Understanding where and why organisms are distributed in the environment are central themes in ecology. Animals live in environments in which they are subject to competing demands, such as the need to forage, to find mates, to reproduce, and to avoid predation. Optimal habitats for these various activities are usually distributed heterogeneously in the landscape and may vary both spatially and temporally, causing animals to adjust their locations in space and time to balance these conflicting demands. In this dissertation, I outline three studies of Procambarus fallax in the ridge-slough landscape of Water conservation Area 3A (WCS-3A). The first section outlines an observational sampling study of crayfish population distribution in a four hectare plot, where I statistically model the density distribution at two spatial scales. ... Secondly, I use radio telemetry to study individual adult crayfish movements at two study sites and evaluate habitat selection using Resource Selection Functions. In the third section, I test the habitat selection theory, ideal free distribution, by assessing performance measures (growth and mortality) of crayfish in the two major vegetation types in a late wet season (November 2007) and early wet season (August 2009). / by Craig van der Heiden. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliographical references at the end of each chapter. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Seasonal variation in food availability is one of the primary limitations to avian populations, particularly during the breeding season. However, the behavioral responses between species may differ based on foraging strategies. I examined the influence of food availability on landscape-level habitat selection, patch-level habitat selection, and movements of two wading bird species with divergent foraging strategies, the Great Egret and White Ibis. On a landscape scale, there appeared to be a relationship among resource availability, the temporal scale of the independent variable, and whether the response was similar or different between species. At the patch level, results demonstrated a relationship between resource availability and the spatial scale of the independent variables selected by birds. Species movements were consistent with the differing strategies. This study is the first to make the link between landscape hydrology patterns, prey availability, and responses in wading bird habitat selection at multiple spatial scales. / by James M. Beerens. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

The West Kendall Tree Island site (8DA1081) is a black dirt midden situated on the northeast end of an everglades tree island. The site has been intensely disturbed by excavation pits, particularly on the highest elevations of the site, and becomes increasingly disturbed by a growing Kendall population. Faunal remains recovered in 2008 are examined to reconstruct past ecological habitats, comparing the faunal composition to tree island sites within the Florida Everglades. Based upon identifications, the composition of the site is similar to those of the region, being comprised primarily of freshwater aquatic species and aquatic reptiles, with minimal selection of terrestrial faunal resources. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

In south Florida, the Greater Everglades ecosystem supports sixteen species of wading birds. Wading birds serve as important indicator species because they are highly mobile, demonstrate flexible habitat selection, and respond quickly to changes in habitat quality. Models that establish habitat relationships from distribution patterns of wading birds can be used to predict changes in habitat quality that may result from restoration and climate change. I developed spatio-temporal species distribution models for the Great Egret, White Ibis, and Wood Stork over a decadal gradient of environmental conditions to identify factors that link habitat availability to habitat use (i.e., habitat selection), habitat use to species abundance, and species abundance (over multiple scales) to nesting effort and success. Hydrological variables (depth, recession rate, days since drydown, reversal, and hydroperiod) over multiple temporal scales and with existing links to wading bird responses were used as proxies for landscape processes that influence prey availability (i.e., resources). In temporal foraging conditions (TFC) models, species demonstrated conditional preferences for resources based on resource levels at differing temporal scales. Wading bird abundance was highest when prey production from optimal periods of wetland inundation was concentrated in shallow depths. Similar responses were observed in spatial foraging conditions (SFC) models predicting spatial occurrence over time, accounting for spatial autocorrelation. The TFC index represents conditions within suitable depths that change daily and reflects patch quality, whereas the SFC index spatially represents suitability of all cells and reflects daily landscape patch abundance. I linked these indices to responses at the nest initiation and nest provisioning breeding phases from 1993-2013. The timing of increases and overall magnitude of resource pulses predicted by the TFC in March and April were strongly linked to breeding responses by all species. Great Egret nesting effort and success were higher with increases in conspecific attraction (i.e., clustering). Wood Stork nesting effort was closely related to timing of concurrently high levels of patch quality (regional scale) and abundance (400-m scale), indicating the importance of a multi-scaled approach. The models helped identify positive and negative changes to multi-annual resource pulses from hydrological restoration and climate change scenarios, respectively. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Thoreau said that, "in wildness is the preservation of the world." The characters in the following collection of stories might be tempted to rephrase that statement to read, "in wildness is the preservation of the criminal world." These stories feature wild places where the natural world often is not as dangerous as the people who seek refuge in the borderlands between wilderness and civilization. Many crime stories take place in cities-for good reason. More people usually equates with more crime. However, anywhere that people choose to live, crime is sure to follow-crime against each other, crime against themselves, and even crime against the world they inhabit. In "Blood and Dirt," two brothers find themselves dependent on their native landscape for different reasons. One will have to let go, but the other will find him harder to shake loose than a cottonmouth wrapped around a cypress knee. "Wet Season" finds a man hiding in plain sight at the southern fringe of civilization, and doing a fine job of it until his past comes looking for him. Instead of watching the last reflection of his inner wildness disappear, the protagonist of "Great Apes" decides to internalize his problems. And in "Itch: A Vampire Story," a group of teenagers who enjoy the dark mythology of the undead learn firsthand of a dark reality in the Everglades. These characters are often seeking to escape the hectic contemporary world of computers and cell phones, mortgages and nine-to-five jobs. What they discover is that, while unspoiled nature may be hard to find, human nature is even more difficult to escape.

Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. They also have the capability to produce and release significant amounts of greenhouse gasses (CO2, CH4) into the atmosphere. Most studies of wetland soil C and gas flux dynamics have been done in expansive peatlands in northern boreal and subarctic biomes. However, wetlands in temperate and tropical climates are vastly understudied despite accounting for more than 20% of the global peatland C stock and storing large amounts of biogenic gasses Although studies investigating greenhouse gas dynamics from peatlands have increased during the last decade, the spatial and temporal distribution of these gases still remains highly uncertain, mainly due to the limitations in terms of spatial and temporal resolution and invasive nature of most methods traditionally used. This thesis combines a series of field and laboratory studies at several sites in the Greater Everglades as examples to show the potential of hydrogeophysical methods to better understand: 1) the belowground C distribution and overall contribution to the global C stocks of certain wetlands (Chapter 2); and 2) the spatial and temporal variability in both C accumulation and releases from peat soil monoliths from several wetland sites in the Greater Everglades (Chapter 3 and 4). To estimate belowground C in the field, I used a combination of indirect non-invasive geophysical methods (GPR), aerial imagery, and direct measurements (coring) to estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods landscape at the Disney Wilderness Preserve (DWP, Orlando, FL). Three-dimensional (3D) GPR surveys were used to define the thickness of stratigraphic layers from the wetland surface to the mineral soil interface within depressional wetlands. Depth-profile cores in conjunction with C core analysis were utilized to visually confirm depths of each interface and estimate changes in soil C content with depth and were ultimately used to estimate total peat volume and C stock for each depressional wetland. Aerial photographs were used to develop a relationship between surface area and total wetland C stock, that were applied to estimate total landscape C stock of all depressional wetlands throughout the entire preserve. Additionally, low-frequency GPR surveys were conducted to image the stratigraphy underneath the peat basin of depressional wetlands to depict lithological controls on the formational processes of depressional wetlands at the DWP. Spatial and temporal variability in biogenic greenhouse gas (i.e. methane and carbon dioxide) production and release were investigated at the laboratory scale. Two 38 liter (0.5 m x 0.23 m x 0.3 m) peat monoliths from two different wetland ecosystems in central Florida (sawgrass peatland and a wet prairie) were compared in order to understand whether changes in matrix properties influence gas dynamics in a controlled environment (i.e. constant temperature). Gas content variability (i.e. build-up and release) within the peat matrix was estimated using a series of high frequency (1.2 GHz) GPR transects along each sample about three times a week. An array of gas traps (eight per sample) fitted with time-lapse cameras were also used in order to constrain GPR measurements and capture gas releases at 15-minute intervals. Gas chromatography was performed on gas samples extracted from the traps to determine CH4 and CO2 content. Also, at the lab scale, temporal variability in biogenic gas accumulation and release was investigated in a large 0.073 m3 peat monolith from the Blue Cypress Preserve in central Florida. An autonomous rail system was constructed in order to estimate gas content variability (i.e. build-up and release) within the peat matrix using a series of continuous GPR transects along the sample. This system ran virtually nonstop using high frequency (1.2 GHz) antennas. GPR measurements were again constrained with an array of gas traps (6) fitted with time-lapse cameras and gas chromatography. The aim of this study is to better constrain temporal scale, and better understand the heterogeneous nature (both in time and space) of gas releases from peat soils. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

