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Title: A habitat suitability model for wading birds in a large subtropical lake: linking hydrologic fluctuations and nesting.
Creator: Botta, Richard A., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Anthropogenic hydrologic alterations can affect the quality of lake littoral zone habitats for wading birds, such as the great egret (Ardea alba), snowy egret (Egretta thula), and white ibis (Eudocimus albus). One such lake in Florida, Lake Okeechobee, has experienced a marked decline in wading bird nesting since the 1970’s, concomitant with changes in lake level management. It’s hypothesized that a reduction in foraging habitat has led to the nesting decline; however, there is little...
Show moreAnthropogenic hydrologic alterations can affect the quality of lake littoral zone habitats for wading birds, such as the great egret (Ardea alba), snowy egret (Egretta thula), and white ibis (Eudocimus albus). One such lake in Florida, Lake Okeechobee, has experienced a marked decline in wading bird nesting since the 1970’s, concomitant with changes in lake level management. It’s hypothesized that a reduction in foraging habitat has led to the nesting decline; however, there is little quantitative evidence of this link. A habitat suitability model was developed for Lake Okeechobee wading birds that incorporate the spatial and temporal dynamics of environmental factors that affect wading bird foraging and tests whether foraging habitat is linked to numbers of nests.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004082
Subject Headings: Birds -- Florida -- Lake Okeechobee -- Geographical distribution, Estuarine ecology -- Florida -- Lake Okeechobee, Restoration ecology -- Florida -- Lake Okeechobee, Water birds -- Habitat
Format: Document (PDF)

Title: Diet and Nesting Habitat of Wading Birds in a Shallow, Eutrophic Lake.
Creator: May, Jenna C., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Avian reproductive success varies depending on environmental conditions, degree of predation, location, and food availability. I examined food availability and nesting habitat of wading birds in South Florida. Evaluating prey availability and prey used by two small heron species demonstrated the ability for small herons to maintain consistent diets through fluctuating environmental conditions, within and across different wetland types. Small herons may be able to cope with environmental...
Show moreAvian reproductive success varies depending on environmental conditions, degree of predation, location, and food availability. I examined food availability and nesting habitat of wading birds in South Florida. Evaluating prey availability and prey used by two small heron species demonstrated the ability for small herons to maintain consistent diets through fluctuating environmental conditions, within and across different wetland types. Small herons may be able to cope with environmental changes by altering foraging locations and strategies. Regarding nesting habitat, man-made sites may provide habitat comparable to natural sites, at least in the short-term. The nest’s position can influence its susceptibility to increased temperatures and predators, particularly for. Climatic conditions such as rainfall can also impact nesting success by altering foraging conditions and fish behavior. Understanding the effects of hydrologic regimes on biota can have practical applications since ecosystems around the world share similar problems with competing demands for resources, and there is a concern for how use can affect the quality of the resource.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013087
Subject Headings: Wading birds., Herons--Ecology., Okeechobee, Lake (Fla.)
Format: Document (PDF)

