Impacts of seagrass food webs on marine ecosystems: A need for a broader perspective

While most recent efforts seek to identify which group of producers (e.g., epiphytic algae, macroalgae, or seagrasses themselves) plays the predominant role in individual seagrass meadows, few have considered the overall importance of all of these components in the flow of energy and nutrients on broader scales. Even though it is widely accepted that seagrass epiphytes can play an important role in controlling local food web productivity, recent results from understudied areas suggest that the importance of seagrasses themselves to marine food webs has been greatly underestimated. There is now ample evidence that grazing on seagrasses, especially in low latitudes, can be substantial. Similarly, the export of seagrass leaves has been correlated with high densities of invertebrates and fishes in both shallow waters and the deep sea. Since seagrass inhabitants (both consumers and their prey) vary greatly from site to site and region to region, our understanding of the importance of seagrasses to marine food webs lags far behind our understanding of such interactions in other habitats. Seagrasses often form extensive meadows that can be found along the coasts of every continent except Antarctica. As such, understanding the dynamics of food web interactions within these habitats, and the degree to which seagrass production is exported, is of considerable theoretical and practical importance.