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Landscape context is integral to population ecology, affecting a range of life history parameters, yet very little is known about how landscape structure influences many taxa. We sampled wetlands at 531 sites across 16 states in the eastern U.S. to examine the influence of landscape heterogeneity and anthropogenic land use on the relative abundance of freshwater turtles, one of the most endangered vertebrate clades in the world. Specifically, we aimed to understand how two components of landscape structure — compositional heterogeneity (wetland diversity) and configurational heterogeneity (wetland aggregation) — influence turtles with varying life history traits. Our results suggest that wetland configuration can modulate the relationship between relative abundance and anthropogenic land use. For example, spotted turtle (Clemmys guttata) was negatively associated with hay/pasture cover when wetlands were less aggregated, but this relationship subsided as aggregation increased. Notably, the way wetland aggregation modulated land use relationships varied across species. These results suggest that some anthropogenic cover types are not strictly positive or negative for certain species, but are instead context-dependent. Relative abundance also generally increased with higher wetland diversity, indicating the potential importance of landscape supplementation for turtles. We report a range of responses to roads that did not strictly correspond with well-established predictions related to body size and terrestrial activity patterns, including positive associations for certain species. Overall, our study supports the use of context-driven approaches to land use-related conservation and management decisions rather than blanket prescriptions, and further emphasizes that effective conservation of freshwater systems requires a landscape-level perspective. • Wetland configuration modulates the effect of land use on relative abundance. • Most turtle species displayed positive relationships with wetland diversity. • Effect of roads varied by species, with positive, negative, neutral relationships. [ABSTRACT FROM AUTHOR]

Turtles are among the most threatened vertebrate groups, and reconstruction of population and distributional trends can be important for evaluating their status and defining conservation targets. Using a two-phase modeling approach along with occurrence records and field surveys, our objectives were to: estimate the potential and current distributions of the wood turtle (Glyptemys insculpta), a semi-terrestrial fluvial specialist of range-wide conservation concern; assess how climate, geomorphology, and land-use relate to its distribution; and estimate habitat loss. Using 1061 occurrences in the northeastern US with stream geomorphology and climate data, we created distribution models at sub-regional scales to estimate that 24% of stream km in the region are potentially suitable for wood turtles. Suitable stream habitat is generally lower gradient, higher sinuosity, and higher flow than random, but varies significantly by subregion, suggesting that distribution or habitat models built at the regional or range-wide level may miss important local variation in habitat and climatic needs at finer scales. We then used landscape composition at multiple spatial scales to predict results from standardized field surveys from 78 sites across 9 states to estimate habitat loss. We estimate that 58% of potential habitat is degraded based on landscape composition. Results support previous observations of decline and habitat loss in the wood turtle, driven by landscape degradation at scales larger than the typical home range, necessitating conservation intervention at multiple spatial scales, and underscoring the importance of models that address locally varying and scale-dependent relationships between species and habitats. [ABSTRACT FROM AUTHOR]