Native Habitat Inventory Final Report 2004 - St. Lucie County

The GIS analysis will assess landscape-level variables such as connectivity, patch
size, and other measures of ecological integrity.
Pandion Systems, Inc. in association with GIS Associates, Inc. initiated this study in
January 2003. An interim technical report (St. Lucie Native Habitat Inventory Final
Technical Report) was completed in April 2003. This report evaluated the losses in
native habitat since 1992 and identified the type and amount of natural areas (as of 2002)
protected through public or private conservation ownership or easements. During the
period of June to August 2003, on-site inventories were made of natural lands considered
suitable for preservation.
The County ESL Program goal is to increase the acreage of native habitat preserved as
well as preserve unique communities and species. As of 2002, there were 19,417 acres of
public conservation land within the County (St. Lucie County ESL020303 shapefile).
Some key protected areas are interspersed with areas under intensive development
pressure such as the coastal and island areas, the high ancient dunes along US 1, as well
as the St. Lucie River and its tributaries. A minimum of 3,052 acres of natural areas was
lost between 1992 and 2002.
In addition to the direct loss of acres of native habitat, there is increased fragmentation of
the remaining natural lands outside of public ownership. Only about half (52%) of the
natural lands left are greater than 100 acres in size. The small areas cost more per acre to
acquire and manage, often have a greater percentage of undesirable edge, fewer species, a
reduced likelihood of long-term persistence, and reduced management options due to
external constraints (e.g., fire and residential areas).
The quantitative assessment of the acres of natural area lost and conserved indicated there
were 93,385 acres of potential natural area within the county. An initial subset was
selected that included all areas designated as Areas of Conservation Interest or Potential
Natural Areas by FNAI (51 sites and 44,031 acres). This list was further reduced to 35
sites with the assistance of the Steering Committee and their knowledge of the county.
Several more sites were eliminated due to lack of landowner-permitted access. In the end,
30 sites (40,142 acres) were surveyed representing different vegetative communities and
locations in the County. The vegetative communities of the sites ranged from coastal
uplands to wet flatlands. The sites ranged in size from 1 acre to 28,789 acres. A
summary of the ecological characteristics including content and context for all the sites is
provided.
A series of 5 quality measures (Vulnerability, Rarity, Connectedness, Completeness, and
Manageability) is given for each FNAI vegetative community type on the site. Each is
ranked from 1 to 5. The 30 sites surveyed were evenly split among A, B, and C quality
sites.
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