What you see is where you go? Modeling dispersal in mountainous landscapes

Inter-patch connectivity can be strongly influenced by topography and matrix heterogeneity, particularly when dealing with species with high cognitive abilities. To estimate dispersal in such systems, simulation models need to incorporate a behavioral component of matrix effects to result in more realistic connectivity measures. Inter-patch dispersal is important for the persistence of capercaillie (Tetrao urogallus) in central Europe, where this endangered grouse species lives in patchy populations embedded in a mountainous landscape. We simulated capercaillie movements with an individual-based, spatially explicit dispersal model (IBM) and compared the resulting connectivity measure with distance and an expert estimation. We used a landscape comprising discrete habitat patches, temporary habitat, non-habitat forests, and non-habitat open land. First, we assumed that dispersing individuals have perfect knowledge of habitat cells within the perceptual range (null model). Then, we included constraints to perception and accessibility, i.e., mountain chains, open area and valleys (three sub-models). In a full model, all sub-models were included at once. Correlations between the different connectivity measures were high (Spearman’s ρ > 0.7) and connectivity based on the full IBM was closer to expert estimation than distance. For selected cases, simple distance differed strongly from the full IBM measure and the expert estimation. Connectivity based on the IBM was strongly sensitive to the size of perceptual range with higher sensitivity for the null model compared to the full model that included context dependent perceptual ranges. Our heuristic approach is adequate for simulating movements of species with high cognitive abilities in strongly structured landscapes that influence perception and permeability.     

Movements of cactus bugs: Patch transfers,matrix resistance,and edge permeability

Individual movement is a key process affecting the distribution of animals in heterogeneous landscapes. For specialist species in patchy habitat, a central issue is how dispersal distances are related to landscape structure. We compared dispersal distances for cactus bugs (Chelinidea vittiger) on two naturally fragmented landscapes (≤ 4% suitable habitat) with different matrix structures (i.e., vegetation height of nonsuitable habitat between suitable patches). Using mark-release-recapture studies, we determined that most transfers between cactus patches occurred during the mating season. Dispersal distances were reduced by > 50% on the landscape that had reduced structural connectivity due to relatively high matrix structure and low patch density. An experiment with detailed movement pathways demonstrated that greater matrix structure decreased mean step lengths, reduced directionality, and thus decreased net displacement by > 60%. However, habitat edges between two matrix elements that differed substantially in resistance to movement were completely permeable. Therefore, the difference in distributions of dispersal distances between the two landscapes mainly reflected the average resistance of matrix habitat and not the level of matrix heterogeneity per se. Our study highlights the merits of combining estimates of dispersal distances with insights on mechanisms from detailed movement pathways, and emphasizes the difficulty of treating dispersal distances of species as fixed traits independent of landscape structure.     

Independent effects of connectivity predict homing success by northern flying squirrel in a forest mosaic

Landscape composition and configuration, often termed as habitat loss and fragmentation, are predicted to reduce species population viability, partly due to the restriction of movement in the landscape. Unfortunately, measuring the effects of habitat loss and fragmentation on functional connectivity is challenging because these variables are confounded, and often the motivation for movement by target species is unknown. Our objective was to determine the independent effects of landscape connectivity from the perspective of a mature forest specialist—the northern flying squirrel (Glaucomys sabrinus). To standardize movement motivation, we translocated 119 squirrels, at varying distances (0.18–3.8 km) from their home range across landscapes representing gradients in both habitat loss and fragmentation. We measured the physical connectedness of mature forest using an index of connectivity (landscape coincidence probability). Patches were considered connected if they were within the mean gliding distance of a flying squirrel. Homing success increased in landscapes with a higher connectivity index. However, homing time was not strongly predicted by habitat amount, connectivity index, or mean nearest neighbour and was best explained as a simple function of sex and distance translocated. Our study shows support for the independent effects of landscape configuration on animal movement at a spatial scale that encompasses several home ranges. We conclude that connectivity of mature forest should be considered for the conservation of some mature forest specialists, even in forest mosaics where the distinction between habitat and movement corridors are less distinct.     

