Abstract
This project will develop a management tool to predict critical thresholds required for seagrass conservation and restoration. Seagrass meadows and the services they provide are declining worldwide as a result of human perturbations. In the Swedish West coast, 60% of the seagrass has been lost since the 1980´s and is not naturally recovering. An increasing number of model-based studies suggest that this may be primarily caused by the disturbance of an important internal feedback mechanism. Dense seagrass meadows facilitate their own growth by improving light conditions - they attenuate currents and waves, trap suspended particles and stabilize sediments. If such a system is perturbed to a degree that it cannot maintain suitable conditions, a threshold for collapse is reached beyond which natural recovery becomes extremely difficult. Although this theory is now well-developed, quantitative assessment of feedback strength and related consequences are lacking. This project aims to empirically quantify how much vegetation can be lost before a system collapse and how much should be re-vegetated to improve the water quality for seagrass recovery. Novel insights about seagrass-sediment-hydrodynamic interactions will be achieved combining field data, experiments and an empirically parameterized numerical model. This model will be applied both as a scientific and as a management tool to the Kungälv area (Sweden), currently targeted for restoration by coastal managers.
Sweden