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projects >
ecosystem
history: terrestrial and fresh-water ecosystems of southern florida >
1998 proposal
Program: FRAGILE ENVIRONMENTS
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 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.
Planned Deliverables/Products:
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.
Deliverables, Products Completed:
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.
Major Equipment/Facility Needs: None
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U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology This page is: http://sofia.usgs.gov/proposals/1998/ehflecop98.html Comments and suggestions? Contact: Heather Henkel - Webmaster Last updated: 11 October, 2002 @ 09:31 PM (KP) |
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