Functional connectivity of lynx at their southern range periphery in Ontario,Canada

Peripheral populations are often small and isolated compared to those in the range core, in part due to the patchy distribution of suitable habitats at range margins. It follows that peripheral populations typically occur at lower densities and are more susceptible to extinction, but their persistence may be facilitated through connectivity with core areas. Relationships between connectivity and the distribution of animal populations have not yet been fully evaluated, especially for large carnivores having extensive spatial needs and specialized habitat requirements. Using observations of snow tracks, we modeled occurrence of Canada lynx (Lynx canadensis) in relation to landscape characteristics along their southern range periphery in Ontario, Canada; we sought to assess functional connectivity of lynx habitat along the southern margins of the range. As observed in other studies, young coniferous forests had the highest probability of lynx occurrence, likely due to their association with snowshoe hares (Lepus americanus). We used the occurrence model to parameterize a resistance surface and then circuit theory to predict functional connectivity along the southern periphery of lynx distribution. Lynx typically travelled through landscapes with higher connectivity than random paths, implying that lynx habitat requirements in their southern range likely extend beyond habitat composition, and that conservation efforts should seek to preserve metapopulation dynamics through functional connectivity of suitable habitat across larger spatial scales.     

Comparing the landscape level perceptual abilities of forest sciurids in fragmented agricultural landscapes*

Perceptual range is the maximum distance from which an animal can perceive the presence of remote landscape elements such as patches of habitat. Such perceptual abilities are of interest because they influence the probability that an animal will successfully disperse to a new patch in a landscape. Furthermore, understanding how perceptual range differs between species may help to explain differential species sensitivity to patch isolation. The objective of this research was to assess the perceptual range of eastern chipmunks (Tamias striatus), gray squirrels (Sciurus carolinensis), and fox squirrels (Sciurus niger) in fragmented agricultural landscapes. Animals were captured in remote woodlots and translocated to unfamiliar agricultural fields. There they were released at different distances from a woodlot and their movements towards or away from the woodlot were used to assess their ability to perceive forested habitat. Observed perceptual ranges of approximately 120 m for chipmunks, 300 m for gray squirrels, and 400 m for fox squirrels, suggest that differences in landscape-level perceptual abilities may influence the occurrence of these species in isolated habitat patches.     

Short perceptual range and yet successful invasion of a fragmented landscape: the case of the red-bellied tree squirrel (<Emphasis Type="Italic">Callosciurus erythraeus</Emphasis>) in Argentina

Dispersal is a key element of the invasion process for introduced species, and is influenced by landscape connectivity. The red-bellied squirrel (Callosciurus erythraeus) was introduced to Argentina in 1970. Suitable forest habitat for this arboreal species is highly fragmented in a rural–urban matrix, but despite this, the squirrel population has spread. Squirrels disperse into new habitat patches using connective features such as forest corridors. They may also cross gaps but up to what extent is not known. Gap crossing success is influenced by perceptual range, which is the distance from which animals can perceive suitable habitat. Perceptual range has been previously estimated for vulnerable species, but not for introduced species. We used a model relating perceptual range to body mass to predict the perceptual range of the red-bellied tree squirrel in Argentina. We then tested our prediction of 202–221 m by releasing squirrels in an unfamiliar arable field at different distances (300, 200, 100 and 20 m) from woodland habitat. We assumed that if woodland could be perceived, squirrels would orientate toward it. We estimated perceptual range to be between 20 and 100 m, considerably lower than predicted. Our results indicate that squirrels can potentially cross small habitat gaps, but dispersal over greater distances lacking connectivity is less likely. Incorporating this information when modelling the spread of exotic squirrels in the Pampas Region can yield more accurate prediction of the invasion process and guide management practices to minimise their expansion.     

