LACLAIRE: UPLAND TEMPORARY POND VEGETATION IN FLORIDA


GP(1989) (Table 9). The amount of time since each pond had held water when
sampled is also presented in Table 9.


 DISCUSSION

 Pond Similarities and Differences

 The similarities found in plant community composition between ponds was
based primarily on the presence of the eight most commonly found taxa and the
study site within which each pond was located. Both similarities and differences
between ponds were related to differences in each pond's hydrologic cycle, as
measured by the time since each pond had held water. This related directly to soil
moisture conditions (LaClaire 1992). Flooded ponds lacked some of the dry
meadow species but had floating-leaved species that were absent from the dry
ponds. Dry meadow species and plants responding to declines in soil moisture
conditions were more abundant in dry pond basins. This is demonstrated by the
low similarity when WE-5 and WE-11 are compared to OS. The flooded WREC
ponds had greater than 80% total cover of OBL but very low total percent cover of
FACW (4% and 3% respectively). One Shot Pond, which had been dry for 4
months when sampled, had 41% total cover of OBL and 45% FACW. The FACW
species were responding to drawdown and specific moisture conditions for which
they are adapted.
 Only four of the study ponds were sampled when drawdown had been recent,
and ruderal or annual/short-lived perennial type species, except for Eupatorium
leptophyllum, were not common in the pond basins. The transects in BP and GP
from 1989 and OS were sampled when drawdown had occurred less than 1 year
previous. One pond, ANF-1, had been dry only for a month when sampled, but
this was too soon for emergent vegetation to respond to the change in the
environment. All the other ponds were either flooded or had been dry a year or
longer. As a result, most of the co-dominant species identified in the ponds were
perennials, as were most of the total species identified across all ponds and all
years. Of course, additional species may have been present as vegetative
propagules or as seeds in the seed bank of ponds. Since annuals have a short life
cycle, frequent sampling would be required for a complete species list.
 Differences between the ponds are obvious from the fact that 78% of the co-
dominant species identified in each pond were present in only one pond. However,
many of these co-dominant species, as well as other component species of the
ponds, shared life histories that were in some way adapted for the cyclic changes in
the temporary pond basin. The most obvious similarity was the dominance of
perennial species in the ponds. Other similarities involved adaptations developed
in response to changes in hydrologic cycle. Several species (Dichanthelium
sabulorum, Juncus repens, and Sagittaria graminea) showed a wide range of shoot