A 2,500-year record of environmental change in Highlands Hammock State Park (Central Florida, U.S.A.) inferred from siliceous microfossils

Authors

Christof Pearce, Centre for Past Climate Studies, Department of GeoSciences, Aarhus University
Holger Cremer, Netherlands Organization for Applied Scientific Research TNO, Geological Survey of the Netherlands
Emmy Lammertsma, Palaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Faculty of Science, Utrecht University
Friederike Wagner-Cremer, Palaeoecology, Laboratory of Palaeobotany and Palynology, Institute of Environmental Biology, Faculty of Science, Utrecht University

Abstract

Analysis of siliceous microfossils of a 79 cm long peat sediment core from Highlands Hammock State Park, Florida, revealed distinct changes in the local hydrology during the past 2,500 years. The coring site is a seasonally inundated forest where water availability is directly influenced by precipitation. Diatoms, chrysophyte statospores, sponge remains and phytoliths were counted in 25 samples throughout the core. Based on the relative abundance of diatom species, the record was subdivided into four diatom assemblage zones, which mainly reflect the hydrological state of the study site. An age-depth relationship based on radiocarbon measurements of eight samples reveals a basal age of the core of approximately 2,500 cal. yrs. BP. Two significant changes of diatom assemblage composition were found that could be linked to both, natural and anthropogenic influences. At 700 cal. yrs. BP, the diatom record documents a shift from tychoplanktonicAulacoseira species to epiphytic Eunotia species, indicating a shortening of the hydroperiod, i.e. the time period during which a wetland is covered by water. This transition was interpreted as being triggered by natural climate change. In the middle of the twentieth century a second major turnover took place, at that time however, as a result of human impact on the park hydrology through the construction of dams and canals close to the study site.

Comments

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Recommended Citation

Pearce, C., H. Cremer, E. Lammertsma, F. Wagner-Cremer. 2013. A 2,500-year record of environmental change in Highland Hammock State Park (Central Florida, U.S.A.) inferred from siliceous microfossils. Journal of Paleolimnology 49(1): 31-43.