Human Impacts, Environmental Disturbances, and Restoration of Seagrasses

The chapter focuses on the lacking natural recovery of eelgrass (Zostera marina). It documents how eutrophication has impacted the coastal environment, leading to ecosystems in a state of multiple stress with losses of essential ecosystem services. The stressors are described, and their thresholds are measured and quantified. The results provide guidelines of how to find optimal locations for restoration of seagrass habitats. This includes several steps where modeling and GIS activities are using the described thresholds of area specific stressors to create suitability maps. Followed by field observations by drones and divers at specific sites before test transplanting activities are carried out as the final indication of viability for large-scale restoration. Finally, we quantify the developing ecosystem services after successful restorations, including carbon, nitrogen and phosphorus sequestration, nitrogen and phosphorus immobilization of nutrients during the growth season, and the development of higher faunal densities, food-web signals, and biodiversity for infauna and epifauna.