Epiphyte vegetation and diversity on remnant trees after forest clearance in southern Veracruz, Mexico Original Research Article

Tropical biodiversity, including that of epiphytes, is endangered by conversion of rainforests into pastures and other forms of land use. The epiphytic vegetation of the lowland rainforest area of Los Tuxtlas, Mexico, is described by listing species and estimating their dry matter on 283 trees. Epiphytes on remnant isolated forest trees and in a forest corridor along a brook in a pasture site logged 28 years ago were compared with cultivated trees on the same pasture and with two undisturbed forest plots. Generally, the number of epiphytic species per tree as well as total estimated epiphytic biomass were best correlated with tree size, measured as diameter at breast height. When this was taken into account, the number of epiphytes on remnant trees was within the range found in the two forest plots. The forest plots, however, differed significantly, possibly due to differences in humidity. Epiphyte numbers on isolated forest trees showed a negative correlation with the distance from the forest border. Cultivated Citrus and Cedrela in the pasture were poor hosts. Differences in the species composition and performance of some groups may in part be explained by their physiological requirements. The attractiveness of remnant trees, many of which are figs, to seed-dispersing birds and bats may account for the comparatively high frequency of some species.