The Florida Keys Coral Reef Monitoring Project (CRMP) began video transect sampling in 1996 and has continuously monitored 107 Florida Keys stations through 2002. The video was downward pointing and produced images from which planar projection data were calculated to determine percent cover of living benthic organisms. An absence of data assessing correlation between octocoral percent cover and octocoral abundance motivated a study to compare octocoral percent cover with abundance data acquired from the same video transects. The methods employed to extract octocoral abundance data from videotape were validated. Temporal changes in octocoral abundance, size and taxonomic group were determined by examination of video transects of 28 randomly selected stations from 1996, 1998, 1999, and 2002. Size classes were defined as40cm (short, medium and tall respectively). Taxonomic groups were Gorgonia ventalina and "other octocorals" in three size classes, and Scleraxonia. An in situ study assessed the accuracy of video-derived counts. Average densities of G. ventalina and Scleraxonia were consistently about one colony/m2. Other octocoral as a group averaged 7-9 colonies/m2. When summarized by height, short and tall averaged about 1-2 colonies/m2, while colonies between 10 and 40 cm in height consistently averaged about 6 colonies/m2. Hurricane Georges, in September 1998, impacted the octocoral assemblage. Abundance declined most at stations near the storm center and stations in shallower water. Storm impact was related to octocoral height. Tall octocorals were removed more frequently than medium, short and encrusting forms. A dramatic increase of short individuals in 2002 is indicative of successful post-hurricane recruitment. By 2002, octocoral abundance had recovered to pre-hurricane levels. This study demonstrated that abundance data can reliably be derived from archived video data, reinforcing the value of standardized video data archives. Octocoral abundance and octocoral percent cover are not strongly correlated because tall individuals disproportionately influence percent cover estimates. Nevertheless, trends in octocoral percent cover are reliable indicators of the trends in octocoral abundance.

The purpose of this study was to compare vegetation systems among three artificially isolated wetlands on the west end of Galveston Island. Sample sites were identified as isolated wetlands and anthropogenic impact was observed. Wetland plant communities were identified through representative field studies using a modified quadrat method. Species composition, species diversity, evenness, cover and frequency were compared among the three sample sites. Salinity at all three sample sites remained at 0 ppt through June, July and August. Salinity increased to 10 ppt in both Lafitte’s Cove Nature Preserve and Dos Vacas Muertas Bird Sanctuary in September. No change in salinity was recorded at Isla Del Sol. At Lafitte’s Cove Nature Preserve the majority of the soil composition included Mustang-Nass. Dos Vacas Muertas Bird Sanctuary consisted of a Mustang fine sand complex while Isla Del Sol consisted of Mustang fine sand and Nass very fine sandy loam. Sampling at Lafitte’s Cove Nature Preserve produced 15 species. Dos Vacas Muertas Bird Sanctuary added 7 new species while Isla Del sol added 6 new species for a total of 28 species within the three sites. The overall plant species’ richness of Lafitte’s Cove Nature Preserve and Dos Vacas Muertas Bird Sanctuary remained low. A high frequency was observed in Sesbania drummondii and Cyperus odoratus at Lafitte’s Cove Nature Preserve. Sesbania drummondii retained the highest percent cover for the site. At Dos Vacas Muertas Bird Sanctuary, Phragmites australis and Spartina patens demonstrated a high frequency as well as percent cover. Frequency was highest in Juncus roemerianus and Eleocharis geniculata at Isla Del Sol. Several plant species exhibited a high frequency while overall frequency was more evenly distributed in Isla Del Sol than the other sample sites. Percent cover was highest in Juncus roemerianus and Borrichia frutescens. Isla Del Sol had the highest species diversity and evenness of all three sample sites. Similarity in species composition was high with the coefficient for pair-wise comparisons in Isla Del Sol and Lafitte’s Cove Nature Preserve being the highest. The three sample sites shared 53% to 73% of their species. Isla Del Sol possessed 6 species that were absent from the other sample sites. Dos Vacas Muertas Bird Sanctuary contained 4 unique species while Lafitte’s Cove Nature Preserve had only 3 unique species. Dos Vacas Muertas Bird Sanctuary had the lowest index score at 10. Lafitte’s Cove Nature Preserve had the highest index score at 24 while Isla Del Sol followed close behind at 22. For the Anthropogenic Activity Index, Lafitte’s Cove Nature Preserve still retained the highest score at 14. Results for Isla Del Sol showed an index score of 13 while Dos Vacas Muertas Bird Sanctuary scored only 7. The results of this study show that although Dos Vacas Muertas Bird Sanctuary had lower levels of disturbance when compared to the other sample sites, it still experienced a lower species diversity. Isla Del Sol had the highest species diversity and evenness of the sites. Lafitte’s Cove Nature Preserve had the highest level of disturbance and maintained a low level of diversity as well. When comparing the results to historical data, a reduction in salt marsh plant species was observed. Species that are often associated with freshwater to brackish marsh wetlands have become more dominant in the sample sites.