Quantifying landscape connectivity through the use of connectivity response curves

Habitat connectivity is an essential component of biodiversity conservation. Simulated landscapes were manipulated to quantify the impact of changes to the amount, fragmentation and dispersion of habitat on a widely applied landscape connectivity metric, the probability of connectivity index. Index results for different landscape scenarios were plotted against the dispersal distances used for their calculation to create connectivity response curves for each scenario. Understanding index response to controlled changes in landscape structure at a range of spatial scales can be used to give context to comparison of alternative landscape management scenarios. Increased amounts of habitat, decreased fragmentation and decreased inter-patch distances resulted in increased connectivity index values. Connectivity response curves demonstrated increases in assessed connectivity for scenarios with continuous corridors or “stepping stone” connectors. The sensitivity of connectivity response curves to controlled changes in landscape structure indicate that this approach is able to detect and distinguish between different types of landscape changes, but that delineation of habitat and method of quantifying dispersal probability incorporate assumptions that must be recognized when interpreting results to guide landscape management. Representing landscape connectivity in this manner allows for the impacts of alternative landscape management strategies to be compared visually through comparative plots, or statistically through the parameters that describe connectivity response curves.     

Fine-scale effects of habitat loss and fragmentation despite large-scale gene flow for some regionally declining woodland bird species

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.     

Integrative approach for landscape-based graph connectivity analysis: a case study with the common frog (Rana temporaria) in human-dominated landscapes

Graph-based analysis is a promising approach for analyzing the functional and structural connectivity of landscapes. In human-shaped landscapes, species have become vulnerable to land degradation and connectivity loss between habitat patches. Movement across the landscape is a key process for species survival that needs to be further investigated for heterogeneous human-dominated landscapes. The common frog (Rana temporaria) was used as a case study to explore and provide a graph connectivity analysis framework that integrates habitat suitability and dispersal responses to landscape permeability. The main habitat patches influencing habitat availability and connectivity were highlighted by using the software Conefor Sensinode 2.2. One of the main advantages of the presented graph-theoretical approach is its ability to provide a large choice of variables to be used based on the study’s assumptions and knowledge about target species. Based on dispersal simulation modelling in potential suitable habitat corridors, three distinct patterns of nodes connections of differing importance were revealed. These patterns are locally influenced by anthropogenic barriers, landscape permeability, and habitat suitability. And they are affected by different suitability and availability gradients to maximize the best possible settlement by the common frog within a terrestrial habitat continuum. The study determined the key role of landscape-based approaches for identifying the “availability-suitability-connectivity” patterns from a local to regional approach to provide an operational tool for landscape planning.     

Movement behavior in response to landscape structure: the role of functional grain

Landscape structure can influence the fine-scale movement behavior of dispersing animals, which ultimately may influence ecological patterns and processes at broader scales. Functional grain refers to the finest scale at which an organism responds to spatial heterogeneity among patches and extends to the limits of its perceptual range. To determine the functional grain of a model insect, red flour beetle (Tribolium castaneum), we examined its movement behavior in response to experimental flour landscapes. Landscape structure was varied by manipulating habitat abundance (0%, 10%, 30%, and 100%) and grain size of patches (fine-2 × 2 cm, intermediate-5 × 5 cm, and coarse-10 × 10 cm) in 50 × 50 cm landscapes. Pathway metrics indicated that beetles used a similar proportion of all landscape types. Several pathway metrics indicated a graded response from the fine to the coarse grain landscape. Lacunarity analysis of beetle pathways indicated a non-linear change in space use between the fine and intermediate landscapes and the coarse-grained landscape. Beetles moved more slowly and tortuously (with many turns), and remained longer in both the overall landscape and individual patches, in fine-grained compared to coarse-grained landscapes. Our research demonstrates how detailed examination of movement pathways and measures of lacunarity can be useful in determining functional grain. Spatially explicit, organism-centered studies focusing on behavioral responses to different habitat configurations can serve as an important first step to identify behavioral rules of movement that may ultimately lead to more accurate predictions of space use in landscapes.     

