Estuaries provide important habitat for many fish and wildlife and are among the most imperiled ecosystems on Earth. One of the many challenges facing estuaries is increasing salinity from factors like sea level rise and reduced freshwater inputs from droughts and human water use. In the San Francisco Bay Estuary salinity is a nascent threat with looming management challenges for species like the Northwestern pond turtle (Actinemys marmorata, WPT). While WPTs in some parts of their range show behavioral and physiological adaptations to increased salinity levels, it is unclear how resilient they will be to future elevated salinity levels. We studied the effects of salinity on the distribution and occurrence of WPTs in Suisun Marsh, which consists of a mosaic of tidal and managed brackish water wetlands with a natural salinity gradient. We analyzed occurrence data from visual encounter surveys using dynamic occupancy models to predict occupancy as a function of environmental covariates. WPTs were observed at 65.8% of sites on at least one occasion and salinity was the most important factor associated with turtle occupancy, which decreased with increasing salinity. By understanding the role that salinity plays in determining the distribution of WPTs, managers can aid future conservation efforts.

Since 2012, Melissa has worked at the California Department of Fish and Wildlife (CDFW) in the Suisun Marsh Program. At CDFW, Melissa works on a multidisciplinary team researching and monitoring a variety of sensitive fish and wildlife species, including Northwestern Pond Turtles and the endangered Salt Marsh Harvest Mouse. She is also pursuing her doctorate degree in Ecology at UC Davis, focusing on Northwestern Pond Turtle habitat use and demography in Suisun Marsh. She is especially interested in studying the effects of tidal restoration and varying land management strategies on wildlife populations.