Can seagrass beds heal themselves after physical disturbance? Implications for restoration

In this study we sought to understand the response of seagrass habitats that were physically disturbed by motor vessel groundings in the Florida Keys National Marine Sanctuary (FKNMS).  This information is needed to plan the scope of restoration efforts for future groundings as required by Section 312 of the National Marine Sanctuaries Act. We monitored 27 vessel grounding sites in Thalassia testudinum dominated shallow water habitats of the FKNMS for seagrass recovery.  These injuries represent a broad spectrum of disturbance sizes, volume of displaced sediment, ages, depths, and local environmental settings.  We used classification and regression trees, multiple regression, and discriminant function analysis to identify those site and injury characteristics that significantly contributed to the natural recovery (or lack thereof) of the injuries.  Preliminary results suggest that simply the volume of displaced sediment from the original injury plays the most important role in driving subsequent natural recovery.  This finding suggests that restoration efforts could be significantly accelerated by expeditiously returning injuries to their original sediment level.