ince 2000, a captive breeding and restocking program for the european pond turtle Emys orbicularis has been ongoing in liguria, northern Italy, with the aim of preventing the extinction of the species in that region. In a previous study, we used a population model to predict the growth of a restocked population and to assess whether it would be better to release turtles of three, four or five years of age. However, that initial model was based on limited information, leading to uncertainty of our predictions. Here, we validate that initial study by analyzing the results of post-release monitoring for the first seven years of releases. We used a Cormack-Jolly- seber (CJs) model to estimate survival of released individuals. We then updated the uncertain estimates of survival in the original model and assessed whether the best decision had changed and the benefits of having obtained empirical data from monitoring. Modelling results suggests that released turtles have sufficiently high survival, matching prior expectations, such that local extinction has been averted in the short-term. survival was similar among candidate age classes for releases, suggesting the release of younger individuals can provide positive outcomes while reducing management costs. on the other hand, survival varied among sites, indicating the need for ongoing in-situ habitat management. In sites with less than ideal conditions, updated models of population viability suggest that long-term persistence depends on site conditions. Moreover, the late onset of sexual maturity in the species means reproduction of released animals cannot yet be determined with certainty. Captive breeding and reintroduction programs normally require long-term efforts; therefore, focused monitoring that is clearly linked to decision-making is necessary to continually refine and adjust management strategies.

Analysis of monitoring data from the captive breeding and restocking program for Emys orbicularis in Liguria

Sebastiano Salvidio;Dario Ottonello
2017

Abstract

ince 2000, a captive breeding and restocking program for the european pond turtle Emys orbicularis has been ongoing in liguria, northern Italy, with the aim of preventing the extinction of the species in that region. In a previous study, we used a population model to predict the growth of a restocked population and to assess whether it would be better to release turtles of three, four or five years of age. However, that initial model was based on limited information, leading to uncertainty of our predictions. Here, we validate that initial study by analyzing the results of post-release monitoring for the first seven years of releases. We used a Cormack-Jolly- seber (CJs) model to estimate survival of released individuals. We then updated the uncertain estimates of survival in the original model and assessed whether the best decision had changed and the benefits of having obtained empirical data from monitoring. Modelling results suggests that released turtles have sufficiently high survival, matching prior expectations, such that local extinction has been averted in the short-term. survival was similar among candidate age classes for releases, suggesting the release of younger individuals can provide positive outcomes while reducing management costs. on the other hand, survival varied among sites, indicating the need for ongoing in-situ habitat management. In sites with less than ideal conditions, updated models of population viability suggest that long-term persistence depends on site conditions. Moreover, the late onset of sexual maturity in the species means reproduction of released animals cannot yet be determined with certainty. Captive breeding and reintroduction programs normally require long-term efforts; therefore, focused monitoring that is clearly linked to decision-making is necessary to continually refine and adjust management strategies.
ATTI XI Congresso nazIonale Societas Herpetologica Italica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10278/3694240
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