Project: Network Analysis of Trophic Dynamics in South Florida Ecosystems

Web Sites: ATLSS.ORG

Location: The total system

Principal Investigators: Robert E. Ulanowicz and Johanna J. Heymans, University of Maryland, Chesapeake Biological Laboratory, Solomons, MD 20688-0038, Phone: 410-326-7266, e-mail: ulan@cbl.umces.edu

Project Personnel: Donald L. DeAngelis, Phone: 305-284-1690, e-mail: ddeangelis@umiami.ir.miami.edu

Other Supporting Organizations: USGS/BRD, NPS, ACE, EPA

Associated Projects: Component of ATLSS Program

Overview & Status: The ATLSS Program, created to assess the effects of changes in hydrological regime upon South Florida wetlands biota, must be calibrated and verified before it can be employed as a management tool. The highly complex and comprehensive nature of the ATLSS model means that the data set used for calibration must be correspondingly intricate. Towards this end, a set of networks of trophic exchanges, detailing who eats whom and at what rates, is being compiled for each of the four major biomes of S. Florida - the cypress wetlands, the mangrove estuaries, Florida Bay and the graminoid wetlands. In addition to serving as calibration tools, the process of assembling the networks itself reveals numerous interesting aspects of how these ecosystems are functioning, including: 1) The primary resource for the higher fauna of the cypress wetlands is not the detrital litterfall, but rather production by understory vegetation; 2) The diet of the American alligator is instrumental in maintaining the biodiversity of wetland fauna; 3) The cypress, mangrove and especially the graminoid wetlands all sequester significant amounts of carbon on an annual basis. (Important for mitigating global warming.); 4) Algal periphyton usually contributes more directly to sustaining animal life in the graminoid wetlands and Florida Bay than does macrophytic vegetation; and, 5) Ecological activity in the graminoid wetlands is significantly higher on a per- unit- area basis than that of the cypress and mangrove wetlands or of Florida Bay.

Needs & Products: Some study milestones and results include: 1.The primary resource for the higher fauna of the cypress wetlands is not the detrital litterfall, but rather production by understory vegetation (June, 1997); 2.The diet of the American alligator is instrumental in maintaining the biodiversity of wetland fauna (December, 1997); 3. The cypress, mangrove and especially the graminoid wetlands all sequester significant amounts of carbon on an annual basis (important for mitigating global warming) (May, 2000); 4.Algal periphyton usually contributes more directly to sustaining animal life in the graminoid wetlands and Florida Bay than does macrophytic vegetation (May, 2000); 5.Ecological activity in the graminoid wetlands is significantly higher on a per- unit- area basis than that of the cypress and mangrove wetlands or of Florida Bay (May, 2000).

Application to Everglades Restoration: Networks constitute a necessary preliminary to running the ATLSS model. Compiled data represents an extremely valuable library resource for all biological modeling activities in S. Florida. (Available on the Web at http://www.cbl.umces.edu/~atlss), as well as a valuable potential addition to USGS' South Florida Ecosystem Database http://www.envirobase.usgs.gov. It also serves as a potential resource for the activities of the Committee on the Restoration of the Greater Everglades Ecosystem (CROGEE).