Regional assessment on influence of landscape configuration and connectivity on range size of white-tailed deer

Variation in the size of home range of white-tailed deer (Odocoileus virginianus) has broad implications for managing populations, agricultural damage, and disease spread and transmission. Size of home range of deer also varies seasonally because plant phenology dictates the vegetation types that are used as foraging or resting sites. Knowledge of the landscape configuration and connectivity that contributes to variation in size of home range of deer for the region is needed to fully understand differences and similarities of deer ecology throughout the Midwest. We developed a research team from four Midwestern states to investigate how size of home range of deer in agro-forested landscapes is influenced by variations in landscape characteristics that provide essential habitat components. We found that for resident female deer, annual size of home range in Illinois (mean = 0.99 km²), Michigan (mean = 1.34 km²), Nebraska (mean = 1.20 km²), and Wisconsin (mean = 1.47 km²) did not differ across the region (F _3,175 = 0.42, P = 0.737), but differences between agricultural growing and nongrowing periods were apparent. Variables influencing size of home range included: distance to forests, roads, and urban development from the centroid of deer home range, and percent of crop as well as four landscape pattern indices (contrast-weighted edge density, mean nearest neighbor, area-weighted mean shape index, and patch size coefficient of variation). We also identified differences in model selection for four landscapes created hierarchically to reflect levels of landscape connectivity determined from perceived ability of deer to traverse the landscape. Connectivity of selected forested regions within agro-forested ecosystems across the Midwest plays a greater role in understanding the size of home ranges than traditional definitions of deer habitat conditions and landscape configuration.     

Functional habitat connectivity for beach mice depends on perceived predation risk

Landscape features that promote animal movement contribute to functional habitat connectivity. Factors that affect the use of landscape features, such as predation risk, may alter functional connectivity. We identify factors important to functional habitat connectivity by quantifying movement patterns of the Santa Rosa beach mouse (Peromyscus polionotus leucocephalus) in relation to landscape features and by examining how ambient perceived predation risk, which is altered by moon phase, interacts with landscape features. We use track paths across the sand to relate the probability that beach mice cross gaps between vegetation patches to gap width, patch quality, landscape context and moon phase. Overall activity levels were lower during full versus new moon nights, demonstrating that beach mice respond negatively to moonlight. Gap crossing was more likely during new moon nights (25 % of gaps crossed vs. 7 % during full moon nights), and across narrower gaps (<8.38 m) that led to larger vegetation patches (>11.75 m²). This study suggests that vegetation recovery is necessary for functional connectivity in post-hurricane landscapes commonly inhabited by beach mice and provides initial guidelines for restoring landscape connectivity. More broadly, this study highlights the importance of considering predation risk when quantifying landscape connectivity, as landscape features that facilitate connectivity when predation risk is low may be ineffective if predation risk increases over time or across space.     

Functional rather than structural connectivity explains grassland plant diversity patterns following landscape scale habitat loss

Context

Functional 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.

Objectives

We 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.

Methods

We 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.

Results

Increased 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.

Conclusions

Protecting 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.

     

Context matters: the landscape matrix determines the population genetic structure of temperate forest herbs across Europe

Landscape Ecology - Plant populations in agricultural landscapes are mostly fragmented and their functional connectivity often depends on seed and pollen dispersal by animals. However, little is...     

Evaluating functional connectivity with matrix behavior uncertainty for an endangered butterfly

