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.

Context

The study of habitat fragmentation is complex because multiple, potentially synergistic, ecological processes may be acting simultaneously. Further, edge effects themselves may be complex in that additivity from multiple edges can give rise to heterogeneous nearest–edge gradients.

Objectives

We used heat diffusion as a proxy for additive edge effects in two study landscapes in order to test whether two key observations recently attributed to synergy between edge and area effects could be more simply explained by additivity; namely, steeper edge gradients in larger fragments and variation in slopes of species–area relationships as a function of distances to fragment edges.

Methods

We sampled forest structure in northwestern Madagascar at various distances from the edge in fragments and continuous forest and used an inverse modelling approach to parameterize the model. In addition, we applied the model to data from a published study of beetle communities in fragmented forests in New Zealand.

Results

With increasing proximity to edges, woody stem densities decreased and, as predicted, smaller fragments had lower stem densities and less steep edge gradients than larger ones. The model successfully predicted shifts in species–area relationships as a function of nearest–edge distances for beetle species, although observed richness for forest specialists in the smallest fragments was lower than predicted.

Conclusions

Two key observations attributed to synergy between edge and area effects were explained by edge additivity. The model is particularly useful in that it can help to disentangle the complex sets of processes acting in fragmented landscapes.

Context

The conversion of agricultural landscapes to tree plantations is a major form of landscape transformation worldwide, but its effects on biodiversity, particularly key population processes like reproductive success, are poorly understood.

Objectives

We compared bird breeding success between woodland remnants surrounded by maturing stands of plantation Radiata Pine and a matched set of woodland remnants in semi-cleared grazing land.

Methods

Our study was conducted in the Nanangroe region in south-eastern New South Wales, Australia. Using repeated field measurements, we quantified bird breeding success in 23 woodland remnants; 13 surrounded by Radiata Pine plantations and 10 on farms where remnants were surrounded by semi-cleared grazing land. We matched the attributes of native remnant patches between two types of matrix.

Results

We found that: (1) rates of nesting success of smaller-bodied birds in woodland remnants surrounded by grazing land were significantly higher than in woodland remnants surrounded by pine plantations; and (2) taxa with domed nests were more successful at nesting than species that constructed open cup/bowl nests in woodland remnants within farmlands.

Conclusions

Our findings suggest that bird breeding success in remnant woodland patches is significantly diminished as a result of the conversion of semi-cleared grazing land to pine plantations.

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.

Context

Testing the influence of edges on animal distributions depends on our capacity to quantify ‘edge’, particularly in heterogeneous landscapes. Habitat quality is likely to differ in instances where edges are abrupt and anthropogenic in origin, versus diffuse, disturbance-created edges.

Objectives

We tested whether or not structurally distinct edge types influence northern spotted owl habitat selection and whether the relationship between edge type and use varied across spatial scales relevant to owl foraging (<3 ha) and home range selection (50–800 ha).

Methods

We used remotely sensed disturbance severity data to define two distinct edge types, ‘hard’ and ‘diffuse’, following a 11,000 ha fire and subsequent salvage logging in southern Oregon. The approach quantifies the steepness of gradients directly by measuring the ‘slope’ of change in disturbance severity. We tested the degree to which 23 radio-collared spotted owls responded to edge characteristics caused by fire and logging.

Results

Spotted owls showed a strong negative association with hard edge, even after accounting for habitat suitability and other confounding variables. However, this negative relationship was highly scale-dependent; spotted owls were resilient to hard edges at broad scales, but avoided the same feature at fine scales. On the other hand, spotted owls showed a positive association with diffuse edge, especially at broader scales.

Conclusions

Differential use of edge types indicates that owls favor disturbances that create diffuse edge habitat (e.g. low and mixed-severity fire) and rather than abrupt boundaries created by high severity disturbance.

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.

Context

Edge effects due to habitat loss and fragmentation have pervasive impacts on many natural ecosystems worldwide.

Objective

We aimed to explore whether, in tandem with the resource-based model of edge effects, species feeding-guild and flight-capacity can help explain species responses to an edge.

