In estuaries, like the Indian River Lagoon, mesozooplankton have a vital role in the food web by connecting trophic levels. In this study, mesozooplankton abundance and species composition were monitored weekly on the incoming and outgoing tides from September 2006 to May 2009. For the incoming tide, the mean abundance was 2298.2 mesozooplankton/m3 (+/-325.2), and for the outgoing tide the mean abundance was 1180.0 mesozooplankton/m3 (+/-153.1). The mesozooplankton abundance on the incoming tide was significantly greater than on the outgoing tide. The most abundant type of mesozooplankton was the copepod Acartia tonsa, representing 35.0% and 52.1% of the individuals on the incoming and outgoing tides respectively. Mesozooplankton abundance values were compared with environmental data obtained from the South Florida Water Management District. The strongest positive correlation was found between chlorophyll a concentrations and A. tonsa abundance, likely due to phytoplankton being the primary food source for A. tonsa. / by Miranda Hoover Kerr. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

It can be difficult to disentangle the factors that determine population success in freshwater systems, particularly for organisms with disturbance-resistant life stages like aquatic invertebrates. Nevertheless, the effects of environmental variation and habitat structure on animal population success in wetlands are important for understanding both trophic interactions and biodiversity. I performed two experiments to determine the factors limiting crayfish (Procambarus fallax) and dragonfly (Family: Libellulidae) populations in wetland environments. A simulation of a dry-disturbance and subsequent sunfish (Family: Centrarchidae) re-colonization revealed that crayfish populations are sensitive to sunfish, while dragonfly naiads seemed to be limited by other drying-related factors. A second manipulation revealed that small-bodied fishes and habitat structure (submerged vegetation) shaped dragonfly communities primarily through postcolonization processes. / by Natalie Knorp. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Fire plays a key role in the ecology of the Everglades and is a ubiquitous tool for managing the structure, function, and ecosystem services of the Greater Everglades watershed. Decades of hydrologic modifications have led to the alteration of plant community composition and fire regime in much of the Everglades. To create a better understanding of post-fire recovery in sawgrass (Cladium jamaicense) communities, sawgrass marshes in the northern Everglades were studied along a chronosequence of time since fire and along a nutrient gradient. Areas closer to a water nutrient source and with fewer mean days dry contained greater total and dead aboveground graminoid biomass whereas live graminoid biomass was greater in areas with less time since fire and with fewer days dry. Post-fire characteristics of sawgrass marshes can provide insight on the effectiveness of fire management practices in the maintenance and restoration of quality habitat in the northern Everglades. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Successful foraging by avian predators is influenced largely by prey availability. In a large-scale experiment at the Loxahatchee Impoundment Landscape Assessment project within the Arthur R. Marshall Loxahatchee National Wildlife Refuge, I manipulated two components of prey availability, water depth and vegetation density (submerged aquatic vegetation and emergent vegetation), and quantified the response by wading birds in terms of foraging habitat selection and foraging success. Manly's standardized selection index showed that birds preferred shallow water and intermediate vegetation densities. However, the treatments had little effect on either individual capture rate or efficiency. This was a consistent pattern seen across multiple experiments. Birds selected for certain habitat features but accrued little benefit in terms of foraging success. I hypothesize that birds selected sites with shallow water and intermediate vegetation densities because they anticipated higher prey densities, but they did not experience it here because I controlled for prey density. / by Samantha Lantz. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

Oyster reefs are biodiverse communities that provide many ecological and commercial benefits. However, oyster reefs have declined around the world from human activities. Oyster reef restoration programs have begun to limit some of the decline, but the need for determining the success of a program has been problematic. Passive acoustic techniques can use naturally occurring sounds produced by organisms to assess biodiversity. Passive acoustics was utilized to compare the sounds in natural and restored oyster reefs, with special attention on snapping shrimp (Alpheus spp.) snap sounds, in the St. Lucie Estuary, Florida over a one year period. Season, estuary region, habitat and day period had an effect on sound production. Passive acoustic monitoring of snapping shrimp sound production may be a useful non-destructive technique for monitoring the progress of oyster reef restoration projects once further correlations are established between environmental effects and sound production. / by Hilde P. Zenil Becerra. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.

