Since the 1950s, exurban landscapes have been the fastest growing land-use type in the United States. Exurban landscapes are large lot residential parcels located between suburban and rural areas. While exurbanization can increase habitat fragmentation, the conversion to exurban land use creates heterogeneous parcels that may provide suitable habitat benefitting local biodiversity. However, exurban parcels are individually managed and management decisions made by the parcel owner, such as pesticide use, may disproportionately impact biodiversity. We aimed to determine how exurban parcel size and land cover type impacted amphibian occurrence, abundance, and richness on exurban parcels in an agricultural region of the US Midwest. We hypothesized that larger and primarily forested parcels would positively impact anuran occurrence, abundance, and richness. Alternatively, other local land use features or landscape-level factors may be important in predicting these responses. Eighty parcels with a pond were selected at approximately 2.5 or 5.0 acres and had a land cover of >70% forest or >90% pasture. Anuran call surveys were conducted during the breeding season at each site twice per month.
Results/Conclusions
Six anuran species were detected at our study sites including: Spring peeper (Pseudacris crucifer), American toad (Anaxyrus americanus), Cope’s gray treefrog (Hyla chrysoscelis), Blanchard’s cricket frog (Acris blanchardi), green frog (Lithobates clamitans) and bullfrog (Lithobates catesbeianus). Overall, species richness was not significantly different across parcel size or land cover type; however, species specific differences in occupancy were observed. Spring peepers had significantly higher occupancy on larger parcels with open land cover, American toads were significantly higher on larger forest and smaller open parcels, and bullfrogs had significantly higher occupancy on open land cover parcels. Cope’s gray treefrogs had no significant differences across land cover type which is surprising as they are forest associated. No significant differences were observed in abundance across all species. Overall, I rejected the hypothesis as neither parcel size or land cover impacted species richness on the landscape, suggesting other local and landscape level factors such as temperature and pond area may play a more significant role. This research will provide valuable information on factors that influence amphibians on exurban landscapes and could impact future policy development.