Long-term Monitoring of Snake Fungal Disease in the Eastern Massasauga in Illinois

The eastern massasauga (Sistrurus catenatus) is state endangered in Illinois and federally threatened in the USA. In Illinois, the massasauga is limited to several small populations around Carlyle Lake, Illinois. Monitoring for the massasauga at Carlyle Lake started in 1999 and this field season marked the 21st year of the project. Over that time, we have collected information on movements, environmental data, demography, behavior, mark/recapture history, growth, health, and disease. These data are useful for assessing long-term population trends and determining what factors are impacting population size over time. Managing small disjunct populations has become increasingly common and therefore understanding how management affects population trends is imperative for small populations. Several management endeavors have occurred at our sites containing eastern massasaugas allowing us to assess the impact and success of such management activities with regards to population size, health, and disease prevalence. With the discovery of Snake Fungal Disease (SFD) in the early 2000s, health and disease information became increasingly important and added another consideration for the management of this species. We started collecting skin swabs in 2008. Since then we have swabbed 648 snakes and SFD prevalence has been approximately 20 percent consistently. Of the 648 snakes swabbed, 181 were between year recaptures allowing us to look at individual changes in SFD over time. The combination of these data has given us a holistic understanding of the population status of eastern massasaugas in Illinois and the threats to their survival.