterranean forests is influenced not only by fragments characteristics but also by the structure of the landscape. We introduce a temporal dimension in order to evaluate if the historical landscape structure is relevant for current epiphytic communities.Methods
40 well-preserved forest fragments were selected in a landscape with a large habitat loss over decades, but with a recovery of forest surface in the last 55 years. The most relevant fragment and landscape-scale attributes were considered. Some of the variables were measured in three different years to incorporate a temporal framework.Results
The results showed that variables at fragment scale had a higher influence, whereas variables at the landscape scale were irrelevant. Among all the historical variables analyzed, only the shift in forest fragment size had influence on species richness.Conclusions
Mediterranean forests had suffered fragmentation along centuries. Their epiphytic communities also suffer the hard conditions of Mediterranean climate. Our results indicate that Mediterranean epiphytic communities may be in a threshold since it they will never be similar to those communities existing previous fragmentation process even a recovery habitat occur or, they may require more time to response to this habitat recovery.7.
Mark R. Herse Michael E. Estey Pamela J. Moore Brett K. Sandercock W. Alice Boyle 《Landscape Ecology》2017,32(12):2351-2364
Purpose
Wildlife conservation requires understanding how landscape context influences habitat selection at spatial scales broader than the territory or habitat patch.Objectives
We assessed how landscape composition, fragmentation, and disturbance affected occurrence and within-season site-fidelity of a declining grassland songbird species (Henslow’s Sparrow, Ammodramus henslowii).Methods
Our study area encompassed eastern Kansas (USA) and North America’s largest remaining tracts of tallgrass prairie. We conducted 10,292 breeding-season point-count surveys over 2 years, and related occurrence and within-season site-occupancy dynamics of sparrows to landscape attributes within 400-, 800-, and 1600-m radii.Results
Sparrows inhabited < 1% of sites, appearing and disappearing locally within and between breeding seasons. Early in spring, sparrows responded to landscape attributes most strongly within 400-m radii, settling in areas containing > 50% unburned prairie. Later in summer, sparrows responded to landscape attributes most strongly within 800-m radii, settling in areas containing > 50% unfragmented prairie, including sites burned earlier the same year. Sparrows avoided landscapes containing woody vegetation, disappeared from hayfields after mowing, and were most likely to inhabit landscapes containing Conservation Reserve Program (CRP) fields embedded within rangeland.Conclusions
Landscape context influenced habitat selection at spatial scales broader than both the territory and habitat patch. Protecting contiguous prairies from agricultural conversion and woody encroachment, promoting CRP enrollment, and maintaining portions of undisturbed prairie in working rangelands each year are critical to reversing the conservation crisis in North America’s remaining grasslands. As landscape change alters natural areas worldwide, effective conservation requires suitable conditions for threatened species at multiple spatial scales.8.
Context
Habitat destruction is the leading threat to terrestrial biodiversity, isolating remnant habitat in a matrix of modified vegetation.Objectives
Our goal was to determine how species richness in several broad taxonomic groups from remnant forest was influenced by matrix quality, which we characterized by comparing plant biomass in forest and the surrounding matrix.Methods
We coupled data on species-area relationships (SARs) in forest remnants from 45 previously published studies with an index of matrix quality calculated using new estimates of plant biomass derived from satellite imagery.Results
The effect size of SARs was greatest in landscapes with low matrix quality and little forest cover. SARs were generally stronger for volant than for non-volant species. For the terrestrial taxa included in our analysis, matrix quality decreased as the proportion of water, ice, or urbanization in a landscape increased.Conclusions
We clearly demonstrate that matrix quality plays a major role in determining patterns of species richness in remnant forest. A key implication of our work is that activities that increase matrix quality, such as active and passive habitat restoration, may be important conservation measure for maintaining and restoring biodiversity in modified landscapes.9.
