Short-term response of secondary forests to hurricane disturbance in Puerto Rico, USA

We examined the short-term (4–5 years) dynamics of stand structure and species composition of two chronosequences of secondary forest stands derived from abandoned cattle pastures (15–81 years since abandonment) in the Luquillo and Carite Mountains of eastern Puerto Rico. In 1998, Hurricane Georges struck Puerto Rico, affecting both chronosequences. Stem densities decreased in all sites with a significant effect of age-class. Intermediate-aged sites had the greatest decrease in density and the largest change in the distribution of size classes. Although there was a significant decrease in the small size classes (<10 cm dbh), due to physical damage from falling debris, there was a large increase in the 10–20 cm dbh classes, due to growth of surviving stems. Basal area decreased in 11 of the 15 sites and showed only a slight gain in the other sites. Species richness decreased in all but one site and there was a greater proportional loss of shrub species than tree species. Multivariate ordination successfully placed the resampled sites within their original ordinations with acceptable stress, indicating there was no significant change in species composition or deviation from successional pathways during the period. Compared with effects of land-use, hurricanes create minor variation from expected successional pathways. However, hurricanes contribute to regional- and landscape-scale variation in both stand structure and species composition.