REU in Tropical Ecology

El Verde Field Station, Puerto Rico


Application process and mentor list -

STEP 1 - make sure that you are eligible, you must:

  • have US citizenship or permanent residency

  • be an undergraduate student pursuing a bachelor degree at a college or university during the summer

  • have an interest in pursuing graduate studies in ecology or evolution

  • if selected, work full-time in our program, participating in all activities, for 10 weeks during summer (including weekends)

  • be a sophomore or higher with a GPA over 3.0.

  • submit all information required by the deadline


STEP 2 - complete and submit the application form

Before filling the application form, please have the following information with you:

  • Name and e-mail of two people writing letters of recommendation

  • Select three research areas of your preference from the list provided below (scroll down)

  • An essay describing how your professional career would benefit from participating of our summer program. Include information about Academic Goals (300 words max), Past Research Experiences (300 words max), and How will our program help you advance your career goals? (300 words max). The text goes in the application form.


STEP 3 - submit your transcripts and two letters of recommendation

  • Submit a copy of your transcripts via e-mail (as pdf or jpeg). Please send unofficial transcripts downloaded from your university web site or a copy of a recent original will do. We will contact you if we have questions.

  • Your two letters of recommendation must be e-mailed to us by the person writing them. Use this address: reu@ramirezlab.net

  • Important - Incomplete applications will not be processed.

Click here to fill the application form

Projects and Mentors

Summer 2022

Microbial Ecology and Climate Change

Dr. Sharon A. Cantrell, Univ. Ana G. Méndez, conducts research in 2 main areas where REU students can develop their projects: (1) Impact of natural disturbances (hurricanes and drought) on soil and leaf litter microbial communities; and (2) Microbial diversity along altitudinal, temperature, moisture, pH, and land cover gradients. Microbes are important components of all ecosystems, but little is known about how they are affected by natural and anthropogenic disturbances in the tropics. The first research area will focus on natural disturbances, such as hurricanes, as they alter forest structure by opening the canopy and depositing large amounts of debris (leaves and branches) on the forest floor. Our studies show that canopy opening is an important driving factor affecting soil microbial diversity. Leaf litter microbial diversity is largely affected by both canopy opening and the amount of debris. Landslides are another frequent natural disturbance in tropical regions. In temperate regions, mycorrhizal diversity is an important determinant in the successional process after landslides, but little is known for tropical regions. The second area involves the study of microbial diversity along environmental gradients of vegetation, moisture, pH, or land cover. Puerto Rico is an ideal setting to study how environmental gradients affect soil and leaf litter microbial diversity in tropical regions.

Ecological responses to disturbance

Dr. Jesus Gomez, UPR, studies how disturbance affects species and functional group assembly. His research focuses on: (1) community assembly rules, particularly how species diversity of arthropods and/or small vertebrates change in response to natural and anthropogenic disturbances; and (2) Predator-prey dynamics, with emphasis on the role of introduced species on food web structure and species distribution / habitat use. To address these questions he uses analytical tools like multivariate analysis, structural equation modeling, the Akaike information criterion (AIC), ANOVA, and Linear Mixed models. REU students can develop their independent projects developing hypotheses related to how disturbance affect communities in aquatic or terrestrial ecosystems. Disturbance is a major driver of ecosystem dynamics in the Luquillo Mountains, taking the form of small events (e.g., landslides, floods) or major catastrophic occurrences (e.g., droughts, hurricanes).

Aquatic Insect Ecology

Dr. Alonso Ramírez, NCSU, works on the ecology of aquatic insects. His research program makes emphasis on the role that insects play within their ecosystems and how they respond to major disturbances (e.g., droughts and hurricanes). Students can develop their own independent research projects in areas such as: (1) Importance of insects on ecosystem processes (e.g., insects vs. decapods in processing organic matter); (2) Insect responses to hydrological disturbances (e.g., flooding); or (3) Insect and ecosystem recovery from hurricane impacts. Climate change predictions for the Caribbean indicate that droughts and hurricanes will become more frequent in the future. In this context, it is critical to understand how those events might affect the functioning of stream ecosystems. By focusing on insects, students can develop hypothesis-driven projects on the role of insects in their ecosystems and how they might be affected by disturbances created by drought (e.g., low oxygen, low flow) and hurricanes (e.g., open forest canopy, less detritus).

Chironomidae Ecology

Roberto Reyes is a Ph.D. student in the Biology department at the University of Puerto Rico, Rio Piedras. He will be advising a student interested in working with aquatic insects of the family Chironomidae (non-biting midges). The selected student will have the opportunity to work in one of the following projects: (1) Chironomidae diversity on aquatic habitats around El Verde Field Station; (2) Mouth parts deformities in Chironomus sp. Florida larvae after exposure to sediments collected from urban streams; (3) Effect of fluctuating temperatures on the development, biomass, and behavior of Chironomus sp. Florida larvae. With these projects the students will have the opportunity to explore the different techniques used to collect these insects in the field, learn about their taxonomy and anatomical structures, and obtain laboratory skill to properly manage them under laboratory conditions.

