Coastal ecosystem resilience: how eelgrass donor population structure influences restoration success

PRINCIPAL INVESTIGATOR: Kerry Naish (University of Washington)

CO-INVESTIGATORS: Jennifer Ruesink (University of Washington), Jeffrey Gaeckle (Washington State Department of Natural Resouces), Cinde Donoghue (WA Department of Natural Resources)

Only half of seagrass restoration projects on the U.S. West Coast have resulted in persistent populations. While reasons for reduced success may vary, the choice of donor site is regarded as significant because specific eelgrass populations may be adapted to local environmental conditions. In Washington state in particular, there is extensive variation in phenotypic traits related to growth, reproduction and fitness. However, little is currently known about the magnitude of genetic versus environmental control of these traits, and less about how such variation may impact restoration success. Further, since thermal responses in eelgrass differ across populations, there is an urgent need to understand the specific role particular populations might play in future restoration and resilience as habitats change under warming trends.

This project will firstly evaluate source and common garden populations for both genotypic and phenotypic traits across an environmental (depth, stress) gradient, and determine how source populations with distinct morphologies and life history traits perform under different conditions following transplantation. The second aim is to examine how transplanted populations respond to environmental changes due to additional shoreline restoration activities. In achieving these aims, the project will provide tools and analyses relevant for assessing eelgrass restoration strategies and resilience to environmental change and inform long-term scenario planning and efforts conducted by an increasing number of local communities to restore resilient eelgrass populations.