PARENT SESSION
Poster Session #12: Modeling.
Tuesday, August 7, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Declines in diamondbacks: Terrapin population modeling and implications for management.

Hart, Kristen¹, Crowder, Larry¹, Heppell, Selina², Auger, Peter³, ^{1 2 3}

ABSTRACT- Diamondback terrapins (Malaclemys terrapin) are declining in many parts of their range due to habitat loss and anthropogenic mortality. To gain insight on the life history and demography of this species, we constructed an age-based matrix model using data from a stable population in MA. We analyzed sixteen years of mark-recapture data to estimate survival rates (adult survival = 0.83, juvenile survival = 0.74, hatchling survival = 0.23). We then compiled terrapin life history information and created a series of population scenarios (i.e., matrices) that represent populations in different parts of their range (e.g., bycatch in crab pots (NC) or with highly skewed sex ratios (FL). We also examined the effects of variability in vital rates on population dynamics and assessed the potential impacts of different mortality sources and management strategies. As with some other turtles, elasticity analysis revealed that juvenile annual survivorship has the greatest proportional effect on population growth rate (lambda, ), suggesting that conservation and research efforts should be directed towards this life stage.

KEY WORDS: matrix modeling, elasticity analysis, turtle, Diamondback terrapin