Thirty Year Record of Hurricane Disturbance and Recovery in Mangrove Forests Across the Caribbean Basin

Abstract:

Mangrove forests occupy a large portion of coastlines in the tropical and sub-tropical latitudes. They provide numerous ecosystem services, including stabilizing coastlines, sequestering carbon, and reducing erosion. Mangroves also act as a buffer during severe storm events, absorbing wave and wind energy and storm surges. In the Caribbean, where tropical storms are common, mangroves protect the inland area from greater destruction but can be heavily damaged themselves. The rate at which a mangrove forest recovers, if it recovers at all, is variable and what environmental factors that impact recovery are not fully understood at the landscape scale.

This research analyzes hurricane disturbance events in the Caribbean to better understand mangrove resilience. Using satellite imagery, airborne lidar, and historic cyclone paths, we estimate the overall impact area of tropical storms categorized by tropical storm intensity, the extent of forest damage, and the loss of canopy height. Within each of the impact areas we estimate the annual area of damage based on significant and persistent changes in remotely sensed vegetation metrics to capture areas of prolonged canopy turnover. Then the trajectory of forest regreening was monitored for the following year in damaged areas in order to differentiate between short- and long-term hurricane impacts. Our analysis shows that total mangrove damage across the Caribbean increases with increasing storm intensity, canopy height, and landfall of hurricanes in Mexico, Cuba, and the United States - the Caribbean’s major mangrove-holding nations. Despite extensive mangrove damage during highly active hurricane years (2017, 2008, 2004, 2005, and 2001), mangroves are a highly resilient species. Only 56 of 24,053 km2 of mangrove forests considered within this study were potentially lost due to hurricane damage, while only 1,501 km2 were significantly damaged even though 17,995 km were within the path of hurricanes. However, areas that take more than 4-5 years to recover completely can experience further loss or collapse. By analyzing these patterns in recovery time and forest structure related to storm intensity, we are able to identify landscape and geomorphic patterns that influence mangrove resilience which enable the prediction of vulnerability to future storms.