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Projects of Research Associates

Ricardo Betancur-R., Ph.D

Fish Phylogeny Lab

Project: Phylogeny, Biogeography and Evolution of the Antillean Freshwater Fish Fauna

Description: This project aims to acquire more in-depth knowledge of the diversity and evolution of the ichtyiofauna of the Antilles through the accurate taxonomic identification of the populations and the species, the knowledge of its distribution range, phylogenetic relationships, phylogeography and demography. For this purpose, the most modern techniques and resources within these areas of knowledge will be used in order to explain the mechanisms influencing the pheno and genotype of these groups of fishes. The phylogenetical studies sequencing 1735 exons via "exon capture" makes of this a cutting-edge project at the frontier of knowledge. Gathering all this information will allow us to formulate one or a couple of hypothesis about the evolution and biogeography of the Antilles, that will have explanatory power for the fauna current distributions and will allow us to test preexisting biogeographical models. 

 

Patricia A. Burrowes, Ph.D

Project: The reproductive biology and population genetics of a Puerto Rican cave-dwelling frog

Description: I am currently interested in the effect of climate change on population fluctuations of amphibians, as well as, the role of seasonality in modulating disease ecology, specifically chytridiomycosis, on direct-developing frogs. Museum specimens are an important source of information for my work, because with from a simple skin swab from preserved frogs we can detect pathogens via molecular tools, and answer historical questions about disease prevalence.

 

Ana Carolina Monmany, Ph.D

Project: Landscape complexity and vegetation structure as drivers of parasitoid community structure and function in the subtropical Chaco, Argentina

Description: Parasitoids are wasps and flies that oviposit in or on other insects eventually killing them. Parasitoids are responsible for the control of herbivory in most terrestrial ecosystems.  For this reason, understanding what regulates their communities has been a main interest.  In my thesis I examined how landscape complexity as derived from a satellite image and vegetation structure as measured in the field influence parasitoid richness, abundance, composition, and parasitism in a subtropical agricutural frontier in Argentina.  In addition I examined herbivore host body size diversity and herbivore abundance as regulatory variables of communities.

 

Ruber Rodríguez Barreras, Ph.D Candidate

Project: Current status of the long-spined sea urchin Diadema antillarum in Puerto Rico.

Description: The long-spined sea urchin Diadema antillarum suffered a die-off in 1983 in the Western Atlantic with final mortality rates reaching up to 99.9%. The epizootic event spread from Panama to Bermudas in less than two years to where it stopped in August 1984. The cause remains unknown; however, scientist suspect that the disease was causes by a water-borne pathogen. Currently, D. antillarum is going through a slow and non-uniform recovery process where populations exhibit low densities in many Caribbean reefs and continue to be locally extinct in others. The causes of its slow recovery are not evident although several explanations have been proposed, such as food limitation due to low assimilation, predation and substrate conditions that do not facilitate urchin recruitment. Although fleshy algae coverage has increased in many coral reefs, algae could potentially be a limiting resource for D. antillarum depending on their quality and presence of secondary metabolites. Therefore it is important to characterize the sea urchin’s diet in oligotrophic and eutrophic reefs systems via isotopic analysis. Predation is another factor thought to be hindering the recovery process. Predation can act directly by increasing mortality and indirectly by reducing growth rate as a result of urchins spending more time in refuges as a result of predator presence. We will conduct a capture-mark-recapture study to measure growth rate and survivorship under different predation pressure (i.e. inside and outside a No-take Reserve). We will also test the hypothesis that absence of adult urchins and the resulting overgrowth of fleshy algae impede urchin recruitment by manipulating adult urchin densities in experimental cages. In general, we will test whether predation, diet, and substrate conditions may or may not be hindering the recovery process of D. antillarum. At the same time I'm conducting a capture-mark-recapture study to measure growth rate and survivorship  under different predation pressure inside and outside a No-take Reserve.

 

Alonso Ramirez, Ph.D.; Pablo E. Gutiérrez Fonseca, Ph.D candidate

Project: Aquatic Insect Diversity in Puerto Rico

Description:Aquatic insects are conspicuous components of stream, wetland, and other freshwater ecosystems.  Our project is assessing the diversity of aquatic insects and other macroinvertebrates in Puerto Rico.  Most taxonomic works (description of species and faunistic inventories) on the island were conducted in the first half of last century by Wolcott (1948), Garcia-Diaz (1938) and others.  Currently there are 61 families of aquatic insects reported for the island.  While most groups of aquatic insects are poorly known, taxonomic efforts in the past have focused on Ephemeroptera, Odonata, and Trichoptera.

Our ongoing diversity inventory aims at increasing the knowledge of the fauna of Puerto Rico.  Insect are been collected around the island (e.g., El Yunque, Culebra, Vieques, Guánica) and all specimens are processed and deposited at the museum.  We are also collaborating with researchers associated with the Environmental Protection Agency and the Department of Natural Resources in projects that usually donate the collected material to be deposited at the collection of aquatic entomology.  More information, publications, and a list of families reported for Puerto Rico can be found at http://www.ramirezlab.net/.

 

Alonso Ramirez, Ph.D; Pablo E. Gutiérrez Fonseca, Ph.D. candidate; Keysa Rosas, M.Sc. student; Checo Colon-Gaud, Ph.D.

Project: Long-term patters in aquatic macroinvertebrate assemblage composition and structure

Description:Studies of the long-term dynamics of animal populations are critical to understand their responses to infrequent events (e.g., hurricanes, drought) and global change (e.g., climate change or urban expansion).  We are studying the long-term dynamics of stream macroinvertebrates in two contrasting environments, the highly urbanized Río Piedras watershed and natural rainforest streams at El Yunque National Forest.  Given the degree of urbanization on the island and predicted changes in climate, our main goal is to assess changes in macroinvertebrate diversity associated with urban grow from those associated with climate change.