Doctoral students

Sean Kelly
Stream riparian connectivity: importance of stream resources for riparian spiders

Web spinning spiders represent an important link between aquatic and terrestrial food webs as a major consumer of emerging aquatic insects from freshwater ecosystems.  The majority of the studies investigating these links however has been limited to streams in temperate regions and in forested areas but these may not be suitable for comparison with tropical stream ecosystems in urban areas.  For my PhD dissertation I am working with a number of small streams in the north eastern metropolitan area of Puerto Rico.  Streams in urban areas are impacted in numerous ways such as increased levels of contaminants and changes in the riparian vegetation.  This generally results in an altered macroinvertebrate community.  My research focuses on determining if there are any indirect effects from urbanization on communities of riparian web-spinning spiders.  I will be using naturally occurring stable isotope analyses to quantify the amount of aquatic insects that the spiders are consuming, along with additional analyses for detecting possible contaminants such as heavy metals, PCBs and PCCPs that are bioaccumulating through the aquatic food web.


Natalia M. Rodríguez Ortiz
El Río Piedras y su gente: Una perspectiva Socio-Ecológica de la Canalización del Río

La canalización es la opción generalmente sugerida para resolver problemas de inundaciones y seguridad. Sin embargo, la canalización tiene costos importantes sobre la diversidad y la sociedad. Estudiamos cómo la política pública sobre el manejo de los ríos ha influenciado el proceso de canalización del Río Piedras, y los efectos negativos de la canalización sobre las comunidades humanas cerca del río, y la diversidad de la fauna acuática.


Josué D. Santiago Vera
Drought and tropical streams: Effects of flow reduction on the community structure of meiofauna

En construcción - La meiofauna es un grupo de organismos de tamaño pequeño, por lo que son poco estudiados en ecosistemas tropicales.  La tesis se enfocará en entender los factores ambientales que afectan la meiofauna en quebradas de bosque y en el impacto de la sequía sobre estos organismos.


Master students

Roberto Reyes Maldonado
Response of native Puerto Rican Chironomidae to sediment pollution with heavy metals
The Chironomidae family can be found in almost any aquatic or semiaquatic habitat. Due to this quality, this insect family has been used to assess disturbances in freshwater ecosystems around the world. This project focuses on developing an assessment tool for Puerto Rico using chironomids as indicators of contamination with heavy metals.

Post-doctoral associates 

Pablo E. Gutiérrez Fonseca
In association with the Luquillo LTER program
- Effects of experimental drought on stream ecosystems in Puerto Rico 

The Luquillo LTER is a program that studies tropical ecosystems in Puerto Rico from a long-term perspective.  

One of the main climatic prediction for the island is a decrease in precipitation and increase in the frequency of drought.  Ours is a collaborative project that focuses on the effects of drought on rain forest stream ecosystems.


Visiting Faculty 

Prof. Adriana M. Forero
Universidad del Tolima, Colombia
- Interspecific interactions between shrimp and Ephemeroptera in tropical streams, Puerto Rico 

Facilitation is a particular type of interspecific interaction, where one of the participating species benefits from the presence of the other. Facilitation often aids in maximizing resource utilization by consumers. In tropical coastal and island streams, shrimps are known to have strong interactions with other components of the community. Shrimp feeding activities reduce benthic organic matter, algal and invertebrate biomass, and changes the composition of benthic assemblages. Leptophlebiidae mayflies (Ephemeroptera) is one group that appear to benefit from shrimp presence. Leptophlebiids increase in numbers when shrimp are present, suggesting facilitation between the two groups. The objective of my research is to assess the mechanism by which shrimp activity benefits mayfly nymphs. We are conducting field and laboratory studies to assess mayfly performance with and without shrimp.  Overall, our study shows that shrimp foraging activities facilitate mayfly access to food resources and potentially increase their population success in tropical streams in Puerto Rico.