Patterns of Herpetofaunal Species Richness: Relation to Temperature, Precipitation, and Variance in Elevation

Abstract

In Texas the relationship between eight physical environmental factors and species richness of salamanders, frogs and toads, turtles, lizards and snakes was investigated by multiple regression methods. Variance in elevation was significant for each reptilian taxon and was relatively more important for lizards and snakes than for turtles. Mean annual precipitation was significant for each taxon but was a stronger predictor for salamanders, frogs and toads, and turtles than for lizards and snakes. Mean annual temperature range was used to test the climatic stability hypothesis of species richness. This variable was significant, with negative coefficients, for frogs and toads, turtles and lizards and was consistent with the stability hypothesis. Mean intermonthly variability of precipitation, also interpreted as a stability measure, had a positive and significant relationship to snakes and was contradictory to the stability hypothesis. The standard deviation of mean January and July temperatures and the maximum and minimum temperatures of record were used to test the intermediate disturbance hypothesis of species richness. Variation in turtle and lizard species richness was significant for maximum and minimum