While motivated by a conservation ethic, my research focuses on understanding fundamental roles of both abiotic factors and organisms in shaping ecosystem structure and function.
Aquatic ecosystem impacts of land sharing versus sparing: Nutrient Loading to Southeast Asian Rivers
From the time of Charles Elton (1927) and Raymond Lindeman (1942), scientists have recognized that quantifying the pathways by which energy flows from primary producers (plants) to higher trophic levels (animals) is central to ecological understanding of nature. Energy storage, or growth, by plants in streams and rivers is often limited by nutrients, typically either nitrogen (N) or phosphorus (P). In recent decades, Southeast Asian farmers have increased total farmland area and have begun growing crops with high demand for N and P, like corn, that require application of synthetic fertilizers. I set out to see what the effect of changing agricultural practices might be having on algal production in Thai rivers.
Direct and indirect top-down effects of fish on algal production in a tropical river
Fish, of course, are not passive actors in tropical ecosystems, but the degree to which consumption of algae and aquatic insects by fish can affect community structure and ecosystem processes continues to be an active area of science. The work of Bob Paine in Mukkaw Bay, Washington first showed that predators can affect competition among lower trophic groups. Later work by Steve Carpenter and colleagues showed that these effects can cascade down from higher trophic levels all the way to primary producers. I am interested in whether these same types of consumer-induced ecosystem changes occur in tropical freshwater systems, where the interaction strength between species is reduced.