Evaluating the effectiveness of headstarting for wood turtle (glyptemys insculpta) population recovery

Abstract

Headstarting is a conservation strategy that assumes raising hatchling turtles to larger body sizes increases their survivorship compared to wild non-headstarted turtles. This increased survivorship should increase population growth rate relative to wild recruitment. There are, however, few published results of long-term population recovery using headstarting. The lack of demographic assessment of population recovery has led to an overall lack of quantitative assessment of the effectiveness of headstarting as a conservation action. Headstarting needs to be efficient and effective as a poorly executed headstarting project can result in species extinction given it is often used with critically endangered species. We released 3 cohorts of headstarted Wood Turtles (Glyptemys insculpta) with varying degrees of headstarting to determine if headstarting increases survivorship. I showed that headstarting turtles to a larger body size confers a survival advantage, and this survival advantage should increase population growth rate relative to wild recruitment. I then quantitatively assessed the effectiveness of a 15-year Wood Turtle headstarting program by modeling population-specific demographic parameters to evaluate recovery efforts, and determine the next phase of recovery. I found some evidence of population recovery, but also identified challenges and make several management recommendations that should enhance the success of the headstarting program. Overall, I have provided support for headstarting as an effective conservation strategy, with the caveat that all headstarting projects must be paired with management plans that maintain high adult and juvenile survival.