Everglades Predators Research Projects

The Florida Coastal Everglades (FCE) is part of the National Science Foundation’s (NSF) Long Term Ecological Research (LTER) Project established in 1980. Researchers in the FCE study how hydrology, climate, and human activities affect ecosystem and population dynamics in the ecotone and coastal Everglades. The Heithaus Lab has investigated the role of top predators in Everglades National Park for over a decade. The coastal Everglades is comprised of diverse habitat types including creeks, rivers, shallow inland bays with mangrove islands, and coastal oceans of the Gulf of Mexico and Florida Bay. The coastal Everglades estuary is relatively nutrient-poor and limiting nutrients (primarily phosphorus) are derived from the Gulf of Mexico.

The hydrology of the coastal Everglades has been radically altered by humans, but there are ongoing efforts to restore water flow to a more natural state. How these changes will impact the large predators is largely unknown. We’ve initiated studies, using a combination of telemetry, stable isotopic analysis, and experiments to understand what drives habitat use, movements, and interactions of top predators like juvenile bull sharks (Carcharhinus leucas), American alligators (Alligator mississippiensis), and common bottlenose dolphins (Tursiops truncatus). We’re interested in factors associated with individual specialization in movements and foraging patterns of predators and their potential to have ecosystem-level effects by transporting nutrients.

Juvenile Bull Sharks
Bull sharks (Carcharhinus leucas) use the bays and upstream areas of the southwest Everglades National Park Shark River basin as a nursery. These habitats support many juvenile sharks where they are an important top predator. We’ve studied juvenile coastal Everglades bull sharks for over a decade. The goal is to anticipate how they will respond to changes in water flow from an ongoing large scale restoration project that re-directs fresh water back into the Everglades. Using acoustic tracking, population size monitoring, and stable isotopes, we’re studying the movements, behavior, and trophic roles of juvenile bull sharks and how these roles may change with restoration.

Alligators
Alligators (Alligator mississippiensis) are an abundant, large-bodied predator in the Everglades freshwater and estuarine habitats. We’ve conducted research on alligators in this area for almost a decade. Our research has focused on the transition zones between saltwater and freshwater areas in the Shark River basin. The goal is to anticipate how these animals will respond to changes in water flow from an ongoing large scale restoration project. The lab is also conducting surveys and experiments to look at the ecosystem-level effects of alligators through their role as ecosystem engineers primarily in phosphorus-poor Everglades freshwater marshes.