Deforestation threatens biodiversity in the tropics, not only by reducing the amount of forest, but also by dividing the forest that remains into small, isolated patches that species may not be able to reach or where species may not be able to survive once they get there. Epiphytes, plants that live atop other plants instead of on the ground, are a major part of the biodiversity in many species-rich tropical forests, and many of these epiphytes are orchids. Orchids have tiny seeds that wind can move over long distances, so they might be able to travel from one patch of forest to another. However, the tiny seeds cannot grow without the aid of specialized fungi,known as mycorrhizal fungi,that provide the orchids with nutrients. If the fungi are missing from a forest patch, the orchids will not survive once they get there. This research will test whether it is the dispersal of the seeds or the absence of the fungi that keeps orchids from growing in patches cut from tropical forest. Work will focus on Epidendrum firmum, an orchid found in the heavily used, mid-elevation forests of Costa Rica, and use a combination of molecular genetics in the U.S. and field experiments in Costa Rica.
Because tropical epiphytes are among the most globally threatened groups of species, this research has practical value for conservation of natural resources. The work should provide valuable insights into the special ways in which dividing tropical forests into smaller patches can affect the many orchids that grow on tropical trees, whether by causing seeds to fall short or by disrupting the special ecological relationships upon which the orchids depend. The results should help guide efforts to conserve and restore the diversity of species in tropical forests. Furthermore, the project will train graduate and undergraduate students in tropical field research and molecular biology, and strengthen international scientific collaboration.
Deforestation threatens tropical biodiversity by reducing the amount of habitat for forest species, limiting their ability to disperse among remaining habitat patches, and by limiting their ability to survive there. A major component of the plant biodiversity in many species-rich tropical forests is epiphytic plants (i.e., non-parasitic plants that live on trees, and many of these epiphytes are orchids. Epiphytic orchids produce many tiny seeds that the wind can potentially disperse across long distances, but these tiny seeds require the presence of specific fungi, known as mycorrhizal fungi, in order to obtain the nutrients that they need to grow. Our research assessed whether limited seed dispersal or the absence of fungi alters the ability of orchids to germinate in remnant habitat patches of tropical forest in an agricultural landscape. This research focused on Epidendrum firmum, an orchid found in the mid-elevation forests of Costa Rica, and used a combination of molecular techniques in the U.S. and field experiments in Costa Rica. This project contributed to the dissertation research of one graduate student, provided mentoring opportunities for a post-doctoral research associate, and provided training in molecular laboratory techniques for a second graduate student and two undergraduate students from diverse backgrounds at the University of Georgia. These research activities have contributed to the development of molecular laboratory resources and protocols as well as novel experimental techniques in the field. Since tropical epiphytes generally represent an at-risk community of species, this research has practical value for the conservation of biodiversity and natural resources. We have gained valuable insights into how fragmenting tropical forests into smaller patches can affect the orchids that grow on tropical trees and we are communicating (via scientific publications as well as national and international meetings) suggested conservation practices for the preservation of the ecological relationships upon which the orchids depend.
