Context: Species distributions are a function of an individual’s ability to disperse to and colonize habitat patches. These processes depend upon landscape configuration and composition. Objectives: Using Blanchard’s cricket frogs (Acris blanchardi), we assessed which land cover types were predictive of (1) presence at three spatial scales (pond-shed, 500 and 2500 m) and (2) genetic structure. We predicted that forested, urban, and road land covers would negatively affect cricket frogs. We also predicted that agricultural, field, and aquatic land covers would positively affect cricket frogs. Methods: We surveyed for cricket frogs at 28 sites in southwestern Ohio, USA to determine presence across different habitats and analyze genetic structure among populations. For our first objective, we examined if land use (crop, field, forest, and urban habitat) and landscape features (ponds, streams, and roads) explained presence; for our second objective, we assessed whether these land cover types explained genetic distance between populations. Results: Land cover did not have a strong influence on cricket frog presence. However, multiple competing models suggested effects of roads, streams, and land use. We found genetic structuring: populations were grouped into five major clusters and nine finer-scale clusters. Highways were predictive of increased genetic distance. Conclusions: By combining a focal-patch study with landscape genetics, our study suggests that major roads and waterways are key features affecting species distributions in agricultural landscapes. We demonstrate that cricket frogs may respond to landscape features at larger spatial scales, and that presence and movement may be affected by different environmental factors.
Bibliographical noteFunding Information:
We thank Maarten van Strein and Valerie Peters for assistance with mixed model analyses; and Andrew McDermott and Paula Cimprich for helping to conduct surveys and collect tissue samples. Funding was provided by the U.S. Fish and Wildlife Service. All procedures were approved by Miami University (IACUC 827).
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- Focal patch
- Functional connectivity
- Landscape genetics
- Species distribution