1. Department of Environmental Science and Policy; George Mason University; Fairfax Virginia USA
2. Department of Veterinary and Biomedical Sciences; The Pennsylvania State University, University Park; Pennsylvania USA
3. Ecological Services; US Fish and Wildlife Service; Raleigh North Carolina USA
4. National Health and Environmental Effects Research Laboratory; US Environmental Protection Agency; Research Triangle Park North Carolina USA
5. Ecological and Biological Sciences Practice; Exponent; Alexandria Virginia USA
6. Faculty of Agricultural and Environmental Sciences; McGill University; Montreal Canada