Hurricanes are frequent but episodic natural disturbances particularly along tropical and subtropical coastal regions around the world that can have major impacts on ecosystem structure and function. The purpose of this presentation is to explore the historical record to develop a comprehensive perspective and understanding of how hurricanes impact mangrove ecosystems and their recovery.
Results/Conclusions
The National Hurricane Center documents hundreds of hurricanes that that came ashore in Florida and the Gulf of Mexico since 1851, with many areas hit repeatedly. Historical evidence shows that some areas of the coast have been focal points for hurricane activity, but records of multiple hurricanes making landfall at the same area of coast in a given season are extremely rare. These storms have had direct and indirect effects on coastal ecosystems across this region. In mangrove forests, initial ecosystem damage and subsequent recovery have been shown to depend not only on hurricane intensity (wind speed, forward speed, storm surge), but also on vegetation structure (stand density, tree height, biomass accumulation) and environmental gradients (tidal elevation, salinity, nutrient availability). Experimental studies have shown that increased availability of nutrients can increase the vulnerability of mangroves to hurricane damage and prolong the time to full recovery. Rates and patterns of recovery are often influenced by huge subsidies of sediments and fresh water delivered to the coastal zone by hurricanes. Damage has been shown to vary across the coastal landscape with the level of the disturbance dependent on distance from the hurricane eye wall. Damage has been correlated with mangrove tree size and stand density, with greater destruction recorded in forests with larger and lower densities of trees. A few long-term studies found that a large fraction of the damage caused by hurricanes occurs as delayed mortality in the years after the storm. Besides the direct physical damage, indirect impacts of hurricanes also alter many ecological processes including reproduction, nutrient cycling, and biotic interactions. In addition to inflicting physical damage, historical records and imagery suggest that hurricanes can play an important role in long-distance dispersal that can be a major driver for regime shift in the coastal zone.