The Trophic Dynamics & Community Structure working group has two primary goals: 1) investigating how habitat characteristics and food quality influence community composition and trophic structure of consumers, especially fishes and 2) studying the role of large consumers in redistributing nutrients from marsh and oceanic habitats into the mangrove ecotone region. Investigators hope to gain a functional understanding of the movements of large consumers and community dynamics with the goal of being able to predict how climate change (e.g. sea level rise) and other anthropogenic impacts (e.g. increased freshwater flow) will influence the consumer community and their ecological role. To do this, a variety of techniques are used to sample fish communities and conduct tracking studies of representative consumer species (especially bull sharks, alligators, snook, and Florida gar). Trophic structure and consumer-mediated nutrient flow are investigated using stable isotopic analysis and fatty acid analysis. Investigators take advantage of seasonal and interannual variation in environmental conditions (e.g. temperature, salinity) to determine the impact of freshwater flow on the consumers of the coastal Everglades. They are also conducting experimental manipulations of food resources and consumer composition to determine the importance of living and dead (detrital) and resources to different levels of the food web.
Photo by Garrett Miller
Mike Heithaus's field crew catches bull sharks from the mouth of the Shark River to 27 km upstream.
Photo by Mike Heithaus