Linking the movement of black howler monkeys to the seed dispersal service they provide to degraded forests
Onja Razafindratsima, Professor
Integrative Biology
Applications for Spring 2025 are closed for this project.
Seed dispersal, the movement of seeds away from parent plants, is vital for plant population dynamics and habitat colonization. In tropical forests, most plants rely on frugivorous animals for dispersal via endozoochory, where animals consume fruits and defecate viable seeds at favorable microsites.
The dispersal patterns of frugivores depend on their behavior, including fruit preference, movement, gut retention, and habitat selection. These factors influence seed deposition and forest composition by linking animal services to plant demography. Primates, a significant portion of frugivorous biomass in neotropical forests, are key seed dispersers. However, frugivorous primates in modified landscapes face reduced food availability and restricted movement, potentially limiting their ability to disperse seeds effectively.
Howler monkeys (Alouatta spp.) contribute to forest regeneration by dispersing seeds, enhancing survival and establishment at suitable sites. Specifically, black howler monkeys (A. pigra), found in Southeast Mexico, Guatemala, and Belize, disperse larger seeds (up to 40 mm) and a broader range of tree species than their close relatives (A. palliata) in continuous forests. However, forest degradation threatens their capacity to offer high-quality seed dispersal to the tree species they feed on, particularly the large-seeded species that have no other remaining dispersers in these anthropogenic sites.
This project examines how black howler monkey movement influences seed dispersal across a gradient of anthropogenic disturbance. We aim to:
1. Assess how vegetation structure impacts black howler monkeys’ seed dispersal potential.
2. Evaluate seed dispersal quality, including distances and germination outcomes that black howler monkeys provide to seeds of different functional traits
3. Estimate the effects of black howler monkey movement on seed dispersal distance using an agent-based model.
Role: The URAP students will contribute to both scientific research and conservation outreach through:
1. Processing photographs and categorizing seed traits: Assist in analyzing field-collected seed samples by organizing and categorizing traits such as size, shape, and condition from photographs.
2. Assist with data analysis of seed deposition, feeding behavior, and movement patterns: Work with datasets to examine how black howler monkeys influence seed dispersal distances. This includes data organization, some statistical analysis, and interpretation of seed dispersal patterns.
This project will provide students with hands-on experience in data management, analysis, and applied scientific research. Student contributions will advance the understanding of the ecological importance of an endangered primate and support the development of scientific research, science communication materials, and conservation efforts.
Qualifications: The ideal candidate for this position is a hardworking and motivated student interested in pursuing a career in ecology, biology, or conservation science. All students should have excellent reading, writing, and organizational skills, as well as previous experience or general knowledge of animal behavior and/or tropical forest ecology. Preferred qualifications include undergraduate coursework in statistics and ecology and some experience programming in R. Experience with image processing and/or reading Spanish is a plus.
Day-to-day supervisor for this project: Anaid Cardenas-Navarrete, Ph.D. candidate
Hours: 6-8 hrs
Biological & Health Sciences