چکیده (انگلیسی):

Large numbers of epiphytic bromeliads are regularly harvested from the canopy of cloud forests for traditional uses and illegal trade, with detrimental effects on the viability of populations. Since a significant proportion of natural mortality in epiphytes is caused by detachment from the support trees, harvesting of fallen plants represents a potential supply for commercial use that would have no impact on bromeliad population dynamics. We evaluated the potential of four cloud forest sites in southern Mexico to supply epiphytic bromeliads for commercialization. Bromeliad diversity and abundance was determined by sampling eight trees in each forest site and the number of fallen plants from these trees was recorded over three years. To determine the size of the potential harvest from the forest floor, the rate of bromeliad fall, and the species, condition and size of fallen individuals were recorded monthly in 10 plots
(10 _ 10 m) at each site over a period of five months. Bromeliad fall rate varied from 26,910 to 92,712 rosettes ha_1 y_1. Of these, ca. 60% (16,770 to 55,992 rosettes ha_1 y_1) of the 18 species identified were in a suitable condition for commercialization. Diversity and abundance in the canopy were positively related to that of the fallen rosettes (P < 0.05), indicating that the harvesting rate can be estimated from population densities in the host trees and that the fallen plants could therefore be used to indirectly evaluate the epiphyte community. Assessment revealed that the forest canopy could act as a nursery to supply a constant ‘‘rain’’ of bromeliads with minimum production costs. Even one ha of cloud forest can supply thousands of marketable bromeliads every year. Harvesting of fallen epiphytic bromeliads could add to the diversification of cloud forest management, contribute to the reduction of excessive canopy harvesting pressure and supply plants for forest enrichment programs. The results of this study are discussed in the context of the local stakeholder participation and national conditions..