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Gewählte Doctoral Thesis:

Susanne Scheffknecht (2013): GERMINATION AND SEEDLING ESTABLISHMENT OF EPIPHYTES IN MEXICAN FORESTS AND COFFEE PLANTATIONS.
Doctoral Thesis - Institut für Botanik (Botany), BOKU-Universität für Bodenkultur, pp 62. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
Shade coffee plantations can be important refuges for epiphytes, but are not suitable for all species. We compared germination, growth and mortality rates of epiphyte species that differ in their ability to colonize shade trees in coffee plantations in central Veracruz, Mexico. We tested if germination rates of three bromeliad species (Tillandsia juncea, T.heterophylla, T.viridiflora) were related to their distribution between the three different habitats (forests, old and young coffee plantations) and to what extent substrate and microclimate affected germination. We analyzed growth and mortality rates of transplanted juveniles of the same three bromeliad species and of two orchid species (Jaquiniella teretifolia, Lycaste aromatica) to see if the different habitat features affected growth and survival of plants. We tested if tree and branch characteristics were related to growth and survival of the epiphytes. We found that germination rates, growth and mortality of our study species generally reflected the natural patterns of species occurrence and abundance in the three habitats, with species restricted to forests showing lower germination, growth and survival rates in coffee plantations compared to forests, whereas the colonizing species showed higher germination and growth rates in coffee plantations. In coffee plantations, herbivory had a severe effect on some of the bromeliad juveniles during the wet season. Given the substantial contribution of herbivory to the mortality of juveniles and the significant differences between habitats, herbivory may partly impede the colonization of young coffee plantations by some epiphytic bromeliads. Our results also suggest that higher mortality rates of the forest species as well as lower growth rates may co-limit the colonization of coffee plantations, especially in young plantations with small shade trees. We also found that a more humid microclimate favors germination and growth of the species restricted to forests.

Betreuer: Hietz Peter

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