Widemouth gambusia (Gambusia eurystoma)

Mohamed bin Zayed Species project number 142510044

Conservation of endangered evolutionary model systems inhabiting extreme environments

Southern Mexico is home to some of the most extreme freshwater environments in the world. Only few organisms have evolved to successfully cope with the toxicity found in hydrogen sulfide-rich springs. Many of them are highly endemic, only occurring in one or a few spring complexes that provide suitable environmental conditions. The current project particularly focuses on the balneario "Baños del Azufre" near Teapa, Tabasco. This is a complex of warm, sulfide springs where locals come to swim, relax, and barbecue. Once dense forest, the land directly around the Baños del Azufre was clear-cut many decades ago. Until recently, the area adjacent to the springs was primarily used as grazing pastures for cattle. In the last few years, however, we have witnessed massive land-use changes in the form of the installation of palm oil tree plantations. Such palm oil plantations had notorious impacts on endangered species around the world. Deforestation and understory death resulting from these plantations lead to increases in erosion, unnatural sediment loads in streams, and negative consequences for aquatic biodiversity.
The Baños del Azufre springs represent the key focal habitat for this project, because it is the only confirmed locality for two critically endangered fish species: Gambusia eurystoma (large-mouth mosquitofish) and Poecilia sulphuraria (sulfur molly). The small habitat, small population sizes, and impending ecosystem alterations make the Baños del Azufre a priority to protect these species. In addition to this primary sulfide spring site, the project will also survey two other spring complexes in the surrounding area, where other populations and species of endemic fish have been recorded. The project will focus on ecological assessments and conservation genetic analyses to develop management solutions for the effective conservation of these unique species.
More information on our research can be found on http://www.sulfide-life.info/mtobler/