Connectivity in Heterogeneous Landscapes: Analyzing the Effect of Topography

Animal response to landscape heterogeneity directs dispersal and affects connectivity between populations. Topographical heterogeneity is a major source of landscape heterogeneity, which is rarely studied in the contexts of movement, dispersal, or connectivity. The current study aims at characterizing and quantifying the impacts of topography on landscape connectivity. We focus on ‘hilltopping’ behavior in butterflies, a dispersal-like behavior where males and virgin females ascend to mountain summits and mate there. Our approach integrates three elements: an individual-based model for simulating animal movements across topographically heterogeneous landscapes; a formula for the accessibility of patches in homogenous landscapes; and a graphical analysis of the plots of the simulation-based vs. the formula-based accessibility values. We characterize the functional relationship between accessibility values and landscape structure (referred to as ‘accessibility patterns’) and analyze the influence of two factors: the intensity of the individuals’ response to topography, and the level of topographical noise. We show that, despite the diversity of topographical landscapes, animal response to topography results in the formation of two, quantifiable accessibility patterns. We term them ‘effectively homogeneous’ and ‘effectively channeled’. The latter, in which individuals move toward a single summit, prevails over a wide range of behavioral and spatial parameters. Therefore, ‘channeled’ accessibilities may occur in a variety of landscapes and contexts. Our work provides novel tools for understanding and predicting accessibility patterns in heterogeneous landscapes. These tools are essential for linking movement behavior, movement patterns and connectivity. We also present new insights into the practical value of ecologically scaled landscape indices.     

A Network Approach for Analyzing Spatially Structured Populations in Fragmented Landscape

We extend the recently proposed graph-theoretical landscape perspective by applying some network-centric methods mainly developed in the social sciences. The methods we propose are suitable to (1) identify individual habitat patches that are disproportionally high in importance in preserving the ability of organisms to traverse the fragmented landscape, and (2) find internally well-connected compartments of habitat patches that contribute to a spatial compartmentalization of species populations. We demonstrate the utility of these methods using an agricultural landscape with scattered dry-forest patches in southern Madagascar, inhabited by the ring-tailed lemur, Lemur catta. We suggest that these methods are particularly suitable in landscapes where species’ traversability is not fully inhibited by fragmentation, but merely limited. These methods are potentially highly relevant in studying spatial aspects of resilience and in the design of natural reserves.     

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.     

Landscape – What’s in it? Trends in European Landscape Science and Priority Themes for Concerted Research

Reflecting on the other papers in this special issue, this synopsis characterises some essential trends in European Landscape Ecology, including the challenges it is facing in society. It describes the various perspectives on the ‘contents’ of landscape that are currently being practiced, and especially considers the notion of ‘environment’ as something intrinsic to human activity. Landscape classification and typology are discussed in their potential but limited use for landscape science. The specificity of the European approach appears to be related to the large diversity of cultural landscapes, currently losing their functional ties with the land-use systems that had formed them. European landscape research reports show a large commitment to this decreasing diversity, a dedication characterised by a strong sense of ‘loss and grief’. On the other hand, it is concluded that European landscape research has a specific niche with a clear focus on applied landscape studies explicitly including people’s perceptions and images, as well as the participation of the public and stakeholders. Since globalisation tends to reinforce the detachment of people from their environment; an increased effort is needed to compensate for this effect, and therefore the consideration of the various dimensions of the landscape is today more pertinent than ever. Meeting the challenges of present landscapes, in the face of new multifunctional demands in old diverse landscapes, requires more than before the combination of various perspectives and methods, and of various scales of application, in order to design innovative and adaptive paths for the future.     

