Competitive Interactions between Cricket Frogs (Acris blanchardi) and Other Anurans

摘要

In recent decades, created ponds have become one of the dominant aquatic habitats in anthropogenic landscapes. Understanding how competition between colonizing species influences community assembly in these new habitats is important for predicting species distributions across the landscape. The objective of this study was to examine competition between larval Cricket Frogs (Acris blanchardi), which are showing declines in parts of their range, and other anurans including Bullfrogs (Lithobates catesbeianus), Green Frogs (Lithobates clamitans), and Cope's Gray Treefrogs (Hyla chrysoscelis). Using two separate experiments, we examined competitive interactions between larvae of (1) Cricket Frogs and different size classes of Bullfrogs; and (2) Cricket Frogs and Green Frogs, Cricket Frogs and Cope's Gray Treefrogs, or all three species together. We found no effect of either recently hatched or overwintered Bullfrog larvae on Cricket Frog metamorphosis. However, we found that Green Frogs reduced Cricket Frog survival and that Cope's Gray Treefrogs increased Cricket Frog time to metamorphosis. Because Cricket Frog populations have an annual life cycle, they might be sensitive to factors that influence recruitment, including competition with some species. Dispersal and landscape connectivity could be vital for maintaining Cricket Frog populations in areas with high densities of competitors (i.e., Green Frogs and Treefrogs). Conversely, the lack of competition between Cricket Frogs and Bullfrogs could explain why both species are able to coexist.