Efficacy Of Constructed Wetlands Of Various Depths For Natural Amphibian Community Conservation

Wetlands provide critical habitat for a diverse group of amphibians and provide important ecosystem functions and services to humans. Despite this, most natural wetlands have been lost to land use practices. Consequently, constructing wetlands has become a common practice to mitigate for removed wetlands and to manage for wildlife. There were three primary objectives of this research: 1) to examine whether or not constructed wetlands located on ridge tops in eastern Kentucky in the Daniel Boone National Forest (DBNF) had amphibian communities comparable to natural ephemeral wetlands, 2) to examine amphibian predator-prey relationships within the constructed wetlands, and 3) to determine what wetland characteristics affect species composition. Three types of wetlands were sampled forested natural ephemeral, shallow constructed (\u3c 20 cm minimum depth), and deep constructed wetlands (\u3e 20 cm minimum depth). Within this system, natural wetlands are ephemeral, whereas constructed wetlands typically do not dry. As a result, many species of the natural ridge-top amphibian community were scarce in shallow constructed wetlands and absent in deep constructed wetlands. Additionally, due to constructed wetlands, dominant amphibian predator species, primarily associated with permanent water, Rana catesbeiana (American bullfrog) and Notophthalmus viridescens (eastern newt), were in greater abundances than would occur naturally. Stomach contents of R. catesbeiana contained amphibian remains confirming interspecies predation. Further, in constructed wetlands, water depth, pH, dissolved oxygen, water temperature, and emergent vegetation were greater, whereas canopy closure was lower compared to natural wetlands. These data have influenced DBNF land managers to revise wetland construction methods and renovate older deep constructed wetlands to attempt to replicate the hydrology of natural ridge-top wetlands