Title: EVOLVING RESPONSE OF THE WOOD STORK (MYCTERIA AMERICANA) TO URBANIZATION AND HYDROLOGICAL CHANGE IN THE UNITED STATES.
Creator: Shlepr, Katherine R., Gawlik, Dale E., Milton, Sarah L., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Urbanization and land development, climate change, pollution, the spread of invasive species, and sea level rise are unprecedented challenges that have led to 25% of avian species worldwide facing an elevated risk of extinction. Under rapidly changing environmental conditions, traditional population models are not ideal because they typically assume that demographic parameters are static in order to estimate the probability of species extinction over a chosen timeframe. This assumption...
Show moreUrbanization and land development, climate change, pollution, the spread of invasive species, and sea level rise are unprecedented challenges that have led to 25% of avian species worldwide facing an elevated risk of extinction. Under rapidly changing environmental conditions, traditional population models are not ideal because they typically assume that demographic parameters are static in order to estimate the probability of species extinction over a chosen timeframe. This assumption disregards species’ potential to adapt to environmental change; adaptations which could alter not only a species’ extinction outlook but also its legal protection status. The goal of my PhD research is to re-evaluate the risk of extinction of one threatened species, the Wood Stork (Mycteria americana), by accounting for potential adaptation in the context of planned and predicted changes in the southeastern United States. Since the 1970s, Wood Storks have shifted the timing of their breeding season, expanded their range northward and into novel habitats in urban areas, and begun consuming non-native fishes. I investigate these observations by comparing the physiology and diet of Wood Storks nesting in the historical core of their U.S. range (tree islands in the flooded Everglades marsh) with storks occupying novel habitats in urban and temperate locations. Faster growth rate, improved body condition, and increased survival by nestlings in urban areas would be evidence that colonies on the leading edge of the species’ range may be capable of sustaining growth of the whole population. In a third and final chapter, I forecast nest abundance and distribution patterns in the entirety of the U.S. range given various hydrological scenarios. Increased Wood Stork population size and stability are recovery criteria which must be met before the species can qualify for removal from the federal Endangered Species List. More broadly, understanding Wood Stork response to human development in the Everglades illuminates general patterns in avian species response to extreme changes in landscape, and could serve as a framework for proactively incorporating evolutionary potential into the framework of Endangered Species Act recovery in other species which have a high adaptive capacity.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013916
Subject Headings: Wood stork, Urbanization, Adaptation (Biology), Wildlife conservation
Format: Document (PDF)

Title: FORAGING ECOLOGY OF A WADING BIRD IN TIDALLY INFLUENCED HABITATS: A SEQUENTIAL MODELING FRAMEWORK.
Creator: Martinez, Marisa Takada, Gawlik, Dale E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: I used empirical data to inform spatially- and temporally-explicit predictions of time-integrated habitat availability (TiHAB), quantify spatiotemporal patterns of resource selection by Little Blue Herons (Egretta caerulea), and evaluate foraging activity as function of resource availability and prey dynamics. Evaluating resource availability over time accounts for the magnitude and duration of resource change. This approach is useful for understanding mechanisms that underlie resource...
Show moreI used empirical data to inform spatially- and temporally-explicit predictions of time-integrated habitat availability (TiHAB), quantify spatiotemporal patterns of resource selection by Little Blue Herons (Egretta caerulea), and evaluate foraging activity as function of resource availability and prey dynamics. Evaluating resource availability over time accounts for the magnitude and duration of resource change. This approach is useful for understanding mechanisms that underlie resource selection in dynamic environments and for guilds that are sensitive to changes in prey availability like wading birds. I found that average TiHAB varied interannually whereby gains and losses in Little Blue Heron foraging habitat at the landscape scale (1-8 km) occurred from slight differences in annual tidal cycles otherwise imperceptible with water depth data alone. Local patterns of resource selection by Little Blue Herons were temporally consistent but spatially variable across tidally influenced environments. TiHAB was the most important habitat attribute over time and space and was superior to other environmental features and prey density as a predictor of Little Blue Heron resource selection. Foraging activity did not show a clear association with probability of resource selection, but foraging metrics were best described by changes in TiHAB consistent with changes in foraging strategy. I conclude that spatiotemporal variation in resource availability reliably predicts patterns of dynamic habitat selection and supports an energy-maximizing foraging strategy for wading birds in tidally influenced habitats. This modeling framework can be applied to quantify the spatiotemporal availability of resources in real-time or under hydrologic restoration regimes and sea level rise scenarios, and track species responses to hydrologic and other environmental fluctuations.
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013925
Subject Headings: Ecology, Herons, Wading birds, Ecological modelling
Format: Document (PDF)

