TIMBER RATTLESNAKES AND LOUISIANA PINE SNAKES OF THE WEST GULF COASTAL PLAIN: HYPOTHESES OF DECLINE

摘要

Timber rattlesnakes (Crotalus horridus) and Louisiana pine snakes (Pituophis melanoleucus ruthveni) are large-bodied snakes occurring on the West Gulf Coastal Plain. Both species are thought to be declining due to increasing habitat alteration. Timber rattlesnakes occur in closed canopy hardwood and pine-hardwood forests, and Louisiana pine snakes in pine forests on sandy, well drained soils. While various factors are probably involved in population declines, this study examined one factor for each species that may have widespread consequences for population viability. Results obtained in this study support the premise that timber rattlesnakes are vulnerable to mortality associated with roads and vehicular traffic. Data and discussion are presented suggesting that populations are negatively impacted in areas of eastern Texas having a high road density. Conversely, Louisiana pine snakes appear to be affected by changes in the fire regime which has altered vegetation structure resulting in decreases in pocket gopher (Geomys breviceps) density. Decreases in gopher densities are further hypothesized to result in decrease or extirpation of pine snake populations.