Fire occurrences in the Everglades have increased since hydrologic alterations began, yet the vulnerability of Everglades peat to combustion during wildfires has yet to be determined. Natural fire regimes help maintain ecosystem functions and services and disruptions of natural disturbance regimes can have detrimental impacts, jeopardizing ecosystem health. Severe peat combustion can destroy native vegetation, alter microtopography, and release large amounts of stored carbon into the atmosphere. To create a better understanding of the mechanistic controls on Everglades ground fires, the soil's physical properties within several sites of Water Conservation Area 3 and how changes in water table affect these physical characteristics were determined. Areas disturbed by hydrologic alterations contain higher mineral content and therefore require lower water content to combust when compared to preserved regions. Changes in water tables have a significant effect on soil moisture and lower water tables drastically increase the vulnerability of a region. / by James Johnson. / Thesis (M.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Over drainage due to water management practices, abundance of native and rare species, and low-lying topography makes the coastal Everglades especially vulnerable to Sea-Level Rise (SLR). Water depths have shown to have a significant relationship to vegetation community composition and organization while also playing a crucial role in vegetation health throughout the Everglades. Modeling potential habitat change and loss caused by increased water depths due to SLR requires better vertical Root Mean Square Error (RMSE) and resolution Digital Elevation Models (DEMs) and Water Table Elevation Models (WTEMs). In this study, an object-based machine learning approach was developed to correct LiDAR elevation data by integrating LiDAR point data, aerial imagery, Real Time Kinematic (RTK)-Global Positioning Systems (GPS) and total station survey data. Four machine learning modeling techniques were compared with the commonly used bias-corrected technique, including Random Forest (RF), Support Vector Machine (SVM), k-Nearest Neighbor (k-NN), and Artificial Neural Network (ANN). The k-NN and RF models produced the best predictions for the Nine Mile and Flamingo study areas (RMSE = 0.08 m and 0.10 m, respectively). This study also examined four interpolation-based methods along with the RF, SVM and k-NN machine learning techniques for generating WTEMs. The RF models achieved the best results for the dry season (RMSE = 0.06 m) and the wet season (RMSE = 0.07 m) WTEMs. Previous research in Water Depth Model (WDM) generation in the Everglades focused on a conventional-based approach where a DEM is subtracted from a WTEM. This study extends the conventional-based WDM approach to a rigorous-based WDM technique where Monte Carlo simulation is used to propagate probability distributions through the proposed SLR depth model using uncertainties in the RF-based LiDAR DEM and WTEMs, vertical datums and transformations, regional SLR and soil accretion rates. It is concluded that a more rigorous-based WDM technique increases the integrity of derived products used to support and guide coastal restoration managers and planners concerned with habitat change under the challenge of SLR. Future research will be dedicated to the extension of this technique to model both increased water depths and saltwater intrusion due to SLR (saltwater inundation). / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Shallow water availability coupled with anthropogenic degradation of seagrass beds limits wading bird food resources in dynamic coastal ecosystems. Identifying prey species critical to wading bird reproductive success and the environmental drivers of key prey species abundance is important for understanding how environmental stressors influence prey and change the quality of foraging patches. Little Blue Herons (Egretta caerulea) are reportedly generalists eating insects, crustaceans, and fish; however, the proportions of prey items in the diet may shift spatially and temporally from freshwater to marine systems during breeding and non-breeding periods. I investigated prey selection by Little Blue Herons in Florida at the Great White Heron National Wildlife Refuge and the western Florida Bay, during 2016 and 2017 breeding seasons by investigating prey availability at low-tide locations along mudflats compared to stomach regurgitate samples collected from Little Blue Heron chicks 1 to 4 weeks old. Little Blue Herons selected Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) from the estuarine environment, but also consumed terrestrial prey (e.g. tree crabs) suggesting Little Blue Heron foraging habitat is not restricted to tidal flats. Additionally, these results support the characterization of Little Blue Herons as a generalist. After identifying important prey species, I modeled the associations of selected prey species with submerged aquatic vegetation density and abiotic variables to better understand habitat preferences and important habitat characteristics that drive prey density. Models support total seagrass density and algal density as having the greatest effect on prey selected by Little Blue Herons. Prawn density has a strong positive association with seagrass density. Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) had strong positive association with algae while pipefish (Syngnathidae) had a strong negative association with algae suggesting algae density in seagrass meadows should be considered when assessing the quality of seagrass meadows for Little Blue Heron prey and habitat suitability. My results varied from previous studies where prawns and gulf toadfish were associated with specific seagrass species. Therefore, some Little Blue Heron prey species in south Florida may not be affected by changes in submerged aquatic vegetation community composition if submerged aquatic vegetation densities remain constant. Studies are needed that clarify the complex interactions between prey and specific habitat metrics to validate the strength of landscape scale drivers of wading bird prey densities in dynamic coastal ecosystems and to determine how these communities will respond to anthropogenic environmental change. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Juvenile green turtle (Chelonia mydas) abundance differs among nearshore reefs, but why some sites are preferred over others is unknown. My study had two objectives: to quantify differences in abundance over time (one year) and to determine what ecological factors were correlated with those differences. I conducted quarterly surveys on reefs in Palm Beach and Broward Counties and compared reef sites with respect to (i) water depth, (ii) algal abundance and composition, and (iii) changes in reef area (caused by sand covering) through time (11 years). Turtles were most abundant on shallow reefs exposed to high light levels that remained stable (uncovered by sand) for long periods of time. These reefs had the highest diversity of algal species, in part because cropping by the turtles prevented any one species from becoming dominant. My results suggest that both physical and biological factors make some reefs more attractive to turtles than others / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

A challenge to ensure the health of wading bird populations is to have a better understanding of the altered habitats that we must now consider part of their natural history. Throughout their range endangered Wood Storks (Mycteria americana) have been reported to forage in ditches, a disparate category of linear man-made waterways. In a 52-kmP 2 P study area on the east coast of central Florida, the characteristics of hydrologically diverse ditches were quantified, and their use by Wood Storks documented during their non-breeding season. Logistic regression analyses were carried out using the ditch characteristics as independent variables and Wood Stork presence/absence as the dependent variable. This study confirms the use of these marginal wetlands, and identifies the significance of emergent vegetation on the foraging habitat selection of Wood Storks in the dry season. / by Eleanor K. Van Os. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.