Title: Foraging ecology of wading birds in a sub-tropical intertidal zone.
Creator: Calle, Leonardo, Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: The first of five chapters describe the study area and study species, including a short description about the impetus for this research. The second chapter describes a unique hydrologic model for application in tidal ecosystems. The second chapter represents new information on the effects of various abiotic and biotic factors on foraging wading birds in this highly dynamic environment. The third chapter identifies important factors affecting the abundance of foraging wading birds in...
Show moreThe first of five chapters describe the study area and study species, including a short description about the impetus for this research. The second chapter describes a unique hydrologic model for application in tidal ecosystems. The second chapter represents new information on the effects of various abiotic and biotic factors on foraging wading birds in this highly dynamic environment. The third chapter identifies important factors affecting the abundance of foraging wading birds in intertidal environments. The fourth chapter presents a study of the foraging habitat preferences of two wading bird species in intertidal environments. The fifth chapter describes a conceptual model of wading bird foraging ecology and a predictive model of foraging habitat in intertidal zones. The conceptual model captures the major drivers and linkages between the abiotic and biotic variables thought to affect wading bird foraging abundance in intertidal habitats. The conceptual model also identifies major knowledge gaps in our understanding of foraging ecology of wading birds in coastal intertidal areas. The predictive model of foraging habitat is meant to be used by resource managers, but its framework may be useful for ecological studies in general. The final and sixth chapter provides a summary of all the major findings. Each chapter has been written so as to be independent of the other chapters. As such, a full background, along with a discussion of the relevance of the chapter's findings is provided for each chapter.
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Date Issued: 2014
PURL: http://purl.flvc.org/fau/fd/FA00004087
Subject Headings: Habitat selection, Population biology, Predation (Biology), Water birds -- Geographical distribution, Water birds -- Habitat
Format: Document (PDF)

Title: INFLUENCE OF HYDROLOGICAL VARIATION ON WADING BIRD DIETS AND REPRODUCTION IN A LACUSTRINE WETLAND.
Creator: Essian, David A., Gawlik, Dale E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Wetlandscape topography creates spatial variation in hydroperiod, which in turn creates spatial variation in biotic communities. Such spatiotemporal variation occurs on a large scale in some of the most productive wetlands in the world, including those of south Florida, U.S.A. Wading birds (Pelicaniformes and Ciconiiformes) are iconic, top-level consumers of such ecosystems. Infrequent drying is necessary to maintain the primary nest substrate (Salix caroliniana), and prey availability is...
Show moreWetlandscape topography creates spatial variation in hydroperiod, which in turn creates spatial variation in biotic communities. Such spatiotemporal variation occurs on a large scale in some of the most productive wetlands in the world, including those of south Florida, U.S.A. Wading birds (Pelicaniformes and Ciconiiformes) are iconic, top-level consumers of such ecosystems. Infrequent drying is necessary to maintain the primary nest substrate (Salix caroliniana), and prey availability is regulated by production of prey biomass in the wet season and the subsequent concentration of prey biomass into shallow pools during the dry season. The goal of this dissertation was to explicitly model wading bird nest abundance and survival as functions of water-level fluctuations, which were spatially nested (i.e., the effects of water-level fluctuations that occurred over a large scale were measured separately from the effects of water-level fluctuations that occurred over a small scale). In Chapter 2, I modeled colony-specific effects of wetlandscape water level fluctuations on wading bird nest abundance. Modeling the response at the colony level allowed the inclusion of important parameters that cannot be measured at the wetlandscape scale. For instance, each colony had its own optimal range of lake stage, which depended on local topography. I used the models to predict cumulative nest abundance under six hydrologic scenarios that were based on potential water management actions at Lake Okeechobee. I found that increasing water levels at the lake would marginally benefit the Great Egret but would substantially reduce long-term Snowy Egret and White Ibis populations. In Chapter 3, I modelled spatiotemporal distributions of fish biomass density in Lake Okeechobee’s littoral zone as a function of hierarchically nested hydrological variables. These models were consistent with the dynamic landscape connectivity model previously described in the literature. I modified the models to predict a binomial response which could then be linked to wading bird foraging threshold. The model predictions were used to estimate the number of available patch days during the breeding season, which was highly correlated with the number of nests for the great egret (Ardea alba), the snowy egret (Egretta thula), and the white ibis (Eudocimus albus). In Chapter 4, I used spatial statistics to better understand how interannual variability in resource wave patterns in the littoral zone influenced wading bird nest abundance. I found that more birds nested in years when the drying edge of the marsh moved further across the landscape. Great egret nest survival increased also, but small heron nest survival decreased. This decrease was likely because small herons continued to nest late into the season in years with longer waves, and, as with most bird species, nests that are initiated later in the season. In Chapter 5, I compiled conventional nestling diet data from 5 wading bird species sampled in 4 wetland types from 2010 to 2020 (not every wetland type was sampled in every year). This chapter provides a comprehensive, broad description of wading bird diets in south Florida, and quantifies interspecies, spatial, and interannual variation in nestling diets. By using a model-based approach to quantify the relative biomass of prey species and prey traits in nestling diets, I provide the first diet analysis that is fully reproducible across the large sympatric range of the wading bird species in the study (great egret, snowy egret, tricolored heron [Egretta tricolor], little blue heron [Egretta caerulea], and wood stork [Mycteria americana]).
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Date Issued: 2022
PURL: http://purl.flvc.org/fau/fd/FA00013908
Subject Headings: Wading birds, Wetland ecology, Okeechobee, Lake (Fla.), Lacustrine ecology, Lake ecology--Florida.
Format: Document (PDF)