Methods

We used a two-sided edge gradient that extended from 1000 m into native Eucalyptus forest to 316 m into an exotic pine plantation. We used generalised additive models to examine the continuous responses of beetle species, feeding-guild species richness and flight-capable group species richness to the edge gradient and environmental covariates.

Results

Phytophagous species richness was directly related to variation in vegetation along the edge gradient. There were more flight-capable species in Eucalyptus forest and more flightless species in exotic pine plantation. Many individual species exhibited multiple-peaked edge-profiles.

Conclusions

The resource based model for edge effects can be used in tandem with traits such as feeding-guild and flight-capacity to understand drivers of large scale edge responses. Some trait-groups can show generalisable responses that can be linked with drivers such as vegetation richness and habitat structure. Many trait-group responses, however, are less generalisable and not explained by easily measured habitat variables. Difficulties in linking traits with resources along the edge could be due to unmeasured variation and indirect effects. Some species’ responses reached the limits of the edge gradient demonstrating the need to examine edge effects at large scales, such as kilometres.

Context

Anthropogenic landscape simplification and natural habitat loss can negatively affect wild bees. Alternatively, anthropogenic land-use change may diversify landscapes, creating complementary habitats that maintain overall resource continuity and diversity.

Objectives

We examined the effects of landscape composition, including land-cover diversity and percent semi-natural habitat, on wild bee abundance and species richness within apples, a pollinator-dependent crop. We also explored whether different habitats within diverse landscapes can provide complementary floral resources for bees across space and time.

Methods

We sampled bees during apple bloom over 2 years within 35 orchards varying in surrounding landscape diversity and percent woodland (the dominant semi-natural habitat) at 1 km radii. To assess habitat complementarity in resource diversity and temporal continuity, we sampled flowers and bees within four unique habitats, including orchards, woodlands, semi-natural grasslands, and annual croplands, over three periods from April–June.

Results

Surrounding landscape diversity positively affected both wild bee abundance and richness within orchards during bloom. Habitats in diverse landscapes had different flower communities with varying phenologies; flowers were most abundant within orchards and woodlands in mid-spring, but then declined over time, while flowers within grasslands marginally increased throughout spring. Furthermore, bee communities were significantly different between the closed-canopy habitats, orchards and woodlands, and the open habitats, grasslands and annual croplands.

Conclusions

Our results suggest that diverse landscapes, such as ones with both open (grassland) and closed (woodland) semi-natural habitats, support spring wild bees by providing flowers throughout the entire foraging period and diverse niches to meet different species’ requirements.

Context

Landscape heterogeneity (the composition and configuration of different landcover types) plays a key role in shaping woodland bird assemblages in wooded-agricultural mosaics. Understanding how species respond to landscape factors could contribute to preventing further decline of woodland bird populations.

Objective

To investigate how woodland birds with different species traits respond to landscape heterogeneity, and to identify whether specific landcover types are important for maintaining diverse populations in wooded-agricultural environments.

Methods

Birds were sampled from woodlands in 58 2 × 2 km tetrads across southern Britain. Landscape heterogeneity was quantified for each tetrad. Bird assemblage response was determined using redundancy analysis combined with variation partitioning and response trait analyses.

Results

For woodland bird assemblages, the independent explanatory importance of landscape composition and landscape configuration variables were closely interrelated. When considered simultaneously during variation partitioning, the community response was better represented by compositional variables. Different species responded to different landscape features and this could be explained by traits relating to woodland association, foraging strata and nest location. Ubiquitous, generalist species, many of which were hole-nesters or ground foragers, correlated positively with urban landcover while specialists of broadleaved woodland avoided landscapes containing urban areas. Species typical of coniferous woodland correlated with large conifer plantations.

Conclusions

At the 2 × 2 km scale, there was evidence that the availability of resources provided by proximate landcover types was highly important for shaping woodland bird assemblages. Further research to disentangle the effects of composition and configuration at different spatial scales is advocated.

Context

Biodiversity is modulated by the spatial structure of the landscape. Thus, landscape metrics can be useful indicators of biota integrity and vulnerability, helping in conservation and management decisions.

