Why do research at UGA Costa Rica?

UGA Costa Rica has inspired and hosted many research projects over the years, including UGA Faculty, students, and independent researchers. We've selected a few projects to highlight below.

Managing Water Resources and Restoration

Abstract:

For the past three years, the Arenal-Tempisque Irrigation District governed by Costa Rica’s National Service of Underground Water, Irrigation, and Drainage (SENARA), has experienced drought conditions complicating water management and agricultural production. To facilitate the responsive water management decision-making process, the Costa Rica Water Resources team collaborated with SENARA, the Costa Rican Embassy to the United States, and the University of Georgia, Costa Rica Campus. The team created a Soil and Water Assessment Tool (SWAT) model based on NASA Earth observations and in situ data in order to study the local hydrological processes. From this model, the team developed a water resource inventory for the study area. The team utilized NASA Earth observations including Landsat 5, 7, and 8, Aqua and Terra, and Tropical Rainfall Measuring Mission (TRMM) Imagery to complete these tasks. The end user at SENARA was provided with continuous data to more efficiently manage water resources, benefitting local stakeholders including irrigators, and more than 1,000 individual users of the stream.

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Manipulating tropical fire ants to reduce the coffee berry borer

Manipulating tropical fire ants to reduce the coffee berry borer: Waring Trible, The Rockefeller University, New York , New York; Ron Carroll, Odum School of Ecology, University of Georgia, Athens, Georgia

1. The coffee berry borer Hypothenemus hampei (Coleoptera, Curculionidae) (Ferrari) is the most important pest of coffee production worldwide.
2. The hypothesis that the tropical fire ant, Solenopsis geminata Westwood, indirectly protects the coffee berry borer by suppressing other ant species that are the coffee berry borer’s primary predators was tested.
3. It was found that removing S. geminata from coffee plots significantly increased the disappearance of adult coffee berry borer beetles from coffee berries compared with control plots. An average of 6% of beetles disappeared from plots with S. geminate whereas 23% of beetles disappeared from plots from which S. geminata was removed. This pattern was observed on two shade coffee farms with marked differences in ant species composition, one in the rainforest in central Costa Rica and one in the cloudforest in northwest Costa Rica.
4. If the results of this small-scale study can be replicated on the farm level, then S. geminata suppression may represent a new management technique for the coffee berry borer throughout Central and South America.

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A Simplified Method for the Design and Sizing of Anaerobic Digestion Systems for Smaller Farms

A Simplified Method for the Design and Sizing of Anaerobic Digestion Systems for Smaller Farms: Will Grant, UGA Engineering student; Dr. Thomas Lawrence, UGA College of Engineering

Accepted for Publication: July 2013, Environment, Development and Sustainability

Anaerobic digestion (AD) as a waste treatment practice has existed for nearly 200 years and has become an accepted option for many farming and small scale residential operations. Many developing countries now encourage the use of AD in order to meet new environmental regulations and/or to provide small amounts of energy resulting from methane generated during the process. This development has been met with some difficulty due to the lack of resources and knowledge of the systems in many of the rural communities in which these digesters are placed. A properly designed AD system can help prevent soil and water pollution as well as help mitigate methane emissions by capturing them for use as a potential energy source. This paper focuses on providing guidance to the proper design and sizing of an AD system for typical small farms, which account for the majority of dairy farms worldwide. A focus was on the implementation of such systems as they might be applied in Central America, although the aspects studied here can be applied for AD systems handling animal waste streams practically anywhere. We provide a method for sizing of anaerobic digester systems based on design standards from the U.S. National Resource Conservation Service and using field sampled data of holding pen wash water runoff. An overview of the decision process for alternative designs is given, and simple to use nomographs are presented for use in sizing of an anaerobic digester system for smaller (non-industrial) scale farms.