Plant Population Ecology and Invasive Species Biology

Dr. James D. Ackerman, UPR, conducts research in 3 main areas in which REU students can develop their independent projects: (1) Natural history and the evolution of orchids; (2) Dispersion of plants and its relationship to land use history and recruitment; and (3) Invasive plant species biology. The first has its roots in evolutionary biology using Darwin's favorite model system, the orchids. As orchids are one of the most diverse groups of plants with a remarkable array of adaptations for survival and for specialized pollination, orchids are a good model system to gain insight in the diversification of flowering plants. The goal is to detect natural selection when reproductive success is rare and how these conditions affect the loss or gain of phenotypic variation. The second area involves the spatial aspects of reproductive success from seed germination to growth, development, flowering, fruiting, seed production and dispersal. This work links with studies of natural selection and evolution, but emphasizes ecological aspects at local and landscape scales combining field experiments with current and historical patterns of dispersion. For the third area, invasive species, tropical islands are prone to invasions and Puerto Rico is just beginning to see an explosion in the number of exotic species becoming naturalized and invasive. How such species affect ecosystems and what might be the pattern of spread is of great interest to the integrity natural areas. Data on distribution and reproductive ecology are often combined with species distribution models to address these problems.

Wetland and Riparian Ecology

Dr. Tamara Heartsill-Scalley, US Forest Service, studies ecological connections (e.g., energy and biomass flow) between terrestrial and aquatic ecosystems. REU students will be part of projects in topics related to: (1) Patterns of understory vegetation in riparian zones under different environmental conditions; (2) Export of biomass and nutrients from headwater streams to downstream ecosystems; (3) Botanical survey in the LFDP of habitats with different past land use. The El Verde Research Area in the Luquillo Mountains provides an ideal setting for the study of connections among habitats and ecosystems. Along the longitudinal elevation and rainfall gradient in the mountains there are also lateral gradients related to topographical settings that link terrestrial and aquatic systems. REU student projects could use a combination of techniques to assess population structure dynamics, community composition, biomass pools in neighboring ecosystems and flows among these. Techniques include vegetation identification, organic matter input quantification using leaf fall traps, element ratio analysis, multivariate statistics, and assessment of environmental conditions.

Community responses to disturbance

Dr. Josué D. Santiago-Vera, Mount Mercy University, works on community ecology, using protozoa or aquatic invertebrates as model organisms to test the effect of disturbance to community structure. His research focus in studying species diversity, particularly how the community structure change in a natural habitat after any disturbance event (e.g., hurricanes, floods, droughts, anthropogenic etc.) or by recreating environmental changes under laboratory conditions to observe its effect on the community structure. Disturbance plays a major role in the community dynamics in the Luquillo Experimental Forest. Due to climate change, some disturbance events are predicted to increase. Disturbance such as droughts and hurricanes in Puerto Rico will become more frequent in the future. By focusing on either protozoa or aquatic invertebrates, students can develop hypothesis-driven research projects on how disturbance affect these organisms.

Freshwater Fish Ecology and Conservation

Dr. Gus Engman, University of Tennessee, studies the ecology, conservation, and management of inland fishes. His research focuses on how anthropogenic drivers, such as urbanization, dams, invasive species, and climate change affect fish habitats and assemblages. Students can develop their own research projects in area such as: (1) the fish species composition of river reaches downstream of dams; (2) impacts of non-native/invasive fish species on native fishes; or how hydrology mediates native-invasive species interactions and species dominance in novel fish assemblages.

Movement Ecology of Freshwater Shrimp

Dr. Santo's work in the Luquillo LTER concentrates on the movement ecology of freshwater shrimp. Specifically, he is interested in the shrimp species' movement response as a function of hydrological disturbances and how individual movements produce emergent patterns of the shrimp spatial distribution and abundance along tropical forests streams. To accomplish this overarching research objective, he performs laboratory and experimental experiments that students could get involved in to acquire research experience. For instance, students can develop independent projects concerning topics such as: 1) spatial dynamic of freshwater shrimp species; 2) fine-scale movements of shrimp in response to stream hydrological conditions; 3) intra- and inter-specific interactions of shrimps; 4) life-history traits of aquatic fauna, and the 4) survivorship of shrimp species in relation to movement sampling techniques and environmental characteristics. The ultimate function of movement responses is to maximize fitness through optimal use of varying resources. Thus, students' involvement could help address knowledge gaps on where, why, how shrimp species move, critical pieces of knowledge considering their vital ecological roles, and the projected changes of tropical forest ecosystems due to climate change.