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Urbanization poses a global challenge to species conservation. This is primarily understood in terms of physical habitat loss, as agricultural and forested lands are replaced with urban infrastructure. However, aquatic habitats are also chemically degraded by urban development, often in the form of toxic stormwater runoff. Here we assess threats of urbanization to coho salmon throughout developed areas of the Puget Sound Basin in Washington, USA. Puget Sound coho are a sentinel species for freshwater communities and also a species of concern under the U.S. Endangered Species Act. Previous studies have demonstrated that stormwater runoff is unusually lethal to adult coho that return to spawn each year in urban watersheds. To further explore the relationship between land use and recurrent coho die‐offs, we measured mortality rates in field surveys of 51 spawning sites across an urban gradient. We then used spatial analyses to measure landscape attributes (land use and land cover, human population density, roadways, traffic intensity, etc.) and climatic variables (annual summer and fall precipitation) associated with each site. Structural equation modeling revealed a latent urbanization gradient that was associated with road density and traffic intensity, among other variables, and positively related to coho mortality. Across years within sites, mortality increased with summer and fall precipitation, but the effect of rainfall was strongest in the least developed areas and was essentially neutral in the most urbanized streams. We used the best‐supported structural equation model to generate a predictive mortality risk map for the entire Puget Sound Basin. This map indicates an ongoing and widespread loss of spawners across much of the Puget Sound population segment, particularly within the major regional north‐south corridor for transportation and development. Our findings identify current and future urbanization‐related threats to wild coho, and show where green infrastructure and similar clean water strategies could prove most useful for promoting species conservation and recovery.

Conservation strategies to tackle habitat loss and fragmentation require actions at the local (e.g., improving/expanding existing habitat patches) and landscape level (e.g., creating new habitat in the matrix). However, the relative importance of these actions for biodiversity is still poorly understood, leading to debate on how to prioritize conservation activities. Here, we assess the relative importance of local vs. landscape-level attributes in determining the use of woodlands by bats in fragmented landscapes; we also compare the role of habitat amount in the surrounding landscape per se vs. a combination of both habitat amount and configuration and explore whether the relative importance of these attributes varies with species mobility and landscape context. We conducted acoustic surveys in 102 woodland patches in the UK that form part of the WrEN project (www.wren-project.com), a large-scale natural experiment designed to study the effects of 160 yr of woodland creation on biodiversity and inform landscape-scale conservation. We used multivariate analysis and a model-selection approach to assess the relative importance of local (e.g., vegetation structure) and landscape-level (e.g., amount/configuration of surrounding land types) attributes on bat occurrence and activity levels. Species mobility was an important trait determining the relative importance of local vs. landscape-level attributes for different bat species. Lower mobility species were most strongly influenced by local habitat quality; the landscape became increasingly important for higher mobility species. At the landscape-scale, a combination of habitat amount and configuration appeared more important than habitat amount alone for lower mobility species, while the opposite was observed for higher mobility species. Regardless of species mobility, landscape-level attributes appeared more important for bats in a more homogeneous and intensively farmed landscape. Conservation strategies involving habitat creation and restoration should take into account the mobility of target species and prioritize landscape-level actions in more homogeneous and intensively farmed landscapes where habitat loss and fragmentation have been more severe.

Conservation planning and biodiversity management require information on landscape connectivity across a range of spatial scales from individual home ranges to large regions. Reduction in landscape connectivity due changes in land use or development is expected to act synergistically with alterations to habitat mosaic configuration arising from climate change. We illustrate a multiscale connectivity framework to aid habitat conservation prioritization in the context of changing land use and climate. Our approach, which builds upon the strengths of multiple landscape connectivity methods, including graph theory, circuit theory, and least-cost path analysis, is here applied to the conservation planning requirements of the Mohave ground squirrel. The distribution of this threatened Californian species, as for numerous other desert species, overlaps with the proposed placement of several utility-scale renewable energy developments in the American southwest. Our approach uses information derived at three spatial scales to forecast potential changes in habitat connectivity under various scenarios of energy development and climate change. By disentangling the potential effects of habitat loss and fragmentation across multiple scales, we identify priority conservation areas for both core habitat and critical corridor or stepping stone habitats. This approach is a first step toward applying graph theory to analyze habitat connectivity for species with continuously distributed habitat and should be applicable across a broad range of taxa.

