SPECIES-DIVERSITY AND SEASONAL ABUNDANCE OF SNAKES IN A MIXED PINE-HARDWOOD FOREST OF EASTERN TEXAS

Drift fences were used to live-trap snakes over a 4-year period in three habitats of a 32.2-ha forest preserve in northeastern Texas. The upland deciduous woodland had the most species (17 with 99 individuals) and the highest species diversity, but the lowland floodplain had the greatest number of snakes (15 species, 142 individuals). The upland coniferous woodland had the fewest snakes and the lowest species diversity (10 species, 72 individuals). The southern copperhead, Agkistrodon contortrix, was the dominant species in both upland habitats, and the western cottonmouth, Agkistrodon piscivorus, was the most abundant snake in the lowland habitat. The lowland floodplain had six species restricted to that habitat, the upland deciduous woodland had two, but no species were found only in the upland pine area. The Texas rat snake, Elaphe obsoleta, was the first species captured in the spring. Agkistrodon contortrix and the eastern coachwhip, Masticophis flagellum, were abundant in mid-summer, and Agkistrodon piscivorus was numerous in the fall. Agkistrodon contortrix was most abundant in the rocky upland deciduous woodland in the spring and increased its numbers in the other habitats in mid-summer. Elaphe showed the greatest habitat niche width, whereas A. piscivorus had the narrowest. The greatest niche overlap occurred between M. flagellum and E. obsoleta, whereas the least overlap was between M. flagellum and A. piscivorus.