Effects of Timber Harvest on Amphibian Population: Understanding Mechanisms from Forest Experiments

Raymond D. Semlitsch¹, Brian D. Todd², Sean M. Blomquist³, Aram J. K. Calhoun³, J. Whitfield Gibbons², James P. Gibbs⁴, Gabrielle J. Graeter², Elizabeth B. Harper¹, Daniel J. Hocking¹, Malcolm L. Hunter Jr.³, David A. Patrick³, Tracy A. G. Rittenhouse¹, and Betsie B. Rothermel²

¹Division of Biological Sciences, University of Missouri, Columbia, MO
²University of Georgia, Savannah River Ecology Laboratory, Aiken, SC
³Department of Wildlife Ecology, University of Maine, Orono, ME
⁴State University of New York, College of Environmental Science and Forestry, Syracuse, NY

Abstract: Harvesting timber is a common form of land use that has the potential to cause declines in amphibian populations. It is essential to understand the behavior and fate of individuals and the resulting consequences for vital rates (birth, death, immigration, emigration) under different forest management conditions.We report on experimental studies conducted in three regions of the United States to identify mechanisms of responses by pond-breeding amphibians to timber harvest treatments. Our studies demonstrate that life stages related to oviposition and larval performance in the aquatic stage are sometimes affected positively by clearcutting, whereas effects on juvenile and adult terrestrial stages are mostly negative. Partial harvest treatments produced both positive and weaker negative responses than clearcut treatments. Mitigating the detrimental effects of canopy removal, higher surface temperature, and loss of soil-litter moisture in terrestrial habitats surrounding breeding ponds is critical to maintaining viable amphibian populations in managed forested landscapes.