A team from Oregon State University and the US Geological Survey are conducting research at the Siletz Bay National Wildlife Refuge to better understand climate change impacts to tidal wetlands along the west coast of the US. Beginning in 2014, the researchers have initiated several on-going projects at the Refuge:    

Kevin Buffington, an OSU doctoral student, added the Siletz Bay NWR to a west coast-wide network of salt marsh sites developed by USGS researcher Dr. Karen Thorne and USGS emeritus researcher Dr. John Takekawa. With over two dozen sites in California, Oregon and Washington, the network enables a coast-wide comparison of sea-level rise impacts on tidal marsh habitats. At Siletz Bay NWR, Kevin used high-accuracy RTK GPS to produce digital elevation models and conduct vegetation surveys across Millport Slough and the Siletz Keys areas. Using these data, and information about sedimentation rates in past decades from deep sediment cores, the team is modeling how different sea-level rise scenarios may impact the distribution and composition of tidal marshes at the Refuge.    

The Siletz Bay NWR has also been used as a case-study site for the region to study inundation effects on plant productivity and organic matter decomposition, studies led by Dr. Chris Janousek, a research associate at OSU, and Kevin Buffington. Understanding the inputs (and loss) of organic matter to marsh soils is an important component of understanding long-term marsh sustainability as these ecosystems adjust to sea-level rise. During the 2014 and 2015 growing seasons, the team is using field mesocosms deployed at different tidal elevations along Millport Slough to study how differences in flooding level impact above and below-ground plant productivity. The team is also using small litter bags buried in surface soils to study how various environmental factors—including marsh elevation, species composition, and litter size—affect the rates of decomposition in tidal marshes. These data will help improve sea-level rise modeling, and lend insight into basic ecological processes in Oregon tidal wetlands.    

The climate change team conducted a sea-level rise workshop in November 2014 in Newport, Oregon to present preliminary findings from these studies and to engage resource managers working at Siletz and other Pacific Northwest coastal wetlands. Other members of the research team include Dr. Bruce Dugger, a faculty member in the Department of Fisheries and Wildlife at OSU and Dr. Glenn Guntenspergen, a research ecologist with the USGS. For more information about these studies, please contact Karen Thorne at kthorne@usgs.gov.   

USGS link: http://www.werc.usgs.gov/project.aspx?projectid=222