Ecological changes in recent land-bridge islands in French Guiana, with emphasis on vertebrate communities

摘要

In 1993 a multidisciplinary project investigating the effects of tropical rain forest fragmentation on land-bridge islands created by a hydroelectric reservoir, was initiated in French Guiana (the Saint Eugene Fragmentation Project, SEFP). The focusof the study was to document changes in vertebrate groups, including lizards, birds, non-flying small mammals, bats and primates, that have marked differences in dispersal capacities. Results are summarized of the first 4 years of research on SEFP (1 year pre-fragmentation, 3 years post-fragmentation), comparing islands with nearby control plots in continuous forest. Forest fragmentation had rapidly modified vertebrate diversity, regardless of the ability of species to disperse over water. Species present on islands did not represent a random sample of those present before isolation. Rather, a common suite of species rapidly became dominant on each island, and these species shared the following ecological traits: (i) they exhibit some of the largest body sizes in their guild, (ii) they are generalists in habitat and food requirements, (iii) they are naturally abundant in undisturbed forests, and (iv) they have a wide geographic range yet are restricted to tropical rain forest. These results are interpreted in light of other studies of rain forest fragmentation.