Human Impacts

Transformations of freshwater ecosystems and fisheries are increasingly driven by global change-associated stressors. These stressors will become more severe and may interact with local-scale factors in new and unexpected ways in the near future. My research is contributing to our understanding of how climate change and associated alterations to flow regime will influence the balance of native and invasive species in novel fish assemblages. Another aspect of my global change research is evaluating mercury trophodynamics in streams of the Great Smoky Mountains National Park.

Stream urbanization causes alteration of the natural flow regime, degraded water quality, and subsequent loss of biodiversity and ecosystem function. I have conducted extensive research on urban streams to determine how fish assemblages and trophic interactions respond to urbanization. This branch of my research has revealed some key factors related to maintaining stream ecosystem integrity in the face of urbanization.

Dams and other instream barriers are some of the greatest anthropogenic threats to riverine fishes. I conduct research to understand their effects on fish communities and populations. I am proud that my work contributed to the first dam removal for the purpose of fish passage ever in Puerto Rico. Flow regime is a master variable of lotic ecology that is controlled by the operations of dams on regulated rivers. Research such as my studies of migration phenology inform instream flow management to maximize benefits for people and ecosystems.