Land-use change is a major cause of wildlife habitat loss. Understanding how changes in land-use policies and economic factors can impact future trends in land use and wildlife habitat loss is therefore critical for conservation efforts. Our goal here was to evaluate the consequences of future land-use changes under different conservation policies and crop market conditions on habitat loss for wildlife species in the southeastern United States. We predicted the rates of habitat loss for 336 terrestrial vertebrate species by 2051. We focused on habitat loss due to the expansion of urban, crop, and pasture. Future land-use changes following business-as-usual conditions resulted in relatively low rates of wildlife habitat loss across the entire Southeast, but some ecoregions and species groups experienced much higher habitat loss than others. Increased crop commodity prices exacerbated wildlife habitat loss in most ecoregions, while the implementation of conservation policies (reduced urban sprawl, and payments for land conservation) reduced the projected habitat loss in some regions, to a certain degree. Overall, urban and crop expansion were the main drivers of habitat loss. Reptiles and wildlife species associated with open vegetation (grasslands, open woodlands) were the species groups most vulnerable to future land-use change. Effective conservation of wildlife habitat in the Southeast should give special consideration to future land-use changes, regional variations, and the forces that could shape land-use decisions.

The Prairie Pothole Region (PPR) is the primary breeding region for most species of North American dabbling ducks (Anas spp.). Conservation of these species is guided in part by knowledge of relationships between nest survival probability and habitat features. Positive relationships between duck nest survival and amount and configuration of herbaceous perennial vegetation have been observed in previous studies, but these 2- to 4-year studies might not have adequately characterized the temporal effect of wet-dry episodes on nest survival. Over an eight-year period, we studied nest survival of five species of ducks in the PPR relative to spatial and temporal variation in pond density, primary productivity, and hydrologic status of wetlands, soil, and vegetation on 52 study sites selected to span a gradient of spatial variation in proportion of herbaceous perennial vegetation and in number of wetland basins. We observed the fate of 12 754 nests. Consistent with past studies, 90% of nests that failed to hatch were destroyed by predators. Nest survival probability was positively related to current-year pond density and primary productivity, negatively related to pond density and primary productivity during the previous two years, and positively related to the number of wetland basins on the study site. Predicted relationships between nest survival and proportion or configuration of herbaceous perennial vegetation in the surrounding landscape were not supported. For mallard (Anas platyrhynchos), median estimated nest survival probability ranged from 0.02 (SE = 0.01) to 0.22 (SE = 0.02). Estimated nest survival was greatest on sites with numerous wetland basins that had transitioned from dry, unproductive conditions to wet, productive conditions in the previous 1-2 years. Our results were consistent with time-lagged responses of food webs to resource pulses in a broad array of ecosystems. Our study highlighted the importance of wetland basins and wet-dry episodes to duck nest survival in the PPR. Current habitat conservation efforts focus on landscapes with numerous wetland basins and a high proportion of herbaceous perennial vegetation. Our results suggest that future conservation efforts should focus on preserving high-density wetland complexes across as large a geographic extent as possible even in cropland-dominated landscapes.

Conservation scientists have noted that conservation managers rarely use scientific information when making decisions. One of the reasons why managers rarely use scientific information may be that conservation scientists rarely provide their knowledge in a way that can directly be used by conservation practitioners. Here we show how quantitative recommendations for conservation can be derived. Previous research on terrestrial habitat selection behavior of toads (Bufo bufo and Bufo viridis) showed that wood deposits are a key resource in the terrestrial habitat. We used habitat-dependence analysis to estimate the amount of this key resource, wood deposits, that individual toads require. Based on these estimates we then quantify the requirements for wood deposits for a population. Additionally, we quantified the area that a population requires. Although wood deposits vary strongly in size, we found little evidence for size preferences: only one species preferred smallest sizes of wood deposits. We report all the estimates in a way that can be directly used by conservation managers. Habitat-dependence analysis is a simple and useful tool to quantify habitat requirements. Provisioning of wood deposits may improve the quality of terrestrial habitat for amphibians. Thereby, managers may increase the carrying capacity of terrestrial habitats and support elevated population densities.

