U.S. Department of the Interior
U.S. Geological Survey
OFR 2006-1355

Marl Prairie Vegetation Response to 20^th Century Hydrologic Change

Christopher E. Bernhardt and Debra A. Willard U.S. Geological Survey, Eastern Earth Surface Processes Team, 926A National Center, Reston, VA 20192

Abstract

> Abstract Introduction Marl Prairie Habitat & Community Everglades Hydrologic History Methods Results Discussion Conclusions Acknowledgements References Figures & Tables PDF

We conducted geochronologic and pollen analyses from sediment cores collected in solution holes within marl prairies of Big Cypress National Preserve to reconstruct vegetation patterns of the last few centuries and evaluate the stability and longevity of marl prairies within the greater Everglades ecosystem. Based on radiocarbon dating and pollen biostratigraphy, these cores contain sediments deposited during the last ~300 years and provide evidence for plant community composition before and after 20^th century water management practices altered flow patterns throughout the Everglades. Pollen evidence indicates that pre-20^th century vegetation at the sites consisted of sawgrass marshes in a peat-accumulating environment; these assemblages indicate moderate hydroperiods and water depths, comparable to those in modern sawgrass marshes of Everglades National Park. During the 20^th century, vegetation changed to grass- dominated marl prairies, and calcitic sediments were deposited, indicating shortening of hydroperiods and occurrence of extended dry periods at the site. These data suggest that the presence of marl prairies at these sites is a 20^th century phenomenon, resulting from hydrologic changes associated with water management practices.

Related information:

SOFIA Project: Development and Stability of Everglades Tree Islands, Ridge and Slough, and Marl Prairies