Hurricane disturbance and vegetation dynamics in the Cordillera Central, Dominican Republic

Abstract

Hurricanes are intense, frequent disturbances in the Caribbean basin, often regarded as important agents in structuring ecological patterns and processes. The topography and vegetation of tropical montane forest landscapes interact with the forces of hurricanes to create complex patterns of disturbance. In this study, remote sensing and field inventory of forests were used to reconstruct wind and rain disturbance from Hurricane Georges in the Cordillera Central, Dominican Republic. Spatial patterns of hurricane disturbance and the relationship of disturbance with the topography, the physical forces of the hurricane, and the biota of the landscape were analyzed using geographic information systems. The effects of hurricanes on forests were addressed by comparing structure and composition across forest types and levels of hurricane severity. Hurricane disturbance was distributed over a small portion of the study area; only 11.3% of the landscape was disturbed by wind and 4.3% was disturbed by rain. Disturbance from wind was concentrated at high elevations to the south of the site's major topographic divide. Pine forest was disproportionately affected both in terms of area disturbed and the severity of effects on forests. The proportion of live undamaged basal area was reduced by 7.1% in cloud forest, 32.0% in mixed pine, and 60.5% in pine forest compared to undisturbed control plots. Whereas effects were most severe in pine forest, pine forest composition was unchanged because of the overriding influence of climate. Cloud forest composition saw minor changes with increasing importance of several early-successional species. In mixed pine forest, areas disturbed by the hurricane saw Pinus occidentalis Swartz decrease in importance, but the low magnitude of this change suggests it may take several hurricanes to convert these communities to cloud forest.