California Department of Fish and Wildlife

Climate Change: Spotlight on Elkhorn Slough

Elkhorn Slough National Estuarine Research Reserve (a CDFW ecological reserve) harbors the largest tract of tidal salt marsh in California outside of San Francisco Bay. Located at the center of the Monterey Bay coastline, this reserve provides habitat for hundreds of species of plants and animals, including more than 340 species of birds. The reserve is part of CDFW's Central Region and has several projects underway related to climate change. Special thanks to Becky Suarez and Kerstin Wasson for sharing this information.

Investigating salt marsh sustainability in the face of sea level rise

With state-of-the-art technology and collaborations with NOAA, NGS, and USGS researchers are examining marsh elevations, tidal dynamics, and sediment deposition to determine which, if any, salt marshes at Elkhorn Slough will be sustainable in the face of projected sea level rise. In order to keep up with sea level rise, marsh elevation needs to continually increase, which occurs as a result of sediment deposition. The intricate dance between these variables is complicated to study, yet this knowledge is essential for designing marsh restoration strategies.

Water quality monitoring

Water quality is monitored monthly at 24 estuarine stations in collaboration with the Monterey County Water Resources Agency, the Elkhorn Slough Foundation, and dedicated volunteers. These data have shown a significant increase in temperature at almost all stations over the past 20 years. As part of NOAA's Estuarine Reserve Division System Monitoring Program, water quality is also monitored every 15 minutes at four estuarine stations. In addition, as a part of this program a weather station collects data every 15 minutes. Various predictions have been made about changes to rainfall, salinity, air and water temperature, chlorophyll, and nutrients resulting from global climate change. Researchers will be able to test these predictions in coming years because of the highly accurate 10-year baseline of data from this program.

Breeding bird monitoring

There are two monitoring programs staffed by volunteers at Elkhorn Slough that record the timing and reproductive success of birds breeding on the reserve. Current data includes 10 years of data collection on the timing of egg laying, the duration of incubation and nesting, and fledging success for cavity-nesting birds in 150 nest boxes (mostly Chestnut-backed Chickadees). Other species such as Great Egrets, Great Blue Herons, and Double-Crested Cormorants that nest together in a rookery near one of our wetlands are also monitored resulting in 10 years of data on timing and success of breeding. Both of these datasets will prove useful for examining whether native birds using woodland and wetland habitats, respectively, are shifting timing of breeding or have altered reproductive success in the face of global climate change.

Early detection of invasions by non-native species

Regular surveys of all habitat types on the reserve (estuarine, freshwater, grassland, oak woodland) are conducted to detect new invasions by non-native species. The goal is to detect invasions early enough to eradicate them. In addition to this restoration work, the reserve also maintains a database of all non-native species detected. With this information, researchers will be able to test predictions that southern species will move northward as a result of global climate change. Two non-native invertebrate species have been detected in estuarine habitats that were previously only known to have invaded coastal habitats in Southern California. Current speculation exists that these species were able to colonize Elkhorn Slough during an El Niño year, when warmer water was moving northward.

Reducing the Reserve’s Carbon Footprint

Efforts are continuously made to reduce the "carbon footprint" where possible in all daily operations. There is an overall commitment on behalf of the staff to promote sustainable practices in all activities. In addition, the new research center at Elkhorn Slough has many green building features that were chosen to offer long service life, environmentally sensitive composition, and energy efficiency.