Predicting effects of hydrologic restoration on manatees along the southwest coast of Florida

This project focuses on West Indian manatee (Trichechus manatus latirostris) distribution, habitat use and movement patterns to address questions important to understanding the ecology of several communities in southwest Florida used by manatees, including offshore seagrass beds, estuarine bays, tidal creeks, and rivers. A large proportion of the southwest Florida manatee population occurs throughout the Everglades National Park (ENP) and north into the Ten Thousand Islands (TTI) National Wildlife Refuge. Aerial surveys and telemetry data from tagged manatees provide a valuable means of documenting the response of manatees to natural and human-induced fluctuations in freshwater inflow. This information, combined with water quality data obtained from monitoring stations, will be incorporated into the manatee ATLSS model which will be used to better understand and predict manatee response to different restoration scenarios. The major objectives of the study are to determine relative abundance, distribution, movements, and habitat use of manatees associated with coastal waters and rivers in the western everglades, and to develop an individual-based ATLSS model to predict manatee response to changes in hydrology achieved by the Southern Golden Gate Estates (SGGE) project specifically, and more broadly by the Comprehensive Everglades Restoration Plan. Work has primarily focused on the TTI/SGGE restoration area, with some data also collected from tagged manatees using the southwest portion of ENP. Data for this project is collected via: satellite telemetry and tracking of individuals using a specially designed Global Positioning System (GPS) tag. Data will be used in developing the predictive manatee model which will integrate with the TIME model.

On-going research in this area (Everglades National Park and Ten Thousand Islands NWR) has shown that manatees make frequent movements up tidal creeks to obtain freshwater for drinking and to find thermal refugia during cold weather. Alteration of the freshwater and estuarine ecosystems associated with restoration of the Everglades and Southern Golden Gate Estates is likely to affect this manatee population. In addition, because manatees feed primarily on submerged aquatic vegetation (SAV) in estuarine and near-offshore areas, they are excellent barometers of the health of a range of communities. This research will provide baseline data on these communities that will be important to future monitoring of the effects of the South Florida hydrological restoration efforts.