In situ investigation of the influence of desiccation on sediment seed banks and population recruitment of the seagrass Ruppia sinensis in the Yellow River Delta, China

Abstract

Abstract The alarming rates of decline in seagrass meadows have attracted attention globally. In this study, we investigated the influence of desiccation on the sediment seed bank and population recruitment in a Ruppia sinensis seagrass meadow where the surface sediment occasionally experiences long-term air exposure in the Yellow River Delta. Results showed that habitat desiccation had significantly impacted the R. sinensis population. However, a considerable number of sediment seeds survived the long-term desiccation of the surface sediment. After a 5-month period of desiccation (from December 2017 to April 2018) of the surface sediment, followed by resubmersion, the R. sinensis seedling density in May 2018 was 1360.86 ± 330.66 seedlings m−2, which was similar to that in March 2017. Thus, desiccation appeared to have retarded seed germination and seedling establishment. These results indicated that sediment R. sinensis seeds can survive the long-term desiccation of their habitat. Unlike most seagrass species, we observed for the first time that R. sinensis seeds in sediment exhibited considerable tolerance and adaptability to habitat desiccation. Our results provide new insights into the resilience of R. sinensis populations affected by desiccation and serve as a useful reference for the conservation and restoration of Ruppia populations around the world.