Context
Habitat loss and habitat fragmentation negatively affect amphibian populations. Roads impact amphibian species through barrier effects and traffic mortality. The landscape variable ‘accessible habitat’ considers the combined effects of habitat loss and roads on populations.Objectives
The aim was to test whether accessible habitat was a better predictor of amphibian species richness than separate measures of road effects and habitat loss. I assessed how accessible habitat and local habitat variables determine species richness and community composition.Methods
Frog and tadpole surveys were conducted at 52 wetlands in a peri-urban area of eastern Australia. Accessible habitat was delineated using a highway. Regressions were used to examine relationships between species richness and eleven landscape and local habitat variables. Redundancy analysis was used to examine relationships between community composition and accessible habitat and local habitat variables.Results
Best-ranked models of species richness included both landscape and local habitat variables. There were positive relationships between species richness and accessible habitat and distance to the highway, and uncertain relationships with proportion cover of native vegetation and road density. There were negative relationships between species richness and concreted wetlands and wetland electrical conductivity. Four species were positively associated with accessible habitat, whereas all species were negatively associated with wetland type.Conclusions
Barrier effects caused by the highway and habitat loss have negatively affected the amphibian community. Local habitat variables had strong relationships with species richness and community composition, highlighting the importance of both availability and quality of habitat for amphibian conservation near major roads.10.
Context
In agricultural landscapes, small woodland patches can be important wildlife refuges. Their value in maintaining biodiversity may, however, be compromised by isolation, and so knowledge about the role of habitat structure is vital to understand the drivers of diversity. This study examined how avian diversity and abundance were related to habitat structure in four small woods in an agricultural landscape in eastern England.Objectives
The aims were to examine the edge effect on bird diversity and abundance, and the contributory role of vegetation structure. Specifically: what is the role of vegetation structure on edge effects, and which edge structures support the greatest bird diversity?Methods
Annual breeding bird census data for 28 species were combined with airborne lidar data in linear mixed models fitted separately at (i) the whole wood level, and (ii) for the woodland edges only.Results
Despite relatively small woodland areas (4.9–9.4 ha), bird diversity increased significantly towards the edges, being driven in part by vegetation structure. At the whole woods level, diversity was positively associated with increased vegetation above 0.5 m and especially with increasing vegetation density in the understorey layer, which was more abundant at the woodland edges. Diversity along the edges was largely driven by the density of vegetation below 4 m.Conclusions
The results demonstrate that bird diversity was maximised by a diverse vegetation structure across the wood and especially a dense understorey along the edge. These findings can assist bird conservation by guiding habitat management of remaining woodland patches.11.
Context
Landscape modification is an important driver of biodiversity declines, yet we lack insight into how ongoing landscape change and legacies of historical land use together shape biodiversity.Objectives
We examined how a history of agricultural land use and current forest fragmentation influence the abundance of red-backed salamanders (Plethodon cinereus). We hypothesized that historical agriculture and fragmentation cause changes in habitat quality and landscape structure that limit abundance.Methods
We measured salamander abundance at 95 forested sites in New York, USA, and we determined whether sites were agricultural fields within the last five decades. We used a structural equation model to estimate relationships between historical agriculture and salamander abundance mediated by changes in forest vegetation, microclimate, and landscape structure.Results
Historical agriculture affected salamander abundance by altering forest vegetation at a local scale and forest cover at a landscape scale. Abundance was lowest at post-agricultural sites with low woody vegetation, leaf litter depth, and canopy cover. Post-agricultural sites had limited forest cover in the surrounding landscape historically, and salamander abundance was positively related to historical forest cover, suggesting that connectivity to source populations affects colonization of regenerating forests. Abundance was also negatively related to current forest fragmentation.Conclusions
Historical land use can have legacy effects on animal abundance on par with effects of ongoing landscape change. We showed that associations between animal abundance and historical land use can be driven by altered site conditions and surrounding habitat area, indicating that restoration efforts should consider local site conditions and landscape context.12.
