Ecosystem History of South Florida Estuaries Data

The Ecosystem History Access Database contains listings of all sites (modern
and core), modern monitoring site survey information, and published core data. Two general
types of data are contained within this database: 1) Modern Field Data and 2) Core data -
primarily faunal assemblages.

Scientists over the past few decades
have noticed that the South Florida ecosystem has become increasingly stressed. The purposes
of the ecosystem history projects (started in 1995) are to determine what south Florida's
estuaries have looked like over time, how they have changed, and what is the rate and
frequency of change. To accomplish this, shallow sediment cores are collected within the
bays, and the faunal and floral remains, sediment geochemistry, and shell biochemistry are
analyzed. Modern field data are collected from the same region as the cores and serve as
proxies to allow accurate interpretation of past depositional environments. The USGS South
Florida Ecosystem History Project is designed to integrate studies from a number of
researchers compiling data from terrestrial, marine, and freshwater ecosystems within south
Florida. The project is divided into 3 regions: Biscayne Bay and the Southeast coast,
Florida Bay and the Southwest coast, and Terrestrial and Freshwater Ecosystems of Southern
Florida. The purpose of the projects is to provide information about the ecosystem's recent
history based on analyses of paleontology, geochemistry, hydrology, and sedimentology of
cores taken from the south Florida region. Data generated from the South Florida Ecosystem
History project will be integrated to provide biotic reconstructions for the area at
selected time slices and will be useful in testing ecological models designed to predict
floral and faunal response to changes in environmental parameters. Biscayne Bay is of
interest to scientists because of the rapid urbanization that has occurred in the Miami area
and includes Biscayne National Park. Dredging, propeller scars, and changes in freshwater
input have altered parts of Biscayne Bay. Currently, the main freshwater input to Biscayne
Bay is through the canal system, but many scientists believe subsurface springs used to
introduce fresh groundwater into the Bay ecosystem. Study of the modern environment and core
sediments from Biscayne Bay will provide important information on past salinity and seagrass
coverage which will be useful for predicting future change within the Bay. Plant and animal
communities in the South Florida ecosystem have undergone striking changes over the past few
decades. In particular, Florida Bay has been plagued by seagrass die-offs, algal blooms, and
declining sponge and shellfish populations. These alterations in the ecosystem have
traditionally been attributed to human activities and development in the region. Scientists
at the U.S. Geological Survey (USGS) are studying the paleoecological changes taking place
in Florida Bay in hopes of understanding the physical environment to aid in the restoration
process. As in Biscayne Bay, scientists must first determine which changes are part of the
natural variation in Florida Bay and which resulted from human activities. To answer this
question, scientists are studying both modern samples and piston cores that reveal changes
over the past 150-600 years. These two types of data complement each other by providing
information about the current state of the Bay, changes that occurred over time, and
patterns of change. Terrestrial ecosystems of South Florida have undergone numerous human
disturbances, ranging from alteration of the hydroperiod, fire history, and drainage
patterns through implementation of the canal system to expansion of the agricultural
activity to the introduction of exotic species such as Melalueca, Australian pine, and the
Pepper Tree. Over historical time, dramatic changes in the ecosystem have been documented
and these changes attributed to various human activities. However, cause-and-effect
relationships between specific biotic and environmental changes have not been established
scientifically. One part of the South Florida Ecosystem History group of project is designed
to document 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 what would occur naturally. Specific goals of this part of
the project are to 1) document the patterns of floral and faunal changes at sites throughout
southern Florida over the last 150 years, 2) determine whether the changes occurred
throughout the region or whether they were localized, 3) examine the floral and faunal
history of the region over the last few millennia, 4) determine the baseline level of
variability in the communities prior to significant human activity in the region, and 5)
determine whether the fire frequency, extent, and influence can be quantified, and if so,
document the fire history for sites in the region.