Alex Flecker (AF - Cornell University) and Steven Thomas (ST - Cornell University):

Alex Flecker has more than 25 years of experience investigating tropical streams. His prior research includes large-scale experimental manipulations of fish in natural streams coupled with mesocosm studies to characterize multiple trophic level interactions among fish, invertebrates, and primary producers.

more about Alex Flecker...

Steve Thomas has 14 years of experience studying stream ecosystems and is an expert in the use of isotope tracers to quantify nutrient cycling and oxygen mass balance approaches for measuring ecosystem scale metabolic activity. AF and ST are currently working together to examine the importance of fish in modulating ecosystem processes such as nitrogen cycling and primary productivity, and to evaluate the relationship between nutrient supply, organism stoichiometry and ecosystem measures of nutrient demand.

Together, AF and ST will coordinate: 1) the evaluation and interpretation of ecological interactions associated with guppy introductions, 2) the use of isotope approaches to understand the importance of resource availability and bottom-up controls over the coarse of early life history evolution, 3) the design and execution of light manipulation experiments that assess the role of ecological context in guppy evolutionary patterns, and 4) oxygen mass balance measurements to quantify variation in stream energy flow over the course of the project.