LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA


(Sandweed Zone), Andropogon glomeratus (Bluestem Grass Zone), and Rhexia
mariana var. mariana (Dry Meadow Zone).
 The importance of seed banks in maintaining the temporary pond community
was not addressed directly in this study. However, the seed bank is likely to be
very important to the maintenance of the wetland community and a contributing
factor to pond zonation. Many wetland plant species disperse floating seeds and/or
require specific intervals of inundation or desiccation for seed germination (van der
Valk 1981). The position of these species may be dependent on the extent of
flooding in the basin before drawdown, as well as the duration of drawdown (Lowe
1986; Hull et al. 1989). An overlapping distribution of plant species perhaps
indicates similar hydrologic tolerances, but it may also indicate similar suitability
of the substrate for seed settling, seed germination, and plant growth after the seeds
have dispersed to that position (Hull et al. 1989).


 Wetland Index Values (WIV)


 All of the temporary pond basins studied had WIV less than 3, and, as a result,
their plant communities can be considered wetland vegetation according to the
Federal Manual for Identifying and Delineating Jurisdictional Wetlands (USEPA
1989). Wetland index values generally increased along the transects as the upland
boundary was reached. However, there was not a simple relationship between the
index values and a gradient of soil moisture, described by meters from the pond
center, because of confounding elevation and substrate effects (LaClaire unpubl.
data). The lowest mean WIV was calculated for WE- 1. This was the result of the
almost complete dominance (96%) of this pond basin by OBL. The highest mean
WIV was calculated for DP and was a result of the co-dominant UPL species found
in it. However, DP maintained OBL as the highest total percent cover and, as a
result, maintained its status as wetland.


 Species Richness, Diversity, and Hydrology


 The relationship between status of each pond in its hydrologic cycle, as
represented by time since it was flooded, and species richness and diversity is
complex. The lowest species richness was found in DP, which had been dry longer
than any other pond basin, but also in WE-11, which was flooded at the time of
sampling. Both ponds had low values for evenness as a result of dominance by
Panicum hemitomon, 59% of total cover for DP and 54% of total cover for WE-11.
Welaka pond #11 was almost entirely flooded (35/45 m along the transect) and this