Development of a Southwest Florida Pre-Development Plant Community Map
Michael J. Duever
South Florida Water Management District, Fort Myers, Florida
A map showing pre-development plant communities has been derived for
southwest Florida. Fifteen major types of communities were classified, based on
their relation to the hydrology of the area. The information will be used to
support modeling efforts of the Natural Systems Group for the Southwest Florida
Feasibility Study. Pre-development is defined as the condition of the landscape
prior to the arrival of Europeans in southwest Florida, when hydrology and fire
regimes were the primary determinants of plant community distributions. Two
primary sources of digital data were combined and refined using supplementary
material and professional knowledge of the study area.
A Natural-Soils-Landscape-Positions (NSLP) map had recently been created by
the South Florida Water Management District by aggregating soil-survey units
according to their landscape positions (depressions, flats, knolls, ridges, etc.) and,
to some extent, to their hydrologic regimes. In its initial form, the classification
was inadequate to sort out the individual plant communities or to provide the
hydrologic parameters required by the model. Furthermore, the data did not cover
the entire study area. However, no better source of data was available in digital
format, so the group modified and expanded this classification of the soil-survey
units for a five-county area into a set of 15 plant-community types.
The Big Cypress National Preserve (BCNP) and the adjacent Everglades National
Park (ENP) lands were not included in the NSLP coverage. However, a recent
plant-community classification and vegetation map was available for these areas.
The group reclassified that database into the same fifteen plant-community types.
Only small portions of BCNP have been altered from their pre-development
condition.
Additional adjustments were made to ensure consistency. All "disturbed” areas on
the original maps were reclassified to our best estimate of the pre-disturbance
communities, based on supplementary information such as older soil surveys,
aerial photographs, permitting records, and the knowledge of individuals with
long-term experience in southwest Florida. The soils-based and vegetation-based
maps were joined and adjusted in an effort to create a seamless database.
Additional areas (notably in western Broward County) were adapted from older
soil surveys. The resulting product represents the best information that could be
developed within the time constraints for the project.
We have classified the pre-development plant communities in southwest Florida
into fifteen major types, based on their hydrologic characteristics. The highest
level of classification is whether a community is tidal or non-tidal. The second
level separates various hydrologic regimes according to hydroperiod, average
wet-season water depth, and minimum dry-season water depth during an average
year and during a 10-year drought. Lastly, we divided them according to their
successional stage -- early successional (herbaceous wetland or pine flatwoods
community) or later successional (community dominated by cypress and/or
hardwoods).
The map attempts to reconstruct "pre-development" vegetation. One should not
assume that all differences from existing vegetation/landcover result from
agricultural or urban development. Differences also may reflect changes in
hydrologic and/or fire regimes, as well as the presence of invasive exotic plants.
The map provides a basis for reconstructing hydrology in pre-development
southwest Florida, and is designed to support a hydrologic model having a mesh
(cell size) of about 20 acres.
Major participating agencies on this project include the Collier County Planning
Department, Florida Fish and Wildlife Conservation Commission, South Florida
Water Management District, USDA Natural Resources Conservation Service,
USDI Fish and Wildlife Service, and USDI National Park Service.
Duever, Michael, South Florida Water Management District, 2301 McGregor
Blvd., Fort Myers, FL, 33901, Phone: 239-338-2929, Fax: 239-338-2936,
mduever@sfwmd.gov