While repeated transgressive and regressive sea level cycles have shaped south Florida throughout geological history, modern rates of sea level rise pose a significant risk to the structure and function of the freshwater wetland ecosystems throughout the low-lying Everglades region. Current regionally corrected sea level projections for south Florida indicate a rise of 0.42m by 2050 and 1.15m by 2100, suggesting the salinization of previously freshwater areas of the Everglades is conceivable. As freshwater areas become increasingly exposed to saltwater they experience shifts in vegetation composition, soil microbial populations, plant productivity, and physical soil properties that ultimately result in a phenomenon called peat collapse. Recent work in the Everglades has sought to further explain the mechanisms of peat collapse, however the physical changes to the peat matrix induced by saltwater intrusion are still uncertain. Moreover, the combination of physical alterations to the peat matrix associated with peat collapse and shifts in wetland salinity regimes will also likely disrupt the current carbon gas dynamics of the Everglades. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

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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

Knowledge of the geospatial distribution of vegetation is fundamental for resource management. The objective of this study is to investigate the possible use of airborne LIDAR (light detection and ranging) data to improve classification accuracy of high spatial resolution optical imagery and compare the ability of two classification algorithms to accurately identify and map wetland vegetation communities. In this study, high resolution imagery integrated with LIDAR data was compared jointly and alone; and the nearest neighbor (NN) and machine learning random forest (RF) classifiers were assessed in semi-automated geographic object-based image analysis (GEOBIA) approaches for classification accuracy of heterogeneous vegetation assemblages at Everglades National Park, FL, USA. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Changes in vegetation may influence the quality and quantity of the underlying organic peat soils and have impacts on faunal populations. My goal was to determine whether shifts from native slough communities to invasive cattail in the Florida Everglades could affect peat characteristics that could cascade to impact the dry season survival of crayfish (Procambarus fallax). I contrasted peat soils from native slough and cattail-invaded sites as alternative dry-season burrowing substrates for crayfish. Cattail peat had higher average bulk density and inorganic content within the first ten centimeters of the soil profile. Crayfish showed marginally greater initial burrowing success in slough peat than in cattail peat but survival was equivalent in both peat soils and high overall. Understanding these indirect linkages between vegetation and crayfish populations in the Everglades can provide insight on the consequences of plant invasion on ecosystem trophic dynamics. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

A large part of the environmental restoration required by the Comprehensive Everglades Restoration Plan calls for more water-storage on lands south of Lake Okeechobee in order to restore the natural water flows of the Everglades watershed. The Everglades Agricultural Area (EAA) can be used for increased water storage in order to relieve coastal estuaries of excess water in the rainy season. This water storage can deliver additional ecosystem services of soil retention and reduced CO2 emissions that could compensate farmers for the cost of water storage by increasing long term farm profitability. The goals of this study were 1) to quantify the environmental and economic trade-offs of different water storage scenarios using water-tolerant sugarcane cultivars, and 2) to quantify the amount of water storage possible in the EAA under different water storage scenarios. A mathematical model was developed to calculate soil depth, soil subsidence, depth to the water table, sugarcane production, farm return, water storage and carbon loss for three different sugarcane cultivars with different water-tolerances. A GIS tool is also developed to estimate the amount of water storage possible in the EAA. The study found that even though water-tolerant sugarcane cultivars experience higher yields and net returns than non-water-tolerant cultivars the water storage costs with these water tolerant cultivars was greater. Raising water tables on farm lands did have the environmental benefits of reduced soil subsidence, extended farm life and increased years of water storage. However total CO2 emissions rise from 14 to 136%. Results of the GIS analysis revealed that water storage capacity for a DWT of 61 cm is 1,404,562 ac-ft, 1,417,400 ac-ft for DWT 45 cm and 1,474,692 ac-ft for DWT 20 cm. The GIS analysis was also able to identify flow ways that could possibly carry water south from Lake Okeechobee and ultimately to the WCAs south of the EAA. These results show that raising water tables in the EAA to deliver the ecosystem service of expanded water storage is overall more costly, but yearly costs are very low. Therefore water storage on farmlands is an affordable interim method of water storage.

