2 research outputs found

    Effect of Hydrologic Restoration on the Habitat of The Cape Sable Seaside Sparrow, Annual Report of 2004-2005

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    The major activities in Year 3 on ‘Effect of hydrologic restoration on the habitat of the Cape Sable seaside sparrow (CSSS)’ included presentations, field work, data analysis, and report preparation. During this period, we made 4 presentations, two at the CSSS – fire planning workshops at Everglades National Park (ENP), one at the Society of Wetland Scientists’ meeting in Charleston, SC, and a fourth at the Marl Prairie/CSSS performance measure workshop at ENP. We started field work in the third week of January and continued till June 3, 2005. Early in the field season, we completed vegetation surveys along two transects, B and C (~15.1 km). During April and May, vegetation sampling was completed at 199 census sites, bringing to 608 the total number of CSSS census sites with quantitative vegetation data. We updated data sets from all three years, 2003-05, and analyzed them using cluster analysis and ordination as in previous two years. However, instead of weighted averaging, we used weighted-averaging partial least square regression (WA-PLS) model, as this method is considered an improvement over WA for inferring values of environmental variables from biological species composition. We also validated the predictive power of the WA-PLS regression model by applying it to a sub-set of 100 census sites for which hydroperiods were “known” from two sources, i.e., from elevations calculated from concurrent water depth measurements onsite and at nearby water level recorders, and from USGS digital elevation data. Additionally, we collected biomass samples at 88 census sites, and determined live and dead aboveground plant biomass. Using vegetation structure and biomass data from those sites, we developed a regression model that we used to predict aboveground biomass at all transects and census sites. Finally, biomass data was analyzed in relation to hydroperiod and fire frequency

    Modeling Species Richness within the East Texas Longleaf Pine Ecosystem and a Study of the Intermediate Disturbance Hypothesis

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    The longleaf pine ecosystem had an extensive range throughout the southeast continental United States. Since the arrival of the Europeans to the continent the ecosystem has been reduced to a fraction of its original extent, losing many endemic species. One of the key elements to maintenance of species richness within the longleaf pine ecosystem is the presence of a well-maintained fire regime. An ongoing fire regime within the longleaf pine ecosystem helps to promote the establishment and growth of one of the most rich and diverse ecosystems outside of the tropics. I created a model to predict species richness within this fire-maintained ecosystem. I measured species richness within increasing nested plots at the community level to calculate C and z values to see if I could apply them to predict the species richness at the landscape level. The model was able to predict with some accuracy the species richness of several known floras within the longleaf pine ecosystem of east Texas. Future management within the longleaf pine ecosystem can use this model to predict what standards should be meet for the use of management practices
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