High Mortality for Rare Species Following Hurricane Disturbance in the Southern Yucatan

Hurricanes are an important part of the natural disturbance regime of the Yucatan Peninsula with the potential to alter forest structure and composition, yet investigations of species-level responses to severe winds are limited in this region. The effect of a category 5 hurricane (Hurricane Dean, 21 August 2007) on dry tropical forests across the southern Yucatan was examined with respect to tree damage, mortality, and sprouting. Damage was assessed 9-11 mo following the hurricane in 92 (500 m(2)) plots stratified by wind speed and normalized difference vegetation index (NDVI) change classes over a 25,000 km 2 study area. We investigated the relative importance of biotic (i.e., species, size, and wood density) and abiotic (i.e., wind speed) factors to better explain patterns of damage. Overall mortality was low (3.9%), however, mortality of less common species (8.5%) was elevated more than fourfold above that of 28 common species (1.8%), indicating immediate selective consequences for community composition. Species varied in the degree and type of damage experienced, with susceptibility increasing with tree diameter and height. Wood density influenced damage patterns only in areas where a critical threshold in storm intensity was exceeded (wind speeds >= 210 km/h). Although overall, damage severity increased with wind speed, common coastal species were more resistant to damage than species distributed farther inland. Our findings suggest that selective pressure exerted by frequent hurricane disturbance has, and will, continue to impact the floristic composition of forests on the Yucata'n Peninsula, favoring certain wind-resistant species.