About This Project

Epiphytes grow in the canopy of trees, deriving support from their hosts, but getting water and nutrients from rain and mist. They enhance nutrient and water cycles and provide resources to arboreal animals in forests, but their functions in human-altered habitats remain unknown. As conversion of forest to agricultural land in the tropics is increasing, I wish to examine the effects that pastures have on epiphyte population variability in the tropical landscapes of Costa Rica.

Ask the Scientists

What is the context of this research?

Trees in pastures may act as “keystone” structures, providing connectivity and refuge for plants and animals (Werner et al. 2005). However, pastures support fewer trees separated by greater distances, than in forest habitats. Epiphytes on pasture trees may be vulnerable to lower gene flow and inbreeding because of their isolation (Trapnell & Hamrick 2005). I am focusing on the epiphyte Catopsis nitida in Bromeliaceae (pineapple family) because they are common in both forest and pasture habitats, which is uncommon for many other epiphyte families. Our initial findings show that populations of Catopsis nitida are closely related within pastures. However, between pastures, epiphyte populations are not closely related, suggesting that mating among epiphytes may be restricted within pastures.

What is the significance of this project?

Epiphytes make up about 1/3 of the plant diversity in the tropical forests of Latin America (Gentry & Dodson 1987). Understanding the role of land conversion on epiphyte populations can tell us a great deal about conservation practices and land management for these important tropical plant populations. Because of the previously difficult nature of obtaining epiphyte samples in forest trees (many found high in the canopy of trees), few studies have focused on population genetics of epiphytes. Furthermore, the long standing culture of both dairy farming and land preservation makes the community of Monteverde, Costa Rica an appropriate location for this study because there is a mixture of active pasture farms and preserved forest land (Nadkarni & Wheelwright 2000).

What are the goals of the project?

My near-term goal is to understand the effects that isolated systems (e.g., pasture areas) have on epiphyte populations in the montane tropical landscapes of Costa Rica. The funds will be used to: a) identify the genotypes using microsatellite markers of the epiphyte Catopsis nitida for individuals from pasture trees and from forest trees, b) germinate seeds of Catopsis nitida to compare genotypes of offspring to parental plants, and c) develop microsatellite markers for an additional Bromeliaceae species. My longer-term goal is to relate my findings to other tropical areas and other species in ways that will inform conservationists and land-managers about the vulnerability and resilience of canopy-dwelling plants in tropical landscapes to enable scientifically-sound land use decisions.