Aridity and forest age mediate landscape scale patterns of tropical forest resistance to cyclonic storms

Abstract

Ecological theory holds that tropical forest resistance to hurricanes should increase with stand age and aridity. However, limited data beyond a handful of long-term monitoring sites makes it hard to link resistance to hurricanes with environmental gradients. We address this by using trait data for 410 tree species, remote sensing metrics of canopy structure, and 339 plots to assess whether forest age and aridity mediate the impacts of two hurricanes in Puerto Rico. Hurricanes caused a 45% and 21% decrease in forest canopy height and cover, respectively, with a 25% increase in tree mortality. Old forest stands in wetter regions as well as those with tall canopies dominated by low wood density species were the most affected. Interestingly, high resistance to hurricanes was related to enhanced drought tolerance. These results highlight crucial complexity to include when forecasting the fate of tropical forests to increasingly stronger hurricanes in a changing climate.