WETLAND DYNAMICS AT THE SOUTHERN SHORE OF THE SALTON SEA

Declining water levels in the Salton Sea of southern California have resulted in the formation of unmanaged wetlands maintained by agricultural drains along the freshly exposed playa. Nutrient-rich agricultural runoff has caused explosive growth in many of these wetlands, which has resulted in the colonization of many endangered species such as Yuma Ridgway’s rail and desert pupfish. Federally wetland habitat on nearby wildlife refuges use comparatively clean Colorado River water and maintain habitat productivity by controlled burns. Analysis of satellite imagery shows wetland burning appears to result in an increase in vegetation density and strength during recovery and regrowth. Colorado River water has low levels of dissolved selenium, which evaporatively concentrates and can be present at high concentrations in agricultural drains. Selenium bioaccumulates in wildlife and is known to cause teratogenesis and mortalities in avian species, a phenomena that has been historically observed in piscivorous birds at the Salton Sea. Drought and additional water diversions from the Colorado River to maintain water levels in Lake Mead has increased focus on the sources of water used for wetland habitat at the Salton Sea. Colorado River water used in federally owned habitat is expensive, particularly in comparison to agricultural drain water which would be available for minimal costs. In this study, we will be examining the impact of wetland burning on selenium geochemistry in selected cattail wetlands. Remote sensing applications will be used to enhance observations of wetland recovery, and examine potential interferences caused by local geothermal discharges.