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projects > ecosystem history: terrestrial and fresh-water ecosystems of southern florida > 1998 proposal

Ecosystem History: Terrestrial and Fresh-water Ecosystems of southern Florida

Project Proposal for 1998

Project Title: Ecosystem History: Terrestrial and Fresh-water Ecosystems of southern Florida
Location of Study Area: South Florida
Project Start Date: October, 1994
Project End Date: September, 2000
Project Number: 7220-37091
Project Chief: Debra A. Willard
Region/Division/Team/Section: Eastern Region/Geologic Division/ Eastern Region National Geologic Mapping Team
Phone:(703) 648-5320
Fax:(703) 648-6953
Mailing Address:
U.S. Geological Survey
926A National Center
Reston, VA 20192
Program Element(s)/Task(s) South Florida Element 1 - Modeling and support studies for southern inland coastal systems of south Dade County, Task 1. 16 - Terrestrial and Fresh-water Ecosystem History
Collaborators, Clients:
USGS Partnerships - This project is closely linked with Chuck Holmes' (WRD) Buttonwood Embankment project, Bill Orem's (EERST) Geochemical Processes project, Lynn Brewster-Wingard's (ERNGMT) Florida Bay Ecosystem History project, Scott Ishman's (ERNGMT) Biscayne Bay Ecosystem History project, and Robert Halley's (Marine Geology Team) Sedimentation, Sea-Level Rise, and Circulation in Florida Bay project. We also anticipate collaboration with various aspects of the Mercury Accumulation and Cycling project (particularly the Biotic Interactions and Sulfur Geochemistry components). 210Pb dates will be obtained from Chuck Holmes (WRD). Cross-linkages with other USGS projects are also expected to occur. In particular, Model Review; Vegetative Resistance to Flow; and Evapotranspiration Measurements and Modeling projects in the hydrologic modeling section would greatly benefit from insights into vegetation communities and ecosystem history.

Outside Partnerships - This project collaborates with SFWMD and their contractors to determine areas of particular research interest. SFWMD needs data on historic patterns of vegetational change and fire frequency to calibrate their landscape models. SFWMD has provided logistical support in the form of boats and helicopters and funded two technicians to accelerate processing and analysis of pollen and charcoal. Florida Geological Survey has provided some field support and access to cores. In addition to these groups, results will be shared with other federal through local government agencies and with private organizations with interests in ecosystem history.


Project Summary: Changes in terrestrial ecosystems of southern Florida have been attributed to environmental alteration over the last century, but cause and effect relationships between environmental and biotic changes have not been documented scientifically. This project analyzes the floral and faunal records of southern Florida 1) over the last 150 years to determine whether specific biotic changes are correlated with anthropogenic or natural environmental changes and 2) over the last few thousand years to establish the natural range of variability of the ecosystem.

Project Justification: Terrestrial ecosystems of south Florida have undergone numerous human disturbances, ranging from alteration of hydroperiod, fire history, and drainage patterns through implementation of the canal system to expansion of agricultural activity to the introduction of exotic species. Over historical time, dramatic changes in the ecosystem have been documented, and these changes have been attributed to various human activities. However, the natural variability of the ecosystem Is unknown and must be determined to assess the true impact of human activity on the modem ecosystem. This project is designed to document historical changes in the terrestrial ecosystem quantitatively, to date any changes and determine whether they resulted from documented human activities, and to establish the baseline level of variability in the south Florida ecosystem to estimate whether the observed changes are greater than would occur naturally.

Project Objectives: The project is designed to determine: 1) whether the distribution of vegetation changed over the south Florida region since 1850; 2) establish the timing of any such changes and determine whether they are correlated with onset of any human activities in the region; 3) determine whether such changes are manifested across the Everglades system (i.e., while increased abundances of cattails provide striking evidence of changes in hydroperiod and other edaphic characteristics near the Everglades Agricultural Area (EAA), did these changes have any affect on communities outside of the EAA?); 4) determine the baseline level of variability in biodiversity and vegetational distribution prior to human activity in the region (is it possible that the current state of the ecosystem represents an extreme in the naturally occurring cycles of change?); 5) determine whether fire frequency, extent, and influence prior to modem human disturbance of the ecosystem can be quantified; 6) if so, determine the historic equilibrium frequency of fire for a given region, climate, and floral community.

Overall Strategy, Study Design, and Planned Major Products: A series of short cores are being collected throughout southern Florida to document the floral, faunal, and fire history of the region in detail over the last 150 years and, on a broader scale, over the last few millenia; the particular focus is on the Taylor Slough and Buttonwood Embankment regions. Approximately 50 cores will be collected for analysis of floral, faunal, and charcoal abundances; these cores will be dated using 21OPb and 14C. Additionally, pollen, plant macrofossils, and invertebrate faunas will be analyzed from surface samples. These samples will be collected from sites throughout the region to maximize representation of modem plant communities; the resulting data will provide the basis for comparison with down-core assemblages to determine how much change in vegetational distribution has occurred. Analysis of these cores will result in a synthesis of vegetational changes at selected sites in the Water Conservation Areas, Big Cypress Preserve, and a more detailed overview of biotic and geochemical patterns in the Taylor Slough and Buttonwood Embankment regions.


