Early successional sites and the recovery of vegetation structure and tree species of the tropical dry forest in Veracruz, Mexico

摘要

Secondary successional vegetation represents one-third of the 7% of the original area covered with tropical dry forest that remains in central Veracruz, Mexico. In this region, fallow periods are short, in general, no longer than 7–10 years, and old secondary successional sites are not available. Therefore we evaluated the potential of very early successional stages of tropical dry forest with different land use histories for recovering the structure and composition of regional forest. We compared five early successional sites (7–72 months) with five nearby forest remnants. Successional sites had reached 38 and 30%, respectively, of the average basal area and density recorded for the forest understories, but only 5 and 10%, respectively, of the basal area and density of forest overstories. A total of 132 tree species were recorded, 45 at successional and 107 at forest sites. Individuals of tree species with animal-dispersed seeds (57%) were significantly better represented than wind-dispersed (22%) and self-dispersing (21%) species in both successional and forest sites. Successional sites had already recruited 10% of the intermediate and shade-tolerant species that grow in forest remnants. However, only 20 species occurred in both early successional and forest sites, several showing resprouting ability. We conclude that the entry of forest species to the successional process at very early stages and the recruitment of individuals from resprouting may facilitate the recovery of the dry forest in Veracruz.