BULLETIN FLORIDA MUSEUM NATURAL HISTORY VOL. 38 PT. 11(8)


all three habitats, with each habitat including between 9 and 11 species.
Dominant tree species in the canopy, midstory and ground cover strata were water
oak (Quercus nigra), live oak (Quercus virginiana, laurel oak (Quercus laurifolia,
sweet gum (Liquidambar styraciflua), swamp bay (Persea palustris), sweet bay
(Magnolia virginiana), and pignut hickory (Carya glabra) (Tables 1, 2 and 3).
 The shrub layer differed the most in species composition among the three
habitat types. Dominant shrubs were saw-palmetto (Serenoa repens), fetterbush
(Lyonia lucida), and wax myrtle (Myrica cerifera). The most prevalent difference
occurred in the bottomland swamp (Mill Creek Swamp) with the predominance of
ericaceous shrubs (Table 4).
 Herb composition within the habitats was more diverse than other strata.
Several species of ferns were present in all three habitats. Other species of herbs
and grasses occurred in highest abundance in the mesic hardwood hammock with
open understory (Table 5). Several species of vines, including Smilax and
muscadine grape, occurred in nearly all sites (Table 6).
 Relative densities of plant species in all three habitat types in the three strata
were similar. Relative density of trees, saplings, and seedlings were concentrated
in four species with a range between 12% and 31% (Tables 1, 2, and 3).
Differences in relative densities for shrubs were most pronounced in the mesic
hammock with saw-palmetto understory (Ross and Goose lakes) and bottomland
hardwood swamp habitats with palmetto (44.4%) and fetterbush (54.2%) (Table 4).
Concentrations of relative densities for herbs and vines occurred in four species,
ranging between 13% and 38% (Tables 5 and 6).
 The most significant difference between habitat types was vertical and
horizontal structure, rather than species composition or relative density. Structural
complexity of vegetation in horizontal and vertical planes measured by height,
stem density, and crown diameter varied considerably among habitat types.
 The mean values of vegetation height in the three habitat types are presented
in Table 7. An ANOVA of vegetation height demonstrated significant differences
in all strata for saplings and shrubs by habitat where saplings were tallest in the
bottomland swamp and shortest in mesic hardwoods; shrubs were tallest in mesic
hammock with saw-palmetto understory. Trees, seedlings, and herbs showed no
significant difference in height by habitat type (p=0.05).
 Diameter basal height (DBH) was measured as an index of plant dominance.
An ANOVA demonstrated significant differences for DBH of trees, saplings, and
shrubs between habitats (p=0.05). Mean DBH for trees was highest in the mesic
hardwood forests; shrub DBH was highest in mesic hammock-saw-palmetto; and
the highest DBH for saplings occurred in the bottomland swamp (Table 8).