Discover Life: Moth Collection & Identification

Moth survey of San Luis Valley, Monteverde, Costa Rica: Dr. John Pickering, University of Georgia Odum School of Ecology and Discover Life; Cameron Prybol, UGA undergraduate student and Discover Life Research Intern; Markus Scherer, UGA graduate and Discover Life Research Intern; Philip Barnette, UGA graduate and Disover Life Research Intern; Dr. Mark Fisher, UGA Graduate and Discover Life Intern.

Insect development is closely linked with temperature, yet there is little understanding of how climate change may affect insect species and their interactions within ecological systems. Possible impacts include asynchrony with host plants and changes in levels of parasitism, predation and susceptibility to fungi and other pathogens. This project is documenting how variations in weather patterns across years affect moth relative abundance, phenology, and voltinism. Since May 2012, interns have photographed 35,000 moths at UGA Costa Rica and identified 15,000 of them to 556 species. For details and photographs see www.discoverlife.org/moth.

Impacts of Agricultural Pesticides and Persistent Organic Pollutants on Neotropical Migratory Birds

Impacts of Agricultural Pesticides and Persistent Organic Pollutants on Neotropical Migratory Birds During Migration: Alejandra Maldonado, Texas A&M University; Miguel Mora, Texas A&M University

The overall objective of this study is to examine seasonal patterns of contaminant accumulation in Neotropical migratory songbirds and in addition, evaluate genetic damage and cholinesterase (ChE) activity as biomarkers of exposure to contaminants. The potential for exposure differs among feeding guilds due to specific ways in which contaminants move through food webs. This project also aims to evaluate the diet and trophic position of migratory birds.

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The Relationship between Anthropogenic Land Use and Health/Disease of Wild Birds in Costa Rica

The Relationship between Anthropogenic Land Use and Health/Disease of Wild Birds in Costa Rica: Sonia M. Hernandez-Divers, DVM, DACZM, PhD


PhD Thesis; Hypothesis: A direct relationship exists between the health and pathogen prevalence/diversity of avian hosts and human use of the landscape in two land use types.

Objectives: 1) to describe the relative health of birds inhabiting forest, and shade-grown coffee plantation areas, 2) to describe the pathogen prevalence/diversity of birds in those land use types, 3) to investigate the relationships between pathogens and anthropogenic activity in the area, 4) to explore the mechanisms that are responsible for the movement of these pathogens between land use types.

Of Birds, People (and Coffee): Research and Conservation in Costa Rica; Journal of Avian Medicine and Surgery: Sonia M. Hernandez-Divers, DVM, DACZM, PhD

I am a wildlife veterinarian and currently a doctoral candidate at the University of Georgia's (UGA) Odum School of Ecology. Years ago, I was fortunate enough to collaborate with an ecologist on a study on tapirs (Tapirus bairdii) in a stretch of lowland rainforest in Costa Rica. That opened up a world for me and set me on a path towards my current professional passion: to merge veterinary medicine with an ecological perspective, in particular towards applied conservation. However, I felt I was missing the tools to truly take the host-pathogen interactions I had learned in veterinary school to the population, community, or landscape level, which an advanced ecology degree could offer. The general theme of my dissertation work revolves around how human-altered landscapes affect disease

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Habitat Use and Nest Ecology of Long-tailed Manakins in Cloud Forest Ecosystems of Costa Rica

Habitat use and nest ecology of Long-tailed Manakins (Chiroxiphia linearis) in cloud forest ecosystems of Costa Rica: Ryan Malloy

Habitat loss is the number one cause of species decline and extinction worldwide (Cayuela et al. 2006; Martinez-Morales 2005; Hale 2006). Tropical ecosystems are no exception. On average, forests are cut down at a rate of over 5% per year across Central America, with the majority of deforestation occurring in high-elevation cloud forest ecosystems (Sanchez-Afofeifa et al. 2001, Sader and Joyce 1998; Martinez-Morales 2005). Conservation efforts are in place for many threatened and endangered species; however, monitoring all species, whether threatened or not, is virtually impossible.

