Native Americans, regional drought and tree Island evolution in the Florida Everglades




This study uses palynologic data to determine the effects of regional climate variability and human activity on the formation and development of tree islands during the last ~4000 years. Although prolonged periods of aridity have been invoked as one mechanism for their formation, Native American land use has also been hypothesized as a driver of tree island development. Using pollen assemblages from head and near tail sediments collected on two tree islands and documented archeological data, the relative roles of Native Americans, climate variability, and recent water-management practices in forming and structuring Everglades tree islands are examined. The timing of changes recorded in the pollen record indicates that tree islands developed from sawgrass marshes ~3800 cal. yr BP, prior to human occupation. Major tree island expansion, recorded near tail sediments, occurred ~1000 years after initial tree island formation. Comparison of the timing of pollen assemblages with other proxy records indicates that tree island expansion is related to regional and global aridity correlated with southward migration of the Intertropical Convergence Zone. Local fire associated with droughts may also have influenced tree island expansion. This work suggests that Native American occupation did not significantly influence tree island formation and that the most important factors governing tree island expansion are extreme hydrologic events due to droughts and intense twentieth century water management.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Native Americans, regional drought and tree Island evolution in the Florida Everglades
Series title Holocene
DOI 10.1177/0959683611400204
Volume 21
Issue 6
Year Published 2011
Language English
Publisher SAGE Publications
Publisher location Thousand Oaks, CA
Contributing office(s) Branch of Regional Research-Eastern Region
Description 12 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Holocene
First page 967
Last page 978
Country United States
State Florida
Other Geospatial Florida Everglades
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