Actively restored ecosystems as a refuge for biological diversity: A case study from eelgrass (Zostera marina L.)

As nearshore ecosystems are increasingly degraded by human activities, active restoration is a critical element in ensuring the continued provision of goods and services by coastal habitats. Since 1997, over 1800 ha of the foundational species eelgrass (Zostera marina L.) has been reestablished in the coastal bays of the mid-western Atlantic. Here, we follow the functional recovery of the epifaunal invertebrate community associated with the restored eelgrass habitat from 2001-2013. After less than a decade, the invertebrate community in the restored bed was richer, more even, and exhibited greater variation in functional traits than a nearby reference bed. Analysis of environmental and physical data using random forests revealed the primary drivers of these differences was the increasing area and density of eelgrass directly attributable to ongoing restoration efforts. We also infer based on existing paradigms that the diverse epifaunal communities observed may have positive consequences for critical ecosystem services, including removal of fouling epiphytes from eelgrass blades and transfer of energy to higher trophic levels. Given that restored eelgrass now make up 32% of total seagrass cover in the mid-Atlantic coastal bays, this restoration may foster regional biodiversity by providing new habitat, particularly given the general decline of natural eelgrass in this region and globally.