Response of Herpetofaunal Communities to Forest Cutting and Burning at Chesapeake Farms, Maryland
McLeod, Roderick F., Gates, J. Edward, The American Midland Naturalist
ABSTRACT.-The distribution and abundance of amphibians and reptiles in forest stands subjected to salvage cutting and prescribed burning were compared with their unmanaged counterparts. The study was conducted on the Atlantic coastal plain at Chesapeake Farms near Chestertown, Maryland. Three herpetofaunal trapping arrays were systematically located in each of four forest stand types: hardwood (Hardwood), cut-over hardwood (Cut), mixed pine-hardwood (Pine) and prescribed burn pine (Burn). A total of 3931 individuals representing 29 species were captured in 30,540 trap nights during the spring and summer 1992 and 1993. Felling of hardwoods and prescribed burning of pine resulted in similar responses from the herpetofaunal communitites; Hardwood had the most distinctive herpetofaunal community of the four stands. Adults and young-of-the-year (YOY) of six amphibian species were significantly more abundant in Hardwood than Cut. Only one amphibian species, Pseudarris triseriata, was less abundant in Hardwood than Cut. Total ranid captures did not differ between Hardwood and Cut. Snake and total reptile captures, and Elaphe obsolete and Eumeces faiatus abundances were significantly less in Hardwood than Cut. Hardwood also had fewer small mammals than Cut, particularly Microtus pennsylvanicus and Zapus hudsonius, that might serve as prey for large snakes. Adults of four amphibian species, YOY of five amphibian species, and three reptiles (Carphophis amoenus, Storena deka and Thamnophis sirtalis) were significantly more abundant in Pine than Burn; two reptile species (Coluber constrictor and Lampropeltis getula) were significantly less abundant. Potential small mammal prey of the latter two snakes were not significantly different between Pine and Burn; however, Zapus hudsonius was less abundant in Pine than in Burn. More amphibians were captured in Hardwood and Pine stands than in their respective logged and burned counterparts. The trend for reptiles tended to depend on the mix of species present and their habitat preferences. Greater canopy cover and depth of leaf litter in Hardwood and Pine stands likely had a moderating effect on temperature and helped to maintain a moist microenvironment for mesophilic species. Disturbance of a small patch of forest could locally decrease herpetofaunal diversity, but diversity on a much larger scale would likely increase.
Logging and prescribed burning are two commonly used forest management practices that modify forest habitat by changing vegetation composition and structure, and which have been shown to alter the abundance or occurrence of amphibians and reptiles (Means and Campbell, 1981; Bury, 1983; Enge and Marion, 1986; Welsh and Lind, 1988; Petranka et al., 1993; deMaynadier and Hunter, 1995). Opening the canopy by cutting of large trees results in greater fluctuation in air and soil temperature, relative humidity, light intensity and wind speed (Blymyer and McGinnes, 1977; Bury, 1983; Enge and Marion, 1986; Welsh and Lind, 1988); and reduces or removes amphibian microhabitat produced by leaf litter and coarse woody debris (Bury, 1983; Corn and Bury, 1990).
Unlike many amphibians, reptiles have relatively impermeable skin and are therefore able to take advantage of the warmer temperatures of open canopy areas without dehydrating (Enge and Marion, 1986; Bury and Corn, 1988; Zug, 1993). Abundant stumps in clear-cuts also provide refuge (Corn and Bury, 1990; Conant and Collins, 1991). Little information is presently available regarding the effects of prescribed fire on amphibians and reptiles. Research on this topic has been restricted primarily to southern California chaparral communities (Howard et al., 1959; Kahn, 1960; Lillywhite and North, 1974; Lillywhite, 1977; Lillywhite et al., 1977) and the southeastern United States (Komarek, 1969; Means and Campbell, 1981). Most authors have found very little herpetofaunal mortality directly associated with fire (Howard et al. …