The purpose of this thesis is to determine the factors that contributed to the decline of Florida apple snail ( Pomacea paludosa) populations in the A.R.M. Loxahatchee National Wildlife Refuge with the goal of devising management recommendations to the Refuge regarding population management strategies. The factors examined that could have potentially contributed to population decline include the use of copper-based herbicides, insecticide application, the occurrence of drought, the use of other herbicides, the occurrence of fire, and non-avian predation. Annual Narrative documents produced by Refuge managers and staff members, dated from 1951 to 2007, were used to collect historical data for these factors. The quality of data reporting within the Annual Narratives was also examined. To support data on droughts documented in the Annual Narratives, surface water and rainfall data were obtained and analyzed. The methodology includes the use of conceptual ecological models and historical ecology to determine whether or not the factors examined produced an ecological effect capable of affecting the Refuge population of apple snails. Evidence from the Annual Narratives suggests that the use of copper-based herbicides, the occurrence of drought, and predation by alligators were responsible for the decline of the apple snail on the Refuge. A lack of consistently reported data regarding apple snail densities makes it difficult to determine the degree to which each factor had an effect on the apple snails or to determine if any spatio-temporal relationship existed between the Florida apple snail and Everglade snail kite ( Rostrhamus sociabilis plumbeus) based on copper-based herbicide use. The overall quality of the Annual Narratives improved throughout the study period and eventually focused heavily on investigative studies. Several management recommendations were suggested to improve Florida apple snail populations on the Refuge. First, in order to monitor the health and trends of the apple snail population, a monitoring network needs to be established with results maintained in a geodatabase. Both apple snail density and egg cluster counts need to be made following an established sampling method. Second, in an attempt to sustain higher apple snail densities, stocking of the interior should be attempted. Finall, in the event that adjacent farmlands are to be restored, soil samples need to be analyzed to determine if concentrations are high enough that desorption of copper from the flooded agricultural soils could pose a serious threat to the Refuge by reintroducing toxic levels of copper.

Methyl halides are trace gases with both natural and anthropogenic origins. Once generated, these gases transport chlorine and bromine into the stratosphere, where they play an important role in ozone depleting catalytic cycles. The Florida Everglades is one location where methyl halide emissions have been proposed to be elevated due to high primary production and ionic halogens. This region also provides a unique study environment due to salt water intrusions, which occur during storm or low marsh water level-high tide events. The purpose of this research was twofold. First, quantification of methyl chloride (CH3Cl) and methyl bromide (CH3Br) production from periphyton mats on a temporal scale was needed. Secondly, to determine how varying concentrations of salinity affect CH3Cl and CH3Br production originating from calcareous periphyton mats within the Everglades. Periphyton was exposed to continuous 12 hour dark/light cycles in varying concentrations of salt water (0, 0.1, 1, 5, and 10 parts per thousand). All water samples were analyzed to determine the production rate of CH3Cl and CH3Br in periphyton samples using a gas chromatograph coupled with an electron capture detector (GC-ECD). Periphyton mats were found to be a producer of CH3Cl in all freshwater (0 parts per thousand) trials and sampling times; however, results from CH3Br analysis found production rates that suggest consumption occurred in the majority of the 0 parts per thousand trials. Production rates for CH3Cl ranged from 0.077 to 0.109 g-1hr-1 after 24 hours, 0.027 to 0.073 pM g-1hr-1 after 48 hours, and 0.034 to 0.047 pM g-1hr-1 after 72 hours. Production rates for the CH3Br freshwater experiments ranged from -0.00025 to 0.00185 pM g-1hr-1 after 24 hours, -0.00022 to -0.00078 pM g-1hr-1 after 48 hours, and -0.00042 to -0.00061 pM g-1hr-1 after 72 hours. This research has also shown that increased salinity does have a significant positive effect on the production of CH3Cl and CH3Br from calcareous periphyton mats, which is important in areas that could be prone to salt water intrusions or rising sea levels due to global climate change.

The relative rates of detrital decomposition in four vegetation communities within the Everglades' ridge-slough microtopography were evaluated during two trials. Litterbags with community-specific detritus in proportion to each community's composition were put into the four communities; namely, submerged marsh, emergent marsh, short Cladium ridge, and tall Cladium ridge. These litterbags were paired with litterbags containing control leaf litter from Chrysobalanus icaco and Salix caroliniana during the wet and dry season trials, respectively. No regional differences in decomposition were shown, but there were significant differences across communities, attributed to the initial C:N ratio of the detritus, with the fastest decomposition occurring in the deepest submerged marsh followed by emergent marsh, and the shallower ridge communities had equally slower decomposition. Additionally, both controls followed the same pattern. Thus, decomposition contributes to an active self-maintenance mechanism within the vegetation communities which ultimately helps to conserve the ridges and sloughs. / by Sheryl R. van der Heiden. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

The study examined the past and present spatial distribution of the Florida tree snail, L. fasciatus solidus, in the Long Pine Key area of the Everglades National Park. Remote sensing and mobile GIS were used to create a GIS database of the field research results. Collection and survey-based data were used to create a current spatial distribution map of L. fasciatus solidus throughout the Long Pine Key area. The data collected during the 2006 survey were compared to a 1931 survey of the same study area conducted by Dr. William Clench of the Museum of Comparative Zoology (MCZ) of Harvard University. The data was used to determine the success of L. fasciatus solidus from 1931 to 2006, to evaluate a correlation between hammock size and the number of color forms, and to detect migration patterns of L. fasciatus solidus within the Long Pine Key area of Everglades National Park. Based on the average success rate for the seven color forms and the hammocks, the L. fasciatus solidus population in the Long Pine Key area exemplifies one of a stable community. Each color form used for the analysis had a success rate between 67% and 100%. These percentages can only be the worst case scenario based on the fact that many Liguus were not observed, and any others that would have been observed, would only increase the success rate. / by Jason R. Fadely. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.