The work of this Master of Science thesis project is an analysis of salinity effects on nearshore epifauna along the western shore of Biscayne Bay in southeast Florida, USA. Field collection surveys have found a high probability of occurrence of bigeye mojarra (Eucinostomus havana) in salinities near 25 ppt. In a salinity gradient observation experiment test subjects of the same species and size class were also observed more frequently at 24 ppt. In this analysis presence and abundance patterns found in field surveys were compared with behavioral results obtained in the observation tank. This apparatus provided insight into distribution patterns of the bigeye mojarra (Eucinostomus havana) and possible changes in distribution that may result from habitat changes in the future. Historically, the western shore of Biscayne Bay was more freshwater marsh than the mangrove dominated marine environment that prevails today. Changes to fresh water inputs into the Bay are planned through projects of the Comprehensive Everglades Restoration Plan (CERP). CERP is a joint Florida state and U.S. federal effort to redesign surface water flow through the canal system of South Florida, replenish the Everglades ecosystem, and restore a more natural quantity, timing, and distribution of flow into Biscayne and Florida Bays. Approved by the U.S. Congress as part of the Water Resources Development Act of 2000, CERP will be implemented by the South Florida Water Management District (SFWMD) and the U.S. Army Corps of Engineers (USACE). This plan is designed to restore the ecosystem from its freshwater core to the coastal wetlands recreating a condition close to that existing before the current system of flood control drainage canals was begun in 1903 and continued by the federal Central and Southern Florida Project in 1948 (www.evergladesplan.org). Changes are planned to divert a portion of canal flows to Biscayne Bay into coastal wetlands as sheet flow and surface runoff. Planned changes to freshwater delivery may change the habitat along the shoreline and thus the distribution of prey organisms living in this habitat. This may in turn affect predator fish important to local recreational and commercial fisheries as well as other predators such as wading birds. The analysis and prediction provided in this thesis work is important for better understanding the effects of restoration efforts on the Bay nearshore habitat and its condition as essential fish habitat, which is federally regulated by the Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens, 1996). The distribution of small fish and invertebrate inhabitants of the nearshore environment and habitat environmental qualities have been recorded over the past five years from throw-trap surveys of the western shoreline of Biscayne Bay as part of a CERP-sponsored monitoring program. This pattern is correlated with salinity, but there may be other factors affecting the distribution of this species.

Many large terrestrial ecosystems have patterned landscapes as a result of a positive feedback system between vegetation communities and environmental factors. One example is tree island habitats in the Florida Everglades. Although they only occupy a small portion of the Everglades landscape, tree islands are important features as the focus of nutrient accumulation and wildlife biodiversity in the Everglades ecosystem. The hardwood hammock community on the elevated head of tree island habitats can accumulate high phosphorus concentration in the otherwise P-limited Everglades ecosystem. In this dissertation, I examined two hypotheses derived from the chemohydrodynamic nutrient accumulation model, which suggests that high transpiration of tree island hammock plants is the driving force for nutrient accumulation in tree island soil. According to this model, I hypothesized that tree islands with lower dry season transpiration should have less phosphorus accumulated than the tree islands with higher dry season transpiration. By examining the water use and nutrient status from 18 tree islands in both slough (perennially wet) and prairie (seasonally wet) locations, I was able to compare water availability and nutrient accumulation in slough and prairie tree islands with different marsh hydroperiods. Chapter 1 uses elemental and stable isotope analysis to look at water stress and nutrient concentration in tree island plants. I showed that the prairie tree island plants suffer from drought stress during the dry season, when the marshes in the prairies dry out. Prairie tree islands also have lower soil and plant P concentration than the slough tree islands. Moreover, I showed that foliar N isotope ratio serves as a stable proxy for community level P availability for tree island plants, and prairie tree island plants have less P available than slough tree island plants. In Chapter 2, I showed that the satellite imagery derived normalized difference water index (NDWI) provides a robust indicator of community level canopy water content of these tree islands. NDWI, used as a proxy for water status, was positively related to foliar N isotope ratio, which suggests that water availability is linked to nutrient availability in the tree island hardwood hammock plant communities. These findings are consistent to the chemohydrodynamic nutrient accumulation model. In Chapter 3, I used sap flow sensors on individual trees to provide a real-time measurement of plant transpiration. I showed that tree island plant transpiration is affected by multiple factors including weather fluctuations, marsh water depth regulated by local water management, and canopy structure of different tree islands. Overall, my dissertation establishes a link between tree island plant water use and nutrient accumulation. It could be potentially important for future restoration plan of tree islands and Everglades hydrological management.