Global biodiversity scenarios and landscape ecology

The composition of ecological communities is both cause and consequence of landscape pattern. Predicting biodiversity change involves understanding not only ecology and evolution, but also complex changes in human societies and economies. Scenarios offer a less rigid approach to thinking about biodiversity change in a policy and management context. They shift the focus of research and management from making singular predictions and developing single ‘best’ strategies to exploring uncertainties and assessing the outcomes of alternative policies. The four Millennium Ecosystem Assessment (MA) biodiversity scenarios illustrate current approaches to biodiversity estimation in global scenarios. The MA biodiversity scenarios are built around the species–area relationship and the magnitudes of a few area-dependent processes such as nitrogen deposition and climate change. Some of the most obvious landscape-related omissions from the MA scenarios are pattern-process feedbacks, scale dependencies, and the role of landscape configuration. While the MA has set a new standard for biodiversity scenarios, future exercises would benefit from a more multi-scale and more mechanistic framework. I use examples from research on the landscape ecology and biogeography of African ticks to illustrate how a hypothesis-based approach can be used to analyse the multi-scale, multi-level drivers of change in patterns of species occurrences. Two of the most important challenges for the future development of both landscape ecology and biodiversity scenarios are to become more mechanistic (less pattern-based) and more general (applicable across different landscapes).     

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.     

Genetic isolation by distance and landscape connectivity in the American marten (Martes americana)

Empirical studies of landscape connectivity are limited by the difficulty of directly measuring animal movement. ‘Indirect’ approaches involving genetic analyses provide a complementary tool to ‘direct’ methods such as capture–recapture or radio-tracking. Here the effect of landscape on dispersal was investigated in a forest-dwelling species, the American marten (Martes americana) using the genetic model of isolation by distance (IBD). This model assumes isotropic dispersal in a homogeneous environment and is characterized by increasing genetic differentiation among individuals separated by increasing geographic distances. The effect of landscape features on this genetic pattern was used to test for a departure from spatially homogeneous dispersal. This study was conducted on two populations in homogeneous vs. heterogeneous habitat in a harvested boreal forest in Ontario (Canada). A pattern of IBD was evidenced in the homogeneous landscape whereas no such pattern was found in the near-by harvested forest. To test whether landscape structure may be accountable for this difference, we used effective distances that take into account the effect of landscape features on marten movement instead of Euclidean distances in the model of isolation by distance. Effective distances computed using least-cost modeling were better correlated to genetic distances in both landscapes, thereby showing that the interaction between landscape features and dispersal in Martes americana may be detected through individual-based analyses of spatial genetic structure. However, the simplifying assumptions of genetic models and the low proportions in genetic differentiation explained by these models may limit their utility in quantifying the effect of landscape structure.     

Influence of habitat amount,arrangement, and use on population trend estimates of male Kirtland’s warblers

Kirtland’s warblers (Dendroica kirtlandii) persist in a naturally patchy environment of young, regenerating jack pine forests (i.e., 5–23 years old) created after wildfires and human logging activities. We examined how changing landscape structure from 26 years of forest management and wildfire disturbances influenced population size and spatial dispersion of male Kirtland’s warblers within their restricted breeding range in northern Lower Michigan, USA. The male Kirtland’s warbler population was six times larger in 2004 (1,322) compared to 1979 (205); the change was nonlinear with 1987 and 1994 identified as significant points of change. In 1987, the population trend began increasing after a slowly declining trend prior to 1987, and the rate of increase appeared to slow after 1994. Total amount of suitable habitat and the relative area of wildfire-regenerated habitat were the most important factors explaining population trend. Suitable habitat increased 149% primarily due to increasing plantations from forest management. The relative amount and location of wildfire-regenerated habitat modified the distribution of males among various habitat types, and the spatial variation in their abundance across the primary breeding range. These findings indicate that the Kirtland’s warbler male population shifted its use of habitat types temporally and spatially as the population increased and as the relative availability of habitats changed through time. We demonstrate that researchers and managers need to consider not only habitat quality, but the temporal and the spatial context of habitat availability and population levels when making habitat restoration decisions.     

