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A POPULATION MODEL FOR THE DIAMONDBACK TERRAPIN IN NARRAGANSETT BAY, RHODE ISLAND
Citation:
Mitro, M. A POPULATION MODEL FOR THE DIAMONDBACK TERRAPIN IN NARRAGANSETT BAY, RHODE ISLAND. Presented at Northeast Fish and Wildlife Conference, Portland, ME, April 21-24, 2002.
Description:
The diamondback terrapin Malaclemys terrapin is listed as a state-endangered species in Rhode Island, and there is only one known breeding population in the state. The Barrington Land Conservation Trust has been monitoring the nesting activity of this population since 1990 and has compiled a 12-year mark-recapture data set for nesting females. I analyzed the mark-recapture data using models in programs POPAN and MARK to estimate adult female abundance, apparent survival, and population growth rate. I used these estimates, along with observations of reproductive success, to parameterize an age-classified matrix population model for the diamondback terrapin population in Rhode Island. Using the age-classified model and the mark-recapture- derived estimate of population growth rate I estimated the juvenile survival rate. Preliminary analyses indicated a female adult apparent survival rate of 0.947 (95% confidence interval (CI) [0.928-0.961]). The population growth rate was 1.030 (95% CI [1.007-1.052]). These results suggested that the diamondback terrapin population in Rhode Island has not been declining and may have been increasing. Finally, I used the population model to evaluate the sensitivity of population growth rate to survival and reproductive success, and I evaluated the potential benefits of nesting habitat conservation and of a head-starting program to improve nest incubation success.