We document the response of the Everglades ecosystem to climatic and environmental changes over the last two millennia using pollen records. Centennial-scale intervals of vegetational stasis characterize the time between 0 A.D. and 1900 A.D. From A.D. 0-800, marsh and slough vegetation characteristic of deeper water and longer hydroperiods (annual duration of inundation) than today dominated the study region. Drier conditions between about 800 A.D. and 1200 A.D. resulted in shallower water depths and shorter, fluctuating hydroperiods in Everglades marshes as well as salinity increases near Florida Bay. After a recovery to deep-water conditions in the 14^th century, somewhat drier conditions are suggested between the 17^th and 19^th centuries. These climatically-induced periods of relative dryness are correlated with regional droughts during the intervals known as the Medieval Warm Period (9^th-14^th centuries) and Little Ice Age (15^th-19^th centuries).

Although regional precipitation was greater than average after 1920 A.D., vegetational changes throughout the area indicate reduced water depths and hydroperiods after construction of water-control structures in the early 20^th century. Further, more localized changes occurred after 1960, when the Central & South Florida (C&SF) Project was completed. Thus, restoration goals of achieving pre-C&SF Project hydrologic regimes are aimed at an already disrupted system; a more "natural" restoration target would be the 19^th century Everglades, which had been stable for the past few centuries. Recent land-use changes have resulted in localized rather than system-wide ecosystem responses, at least in part because of the fragmentation of the wetland. This artificially induced ecological heterogeneity makes prediction of future wetland responses to climatic changes problematic.

Citation: Willard, D.A., Holmes, C.W., and Weimer, L.M., 2001, The Florida Everglades Ecosystem: Climatic and Anthropogenic Impacts over the Last Two Millennia. In Wardlaw, B.R. (ed), Paleoecology of South Florida. Bulletins of American Paleontology, v.361: 41-55.

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