Enhancing restoration of a generalist seagrass: seed processing and germination improvements for <i>Ruppia maritima</i>

Abstract Introduction Seagrass meadows, composed of submersed aquatic vegetation (SAV), are changing due to climate change, increasing the need for adaptive restoration approaches such as incorporating native species that thrive under new environmental regimes. For example, in the Chesapeake Bay, Virginia, the expansion of generalist species Widgeongrass ( Ruppia maritima ) despite continuing environmental change offers a new route for SAV restoration, but little research is available surrounding Widgeongrass's restoration potential. Objectives This study examines the impacts of seed characteristics—area, fall velocity, and shape—and length of time in cold storage on germination in order to inform best practices for Widgeongrass restoration. Methods Germination was quantified every month for a year after cumulative cold storage; and seedling emergence in soil was measured after unoxygenated cold storage of 1 and 2 years. Results We found that seed size is positively correlated with fall velocity, which is positively correlated with germination, but the polymorphic seeds exhibit different germination rates. We observed that short‐term cold storage enhanced germination rates, which peaked after 5–7 months before decreasing, while emergence was negatively impacted after 2 years of cold storage. Conclusions These results provide the basis for clear recommendations for Widgeongrass seed processing, storage, and restoration planning. While our results are specific to Widgeongrass in the temperate lower Chesapeake Bay, the species occurs worldwide and our methods provide a guide that can be adapted to other climatic regions.