Turtle Population Demography: Planning Considerations for Addressing Human Impacts and Declines in Long-lived Organisms

Long-lived organisms tend to share a suite of life history characteristics which make them particularly susceptible to population decline and extinction in a developing landscape. The suite of life history characteristics includes: highly variable reproductive success (relative, even successful years aren't that great), low hatchling/juvenile survivorship, delayed sexual maturity, and high adult survivorship.

An evaluation of the literature on turtles consistently demonstrates the necessity of protecting breeding adults to be successful in reversing population declines. Good buffers can be just as important as wetlands for aquatic and semi-aquatic turtles. Terrestrial impacts disproportionately affect female turtles which are exposed more because of nesting forays. The presence of roads near a wetland is correlated with altered population structure (high male to female ratios) which is a part of the pattern documented in the extinction of several turtle populations. Other major problems include collection for the pet trade, consumption, fishing nets (crab pots for diamondback terrapin)/trawling (sea turtles), agriculture, and lawn maintenance. Essentially, anything that removes adults and sub-adults from the population.

Courtesy of NRCS Technology News, April 2005 (in Adobe PDF).