Changes in the herbaceous and vine communities at the Bisley Experimental Watersheds, Puerto Rico, following Hurricane Hugo

While herbaceous species and vines constitute a minor portion of the biomass in tropical closed forest ecosystems, they account for a substantial portion of the diversity of these ecosystems and become more conspicuous after natural disturbances. This study describes the changes in abundance and diversity of the herbs and vines during 5 years following Hurricane Hugo at the Bisley Experimental Watersheds, Puerto Rico. The cover of herbs, ferns, and vine species was sampled within a 5-m2 area in 25 randomly chosen circular permanent plots within the 13 ha of these watersheds. Sampling was done 12, 18, 36, 48, and 60 months after the hurricane. One year after the hurricane the overall mean herbaceous cover in the watersheds was 55%. Four years later, the cover and species richness of herbs and vines, but not ferns, had been significantly reduced. The only change in species diversity (Hʹ) was a significant increase in ferns. These changes are explained in terms of the extent and spatial variability of the hurricane damage, as well as changes in the tree component of this ecosystem.