The Everglades, a wetland ecosystem unique to southern Florida has been degraded by the loss of nearly half of its area to urban and agricultural development as well as by alterations to Florida’s hydrology. Modifications to the flow of water to the Everglades have altered the remaining portion of the Everglades. Most prominent among these changes in the remaining Everglades is the loss of tree islands with a disproportionately greater loss of larger tree islands. Despite their significance as “keystone habitats”, our understanding of how changes to Everglades tree islands will affect fauna is poor. In the work presented, 16 study tree islands of Rock Reef Pass, Everglades National Park, Homestead, FL, were classified into three size classes (large, medium and small) and used animal capture histories collected between February 1994 and December 2005 to investigate the relationship between tree island size classes and indirect indicators of adult female hispid cotton rat (Sigmodon hispidus) and marsh rice rat (Oryzomys palustris) fitness and reproduction. Adult female S. hispidus and O. palustris body weights were used as an indicator of adult female fitness and compared among tree island size classes. The proportions of reproductively active females, the proportions of captures of individuals in the juvenile age class and the number of juveniles per female were used as indirect indicators of female reproduction and compared among island size classes. Animal capture histories were also used to perform multi-state mark-recapture analyses, where sates were defined as three island size classes, to draw inferences about state-specific rates of survival and state transition probabilities for Oryzomys palustris and Sigmodon hispidus as a function of the most salient features of the Everglades ecosystem, namely, its tree islands and its seasonal wet and dry periods. Specifically, Akaike’s, information criterion (AIC) was used to make inferences about factors influencing survival and transition probabilities by comparing the relative fit among models where survival and transition rates are described as functions of tree island size classes and as a function of environmental variables that distinguish seasonal periods (monthly water levels, total monthly rainfall, mean air temperature, days dry, days inundated). The probabilities of individuals remaining within the same island size class were interpreted as an indirect indicator of size-class specific tree island use. Results indicated that greater proportions of S. hispidus adult females were reproductively active and had higher fitness on larger islands than females on smaller islands. The body weights of S. hispidus adult females, the proportions of individuals in the juvenile age class and the number of juveniles per female, were positively correlated with tree island area while the proportions of reproductively active S. hispidus females were not. When compared among tree island size classes, S. hispidus females recaptured on the same large island weighed more than females recaptured on the same and medium or small island suggesting that females with greater fitness are found on larger tree islands. The proportions of reproductively active S. hispidus females and of individuals in the juvenile age class were greater on larger tree islands than on smaller islands, although the number of juveniles per females did not differ among tree islands. The results also indicated that differences in the fitness and reproductive condition of O. palustris females are not as distinct among females on different size tree islands. The body weights O. palustris adult females, the proportions of juveniles and the number of juveniles per female were not correlated with island area, while the proportions of reproductively active females were negatively correlated with tree island area. The body weights of O. palustris adult females recaptured on the same large tree island were higher than those of females on smaller islands while the proportions of females that were reproductively active and the proportions of captures of juveniles were higher on small islands than on large islands. Mark-recapture analysis provided evidence that overall, Sigmodon hispidus survival rates were higher on larger islands than on smaller islands. Evidence was not found that Oryzomys palustris survival rates differed among size classes, perhaps due to the limited spatial scale of this study relative to the spatial sale of O. palustris habitat use. Both species’ survival probabilities differed between seasons with Oryzomys palustris having higher survivorship during wet seasons and Sigmodon hispidus during the dry season. Both Oryzomys palustris and Sigmodon hispidus were more likely to remain on large island than on smaller islands.

Coastal outwelling of organic carbon from mangrove wetlands contributes to near-shore productivity and influences biogeochemical cycling of elements. I used a flume to measure fluxes of dissolved organic carbon (DOC) between a mangrove forest and adjacent tidal creek along Shark River, Florida. Shark River’s hydrology is influenced by diurnal tides and seasonal rainfall and wind patterns. Samplings were made over multiple tidal cycles in 2003 to include dry, wet, and transitional seasons. Surface water [DOC], temperature, salinity, conductivity and pH were significantly different among all sampling periods. [DOC] was highest during the dry season (May), followed by the wet (October) and transitional (December) seasons. Net DOC export was measured in October and December, inferring the mangrove forest is a source of DOC to the adjacent tidal creek during these periods. This trend may be explained by high rates of rainfall, freshwater inflow and subsequent flushing of wetland soils during this period of the year.