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Effects of Constant Resource Availability on Bird & Bee Species Richness in Shade Grown Coffee

Effects of Constant Resource Availability on Bird and Bee Species Richness in Shade Grown Coffee Plantations:Valerie Peters, PhD

Coffee is one of the most important agricultural commodities, supporting the livelihoods of an estimated 100 million people in developing countries. Field research has revealed that shade-grown coffee, grown under more natural, forest-like conditions, can be beneficial to the ecology of local animals. These animals, in turn, provide important ecosystem services, such as pollination that can make coffee-growing more economically viable for small-scale farmers and seed dispersal that sustains local forests.

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Medicinal Plant Use in the San Luis Valley,  Costa Rica: A Proposed Cuadro Basico

Medicinal Plant Use in the San Luis Valley, Costa Rica: A Proposed Cuadro Basico: Douglas A Patton

In this paper, I define the role of a local medicinal plant garden as an integral component in efforts towards conserving biological diversity while simultaneously conserving cultural diversity. The local medicinal plant garden is a botanic garden that features content focusing on a local culture’s use of medicinal plants. The local medicinal plant garden should be implemented amongst other ex-situ and in-situ conservation programs that integrate biological conservation with the local communities that are affected by the conservation measures. The establishment of a local medicinal plant requires an exhaustive study of the local culture, such that the content is accurate and properly targeted to the intended audience. Through the examination of documents that relate to the San Luis valley community’s medicinal plant use, I compile a Microsoft Access database of information on  medicinal plants. From this database, I extrapolate a proposed cuadro basico, a list of a community’s most important medicinal plants. I explain the limitations and the relevance of the cuadro basico to the San Luis valley medicinal plant garden at the University of Georgia’s Ecolodge and Research Station San Luis. This analysis of the San Luis valley  community’s medicinal plant usage is an early step in the development of the understanding of the exact nature of the role of medicinal plants in the lives of the community members of the San Luis valley.

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Gene Flow, Selection, and Maintenance of Mating System Diversity on an Ecological Gradient

Gene flow, selection, and maintenance of mating system diversity on an ecological gradient Judy Stone, PhD (PI), Bryan Prelgovisk, Martha Garro Cruz ;Department of Biology, Colby College, Waterville, Maine.

The steep slopes of the San Luis region provide an outstanding habitat for the study of how organisms respond to environmental heterogeneity. In a space of a few kilometers, the climate changes dramatically, with a concomitant change in organisms. We are interested in species that manage to span this dramatic environmental gradient. In particular, we wonder whether natural selection can optimize phenotypes for such different environments, especially when dispersal among habitats may introduce maladapted genes. We are working on a species in the tomato family called “sulfatillo”, or Witheringia solanacea. In large populations with many pollinators, plants of this species normally have a functioning self-incompatibility (SI) mechanism, whereby they can recognize and reject self-pollen, and thereby producing outbred progeny. Strangely, up at the Montevere Reserve, where pollinators are scarce, most individuals still have a functioning self-incompatibility mechanism, even though it would be beneficial to them to self-fertilize. Such self-compatible (SC) forms do occur in this species. We are conducting a common-garden experiment to document the extent to which the different reproductive strategies would be favored across a range of environments.

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Establishment, Reproduction and Genetics of Epiphytic Bromeliad Communities During Premontane Forest

Establishment, Reproduction and Genetics of Epiphytic Bromeliad Communities during Premontane Forest Succession in Costa Rica:  Alfred Mario Cascante Marin, PhD