Juan Luis H. Cardós Isabel Martínez Victoria Calvo Gregorio Aragón 《Landscape Ecology》2016,31(9):1975-1995
Context
Mediterranean forests have been fragmented intensively over time, thereby yielding small and isolated forest remnants. They host a rich variety of epiphytes, which may be affected by landscape structure. Previous studies have analyzed the influence of habitat quality on these epiphytic communities, but there is little knowledge of the effects of other fragment features.Objectives
We evaluated the impacts of forest loss and fragmentation on epiphytic communities (lichens and bryophytes) at plot and fragment scales after controlling the variation in forest structure and management.Methods
We considered 40 fragments of dense oak forests in a human-modified landscape. We quantified their spatial attributes (size and shape), the quality of the surrounding matrix and the forest stand structure. We modeled community traits, and the presence and abundance of species at fragment and plot scales.Results
Fragment size, shape, and the quality of the surrounding matrix were key factors that affected epiphytic richness and diversity. Larger and more regularly shaped fragments hosted the richest and most diverse communities, possibly offering a larger core area and thus favoring the entry of typical forest species. A high-contrast matrix was only favorable in small fragments, probably allowing the arrival of propagules. The species-level response was highly variable.Conclusions
Landscape structure provides powerful explanations of the richness and diversity losses among epiphytes. Forest management should ensure the retention of the largest possible continuous forests. The management strategy of the matrix will depend on the conservation goal, since we observed different effects related with quality and fragment size.13.
Hanem G. Abouelezz Therese M. Donovan Ruth M. Mickey James D. Murdoch Mark Freeman Kimberly Royar 《Landscape Ecology》2018,33(8):1301-1318
Context
The analysis of individual movement choices can be used to better understand population-level resource selection and inform management.Objectives
We investigated movements and habitat selection of 13 bobcats in Vermont, USA, under the assumption individuals makes choices based upon their current location. Results were used to identify “movement-defined” corridors.Methods
We used GPS-collars and GIS to estimate bobcat movement paths, and extracted statistics on land cover proportions, topography, fine-scale vegetation, roads, and streams within “used” and “available” space surrounding each movement path. Compositional analyses were used to determine habitat preferences with respect to landcover and topography; ratio tests were used to determine if used versus available ratios for vegetation, roads, and streams differed from 1. Results were used to create travel cost maps, a primary input for corridor analysis.Results
Forested and scrub-rock land cover were most preferred for movement, while developed land cover was least preferred. Preference depended on the composition of the “available” landscape: Bobcats moved?>?3 times more quickly through forest and scrub-rock habitat when these habitats were surrounded by agriculture or development than when the available buffer was similarly composed. Overall, forest edge, wetland edge and higher stream densities were selected, while deep forest core and high road densities were not selected. Landscape-scale connectivity maps differed depending on whether habitat suitability, preference, or selection informed the travel cost map.Conclusions
Both local and landscape scale land cover characteristics affect habitat preferences and travel speed of bobcats, which in turn can inform management and conservation activities.14.
Context
Species distributions are driven by a wide variety of abiotic and biotic factors, including nest placement for breeding individuals. As such, the spatial distribution of nests within a landscape can reflect environmental heterogeneity, habitat preferences, or even interactions with predators and other species.Objectives
We determined the extent to which environmental heterogeneity and predation risk accounted for the observed spatial distribution of nests.Methods
We assessed the spatial distribution of 112 nests of a migratory shorebird, the Hudsonian Godwit (Limosa haemastica), at Beluga River, Alaska, from 2009 to 2012, and explicitly tested for the relative influence of habitat characteristics and predation risk on nest locations. We also evaluated the effect of nest location, distance to conspecific nests, and proximity to roads on nest fate using 64 nests that were monitored through completion.Results
Hudsonian Godwit nests were clustered across the landscape despite a lack of significant spatial autocorrelation (i.e., patchiness) in vegetation characteristics at either the micro- or landscape scale. Nest fate also was not predicted by either the distance to the nearest conspecific neighbor or proximity to roads. Thus, neither habitat characteristics nor predation risk explained the clustering of godwit nests.Conclusions
These results suggest that godwits may select nest locations based more on social cues than underlying heterogeneity in vegetation or predation risk. As such, intra- and inter-specific interactions should be considered when developing management plans for species of conservation concern.15.
16.
17.
