A CONCEPTUAL MODEL OF ECOLOGICAL INTERACTIONS IN THE MANGROVE ESTUARIES OF THE FLORIDA EVERGLADES

• Published in: Wetlands (Wilmington, N.C.) N.C.), 2005-12, Vol.25 (4), p.832-842
• Main Authors: Davis, Steven M., Childers, Daniel L., Lorenz, Jerome J., Wanless, Harold R., Hopkins, Todd E.
• Format: Article
• Language: English
• Subjects: Alligator mississippiensis; American crocodile; Annual variations; Aquatic birds; Aquatic ecosystems; Aquatic plants; Brackish water; Climate change; Coastal waters; conceptual ecological model; CONTENTS; Crocodylus; Crocodylus acutus; Drainage basins; Ecological effects; ecological restoration; ecosystem management; ecosystem restoration; El Nino; Estuaries; estuarine geomorphology; Everglades; fish communities; Fish populations; Fresh water; freshwater; Freshwater ecosystems; Global climate; Lakes; mangrove forest; mangrove forests; Mangrove swamps; Mangroves; Mycteria americana; Nesting; plant ecology; Platelea ajaja; Populations; Rainfall; roseate spoonbill; Salinity; Salinity effects; salinity gradients; Sea level; sea-level rise; South Florida; tidal creeks; water flow; Water management; wildlife habitats; wood stork
• ISSN: 0277-5212; 1943-6246
• DOI: 10.1672/0277-5212(2005)025[0832:ACMOEI]2.0.CO;2

A brackish water ecotone of coastal bays and lakes, mangrove forests, salt marshes, tidal creeks, and upland hammocks separates Florida Bay, Biscayne Bay, and the Gulf of Mexico from the freshwater Everglades. The Everglades mangrove estuaries are characterized by salinity gradients that vary spatially with topography and vary seasonally and inter-annually with rainfall, tide, and freshwater flow from the Everglades. Because of their location at the lower end of the Everglades drainage basin, Everglades mangrove estuaries have been affected by upstream water management practices that have altered the freshwater heads and flows and that affect salinity gradients. Additionally, interannual variation in precipitation patterns, particularly those caused to El Niño events, control freshwater inputs and salinity dynamics in these estuaries. Two major external drivers on this system are water management activities and global climate change. These drivers lead to two major ecosystem stressors: reduced freshwater flow volume and duration, and sea-level rise. Major ecological attributes include mangrove forest production, soil accretion, and resilience; coastal lake submerged aquatic vegetation; resident mangrove fish populations; wood stork (Mycteria americana) and roseate spoonbill (Platelea ajaja) nesting colonies; and estuarine crocodilian populations. Causal linkages between stressors and attributes include coastal transgression, hydroperiods, salinity gradients, and the “white zone” freshwater/estuarine interface. The functional estuary and its ecological attributes, as influenced by sea level and freshwater flow, must be viewed as spatially dynamic, with a possible near-term balancing of transgression but ultimately a long-term continuation of inland movement. Regardless of the spatio-temporal timing of this transgression, a salinity gradient supportive of ecologically functional Everglades mangrove estuaries will be required to maintain the integrity of the South Florida ecosystem.