Understanding animal responses to landscape elements helps forecast population reactions to changing landscape conditions. The challenge is that some behaviors are poorly known and difficult to estimate. We assessed how uncertainty in behavioral responses to dense woods, an avoided landscape structure, impacts functional connectivity among reproductive habitat patches for Fender’s blue butterfly, an endangered prairie species of western Oregon, USA. We designed a factorial simulation experiment using a spatially explicit individual-based model to project functional connectivity for female butterflies across current and alternative landscapes. We varied the probability of dense woods entry and turning angle standard deviation for movements within the dense woods over a range of biologically reasonable and observed values. Butterflies in the current landscape (46 % dense woods) and one with prairie encroached by forest (60 % dense woods) showed reductions in functional connectivity estimates consistent with the expectations of habitat fragmentation. Although dense woods entrance uncertainty impacted functional connectivity projections, uncertainty in the dense woods turning angle standard deviation had comparatively little impact on connectivity estimates. Reduction and reconfiguration of the current dense woods to 27 % cover (restored landscape) appeared to facilitate a corridor behavior in dispersing individuals, likely providing a functional connectivity estimate comparable to the historic landscape (<5 % dense woods). Our simulations suggest that additional study of butterfly movement within the dense woods is unnecessary and that a partial reduction in dense woods would be sufficient to achieve historic levels of functional connectivity for Fender’s blue across the study landscape.     

Integrating airborne lidar and satellite imagery to model habitat connectivity dynamics for spatial conservation prioritization

Context

The application of regional-level airborne lidar (light detection and ranging) data to characterize habitat patches and model habitat connectivity over large landscapes has not been well explored. Maintaining a connected network of habitat in the presence of anthropogenic disturbances is essential for regional-level conservation planning and the maintenance of biodiversity values.

Objectives

We quantified variation in connectivity following simulated changes in land cover and contrasted outcomes when different conservation priorities were emphasized.

Methods

First, we defined habitat patches using vegetation structural attributes identified via lidar. Second, habitat networks were constructed for different forest types and assessed using network connectivity metrics. And finally, land cover change scenarios were simulated using a series of habitat patch removals, representing the impact of implementing different spatial prioritization schemes.

Results

Networks for different forest structure types produced very different patch distributions. Conservation scenarios based on different schemes led to contrasting changes during land cover change simulations: the scheme prioritizing only habitat area resulted in immediate near-term losses in connectivity, whereas the scheme considering both habitat area and their spatial configurations maintained the overall connectivity most effectively. Adding climate constraints did not diminish or improve overall connectivity.

Conclusions

Both habitat area and habitat configuration should be considered in dynamic modeling of habitat connectivity under changing landscapes. This research provides a framework for integrating forest structure and cover attributes obtained from remote sensing data into network connectivity modeling, and may serve as a prototype for multi-criteria forest management and conservation planning.

     

Influence of land-use/land-cover change on landscape connectivity for an endemic threatened amphibian (Argenteohyla siemersi pederseni,Anura: Hylidae)

Context

Modifications in natural landcover generally result in a loss of habitat availability for wildlife and it’s persistence will depend largely on their spatial configuration and functional connections. Argenteohyla siemersi is a threatened and endemic amphibian whose habitat is composed of forest patches near rivers and water bodies edges.

Objectives

This study aimed to analyse the accessible habitat for this species and identify key elements to maintain its ecological network in two different types of land uses: an anthropized area with extensive cattle raising and a protected area.

Methods

The structural and functional characteristics of both landscapes were analyzed. The connectivity at landscape level and the contribution of each habitat patch were evaluated through simulation models with different dispersion distances in the context of the graph theory.

Results

In both landscapes, nine types of landcover were identified with different compositions. Remarkable differences were found in habitat connectivity for this amphibian species between both landscapes. As the percentage of dispersion distance increases, reachable habitat increases as well, although with higher percentages in the protected area. Two corridors were identified in the protected landscape and one in the rangeland one; patches and key links constituted all of them.

Conclusions

The present work provides spatially explicit results with a quantitative basis. It could be useful as a tool for the development of management plans aimed at guaranteeing the functionality of the ecological network for this endangered species and, therefore, contribute to its long-term conservation.

