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Last updated: October 11, 2002
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Part 2: Ecosystem History and Living Resources
Ecosystem History
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Sediment cores
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Graph of pollen analysis. (Click on graph for full-sized version.)
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Plant communities of the wetlands of Taylor Slough and nearshore embayments of
Florida Bay are sensitive to changes in freshwater flow and salinity. Scientists use
remote sensing data and pollen analyses of sediment cores to reconstruct past changes
in vegetation. Between 1940 and 1994, the lake outlined in the images below has
decreased by almost 50%. During the same time, the results of pollen analysis, illustrated
to the lower left, show that vegetation in the region has changed from marshes to dwarf
mangroves. Such historic data provide baseline information needed to predict future
impacts of hydrologic alterations.
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Historical photos. (Click on photos for full-sized version.)
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Living Resources
Ecologists and geologists are studying vegetation dynamics across sharp
ecotones, such as this shoreline of Florida Bay above, and the
phenomenon of "mangrove die-off". Preliminary results indicate that
long-term tidal dynamics, storm overwash, and low flows all may play a
role in regulating vegetative structure. The SICS model provides flow
information needed to evaluate cause-and-effect relationships between
changing water conditions and vegetation structures.
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Florida Bay shoreline showing marsh and mangroves. (Click on photo
for full-sized version.)
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Cape Sable Seaside Sparrow (CSSS) habitat.
(Click on photo for full-sized version.)
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The Across Trophic Level System Simulation (ATLSS) program has
developed a suite of ecological simulation models to predict
breeding success and habitat suitability for the Cape Sable Seaside
Sparrow (CSSS) in various proposed restoration scenarios.
The vegetation overlay (left) used in the ATLSS modeling program
highlights primary breeding colonies of the endangered CSSS.
Next: Vegetation Classification and
Resistance
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