Effects of Marine Plant Diversity on Community and Ecosystem Processes
A. Randall Hughes, Florida State University Coastal and Marine Laboratory
31 Aug 2012
Genetic variation in a wide variety of species can have important ecological effects at the population, community, and ecosystem levels. In the seagrass Zostera marina, genotypic diversity enhances the seagrass response to natural and experimental disturbances. In addition, correlations between Zostera genotypic diversity and seagrass shoot density in natural populations suggests that the effect of genotypic diversity on disturbance resistance is sufficiently strong to impact patterns of primary production in the field, despite the presence of many confounding factors. The consequences of lower plant production in low diversity plots extend beyond the seagrass itself to the community of organisms it supports. Likewise, the identity and diversity of the associated community can have important effects on plant biomass and production: a mesocosm manipulation of seagrass genotypic diversity and grazer species diversity confirmed the positive effects of genotypic diversity on seagrass biomass; however, this effect occurred only in the presence of a single grazer species. Recent experiments with the marsh plant Spartina alterniflora demonstrate that such effects are not limited to seagrasses. These results suggest that conservation and restoration efforts should include considerations of plant genetic diversity not only for long-term evolutionary potential, but also for short-term ecological success.