The herpetology of the coastal prairie region of Texas.
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A survey of the reptiles and amphibians of the Coastal Prairie Region of southeast Texas was made to determine how the distributions of individuals and species are related to physiographic, geologic, edaphic, climatic, and other biotic factors. Major consideration was given to differences in species composition in different regional biotic units. The results presented in this study are a summation of two years of field work in the Coastal Prairie Region and adjacent biotic regions. The geographic distribution, abundance, environmental preferences, pertinent aspects of life history, and ecological data on each of the 17 amphibians and 54 reptiles found in the coastal prairie are given. Although predominantly prairie, two major environments were evident in the Coastal Prairie Region: woodland distributed as strips along stream bottoms and typical prairie between the woodland strips. The herpetofauna was more abundant in both individuals and species in woodland than in the prairie. Ten forms were found almost exclusively in woods environment and 27 others showed a decided preference for woods; only 3 were found exclusively in the prairie and 14 others were more abundant in prairie than woods. No reptiles or amphibians were found to be endemic to the Coastal Prairie Region. Reptiles and amphibians were found in fair abundance throughout most of the year, but certain prairie species were found only in late spring and summer. The nature of the underlying geologic formations and the soil had a definite influence on the local distribution of certain species, but physiographic differences as evidence by elevation differences appeared to have a greater influence. Man was found to have the greatest local effect on the herpetofauna. Climatic differences, primarily total rainfall, determine the ranges of many species. An analysis of the differences in species composition of the reptiles and amphibians in relation to differences of flora, physiography, etc., substantiates the suggestion that the Coastal Prairie is a natural biotic unit. The comparatively small differences in species composition at the inland boundary demonstrate the affinity of the bottom woods with the Post Oak Belt. It is concluded that the Coastal Prairie Region is a natural biotic unit of a larger transitional region. It is suggested that transitional effects rather than uniformity in species distribution are to be expected in any regional biotic area.