Examining Drivers of Decline in Smooth Greensnakes

SUMMARY: Researchers will assess threats from industrial heavy metals and emerging fungal diseases in smooth greensnakes to inform land management and grassland snake conservation efforts.

THE PROBLEM: Grassland loss contributes to the decline of the smooth greensnake across its range, including Illinois. Of particular concern are the effects of pollution, including heavy metals and the prevalence of an emerging fungal disease, of which little information exists. 
Heavy metals can build up in the tissues of plants and animals and affect the health and survival of species throughout the food web. However, few studies have explored heavy metal build-up in snakes as a sentinel species. Snake Fungal Disease also harms snakes and has spread across North America and Eurasia. Researchers believe that the disease may spread more quickly in smaller habitats where animals are crowded together, such as the fragmented grassland habitats of smooth greensnakes.

THE PROJECT: Researchers will measure heavy metal amounts in hatched eggshells and soils from 13 sites in five Illinois counties to learn more about heavy metal bioaccumulation in smooth greensnakes. The team will explore differences in heavy metal amounts in eggshells at the regional scale to identify sites of concern. They will then compare data from eggshells of nests in their laboratory to those in the wild. This will allow the team to learn if the transfer of heavy metals from mother snakes to eggs is occurring, as well as transfer from soils.

In the second portion of the study, researchers will collect skin swabs of smooth greensnakes from three Illinois counties to study snake fungal disease distribution and frequency. By identifying areas where the disease is more common, the team can focus their continuing work on its effects on the survival and reproduction of this species.

POTENTIAL IMPACT: Pollution and disease threaten the long-term survival of smooth greensnakes and other native grassland species. Identifying heavy metal build-up in sentinel species, like the smooth greensnake, provides much-needed data and guidance for habitat improvement. Knowing the regional distribution and prevalence of snake fungal disease will also improve rapid response and inform mitigation strategies for this emerging disease threat to snakes in the region.