Epiphytes in coffee plantations

Vascular epiphytes grow in humid tropical forests and substantially contribute to their biodiversity. Humid montane forests, which are particularly rich in epiphytes, are threatened by deforestation and have been replaced by coffee plantations in many areas of the Neotropics. Many, but not all, epiphytes are able to colonise shade trees of coffee plantations, which have thus become a refuge for many species and important for maintaining biodiversity. The planned project will investigate why some species are able to colonise young shade trees fast, others only colonise old shade trees and still others appear restricted to natural forests. The composition of the epiphytic communities in three plantations with young shade trees, three with old trees and three natural forests will be compared. From each of the three main groups of epiphytes in the region (bromeliads, orchids and ferns) three species will be selected, one restricted to forests, a second occurring in forests and old plantations, and a third also found in young plantations. The nine species and nine sites will be compared by studying natural populations and by experimental approaches. Germination trials will test if species are able to germinate and establish or lack safe sites. Studying transplanted seedlings and natural populations will test if growth between sites differs and is potentially limited because of differences in microclimate or herbivory. Pollinator presence will be tested by quantifying fruit set and by baiting orchid bees. Analysis of population genetics will test the hypothesis, that species restricted to the few remaining natural forests are genetically isolated and eroded. The project will contribute to our understanding of the diversity and dynamics of tropical agroforestry systems and plantations, and provide important information for a biodiversity-friendly management.

Vascular epiphytes grow in humid tropical forests and substantially contribute to their biodiversity. Humid montane forests, which are particularly rich in epiphytes, are threatened by deforestation and have been replaced by coffee plantations in many areas of the Neotropics. Many, but not all, epiphytes are able to colonise shade trees of coffee plantations, which have thus become a refuge for many species and important for maintaining biodiversity. The planned project will investigate why some species are able to colonise young shade trees fast, others only colonise old shade trees and still others appear restricted to natural forests. The composition of the epiphytic communities in three plantations with young shade trees, three with old trees and three natural forests will be compared. From each of the three main groups of epiphytes in the region (bromeliads, orchids and ferns) three species will be selected, one restricted to forests, a second occurring in forests and old plantations, and a third also found in young plantations. The nine species and nine sites will be compared by studying natural populations and by experimental approaches. Germination trials will test if species are able to germinate and establish or lack safe sites. Studying transplanted seedlings and natural populations will test if growth between sites differs and is potentially limited because of differences in microclimate or herbivory. Pollinator presence will be tested by quantifying fruit set and by baiting orchid bees. Analysis of population genetics will test the hypothesis, that species restricted to the few remaining natural forests are genetically isolated and eroded. The project will contribute to our understanding of the diversity and dynamics of tropical agroforestry systems and plantations, and provide important information for a biodiversity-friendly management.