We analyzed the differences in species richness, community composition, population structure and within-tree location of epiphytic bromeliads in contiguous secondary and mature forests in a premontane area in Costa Rica. Diversity in the mature forest was highest, and the communities differed in their composition as well as in the recruitment rates of the dominant species. Guzmania monostachia and Catopsis nutans dominated the secondary forests, whereas Tillandsia fasciculata and T. tricolor were more abundant in the mature forest. The secondary forest species showed high rates of seedling recruitment while the opposite was found for the mature forest species. Species presence and  abundance among and within habitats did not correlate with their physiological (i.e. CAM vs. C3 photosynthesis) or morphological attributes. The spatial distribution patterns were similar among habitats; bromeliads tended to aggregate on a few relatively large phorophytes. The species shared a similar vertical stratification within habitats, except for the two dominant species in the early and mid-successional stages, although its ecological implication is not clear. With some exceptions, conspecifics of different ages were located on similar substrate types (i.e. stems, primary, secondary, or tertiary branches) within the tree-crowns, which suggests limited within-tree dispersion. Differences in species composition and rates of seedling recruitment among secondary and mature forest may arise from ecophysiological differences among species; however, the combined effect of seed availability and dispersal differences may have a larger influence. Thus, epiphyte community assembly can only be understood when the differences in habitat conditions, the availability of propagules, their dispersal characteristics and requirements for seedling establishment are known.

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Effects of Fragmentation on Plant Diversity and Microclimate in Premontane Tropical Forests

Effects of Fragmentation on Plant Diversity and Microclimate in Premontane Tropical Forests: Luanna Prevost and Chris Peterson, PhD  Plant Biology Department, University of Georgia

Tropical forest in South and Central America are being lost at the alarming rate of more than 2 million hectares of forest annually (Achard et al., 2002). This deforestation creates extensive landscapes of isolated forest fragments in a “sea” of disturbed habitats such as pasture and agricultural lands. Therefore, to better manage these forests, we need to understand the dynamics of the plant community in fragmented forests.

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Feeding effectiveness of Megaphobema mesomelas (Araneae, Theraphosidae) on two prey types

Feeding effectiveness of Megaphobema mesomelas (Araneae, Theraphosidae) on two prey types: Scott Kosiba, Pablo Allen, and Gilbert Barrantes

Prey selection is essential for individual fitness; therefore, it would be expected that a predator would select prey of a higher rank (energy/time) when exposed to prey of differing quality. In this paper, we compare the feeding effectiveness (biomass consumed/time) of Megaphobema mesomelas (O. P.-Cambridge, 1892) in captivity, and the preference between two prey types: beetles and crickets. Spiders are more effective when feeding on crickets. The heavy exoskeleton of beetles increases prey-handling time in order to access a relatively smaller amount of edible tissue. Effectiveness also increases with spider and prey size (mass), with larger spiders feeding more effectively on larger prey. Spiders show a strong preference for feeding upon crickets over beetles when both prey types are offered at the same time.

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Understanding the performance of tubular anaerobic digesters

Use of physical and biological process models to understand the performance of tubular anaerobic digesters:Maureen N. Kinyua, Jie Zhang, Fabricio Camacho-Cespedes, Andres Tejada-Martinez, and Sarina J. Ergas

Tubular anaerobic digesters are used in developing countries to produce biogas from livestock waste. In this research, field measurements and physical and biological process modeling studies were used to investigate transport and transformation mechanisms for particulate and soluble organic matter in household-scale tubular digesters in the Monteverde region of Costa Rica. Greater than 75% removal of volatile solids and biochemical oxygen demand (BOD5) were observed. The high effluent quality was attributed to the formation of a biologically active floccular sludge layer, which allowed for separation of hydraulic and mean cell residence times (HRT and MCRT). A reduced order transport model was developed and validated using field tracer study data. Key assumptions of the reduced order model were verified via computational fluid dynamics (CFD) analysis. The mean HRT predicted by the reduced order model was 23 days and was in good agreement with the tracer experiment. A simplified floccular sludge biological process model was developed and used to estimate an average MCRT of 115 days. The results showed that household-scale tubular anaerobic digesters can provide enough biogas to meet households’ cooking energy needs, which was consistent with field results. This is the first study to combine mathematical modeling with field studies of tubular anaerobic digester performance.

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