Wetland Characteristics Associated with Reproductive Activity of Rana sylvatica in Denali National Park, Alaska

Abstract

Habitat characteristics greatly impact the distribution of amphibians. While Rana sylvatica has been extensively studied in Northeastern United States and Southeastern Canada, relatively little is known about the characteristics of its habitat in Alaska. Rana sylvatica is the northernmost amphibian in North America and the only one found in the study area. I studied the effects of habitat on reproductive activity of frogs near Wonder Lake in Denali National Park and Preserve, Alaska during the summer of 2004. R. sylvatica tadpoles were found in 98 of 219 randomly sampled wetland sites. A higher proportion of breeding activity was observed for ponds having these characteristics: intermediate surface area, minimum isolation, higher amounts of riparian woody vegetation, maximum water depth between l-2m, intermediate levels of emergent vegetation, and presence of alders. No correlation was observed between reproductive occupancy and elevation. These habitat associations may have consequences concerning climate change because R. sylvatica distribution may change if current climate trends continue. Future research will focus on expanding the study area, testing additional habitat factors, and accounting for yearly variation in distribution patterns.