Resumo

ROXANA, Yockteng  e  CAVELIER, Jaime. Diversidad y mecanismos de dispersión de árboles de la Isla Gorgona y de los bosques húmedos tropicales del Pacífico colombo-ecuatoriano. Rev. biol. trop [online]. 1998, vol.46, n.1, pp.45-53. ISSN 0034-7744.

The flora of the continental Island of Gorgona (Colombia) and that of the forests on the Chocó biogeographical region of Colombia and Ecuador were compared with species-area curves and species diversity indexes, either previously published or calculated using the original data of the vegetation surveys. The curves and the Shannon diversity index showed that the forest of Gorgona is less rich in tree species than the mainland sites. Furthermore, the Shannon equitability index in five continental lowland forests was higher that in Gorgona, suggesting that the number of trees per species is more evenly distributed in the continental forests. In Gorgona, seed and fruit dispersal was primarily carried out by birds (49.7 % of the species), as reported for the islands of Galapagos in Ecuador (60 %) and in the biogeographic island of the cloud forest of the Serranía de Macuira, Guajira, in the north of Colombia (51 %). In contrast, dispersal by mammals was the main mechanism for tree species in the continental forests of Cabo Corrientes, Bajo Calima (Colombia) and Los Tuxtlas (México). Although the forest at Gorgona is not particularly rich on tree species, it plays an important role in the protection of marine ecosystems. A reduction in forest cover would result in an increase in soil erosion rates and landslides that would greatly affect marine biota, particularly of coral reefs.

Palavras-chave : Species richness; diversity; dispersal; lowland rain forest; island; Chocó.