Poliana Mendes Kimberly A. With Luciana Signorelli Paulo De MarcoJr. 《Landscape Ecology》2017,32(4):745-762
Context
Species site-occupancy patterns may be influenced by habitat variables at both local and landscape scales. Although local habitat variables influence whether the site is suitable for a given species, the broader landscape context can also influence site occupancy, particularly for species that are sensitive to land-use change.Objectives
To examine the relative importance of local versus landscape variables in explaining site occupancy of eight bat species within the Brazilian Cerrado, a Neotropical savanna that is experiencing widespread habitat loss and fragmentation.Methods
Bats were surveyed within 16 forest patches over two years. We used a multi-model information-theoretic approach, adjusted for species detection bias, to assess whether landscape variables (percent cover and number of patches of natural vegetation within a 2- and 8-km radius of each forest site) or local site variables (canopy cover, understory height, number of trees, and number of lianas) best explained site occupancy in each species.Results
Landscape variables were among the best models (ΔAICc or ΔQAICc < 2) for four species (top-ranked model for black myotis), whereas local variables were among the best for five species (top-ranked model for vampire bats). Neither local nor landscape variables explained site occupancy in two frugivorous species.Conclusion
Species associated with a particular habitat type will not respond similarly to the amount, distribution or relative suitability of that habitat, or even at the same scale. This reinforces the challenge of species distribution modelling, especially in the context of forecasting species’ responses to future land-use or climate-change scenarios.18.
Tyler R. Bonnell Ria R. Ghai Tony L. Goldberg Raja Sengupta Colin A. Chapman 《Landscape Ecology》2018,33(8):1259-1272
Context
Landscape changes can be an important modifier of disease. Habitat fragmentation commonly results in reduced connectivity in host populations and increased use of the remaining habitat. For environmentally transmitted parasites, this presents a possible trade-off between transmission potential at the local and global level.Objectives
We quantify the effects of fragmentation on the transmission of an environmentally transmitted parasite, teasing apart the relative effects of habitat composition and configuration on both host movement behaviour and subsequent infection patterns.Methods
We use a spatially-explicit epidemiological model to simulate the effects of habitat fragmentation, using, as an example, whipworm (Trichuris sp.) within a red colobus monkey population (Procolobus rufomitratus).Results
We found that habitat fragmentation did not always lead to a trade-off between population connectivity and concentration of habitat use in host movement behaviour or in final population infection patterns. However, our simulation results suggest the spatial configuration of the remaining habitat became increasingly influential on behavioural and infection outcomes as habitat was removed. Additionally, we found common fragmentation metrics provided little ability to explain variation in propagation of infections.Conclusions
Our results suggest an interaction between habitat configuration and composition should be considered when assessing disease related impacts of habitat fragmentation on environmentally transmitted parasites, especially in cases where habitat loss is high (≥?30%). We also propose that spatially-explicit simulations that capture a host’s response to fragmentation could aid in the development of novel landscape metrics targeted towards specific host-parasite-landscape systems.19.
Théophile Olivier Reto Schmucki Benoit Fontaine Anne Villemey Frédéric Archaux 《Landscape Ecology》2016,31(4):865-876
Context
Understanding the factors contributing to maintaining biodiversity is crucial to mitigate the impact of anthropogenic disturbances. Representing large proportions of green area in highly modified landscapes, residential gardens are often seen as local habitats that can contribute to larger networks of suitable environments at the landscape scale.Objectives
We investigated the impact of the landscape context on butterfly communities observed in residential gardens, taking into account garden characteristics, land-use types and presence of linear features in the surrounding landscape. We examined how species traits affected butterflies’ response to landscape context and habitat quality.Methods
We performed a cross-scale study, based on citizen science data documenting butterfly species composition and abundance in 920 gardens across France. We examined the effect of garden quality, the area of different land-use types and the length of linear elements measured at three scales within the surrounding landscape. Species were grouped according to their habitat preference and mobility.Results
Urbanization negatively affected total species richness and the abundance of butterfly in each group. This was related to declining habitat quality and reduced area of suitable habitat in the surrounding landscape. The magnitude of this effect, however, was negatively correlated with mobility, a trait related to habitat preference. The spatial scale at which landscape context best explained variation in butterfly abundance changed with species’ habitat preference.Conclusions
This study highlights the importance of preserving high quality habitats in altered landscapes and considering species’ mobility and habitat preference when assessing the impact of landscapes on butterfly communities.20.
Alexander Peringer Kiowa A. Schulze Ileana Stupariu Mihai-Sorin Stupariu Gert Rosenthal Alexandre Buttler François Gillet 《Landscape Ecology》2016,31(4):913-927