Eelgrass (Zostera marina L.) seed protection for field experiments and implications for large-scale restoration

Eelgrass (Zostera marina L.) restoration efforts have historically focused on the use of adult vegetative shoots because of generally low success usin g seeds, a propagule of potential, but little-known utility, in restoration work. Previous work has shown that approximately 15% of seeds broadcast on unvegetated sediments survive to seedling stage, with losses in part resul ting from predation, burial, or lateral transport. We conducted experiments using seeds in burlap bags under both laboratory and field settings to det ermine if protecting seeds increased survival or germination rates. Retenti on of seeds from preparation to initial sampling six months later was nearl y 100%. Seedling survival at the field sites ranged from 41 to 56% in the b urlap bag treatment, compared to 5-15% for seeds without burlap bag protect ion. Under laboratory conditions, seedling survival was identical in both t reatments (50%). However, successful seedling growth noted in the protected treatment after 6 months was lost by 8 months because of significant sand accumulation over anchored seed bags. These preliminary results are encoura ging for future restoration efforts that shift the focus to the use of seed s rather than adult plants, as greater survival of seeds in a protected env ironment can offer enhanced opportunities for addressing both basic and app lied questions in restoration ecology. (C) 1999 Elsevier Science B.V. All r ights reserved.