Habitat loss threatens large mammals worldwide, and their survival will depend on habitat in human-dominated landscapes. Conservation planners thus face the challenge to identify areas of least conflict with land use, yet broadscale species distribution models rarely incorporate real landscape patterns nor do they identify potential conservation conflicts. An excellent example of such conservation challenges is provided by European bison (Bison bonasus). Almost extinct by the early 20th century, bison can only survive in the wild if large metapopulations are established, but it is unclear where new herds can be reintroduced. Using European bison as an example we conducted a continental-scale habitat assessment based on real landscape patterns. Our specific aims here were to (1) map European bison habitat throughout the species' former range, (2) examine whether broadscale habitat suitability factors differ from previously reported fine-scale factors, and (3) assess where suitable habitat occurs in areas with low potential for conflict with land use. We assessed habitat suitability using herd range maps for all 36 free-ranging European bison herds as habitat use data. Habitat suitability maps were compared with maps of land cover, livestock density, agricultural constraints, and protected areas to assess potential conservation conflicts. Our models had high goodness of fit (AUC = 0.941), and we found abundant potential bison habitat. European bison prefer mosaic-type landscapes, with a preference for broad-leaved and mixed forests. European bison metapopulations do not appear to be limited by habitat availability. However, most potential habitat occurred outside protected areas and has substantial potential for conservation conflicts. The most promising areas for establishing large bison metapopulations all occur in Eastern Europe (i.e., the Carpathians, the Belarus-Ukraine borderlands, and several regions in European Russia). The future of European bison and that of other large mammals in the wild thus clearly lies in Eastern Europe, because habitat there is most abundant and least fragmented, and because the potential for conflict with land use is lower. More generally we suggest that broadscale habitat assessments that incorporate land use can be powerful tools for conservation planning and will be key if large herbivore and carnivore conservation is to succeed in a human-dominated world.

Detailed empirical models predicting both species occurrence and fitness across a landscape are necessary to understand processes related to population persistence. Failure to consider both occurrence and fitness may result in incorrect assessments of habitat importance leading to inappropriate management strategies. We took a two-stage approach to identifying critical nesting and brood-rearing habitat for the endangered Greater Sage-Grouse (Centrocercus urophasianus) in Alberta at a landscape scale. First, we used logistic regression to develop spatial models predicting the relative probability of use (occurrence) for Sage-Grouse nests and broods. Secondly, we used Cox proportional hazards survival models to identify the most risky habitats across the landscape. We combined these two approaches to identify Sage-Grouse habitats that pose minimal risk of failure (source habitats) and attractive sink habitats that pose increased risk (ecological traps). Our models showed that Sage-Grouse select for heterogeneous patches of moderate sagebrush cover (quadratic relationship) and avoid anthropogenic edge habitat for nesting. Nests were more successful in heterogeneous habitats, but nest success was independent of anthropogenic features. Similarly, broods selected heterogeneous high-productivity habitats with sagebrush while avoiding human developments, cultivated cropland, and high densities of oil wells. Chick mortalities tended to occur in proximity to oil and gas developments and along riparian habitats. For nests and broods, respectively, approximately 10% and 5% of the study area was considered source habitat, whereas 19% and 15% of habitat was attractive sink habitat. Limited source habitats appear to be the main reason for poor nest success (39%) and low chick survival (12%). Our habitat models identify areas of protection priority and areas that require immediate management attention to enhance recruitment to secure the viability of this population. This novel approach to habitat-based population viability modeling has merit for many species of concern.