Objective

We performed the first quantitative analysis of the spatial structure of the Caatinga drylands. We estimated the habitat amount and the fragmentation pattern of this region using a multi-scale perspective.

Methods

Using the Brazilian official database of native remnants, we calculated the number and percentage of remaining fragments per size class and we describe how habitat amount changes along the landscape. By simulating different dispersal capacities, we estimated the functional connectivity among remnants. We also calculated the cumulative core area as a function of different edge effect widths.

Results

Caatinga is subdivided into 47,100 fragments. Although 91% of them are smaller than 500 ha, 720 fragments are larger than 10,000 ha, corresponding to 78% of the remaining vegetation. Potentially, 95% of the vegetation is accessible to species that can cross 1000 m of matrix. With one kilometer of edge effect, the core area is reduced to a quarter of the remaining vegetation. The habitat amount analyzes reinforced the regional differences in the spatial distribution of the remnants.

Conclusions

Caatinga remains well connected for species with moderate and high dispersal capacities. However much of its remaining area is vulnerable to anthropogenic disturbances. Expansion of the protected area network and effective natural resource management to avoid overexploitation of the remnants are key strategies for maintaining the Caatinga biodiversity and its services.

Context

Connectivity is fundamental to understanding how landscape form influences ecological function. However, uncertainties persist due to the difficulty and expense of gathering empirical data to drive or to validate connectivity models, especially in urban areas, where relationships are multifaceted and the habitat matrix cannot be considered to be binary.

Objectives

This research used circuit theory to model urban bird flows (i.e. ‘current’), and compared results to observed abundance. The aims were to explore the ability of this approach to predict wildlife flows and to test relationships between modelled connectivity and variation in abundance.

Methods

Circuitscape was used to model functional connectivity in Bedford, Luton/Dunstable, and Milton Keynes, UK, for great tits (Parus major) and blue tits (Cyanistes caeruleus), drawing parameters from published studies of woodland bird flows in urban environments. Model performance was then tested against observed abundance data.

Results

Modelled current showed a weak yet positive agreement with combined abundance for P. major and C. caeruleus. Weaker correlations were found for other woodland species, suggesting the approach may be expandable if re-parameterised.

Conclusions

Trees provide suitable habitat for urban woodland bird species, but their location in large, contiguous patches and corridors along barriers also facilitates connectivity networks throughout the urban matrix. Urban connectivity studies are well-served by the advantages of circuit theory approaches, and benefit from the empirical study of wildlife flows in these landscapes to parameterise this type of modelling more explicitly. Such results can prove informative and beneficial in designing urban green space and new developments.

Context

Complex structural connectivity patterns can influence the distribution of animals in coastal landscapes, particularly those with relatively large home ranges, such as birds. To understand the nuanced nature of coastal forest avifauna, where there may be considerable overlap in assemblages of adjacent forest types, the concerted influence of regional landscape context and vegetative structural connectivity at multiple spatial scales warrants investigation.

Objectives

This study determined whether species compositions of coastal forest bird assemblages differ with regional landscape context or with forest type, and if this is influenced by structural connectivity patterns measured at multiple spatial scales.

Methods

Three replicate bird surveys were conducted in four coastal forest types at ten survey locations across two regional landscape contexts in northeast Australia. Structural connectivity patterns of 11 vegetation types were quantified at 3, 6, and 12 km spatial scales surrounding each survey location, and differences in bird species composition were evaluated using multivariate ordination analysis.

Results

Bird assemblages differed between regional landscape contexts and most coastal forest types, although Melaleuca woodland bird assemblages were similar to those of eucalypt woodlands and rainforests. Structural connectivity was primarily correlated with differences in bird species composition between regional landscape contexts, and correlation depended on vegetation type and spatial scale.

Conclusions

Spatial scale, landscape context, and structural connectivity have a combined influence on bird species composition. This suggests that effective management of coastal landscapes requires a holistic strategy that considers the size, shape, and configuration of all vegetative components at multiple spatial scales.

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.