The Viability of Metapopulations: Individual Dispersal Behaviour Matters

Metapopulation models are frequently used for analysing species–landscape interactions and their effect on structure and dynamic of populations in fragmented landscapes. They especially support a better understanding of the viability of metapopulations. In such models, the processes determining metapopulation viability are often modelled in a simple way. Animals’ dispersal between habitat fragments is mostly taken into account by using a simple dispersal function that assumes the underlying process of dispersal to be random movement. Species-specific dispersal behaviour such as a systematic search for habitat patches is likely to influence the viability of a metapopulation. Using a model for metapopulation viability analysis, we investigate whether such specific dispersal behaviour affects the predictions of ranking orders among alternative landscape configurations rated regarding their ability to carry viable metapopulations. To incorporate dispersal behaviour in the model, we use a submodel for the colonisation rates which allows different movement patterns to be considered (uncorrelated random walk, correlated random walk with various degrees of correlation, and loops). For each movement pattern, the landscape order is determined by comparing the resulting mean metapopulation lifetime T_m of different landscape configurations. Results show that landscape orders can change considerably between different movement patterns. We analyse whether and under what circumstances dispersal behaviour influences the ranking orders of landscapes. We find that the ‘competition between patches for migrants’ – i.e. the fact that dispersers immigrating into one patch are not longer available as colonisers for other patches – is an important factor driving the change in landscape ranks. The implications of our results for metapopulation modelling, planning and conservation are discussed.     

Intermediate landscape disturbance maximizes metapopulation density

The viability of metapopulations in fragmented landscapes has become a central theme in conservation biology. Landscape fragmentation is increasingly recognized as a dynamical process: in many situations, the quality of local habitats must be expected to undergo continual changes. Here we assess the implications of such recurrent local disturbances for the equilibrium density of metapopulations. Using a spatially explicit lattice model in which the considered metapopulation as well as the underlying landscape pattern change dynamically, we show that equilibrium metapopulation density is maximized at intermediate frequencies of local landscape disturbance. On both sides around this maximum, the metapopulation may go extinct. We show how the position and shape of the intermediate viability maximum is responding to changes in the landscape’s overall habitat quality and the population’s propensity for local extinction. We interpret our findings in terms of a dual effect of intensified landscape disturbances, which on the one hand exterminate local populations and on the other hand enhance a metapopulation’s capacity for spreading between habitat clusters.     

Mapping hotspots of multiple landscape functions: a case study on farmland afforestation in Scotland

Many conservation and restoration efforts in developed countries are increasingly based on the premise of recognising and stimulating more ‘multi-functionality’ in agricultural landscapes. Public policy making is often a pragmatic process that involves efforts to negotiate trade-offs between the potentially conflicting demands of various stakeholders. Conservationists’ efforts to influence policy making, can therefore benefit from any tool that will help them to identify other socio-economic functions or values that coincide with good ecological conservation options. Various types of socio-economic objectives have in recent years been mapped across landscapes and so there are now important opportunities to explore the spatial heterogeneity of these diverse functions across the wider landscape in search of potential spatial synergies, i.e. ‘multiple win locations’ or multifunctional ‘hotspots’. This paper explores the potential occurrence of such synergies within the agricultural landscape of northeast Scotland and evaluates an existing woodland planting policy using and combining three different policy objectives. Our results show that there are indeed broad areas of the studied landscape where multiple objectives (biodiversity, visual amenity and on-site recreation potential) could be achieved simultaneously (hotspots), and that the case study which we evaluate (the Farm Woodland Premium Scheme) could be much better spatially targeted with regards to each individual objective as well as with regards to these hotspots of multifunctionality.

Habitat heterogeneity and life-history traits influence presettlement distributions of early-successional tree species in a late-successional, hemlock-hardwood landscape