Overall: Cores have been collected at a series of sites in the Water Conservation Areas, Big Cypress Preserve, and Everglades National Park, with most intensive coring in the Taylor Slough and Buttonwood Embankment regions (see attached map). A transect of cores across the upper reaches of the Shark River Slough also is planned for FY 98. Cores are sampled at closely spaced intervals for dating and examination of the microflora and fauna. Depending on concentration of various floral and faunal components, sampling intervals may be as closely spaced as I cm, which may provide resolution on a decadal scale. Pollen and plant macrofossils are examined from each sample, and, where present, mollusks, ostracodes, foraminifers, and diatoms also are studied. Quantitative data from each group are compared to establish times when several groups changed and to determine the cause of the changes. The concentration of wind-blown charcoal, which is the measure of local to regional fire history, also is being measured in selected cores to establish the accumulation rate of charcoal and, ultimately, assess regional and temporal trends in burning history. For each floral and faunal component, sampling is most intensive in upper part of the core to maximize the temporal resolution over historic time, and the prehistoric record is analyzed from selected cores to determine the baseline levels of variability in the ecosystem prior to human interference. These data will be combined with ongoing offshore research in Florida Bay (L. Brewster-Wingard's "Ecosystem History: Florida Bay and the Southwest Coast" and S. Ishman's "Ecosystem History: Biscayne Bay and the Southeast Coast" projects) to correlate terrestrial and marine responses to changes in physical parameters and/or records of human-induced changes to the environment.


YEAR                           96     97     98      99

Coring                         ----------------

Sampling                       ----------------

Processing                     -----------------

Data Analysis                  ------------------

Write Papers                       ------------------

Drafts to Researchers                ------------------ 

Final Drafts                          -----------------

Meet with Clients            --------------------------

Director's Approval                                   --

Planned Deliverables/Products:

  • Reports on pollen analysis from cores collected throughout southern Florida, with particular emphasis on the Taylor Slough region.
  • Reports on pollen analysis from surface samples and pollen traps distributed throughout the region.
  • Reports on peat petrography and charcoal history of selected cores in the region.
  • Journal articles synthesizing regional patterns of vegetational change and more localized changes in the Taylor Slough region.
  • Synthesis article with other ecosystem history projects on regional biotic changes in the Everglades, Florida Bay, and Biscayne Bay.
  • Vegetational reconstructions for selected time slices.

Planned Outreach Activities: We are working closely with personnel at the South Florida Water Management District in selecting sites for analysis to maximize the impact of this research on their needs. In addition to contact via phone and e-mail, we meet with scientists at the District when we are in the area doing field work and have presented a seminar on results to date. We also interact with other collaborators and clients at a number of meetings throughout the year.

Prior Accomplishments in Proposed Area of Work:

New Directions, Expansion of Continuing Project (if applicable): In FY 98, we plan to complete final coring in the Taylor Slough region and collect a transect of cores across the northern part of Shark River Slough. This transect was suggested by scientists at the South Florida Water Management District and focuses on an area in which the vegetation may have changed in response to changes in water management practices to the east.


Accomplishments and Outcomes, Including Outreach:
  • At a site along Taylor Creek, documented vegetational change from sawgrass marshes to red mangrove forests over the last 50 years.
  • Documented prehistoric patterns of vegetational change in Water Conservation Area 2A (alternation among different types of marsh communities).
  • Documented sea-level rise over the last few hundred years at the Mud Creek site near Joe Bay through analysis of pollen, mollusks, and foraminifers.
  • Assembled database of modem pollen assemblages from across the region; this database is necessary for accurate interpretation of down-core assemblages.

Deliverables, Products Completed:
Willard, D.A., and Holmes, C.W., 1997. Pollen and geochronological data from South Florida: Taylor Creek Site 2. U.S. Geological Survey Open-File Report 97-35, 28 pp.

Willard, D.A., Weimer, L.M., and Holmes, C.W., 1996. Vegetational changes over the last few millenia in south Florida: evidence from the pollen record. Abstracts with Programs, Geological Society of America Annual Meeting v. 28, p. A95.

Willard, D.A., and Holmes, C.W., in prep., Pollen census data and geochronology from southern Florida: sites along a nutrient gradient in Water Conservation Area 2A. U.S. Geological Survey Open-File Report.

Willard, D.A., Holmes, C.W., Fellman, C., Brewster-Wingard, G.L., and Ishman, S.E., in prep. The biotic and geochronologic record from South Florida: Mud Creek Site 1. U.S. Geological Survey Open-File Report.

Willard, D.A., and Weimer, L.M., in prep. Modem pollen assemblages from southern Florida. U.S. Geological Survey Open-File Report.


Required Expertise:
                         97      98      99

Palynologist             1       1       1 	
Pollen prep/analysis     3       3       3
Charcoal/Peat prep       1       1
Diatom Analyst           1       1
Mollusk Analyst          1       1
Foram Analyst            1       1
Ostracode Analyst        1       1

Names of Key Project Staff:

Palynologist                        Debra Willard
Pollen prep/analysis                Lisa Weimer, Neil Waibel, Patrick Buchanan
Charcoal/Peat prep                  James Murray
Diatom Analyst                      Laura Pyle
Mollusk Analyst                     Lynn Brewster-Wingard
Foram Analyst                       Scott Ishman
Ostracode Analyst                   Elisabeth Brouwers

Major Equipment/Facility Needs: None

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