FOREST RECOVERY IN THE KARST REGION OF PUERTO-RICO

Widespread deforestation has led to an increase in secondary forest in the tropics. During the late 1940s in Puerto Rico, forest covered onl y 6% of the island, but a shift from agriculture to industry has led t o the increase of secondary forest. This study focuses on the regenera tion of forest following the abandonment of pastures and coffee planta tions located in the karst region of Puerto Rico. Alluvial terraces an d sinkholes were the principal features used for pastures, shifting ag riculture, and coffee plantations, whereas mogotes (limestone hills of conical shape) were burned periodically or cut for charcoal or wood p roduction. Abandoned pasture sites had a greater woody species diversi ty in comparison with coffee sites. The density of woody stems was gre ater in the abandoned pasture sites and Spathodea campanulata was the dominant species. In coffee sites Guarea guidonia was the most abundan t species. There was no difference in basal area between the two land uses. Canonical Correspondence Analysis applied separately to adults a nd seedlings clearly separated each community according to land use. S eedling composition in coffee sites indicates a resistance to change i n terms of the dominant species while in the pasture sites the composi tion will change as the dominant species S. campanulata is replaced wi th more shade tolerant species. Patches of forest that remained on the steep sides of mogotes and the presence of bats appears to have enhan ced forest recovery, but the land use history of these sites has affec ted the pattern of regeneration and will continue to affect forest dyn amics for many years. The karst area is a critical environment for wat er resources and biodiversity and its conservation and restoration is essential. (C) 1998 Elsevier Science B.V. All rights reserved.