Conservation of endangered species requires comprehensive understanding of their distribution and habitat requirements, in order to implement better management strategies. Unfortunately, this understanding is often difficult to gather at the short term required by rapidly declining populations of many rare vertebrates. We present a spatial habitat modeling approach that integrates a molecular technique for species detection with landscape information to assess habitat requirements of a critically endangered mammalian carnivore, the Iberian lynx (Lynx pardinus), in a poorly known population in Spain. We formulated a set of model hypotheses for habitat selection at the spatial scale of home ranges, based on previous information on lynx requirements of space, vegetation, and prey. To obtain the required data for model selection, we designed a sampling protocol based on surveys of feces and their molecular analysis for species identification. After comparing candidate models, we selected a parsimonious one that allowed (1) reliable assessment of lynx habitat requirements at the scale of home ranges, (2) prediction of lynx distribution and potential population size, and (3) identification of landscape management priorities for habitat conservation. This model predicted that the species was more likely to occur in landscapes with a higher percentage of rocky areas and higher cover of bushes typical of mature mediterranean shrubland mosaics. Its accuracy for discriminating lynx presence was ;85%, indicating high predictive performance. Mapping model predictions showed that only 16% of the studied areas constitute potential habitat for lynx, even though the region is dominated by large extents of well-preserved native vegetation with low human interference. Habitat was mostly clumped in two nearby patches connected by vegetation adequate for lynx dispersal and had a capacity for 28–62 potential breeding territories. The lynx population in Sierra Morena is probably the largest persisting today, but it is still critically small for optimism about its long-term persistence. Model results suggest habitat conservation and restoration actions needed for preserving the species, including reconciliation of hunting management with preservation of mature shrubland over large areas (particularly in rocky landscapes). The approach presented here can be applied to many other species for which the ecological information needed to develop sound habitat conservation strategies is lacking.

In many coastal areas, natural habitats are being fragmented and lost to encroaching human development. These landscape changes can affect the production of recreationally and commercially important fisheries because many exploited species of fish and shellfish are estuarine dependent and utilize coastal marshes as nursery grounds. Brown shrimp are an example of a commercially exploited species that may be highly affected by changes in the spatial distribution of habitat types. We used a spatially explicit, individual-based simulation model to explore the role of marsh vegetation and edge habitat in brown shrimp survival. The model simulated shrimp movement, mortality, and growth of individual shrimp from arrival as postlarvae to 70-mm body length, when they emigrate offshore. Simulations were performed on 100 × 100 m spatial grid of 1-m2 cells, with each cell labeled as “water” or “vegetation”. Predation mortality was influenced by shrimp size, movement, and habitat. Simulated shrimp growth depended on temperature, habitat, and local shrimp density. We examined the relationships between shrimp survival and marsh attributes (amount of vegetation and edge habitat) by simulating a series of four habitat maps that we created from aerial photographs. Biological parameters were derived from published estimates and from field data. We corroborated the model by comparing the simulated shrimp abundance with summary statistics from long-term monitoring data, by comparing the simulated density with fine-scale patterns observed in field studies, and by comparing simulated and measured stable-isotope values. Surviving shrimp grew faster, moved less, spent more time in vegetation, and experienced slightly higher local densities than shrimp that died during the simulation. Habitat maps with more edge habitat invariably produced higher simulated shrimp survival rates. High-edge habitats increased survival by providing shrimp more direct access to vegetation without additional movement-related mortality and density-dependent growth costs associated with low-edge habitats. Model predictions were robust to higher numbers of initial postlarvae and to alterations to the movement rules. The results of this study suggest that the management of brown shrimp should be extended from protecting the spawning stock through catch regulations to also protecting the estuarine life stages through habitat conservation and restoration.

The U.S. Endangered Species Act (ESA) generally requires that critical habitat be designated for all species listed as endangered or threatened. However, it has been designated for only ∼10% of listed species. Recently, in response to several recent court orders and settlement agreements that require critical habitat to be designated for ∼300 species, the U.S. Fish and Wildlife Service decided to divert all available budget resources for 2001 to address the backlog of designations. This decision underscores a central question in the controversies surrounding critical habitat designation: How does critical habitat benefit the conservation and eventual recovery of listed species? Here, we examined how designation of critical habitat influenced the recovery planning process by comparing the content and characteristics of recovery plans for species with and without designated critical habitat. Critical habitat designation did not increase the availability of information on species' habitat requirements or increase the likelihood that recovery plans prescribed habitat management or habitat acquisition among the necessary recovery tasks. Recovery plans for species with critical habitat were not more likely to include habitat considerations among criteria for measuring recovery. Recovery plans for species with critical habitat uniformly ranked habitat concerns among the top threats to species and, on average, proposed a greater diversity of habitat monitoring efforts. Overall, however, we concluded that critical habitat designations have had negligible positive influence in the recovery planning process. We discuss possible explanations and suggest a standards-based system for designating critical habitat that should promote more effective contributions to recovery efforts for threatened and endangered species.