     

Effects of landscape composition and connectivity on the distribution of an endangered parrot in agricultural landscapes

The extent and connectivity of individual habitat types strongly affects the distribution and abundance of organisms. However, little is known of how the level of connectivity and the interactions between different habitat types influences the distribution of species. Here, we used the geographically restricted and endangered regent parrot Polytelis anthopeplus monarchoides as a case study to examine the importance of composition and connectivity between different elements in 39 complex landscape mosaics (each 10 km radius). We compiled a database of 674 regent parrot nesting records, regional vegetation maps and measures of multipath connectivity between core vegetation types under different scenarios of resistance to movement provided by landscape elements. The occurrence of regent parrot nests was strongly affected by landscape composition, being positively related to the extent Eucalyptus camaldulensis riverine forest, but negatively related to the extent of semi-arid woodlands dominated by Eucalyptus largiflorens. Connectivity between E. camaldulensis forest (principal nesting habitat) and mallee (preferred feeding habitat) was a strong predictor of nest locations. Our study shows that the suitability of fragmented agricultural landscapes for supporting species can be greatly affected by connectivity and interactions between preferred and non-preferred habitats. For species that require complementary habitats such as the regent parrot, conservation management activities may be ineffective if they simply focus on a single core habitat type or the impacts of human land uses without regard to the interrelationships among landscape elements. While increasing the amount of primary preferred habitat should remain a cornerstone goal, increasing the extent and improving connectivity with alternative landscape elements also should be priority management objectives.     

Connecting mountains and desert valleys for black bears in northern Mexico

Context

Black bear connectivity studies are scarce in the southern distribution where the species is endangered. The identification of corridors is a strategy to promote conservation in human-modified landscapes.

Objectives

Assess and validate long-distance corridors in the southern black bear distribution using resistance models, occurrence records, and radio-telemetry of an individual that dispersed between the Sierras Madres of Mexico.

Methods

We acquired black bear occurrence records from several sources and telemetry records from one dispersal individual in northern Mexico. We generated ensemble habitat suitability models and resistance landscape surfaces to generate cumulative resistant kernel and least-cost paths to identify connectivity core areas and corridors of importance through Natural Protected Areas. Finally, we assessed long-distance corridors.

Results

We developed three habitat suitability models for black bears southern range; one matches the current distribution of the species. When including radio-tracking records, the landscape resistance is reduced to arid sites with low habitat suitability. We used least resistance connectivity surfaces to merge subpopulations within each Sierra Madre. The long-distance corridor models indicate narrow routes that require individuals with plastic behavioral dispersal capacity. Almost 20% of the connectivity core areas are within Natural Protected Areas. These are the first large-scale corridors using resistance layers in the southern black bear distribution.

Conclusions

Corridors can be functional for a range of temperate and dry habitat species. Landscape connectivity models should include the monitoring of dispersal individuals to identify the plasticity of organisms and the tangible barriers for them.

     

Effect of fragmentation, habitat loss and within-patch habitat characteristics on ant assemblages in semi-arid woodlands of eastern Australia

The reliability of ants as bioindicators of ecosystem condition is dependent on the consistency of their response to localised habitat characteristics, which may be modified by larger-scale effects of habitat fragmentation and loss. We assessed the relative contribution of habitat fragmentation, habitat loss and within-patch habitat characteristics in determining ant assemblages in semi-arid woodland in Queensland, Australia. Species and functional group abundance were recorded using pitfall traps across 20 woodland patches in landscapes that exhibited a range of fragmentation states. Of fragmentation measures, changes in patch area and patch edge contrast exerted the greatest influence on species assemblages, after accounting for differences in habitat loss. However, 35% of fragmentation effects on species were confounded by the effects of habitat characteristics and habitat loss. Within-patch habitat characteristics explained more than twice the amount of species variation attributable to fragmentation and four times the variation explained by habitat loss. The study indicates that within-patch habitat characteristics are the predominant drivers of ant composition. We suggest that caution should be exercised in interpreting the independent effects of habitat fragmentation and loss on ant assemblages without jointly considering localised habitat attributes and associated joint effects. The State of Queensland's right to retain a non-exclusive, royalty free license in and to any copyright is acknowledged.