Title from PDF of title page. / Document formatted into pages; contains 112 pages. / Thesis (M.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The Florida Keys Coral Reef Monitoring Project (CRMP) began video transect sampling in 1996 and has continuously monitored 107 Florida Keys stations through 2002. The video was downward pointing and produced images from which planar projection data were calculated to determine percent cover of living benthic organisms. An absence of data assessing correlation between octocoral percent cover and octocoral abundance motivated a study to compare octocoral percent cover with abundance data acquired from the same video transects. The methods employed to extract octocoral abundance data from videotape were validated. Temporal changes in octocoral abundance, size and taxonomic group were determined by examination of video transects of 28 randomly selected stations from 1996, 1998, 1999, and 2002. Size classes were defined as [10cm, 10-40cm, ]40cm (short, medium and tall respectively). / ABSTRACT: Taxonomic groups were Gorgonia ventalina and "other octocorals" in three size classes, and Scleraxonia. An in situ study assessed the accuracy of video-derived counts. Average densities of G. ventalina and Scleraxonia were consistently about one colony/m2. Other octocoral as a group averaged 7-9 colonies/m2. When summarized by height, short and tall averaged about 1-2 colonies/m2, while colonies between 10 and 40 cm in height consistently averaged about 6 colonies/m2. Hurricane Georges, in September 1998, impacted the octocoral assemblage. Abundance declined most at stations near the storm center and stations in shallower water. Storm impact was related to octocoral height. Tall octocorals were removed more frequently than medium, short and encrusting forms. A dramatic increase of short individuals in 2002 is indicative of successful post-hurricane recruitment. By 2002, octocoral abundance had recovered to pre-hurricane levels. / ABSTRACT: This study demonstrated that abundance data can reliably be derived from archived video data, reinforcing the value of standardized video data archives. Octocoral abundance and octocoral percent cover are not strongly correlated because tall individuals disproportionately influence percent cover estimates. Nevertheless, trends in octocoral percent cover are reliable indicators of the trends in octocoral abundance. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

ABSTRACT Alliaria petiolata (garlic mustard) is an aggressive non-native and invasive forb that negatively impacts native arbuscular mycorrhizal communities and inhibits or prevents the growth of native plant species. Invasive species mitigation and management strategies that use native revegetation vary in success. This study focuses on which species naturally regenerate in areas where A. petiolata has been mitigated to help inform restoration efforts. Seedling emergence of species within the seed bank of four plot types (uninvaded, invaded, chemically treated, and mechanically treated) were observed two years post restoration efforts to determine which native species are likely to persist to seedlings following management. Species abundance and percent cover of all plant species were recorded to evaluate the presence of species in addition to plant health and physiological differences. Native species abundance was significantly reduced within herbicide treated plots as compared to untreated and invaded plots (p=0.02). Plots treated with mechanical removal had the greatest percent cover of native plants as compared to all other plot types but were dominated by colonizing species which is typical of a disturbed habitat. Mechanical removal also resulted in a greater abundance and stability among functional groups of native species, than those treated with herbicide. Forb species dominated coverage of plots over other functional groups when treated with herbicide. Alliaria petiolata invasion and management methods significantly impacted forb and graminoid species, as they had significantly lower abundance in plots treated with herbicide. The results demonstrate that the method of removal as well as the presence of A. petiolata affects emergence of plant species from the seedbank. The additional disturbance of mechanical removal may alter successional trajectories following invasion. Herbicide treatment resulted in the most similar species abundance as the uninvaded reference plots, which had the lowest seedling emergence and percent cover.