Understanding variation in life-history strategies can be important when determining the influence of an organism's environment on its natural history. Variation in strategies can play a significant role on the overall fitness and survival of an individual. Some environmental conditions may influence this variation more than others. In particular, stochastic environments, such as a floodplain, may have large impacts on life history strategies of organisms living within them. Floodplains are known to have high rates of extrinsic mortality. Theoretically this should shift life-history traits toward a fast-type strategy, with fast growth rates, high annual fecundity, and larger mean body-sizes. To test this hypothesis, this study examined life-history strategies, mainly age-structure, body-size, and reproduction of the western ribbon snake (Thamnophis proximus) in East Texas. Two sites within East Texas were examined to determine the influence of floodplains on life-history traits. One was a bottomland forest within the floodplain of the Sabine River, Smith County, Texas. The other was stable lake/pond ecosystem also within Smith County, Texas. We were unable to detect any differences in age-structure or body-size between either population of ribbon snakes in East Texas. Additionally, the reproductive characteristics (mean offspring SVL, mean offspring mass, clutch size, and clutch mass) we measured did not correlate with number of floods, indicating little influence of stochasticity on these traits. The lack of variation in these life-history traits may be attributed to small sample sizes and the use of skeletochronology to assess age-structure. Skeletochronology has not been validated as a tool for measuring age-structure in East Texas. This study also investigates the efficacy of skeletochronology in East Texas using four novel validation techniques.
Date of publication
Chamberlain, Jeremy, "Stochastic Life-History Variation in Populations of Western Ribbon Snakes (Thamnophis Proximus) in East Texas" (2011). Biology Theses. Paper 3.