Context

The biodiversity hotspot for conservation of New Caledonia has facing high levels of forest fragmentation. Remnant forests are critical for biodiversity conservation and can help in understanding how does forest fragmentation affect tree communities.

Objective

Determine the effect of habitat configuration and availability on tree communities.

Methods

We mapped forest in a 60 km² landscape and sampled 93 tree communities in 52 forest fragments following stratified random sampling. At each sampling point, we inventoried all trees with a diameter at breast height ≥10 cm within a radius of 10 m. We then analysed the response of the composition, the structure and the richness of tree communities to the fragment size and isolation, distance from the edge, as well as the topographical position.

Results

Our results showed that the distance from the forest edge was the variable that explained the greatest observed variance in tree assemblages. We observed a decrease in the abundance and richness of animal-dispersed trees as well as a decrease in the abundance of large trees with increasing proximity to forest edges. Near forest edges we found a shift in species composition with a dominance of stress-tolerant pioneer species.

Conclusions

Edge-effects are likely to be the main processes that affect remnant forest tree communities after about a century of forest fragmentation. It results in retrogressive successions at the edges leading to a dominance of stress-tolerant species. The vegetation surrounding fragments should be protected to promote the long process of forest extension and subsequently reduce edge-effects.

Context

Competitive interactions potentially play an important role in structuring bird communities. It is unclear how differences in functional traits influence the niche dimensions of highly mobile waterbird species, particularly when they co-exist in spatiotemporally heterogeneous communities.

Objectives

We investigated the inter-relationships between waterbird trait groupings (movement, dietary and foraging habitat) and environmental variable groupings (rainfall, land cover, vegetation structure and water quality). Specifically, we tested whether the scale of environmental variables filtered movement traits and whether these traits operated in conjunction with dietary and foraging habitat traits to form distinct ecological niches in waterbirds.

Methods

We conducted waterbird and environmental variable surveys in 60 sites, sampled seven times each at bimonthly intervals, in KwaZulu-Natal, South Africa. Trait-environment relationships were tested using a combination of RLQ and fourth-corner analyses.

Results

Several significant trait-environment relationships emerged in bivariate correlations and multivariate ordination space. Movement traits correlated with the scale of environmental variables; migrant and nomadic species responded to broad scale environmental variables. Vegetation structure and land cover were particularly important in explaining the abundance of species foraging in emergent vegetation. Three groups emerged along a gradient in multivariate ordination space providing evidence for ecological niche separation of waterbirds with different movement traits.

Conclusions

Our findings suggest that the scale of landscape resources can act as a filter of movement traits, and that in conjunction with dietary and foraging traits, waterbirds with different movement traits occupy distinct ecological niches.

Context

Although multi-scale approaches are commonly used to assess wildlife-habitat relationships, few studies have examined selection at multiple spatial scales within different hierarchical levels/orders of selection [sensu Johnson’s (1980) orders of selection]. Failure to account for multi-scale relationships within a single level of selection may lead to misleading inferences and predictions.

Objectives

We examined habitat selection of the federally threatened eastern indigo snake (Drymarchon couperi) in peninsular Florida at the level of the home range (Level II selection) and individual telemetry location (Level III selection) to identify influential habitat covariates and predict relative probability of selection.

Methods

Within each level, we identified the characteristic scale for each habitat covariate to create multi-scale resource selection functions. We used home range selection functions to model Level II selection and paired logistic regression to model Level III selection.

Results

At both levels, EIS selected undeveloped upland land covers and habitat edges while avoiding urban land covers. Selection was generally strongest at the finest scales with the exception of Level II urban edge which was avoided at a broad scale indicating avoidance of urbanized land covers rather than urban edge per se.

Conclusions

Our study illustrates how characteristic scales may vary within a single level of selection and demonstrates the utility of multi-level, scale-optimized habitat selection analyses. We emphasize the importance of maintaining large mosaics of natural habitats for eastern indigo snake conservation.

Context

Habitat loss and fragmentation may alter habitat occupancy patterns, for example through a reduction in regional abundance or in functional connectivity, which in turn may reduce the number of dispersers or their ability to prospect for territories. Yet, the relationship between landscape structure and habitat niche remains poorly known.

