Native Habitat Inventory Final Report 2004 - St. Lucie County

influences rather than natural influences. That is, they are often established over wide
areas and across many historic habitat types. For example, a single pasture may be
established in an area that once contained scrub on the deep sandy hill tops then graded
into scrubby flatwoods on the downslope then transitioning to mesic flatwoods on the
slightly richer flats and then graded to hardwood hammock with the richer soils and
finally to bottomland forest as it approaches the creek. In this example the single pasture
would be reclassified into 5 FNAI community types that range from high dry uplands to
riverine associated bottomlands. This results in a less clear relationship between the
FLUCCS to FNAI classifications.
For example, there are 14 potentially natural FLUCCS types (Table 13). Twelve of these
have a one-to-many relationship with the FNAI classification. Of these 12, only in 2
cases (16.7%) does a single FNAI type account for 70% or more of that FLUCCS type.
In other words, there is a predominate FNAI type for only 2 FLUCCS types.
Contrast this to the natural FLUCCS types (Table 14) of which there are 23 FLUCCS
types. Sixteen have a one-to-many relationship, and for 11 (68.8%) of these there is a
clearly predominate FNAI type. This tighter relationship is due to the fact that, although
the natural communities in FLUCCS are broader than in FNAI, they are still well-defined
and delineated along natural boundaries and thus strong corollaries can be drawn between
the two classification systems. Also, for these natural areas, even though several FNAI
types may be listed for a single FLUCCS type, they are often closely related FNAI types
(i.e., those that would naturally co-occur or intergrade into each other) or those that are
generally similar in appearance but differ in the details (e.g., depression marsh and basin
marsh).
For each of the 37 FLUCCS types (Tables 13 and 14), a proportionality relationship was
developed with the FNAI types. For each FLUCCS type, the areal amount (acreage)
assigned to each FNAI type was calculated. For example, 913 acres of FLUCCS type
Sand Pine (413) were sampled. Seventy-eight (78) percent of the time (719 of 913 acres)
the field teams classified it as FNAI type Scrub and the other 22 percent of the time as
another FNAI type (Table 14). Thus there is a one-to-many relationship between the
FLUCCS and the FNAI types and that relationship is also hierarchical (i.e., FNAI type
Scrub is a more likely substitute than Mesic Flatwoods for this FLUCCS type). The
hierarchical relationship is represented by the percentages.
Discussion
As stated above, FLUCCS natural area types tend to be broad whereas FNAI types tend
to be more narrowly defined, thus there is not a one to one relationship between FLUCCS
and FNAI types. Instead, often a single FLUCCS type may be assigned many FNAI
Natural Community types (a one to many relationship). However, there are often strong
relationships. For example, Longleaf Pine-Xeric Oak was reclassified to Scrub 96% of
the time.
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