Eelgrass (Zostera marina) is a globally distributed, nearshore foundation species that is threatened by rapid environmental changes. Climate change, in particular, has contributed to dramatic eelgrass declines in the Pacific Northwest United States. Given this urgency, Washington presently has ambitious conservation and restoration goals on the order of thousands of acres by 2040. Importantly, climate projections depict spatially variable environmental change across the Salish Sea and coastal waters. The uneven climate impacts projected for coastal ecosystems call for a better understanding of how genetic variation may support eelgrass population resilience under emerging conditions. This information is paramount for the State’s prioritization of vulnerable populations and the identification of potential source populations for transplantation.

The capacity to adapt to environmental change depends on genetic variation within a population that provides fitness benefits related to that change. Adaptations, over time, contribute to population differentiation. The Molecular Ecology Research Lab at the University of Washington has described extensive population differentiation in eelgrass across Washington State. This population structure generally corresponds to the oceanographic regions in Washington. The variable environmental conditions across these regions may contribute to population genetic structure through adaptive processes.

With the support of the NW CASC Research Fellowship, Lara will leverage the widely distributed sites in Washington Department of Natural Resources’ (WDNR) Acidification Nearshore Monitoring Network (ANeMoNe) to characterize and evaluate genetic and environmental variation among eelgrass populations. Ongoing monitoring at these sites has the advantage of providing a collection of chronological data points of temperature, dissolved oxygen, pH, light, salinity and depth, which Lara will use to characterize environmental gradients. She’ll then collect individual eelgrass shoots across the ANeMoNe sites for genotyping. Lara will find which environmental gradients are most strongly associated with genetic variation, and then estimate each population’s likelihood of adapting to projected climate change.

Lara will collaborate with WDNR to identify (1) potentially ‘interchangeable’ neighborhoods of ANeMoNe eelgrass populations, and (2) potentially ‘vulnerable’ neighborhoods, or populations. Restoration practitioners could use these delineations to prioritize conservation efforts and inform plant sourcing. Additionally, the ANeMoNe team could use these data in their comparative assessments of eelgrass health and resilience across sites and prioritize potential investments into additional environmental monitoring. These findings will contribute to WDNR’s understanding of local adaptation and differential resilience at a relevant spatial scale, supporting targeted restoration efforts across their portfolio of state-owned aquatic lands.