My current research at La Selva Biological Station, Costa Rica, is an examination of the factors influencing the susceptibility of native tree species to attack by herbivores and pathogens. This work is being done in collaboration with Robert Marquis, University of Missouri, St. Louis, Marcela Arguedas at the Instituto Tecnológico de Costa Rica, and Walter Marín, Universidad de Costa Rica.
Successful conservation of tropical rainforests will be depend on finding alternative uses for already degraded lands. One such use could be to grow native tree species in a plantation setting. The common plantation type is a monoculture, in which a single tree species is planted in large tracts. However, experience with tree plantations in Costa Rica suggests that monocultures of a single tree species are very susceptible to outbreaks of insect herbivores and pathogens. These pests severely depress the economic viability of such plantations. We are currently testing the viability of a moderate increase tree diversity by comparing insect and pathogen attack in five-species plots with that in one-species monocultures. In addition, these plantings have been replicated both in abandoned pasture and under the canopy of early secondary forest. Both types of vegetation are common in parts of Latin America where deforestation has been prevalent. The goal is to determine which combination of tree diversity and light level lead to lowest pest populations and highest tree growth. By studying the populations of the insects and pathogens themselves, we will begin to understand the underlying factors which control population levels of these pests. Such understanding is essential for being able to predict the outcome of plantation forestry in other locations involving other tree species. was initially funded by the U.S. Agency for International Development, and has received additional funding from the General Services Foundation and Occidental College.
Occidental College
students who have worked with this project include: Rebecca Montgomery '93,
Marra Stankus '93, Cathy Woo '93, Christina Allen '93,
Terry McGlynn '94, Suzanne Oppenheimer '94, Pembe Sowers '96, Ethan
Sadacca '97, Sarah Henshaw '97, Rachel Rodriguez '98, and Mika Zipusch '98.
Birds and insects visited the flowers of Puya berteroniana. I was interested in exploring the community-level importance of this resource.