In landscapes dominated by late-successional plant communities, early-successional species may lead a tenuous existence, persisting only as fugitives or relying on refuges in marginal habitats to provide a persistent seed source. The objective of this study was to relate fine-scale distributions of early-successional tree species in hemlock-hardwood forests of northern Wisconsin, USA to potential landscape persistence strategies. A special emphasis was placed on eastern white pine (Pinus strobus), a restoration priority in the region. Witness tree data from nineteenth century US Public Land Survey records (encompassing 40,610?km² and 106,790 trees) were used with modern environmental data to relate species distributions to habitat characteristics. Early-successional tree species had strong positive associations with marginal habitats such as inclusions of sandy soil and margins of lakes, wetlands, and rivers. Marginal habitats occupied ~44 % of the landscape, which may help account for the abundance of early-successional species in our study area relative to other hemlock-hardwood forests. Populations of early-successional species in marginal habitats could also have provided important seed sources for the upland mesic landscape matrix, as >70 % of the landscape was within 200?m of these habitats. The degree to which early-successional species were limited to marginal habitats largely followed predictions based on species life-history characteristics, except that white pine was more common than expected in upland mesic habitats. These findings illustrate the potential importance of landscape heterogeneity for persistence of early-successional species in late-successional forest landscapes and provide baseline information on habitat associations and landscape dynamics that will be useful in restoration efforts.     

Textural Ordination Based on Fourier Spectral Decomposition: A Method to Analyze and Compare Landscape Patterns

We propose an approach to texture characterization and comparison that directly uses the information of digital images of the earth surface without requesting a prior distinction of structural ‘patches’. Digital images are partitioned into square ‘windows’ that define the scale of the analysis and which are submitted to the two-dimensional Fourier transform for extraction of a simplified textural characterization (in terms of coarseness) via the computation of a ‘radial’ power spectrum. Spectra computed from many images of the same size are systematically compared by means of a principal component analysis (PCA), which provides an ordination along a limited number of coarseness vs. fineness gradients. As an illustration, we applied this approach to digitized panchromatic air photos depicting various types of land cover in a semiarid landscape of northern Cameroon. We performed ‘textural ordinations’ at several scales by using square windows with sides ranging from 120 m to 1 km. At all scales, we found two coarseness gradients (PCA axes) based on the relative importance in the spectrum of large (> 50 km⁻¹), intermediate (30–50 km⁻¹), small (10–25 km⁻¹) and very small (<10 km⁻¹) spatial frequencies. Textural ordination based on Fourier spectra provides a powerful and consistent framework to identifying prominent scales of landscape patterns and to compare scaling properties across landscapes.     

Landscape,community, countryside: linking biophysical and social scales in US Corn Belt agricultural landscapes

Understanding the interplay between ecological and social factors across multiple scales is integral to landscape change initiatives in productive agricultural regions such as the rural US Corn Belt. We investigated the cultural context surrounding the use of perennial cover types—such as stream buffers, wetlands, cellulosic bioenergy stocks, and diverse cropping rotations—to restore water quality, biodiversity, and ecosystem function within a Corn Belt agricultural mosaic in Iowa, USA. Through ethnographic techniques and 33 in-depth interviews, we examined what was most important to rural stakeholders about their countryside. We then used photo elicitation to probe how interviewees’ assessments of farm practices involving perennial cover types were related to their sense of place. Our interviewees perceived their rural “countryside” as a linked social and biophysical entity, identifying strongly with the farming lifestyle and with networks of people across the landscape. While most interviewees approved of perennial farm practices on marginal agricultural land, implementation of these practices was neither a priority nor strongly assimilated into rural experience and ethics. We identified three scale boundaries in our interviewees’ perception of place which present key challenges and opportunities for landscape change: landscape-community, individual-community, and community-institution. In all cases, community social norms and networks—exhibited at landscape spatial scales—may be instrumental in bridging these boundaries and enabling networks of perennial cover types that span privately owned and operated farms. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Modeling patch occupancy: Relative performance of ecologically scaled landscape indices