Objectives

We hypothesized that changes in landscape structure associated with habitat loss and fragmentation will reduce the habitat niche breadth of forest birds, either through a reduction in density-dependent spillover from optimal habitat or by impeding the colonization of patches.

Methods

We surveyed forest birds with point counts in eastern Ontario, Canada, and analyzed their response to loss and fragmentation of mature woodland. We selected 62 landscapes varying in both forest cover (15–45%) and its degree of fragmentation, and classified them into two categories (high versus low levels of loss and fragmentation). We determined the habitat niche breadth of 12 focal species as a function of 8 habitat structure variables for each landscape category.

Results

Habitat niche breadth was narrower in landscapes with high versus low levels of loss and fragmentation of forest cover. The relative occupancy of marginal habitat appeared to drive this relationship. Species sensitivity to mature forest cover had no apparent influence on relative niche breadth.

Conclusions

Regional abundance and, in turn, density-dependent spillover into suboptimal habitat appeared to be determinants of habitat niche breadth. For a given proportion of forest cover, fragmentation also appeared to alter habitat use, which could exacerbate its other negative effects unless functional connectivity is high enough to allow individuals to saturate optimal habitat.

Context

Landscape-scale population dynamics are driven in part by movement within and dispersal among habitat patches. Predicting these processes requires information about how movement behavior varies among land cover types.

Objectives

We investigated how butterfly movement in a heterogeneous landscape varies within and between habitat and matrix land cover types, and the implications of these differences for within-patch residence times and among-patch connectivity.

Methods

We empirically measured movement behavior in the Baltimore checkerspot butterfly (Euphydryas phaeton) in three land cover classes that broadly constitute habitat and two classes that constitute matrix. We also measured habitat preference at boundaries. We predicted patch residence times and interpatch dispersal using movement parameters estimated separately for each habitat and matrix land cover subclass (5 categories), or for combined habitat and combined matrix land cover classes (2 categories). We evaluated the effects of including edge behavior on all metrics.

Results

Overall, movement was slower within habitat land cover types, and faster in matrix cover types. Butterflies at forest edges were biased to remain in open areas, and connectivity and patch residence times were most affected by behavior at structural edges. Differences in movement between matrix subclasses had a greater effect on predictions about connectivity than differences between habitat subclasses. Differences in movement among habitat subclasses had a greater effect on residence times.

Conclusions

Our findings highlight the importance of careful classification of movement and land cover in heterogeneous landscapes, and reveal how subtle differences in behavioral responses to land cover can affect landscape-scale outcomes.

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.

Context

Farming practices influence the degree of contrast between adjoining habitats, with consequences for biodiversity and species movement. Little is known, however, on insect community responses to different kinds of edges over time, and the extent of cross-habitat movement in agricultural landscapes.

Objective

To determine temporal changes in beetle responses to different farmland-woodland edges, and document cross-habitat movement.

Methods

We examined species richness, abundance, and movement across edges between remnant woodlands and four farmland uses (plantings, fallow, annual crops, woody debris applied over crops post-harvest) in southeastern Australia. We used directional pitfall traps to infer movement, and sampled at edges, and 20 and 200 m on both sides of edges, during spring and summer.

Results

Detritivore and predator abundance varied between seasons across the edge between woodlands and all farmlands, but seasonal differences were weaker for fallow-woodland and woody debris-woodland edges. Detritivores moved from farmlands towards woodlands, but not across fallow-woodlands and woody debris-woodlands edges during summer. During summer, predators showed short-range movement towards edges from all farmlands except plantings, and towards woody debris from woodlands. Edges showed temporally stable predator richness and higher herbivore richness than adjoining habitats.

Conclusions

Farmland use and season interactively affect beetle abundance across farmland-woodland edges. Woody debris can reduce seasonal fluctuations in beetle edge responses and increase permeability for cross-habitat movement, while plantings provide habitat during summer. Edges provide important resources for beetles in adjoining habitats, however, seasonal movement of predators specifically into edges may affect prey assemblages—a link requiring further study.