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An understanding of the effects of harvest on wild plant populations is essential for discerning the ecological impacts of past and present human uses of wild species, and for conserving species which are currently overexploited. This dissertation builds on theories and methods to describe and predict the impacts of harvesting non-timber forest products (NTFP) through an ethnoecological study of the terrestrial bromeliad Aechmea magdalenae. A. magdalenae is harvested from the rainforests of South-eastern Mexico where it has a long history of exploitation. The fiber extracted from its leaves is used to embroider leather articles in an artwork known as piteado. The sustainable harvest of this species has been promoted in Mexico as a strategy to conserve forests and provide local people with a stable income. / A combination of demographic, ethnobotanical and participatory methods was used to quantify harvest strategies, measure their impacts on A. magdalenae populations, and assess potential for cultivation. The impacts of harvesting: (1) ramets used for forest plantations; (2) leaves and ramets; (3) and whole plants and ramets, were measured by comparing the dynamics of harvested and nonharvested populations. The demographic implications of variation in the ecological and human context of harvest were examined. The effects of variation in traditional management and traditional knowledge of this species were also quantified. / Analyses using matrix models indicate that primary forest populations harvested for their ramets are declining due to overexploitation. Secondary forest populations are tolerant to ramet harvest and show elevated rates of growth and vegetative propagation in wild and cultivated plants. High rates of fiber harvest have little impact on population growth rates and increase A. magdalenae's tolerance to ramet harvest. The economic and ecological implications of local harvesting strategies vary within regions as well as between regions with short and long histories of A. magdalenae management. A test of the accuracy of estimating maximum sustainable harvests using current approaches illustrates that these methods can lead to erroneous conclusions. / The results of this study are used to suggest improvements for approaches to assessing the impacts of NTFP harvest, for combining traditional ecological knowledge and science in management plans, and for using participatory ecological and ethnoecological research to promote conservation.