Survival and rebound of Antillean dry forests: Role of forest fragments

Antillean dry forests have experienced high levels of human impact for almost five centuries. Economic changes in the second half of the 20th century have facilitated forest recovery in Puerto Rico. We quantified the extent of forest cover and the community composition of representative forest fragments in the subtropical dry forest life zone (sensu Holdridge, 1967) in southwestern Puerto Rico. Forest cover, which was largely eliminated by the 1940s, stood at 48% in the western dry forest life zone in 1993. Fragments varied in land-use history and supported from 1% to 86% of the reference species sampled in Guánica Forest, a 4000-ha protected area. Reference species were well represented in forest fragments, even those smaller than 1 ha, if they had never been completely cleared, but were uncommon in forests regenerating on previously cleared sites. The studied fragments are novel ecosystems which combine native and introduced elements; Leucaena leucocephala (Lam.) De Wit, an introduced legume, was the most common species, regardless of land-use history.

► Studied dry forest fragments ranged from 0.006 to 1372 ha.
► Native species were common in sites that had never been completely cleared.
► Native species were less abundant in sites that had been completely cleared.
► Across land-use types, non-native Leucaena leucocephala was the most common species.
► These dry forests are novel ecosystems which combine native and non-native elements.