Paleoecology as a Tool for Modeling and Ecosystem Management: An Example from the Everglades

Throughout the 20th century paleoecology provided a tool for analyzing past environments. In recent years, paleoecologic analysis is being used to solve high-profile societal issues, such as global warming, changes in biodiversity, loss of habitats, and ecosystem restoration. The field of paleoecology has contributed to the massive restoration effort in the Florida Everglades by providing base-line information on the pre-anthropogenic environment of south Florida. Knowledge about the past history of the ecosystem is being used by land management agencies to set performance measures and targets for restoration of a more natural hydrologic system. Two inherent problems with paleoecologic data, however, are (1) time-averaging and (2) chronologic resolution to a scale of annual or seasonal data that is desirable for many Holocene applications. We have developed a method that couples paleoecologic information from sediment cores with regression equations based on instrumental observations of hydrologic parameters within the ecosystem. This method overcomes problems associated with paleo-data by providing daily and seasonal estimates of hydrologic parameters and with issues of uncertainty for the models by utilizing verifiable historical data.

In phase one of the method, molluscan assemblage analysis of a local core is used to determine the paleo-salinity regime for the ~1900 AD pre-disturbance estuary. The Natural Systems Model developed by South Florida Water Management District is adjusted to the salinity regime for the 1900 time frame and used to produce simulated daily and seasonal salinity values. In phase two, linear regression equations are developed from modern observations in freshwater wetlands (flow and stage) and estuaries (salinity). These equations predict the salinity within the estuary, given a stage height (or flow) within the wetlands. The final phase couples the simulated paleo-salinity regime with the equations to produce estimates of flow, stage, and hydroperiod in the historical Everglades wetlands.