Temporal changes in an alligator snapping turtle (Macrochelys temminckii) population

Context. Monitoring populations of long-lived species requires continuous long-term efforts. This is especially applicable for species that have experienced declines range-wide. Aims. Our study assessed the current status of a population of wild Macrochelys temminckii and compared the present results to those from a survey conducted nearly a decade ago. Methods. Trapping in 2010-2011 was conducted on two creeks within the refuge, during the months of May-July. Capture data were compared with data collected by similar methods in 1997-2001. Key results. The population structure of M. temminckii was dominated by juveniles, with few large adults or small juveniles detected and a missing size class was evident. Retrospective analysis of 1997-2001 data revealed that the population was likely to be in decline even then, despite high capture rates. Conclusions. The M. temminckii population showed significant declines that indicated that the population had experienced stressors of unknown origin. The status of M. temminckii at the refuge is concerning, given the protection afforded this remnant population. Implications. Short-term data from 1997-2001 indicated a healthy M. temminckii population, whereas longer-term data showed that the population has declined, resulting in significant demographic changes. Continued monitoring will be necessary to develop management recommendations and track the impact of implemented management practices. Longer-term monitoring of long-lived vertebrates is required to identify population trends.