In fragmented landscapes, the likelihood that a species occupies a particular habitat patch is thought to be a function of both patch area and patch isolation. Ecologically scaled landscape indices (ESLIs) combine a species’ ecological profile, i.e., area requirements and dispersal ability, with indices of patch area and connectivity. Since their introduction, ESLIs for area have been modified to incorporate patch quality. ESLIs for connectivity have been modified to incorporate niche breadth, which may influence a species’ ease in crossing the non-habitat matrix between patches. We evaluated the ability of 4 ESLIs, the original and modified indices of area and connectivity, to explain patterns in patch occupancy of 5 forest rodents. Occupancy of eastern gray squirrels (Sciurus carolinensis), North American red squirrels (Tamiasciurus hudsconicus), fox squirrels (Sciurus niger), white-footed mice (Peromyscus leucopus), and eastern chipmunks (Tamias striatus) was modeled at 471 sites in 35 landscapes sampled from the upper Wabash River basin in Indiana. Models containing ESLIs received support for gray squirrels, red squirrels, and chipmunks. Modified ESLIs were important in models for red squirrels. However, none of the models demonstrated high predictive ability. Incorporating habitat quality and using surrogate measures of dispersal can have important effects on model results. Additionally, different responses of species to area, isolation, and habitat quality suggest that generalizing patterns of metapopulation dynamics was not justified, even across closely related species.     

Human settlement ecology and chimpanzee habitat selection in Mali

Customary land-use practices create distinctive cultural landscapes, including landscapes where abandoned settlements host vegetation that attracts wild animals. Understanding how landscape patterns relate to land-use history can help clarify the ecological effects of particular land uses. This study examines relationships between chimpanzee habitat selection and Maninka settlement practice, to determine how settlement history has affected chimpanzee habitat in Mali’s Bafing Biosphere Reserve, where conservation practitioners assume that the characteristic settlement pattern reflects a process of settlement expansion into undisturbed habitat. Three types of data are reported: (1) ethnographic interviews on settlement history and practice; (2) systematic sampling of chimpanzee habitat use; and (3) ground-based mapping of settlement sites, surface water, and fruit-tree patches. These data show that the Maninka have a shifting settlement system, meaning that most sites are occupied for only relatively brief periods; and that some abandoned settlement sites host fruit-tree patches that are seasonally important chimpanzee habitat. Two main conclusions are: (1) settlement expansion has not occurred; instead, historic settlement has created habitat that is both attractive and available to chimpanzees. Anthropogenic habitat does not appear to be vital for chimpanzee survival, but it spatially and temporally supplements natural habitats. (2) Conservation policies meant to reduce the presumed threat of settlement expansion may have initiated an unintended, long-term threat of habitat loss for chimpanzees. While settlement practices may be a component of short-term threats to chimpanzees, such as hunting, when addressing these threats conservation practitioners should consider long-term settlement processes to avoid creating new threats.     

A collaborative design to adaptively manage for landscape sustainability in north Australia: lessons from a decade of cooperative research

Approaches to manage for the sustainable use of natural and cultural resources in a landscape can have many different designs. One design is adaptive collaborative landscape management (ACLM) where research providers and users work closely together on projects to develop resources while adaptively managing to sustain or maintain landscapes in the long term. We propose that collaborative projects are more useful for achieving outcomes than integrative projects where participants merely join their separate contributions. To foster collaborative research projects to adaptively manage landscapes in northern Australia, a Tropical Savannas Cooperative Research Centre (TSCRC) was established in 1995. The TSCRC is a joint venture of major organizations involved in research and land management. This paper is our perspective on the four most important ‘lessons learned’ after using a ACLM-type approach for over 10 y. We learnt that collaboration (working in combination) not necessarily integration (combining parts into a whole) achieved sustainable outcomes. We found that integration across culturally diverse perspectives seldom achieved sustainable solutions because it devalued the position of the less empowered participants. In addition, positive outcomes were achieved when participants developed trust and respect for each other by embracing and respecting their differences and by sharing unifying concepts such as savanna health. Another lesson learned was that a collaborative organization must act as an honest broker by resisting advocacy of one view point over another. Finally, we recognized the importance of strongly investing in communication and networking so that people could adaptively learn from one another’s experiences, understand each other’s challenges and respect each other’s choices. Our experience confirms the usefulness of the ACLM approach and highlights its role in the process of sustaining healthy landscapes.     

