Henry Merchant Associate Professor of Biology Ecology, Population Energetics and Dynamics, Community and Ecosystem Analysis Department of Biological Sciences The George Washington University Lisner Hall 348, 2023 G Street, NW Washington, D.C. 20052 Office: (202) 994-7123 Fax: (202) 994-6100 E-Mail: hmerchnt@gwu.edu Dept E-mail : biology@gwu.edu

My current research is focused upon a long term study of the population biology of the red-backed salamander (Plethodon cinereus). In this study I am examining common population parameters (size, sex ratio, color morph ratio, spatial distribution, etc.) as they vary seasonally and annually. I am also investigating the environmental factors affecting variation in the size of the reproducing population of the wood frog (Rana sylvatica). Both of these studies are conducted using a natural preserve that is just outside Washington, D.C. and is owned by a private foundation dedicated to environmental education.

I am also studying the natural coexistence of two closely related species of grass shrimp (Palaemonetes pugio and Palaemonetes vulgaris). These investigations center upon environmental, behavioral and physiological aspects that might indicate resource partitioning and avoidance of competition between these two ecologically very similar species. This work is conducted at various locations along the Atlantic seashore and Chesapeake Bay, and is often done in collaboration with Dr. Robert Knowlton of our department.

Although I am particularly interested in amphibian biology, my students (past and present) have pursued ecological studies in a wide variety of areas many of which are not related to my personal research. Student theses and dissertations have included: food habits of shrews, salamanders, mud crabs or tadpoles; invasion of stream banks by Japanese Knotweed; microclimatic variables in crayfish burrows, primary productivity in ornamental ponds; toxicological effects of exposure to motor oil, diesel fuel, or pesticides.