Thursday, August 9, 2007 - 9:00 AMOOS 36-4: Damage and short-term recovery of seasonal tropical forest in the Yucatan Peninsula following consecutive hurricanes
Martha Bonilla and Karen D Holl. University of California-Santa Cruz
Hurricanes are important disturbances shaping forest structure and promoting gap formation in seasonal tropical forests. In the last 35 years frequency and intensity of these events has increased, and it is predicted that they will become even more frequent if the ocean surface warming trend continues. In 2005 the northeast region of the Yucatan Peninsula was affected by two category 5 hurricanes, Emily and Wilma. We took this opportunity to study the immediate damage and short term (1 yr) recovery of forests affected by consecutive disturbances. We surveyed the same transects soon after each disturbance (August and November 2005) and the following year (June 2006). We identified species and type of damage (defoliated, snapped, or uprooted) to all stems ≥5 cm DBH. Stem density, species density and basal area were lower after the second hurricane, compared to the first, and were reduced even further after a year. We recorded the highest percentage of damaged individuals after the second hurricane and the most undamaged individuals a year later. In all cases, defoliation was the most common damage, and uprooting the least common. In general, smaller size classes were more frequently damaged than large ones. The Importance Values of most of the common species remained similar over time; however, a few older successional species increased by the final survey, likely due to lower mortality. Our results show that these forests have a high degree of resilience from multiple disturbances, which is likely due to their long history of adaptation to disturbance.