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- Permanent Link:
- http://dpanther.fiu.edu/dpService/dpPurlService/purl/FI14090755/00001
Notes
- Abstract:
- After developing field sampling protocols and making a series of consultations
with investigators involved in research in CSSS habitat, we determined that vegetation hydrology
interactions within this landscape are best sampled at a combination of scales.
At the finer scale, we decided to sample at 100 m intervals along transects that cross the
range of habitats present, and at the coarser scale, to conduct an extensive survey of
vegetation at sites of known sparrow density dispersed throughout the range of the CSSS.
We initiated sampling in the first week of January 2003 and continued it through the last
week of May. During this period, we established 6 transects, one in each CSSS subpopulation,
completed topographic survey along the Transects A, C, D, and F, and
sampled herb and shrub stratum vegetation, soil depth and periphyton along Transects A,
and at 179 census points. We also conducted topographic surveys and completed
vegetation and soil depth sampling along two of five transects used by ENP researchers
for monitoring long-term vegetation change in Taylor Slough. We analyzed the data by
summarizing the compositional and structural measures and by using cluster analysis,
ordination, weighted averaging regression, and weighted averaging calibration. The mean
elevation of transects decreased from north to south, and Transect F had greater variation
than other transects. We identified eight vegetation assemblages that can be grouped into
two broad categories, ‘wet prairie’ and ‘marsh’. In the 2003 survey, wet prairies were
most dominant in the northeastern sub-populations, and had shorter inferred-hydroperiod,
higher species richness and shallower soils than marshes, which were common in Subpopulations
A, D, and the southernmost regions of Sub-population B. Most of the sites at
which birds were observed during 2001 or 2002 had an inferred-hydroperiod of 120-150
days, while no birds were observed at sites with an inferred-hydroperiod less than 120
days or more than 300 days. Management-induced water level changes in Taylor Slought
during the 1980’s and 1990’s appeared to elicit parallel changes in vegetation. The results
described in detail in the following pages serve as a basis for evaluating and modifying, if
necessary, the sampling design and analytical techniques to be used in the next three
years of the project.
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