The California Spotted Owl (Strix occidentalis occidentalis), like the more well-known Northern Spotted Owl (Strix occidentalis caurina), appears to be in decline over at least a part of its geographic range. Two different types of reserve design have been implemented to protect Spotted Owls. The Spotted Owl Habitat Area (SOHA) system uses a fairly large number of small reserves; each SOHA is capable of supporting 1-3 nesting owl pairs. The Habitat Conservation Area (HCA) plan proposes a smaller number of fairly large reserves, each including 10-20 active Spotted Owl nests. The HCA reserve design strategy has been incorporated into current conservation planning for the Northern Spotted Owl. The Technical Assessment Team of the California Spotted Owl Assessment project has recommended preserving existing SOHAs within a lightly harvested matrix as an interim policy for conservation of the California Spotted Owl. In this paper we present results from two demographic models of the California Spotted Owl. The first model is based on a simple formulation of a birth-death process; the second model is a somewhat more detailed simulation model. The models are intended to provide a comparison of the SOHA and HCA reserve-design strategies. We are particularly interested in the ability of the two reserve designs to withstand recurring environmental catastrophes in the form of forest fires. The HCA strategy always leads to longer persistence times than the SOHA strategy. The essential difference between the two strategies appears to lie in the shape of the function that gives the probability of colonization of an empty nest site. These results have several implications for the conservation of California Spotted Owls and for conservation biology in general. (1) Some variant of the HCA reserve design strategy may be preferable to the interim strategy being proposed for conservation of the California Spotted Owl. (2) Simple, parameter-sparse models like ours can yield results comparable to those of more complex and detailed models. (3) Models that include the effects of catastrophic environmental perturbations have great potential for application in conservation biology.

The conservation of species requires preservation of natural habitats. Where the integrity of natural habitats has been upset, species go extinct. All natural habitats are continuing to decline, both inside and outside of reserves. Habitat change is partly a natural process (e.g., succession), but human activities have accelerated the process of decay so that natural rates of renewal are insufficient to maintain natural habitats. We argue that our only recourse, in light of these scenarios, is to adopt a new conservation strategy that considers the importance of habitat renewal in addition to habitat preservation. Accordingly, in our management decisions we must not only choose the size of area to preserve but also the size of area that balances habitat loss with habitat renewal. We also suggest that this habitat equilibrium point, H*, needs to be decided upon urgently, otherwise many species will become extinct in the next 50 yr according to numerous predictions. There are two ways to achieve H*. The first is to set habitats aside in protected areas in perpetuity. There are two reasons why this protection alone is insufficient: (1) protected areas continue to decline, albeit at a slower rate than outside of their boundaries, and (2) achieving H* simply by setting aside protected areas is no longer an option in many areas where severe habitat degradation or fragmentation has already occurred. The other way to achieve H* is to promote the restablishment of natural habitats, or "habitat renewal." This concept is il- lustrated using a simple trade-off model that balances habitat decay and habitat renewal. We then provide examples of habitat loss outside and inside of protected areas and discuss the potential for habitat renewal to offset these losses. We conclude that continued emphasis needs to be placed on setting aside natural habitat in protected areas. However, our examples of habitat loss show that this policy alone is most likely doomed to failure, so a policy of habitat renewal is also required.

To meet the requirements of Congressional legislation mandating the production of a "scientifically credible" conservation strategy for the threatened Northern Spotted Owl (Strix occidentalis caurina), the Interagency Spotted Owl Scientific Committee employed scientific methods to design a habitat reserve system. Information on the current and historical distributions of the owl and its habitats was reviewed in light of economic, political, and legal constraints; results were used to develop a preliminary reserve system of habitat "polygons." A map representing these polygons and their attendant properties served as a set of hypotheses that were tested. Statistical analyses of empirical data, predictions from ecological theory, predictions from population dynamics models, and inferences drawn from studies of related species were used to test properties of the preliminary map, including the number and sizes of habitat conservation areas (HCAs), their distribution, configuration, and spacing, and the nature of the landscape matrix between HCAs. Conclusions that failed to confirm specific map properties were used to refine the reserve system, a process that continued iteratively until all relevant data had been examined and all map properties had been tested. This conservation planning process has proven to be credible, repeatable, and scientifically defendable, and should serve as a model for wildlife management, endangered species recovery, and national forest planning.