Effect of matrix habitat on the spread of flea beetle introductions for biological control of leafy spurge

Matrix habitats are known to influence the movement patterns of a variety of species but it is less well known whether these effects have strong implications for spatial population dynamics, including the spread of biological introductions. Using a spatially explicit simulation model parameterized with empirical data, we examine how grass and shrub matrix habitats, each offering different resistance to dispersal, influence the spread and impact of a biocontrol agent, Aphthona lacertosa, on the invasive weed, leafy spurge. Model predictions indicate that differential responses to matrix habitat have little effect on the agent’s spread over the study landscape and this is supported by statistical models fit to observed A. lacertosa incidence on the same landscape. Subsequent experimentation with the simulation model suggested that A. lacertosa colonization rates were largely unaffected by increases in amount of the more restrictive shrub matrix. However, simulations of an hypothetical species with greater overall dispersal ability but reduced dispersal rate through shrub matrix showed that colonization rates were noticeably reduced when the percentage of shrub matrix on the landscape approached 50%. Combined these results suggest that some tailoring of release strategies may be required to accommodate the unique dispersal capabilities of different biocontrol agents on particular release landscapes, but for A. lacertosa there appears to be little effect of matrix habitat structure on rates of spread.     

Multi-scale landscape and seascape patterns associated with marbled murrelet nesting areas on the U.S. west coast

Habitat for wide-ranging species should be addressed at multiple scales to fully understand factors that limit populations. The marbled murrelet (Brachyramphus marmoratus), a threatened seabird, forages on the ocean and nests inland in large trees. We developed statistical relationships between murrelet use (occupancy and abundance) and habitat variables quantified across many spatial scales (statewide to local) and two time periods in California and southern Oregon, USA. We also addressed (1) if old-growth forest fragmentation was negatively associated with murrelet use, and (2) if some nesting areas are more important than others due to their proximity to high quality marine habitat. Most landscapes used for nesting were restricted to low elevation areas with frequent fog. Birds were most abundant in unfragmented old-growth forests located within a matrix of mature second-growth forest. Murrelets were less likely to occupy old-growth habitat if it was isolated (> 5 km) from other nesting murrelets. We found a time lag in response to fragmentation, where at least a few years were required before birds abandoned fragmented forests. Compared to landscapes with little tono murrelet use, landscapes with many murrelets were closer to the ocean's bays, river mouths, sandy shores, submarine canyons, and marine waters with consistently high primary productivity. Within local landscapes (≤ 800ha), inland factors limited bird abundance, but at the broadest landscape scale studied (3200 ha), proximity to marine habitat was most limiting. Management should focus on protecting or creating large, contiguous old-growth forest stands, especially in low-elevation areas near productive marine habitat. This revised version was published online in July 2006 with corrections to the Cover Date.     

Landscape context and selection for forest edge by breeding Brown-headed Cowbirds

We evaluated support for four alternate hypotheses explaining the distribution of breeding Brown-headed Cowbirds (Molothrus ater) in forests at varying distances from the forest edge in three Midwestern USA landscapes with varying amounts of forest fragmentation (core forest area ranged from 5 to 70%). We focused on breeding cowbirds’ use of forest because of the risk of nest parasitism to forest-dwelling hosts and to identify factors affecting breeding cowbird habitat selection. We compared distances of cowbird locations in the forest from the forest edge (“edge distances”) to distances of random forest locations in the entire landscape or within individual cowbird home ranges. We analyzed 1322 locations of 84 cowbirds across three landscapes. We found support for the landscape context hypothesis that breeding cowbird preference for forest edge varied with landscape context. Ninety percent of cowbird locations were within 150–350 m of forest edge, despite the overall availability of forest at greater distances from edge (as far as 500–1450 m) both within cowbird home ranges and the entire forested landscape. Cowbird preference for edge varied by landscape context largely due to differences in the availability of forest edge. In a highly fragmented forest cowbirds utilized the entire forest and likely viewed it as “all edge.” In less fragmented forests, cowbirds preferred edge. We consider how variation in cowbird edge preference might relate to patterns in host abundance, host diversity, and host quality because cowbird movements indicate they are capable of using forest farther from edges.