Title: MONITORING WADING BIRD COLONIES USING ACOUSTIC SAMPLING AND REGIONAL SHIFTS IN WADING BIRD NEST ABUNDANCES IN A PULSED WETLAND SYSTEM.
Creator: Larson, Rachel C., Gawlik, Dale E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: Wetland loss and degradation have led to the development of restoration programs worldwide, many of which monitor wading bird populations as indicators of wetland quality. Therefore, efficient, standardized monitoring is integral to restoration progress. I tested the use of passive acoustic monitoring to estimate nest abundances and provisioning rates in wading bird colonies and examined regional nesting dynamics in the Florida Everglades, where a long monitoring record enables analysis of...
Show moreWetland loss and degradation have led to the development of restoration programs worldwide, many of which monitor wading bird populations as indicators of wetland quality. Therefore, efficient, standardized monitoring is integral to restoration progress. I tested the use of passive acoustic monitoring to estimate nest abundances and provisioning rates in wading bird colonies and examined regional nesting dynamics in the Florida Everglades, where a long monitoring record enables analysis of nesting patterns relative to hydrologic changes. I found that call rates can serve as indices of colony nest abundances and begging call rate and timing are indicative of provisioning events. Nesting dynamics suggested that resource availability is asynchronous between regions of the Everglades, but the degree of asynchrony varies with species. The conclusions of this study will facilitate the long-term monitoring of wading bird nesting trends, which are important measures of wetland restoration in Florida and worldwide.
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Date Issued: 2021
PURL: http://purl.flvc.org/fau/fd/FA00013771
Subject Headings: Wetland restoration, Wading birds, Everglades (Fla.), Acoustics
Format: Document (PDF)

Title: Quantifying wading bird resource selection and nesting effort: a tool for the restoration of pulsed ecosystems.
Creator: Petersen, Michelle L., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Understanding the link between indicator species and their environment is imperative to managing and conserving anthropogenically-altered ecosystems. Seasonally-pulsed wetlands are uniquely complex ecosystem where water-level fluctuations shape trophic interactions. Anthropogenic manipulation of water-level fluctuation threatens the integrity of these systems worldwide. Wading birds, a group of species sensitive to landuse changes and fluctuating habitat conditions, serve as important...
Show moreUnderstanding the link between indicator species and their environment is imperative to managing and conserving anthropogenically-altered ecosystems. Seasonally-pulsed wetlands are uniquely complex ecosystem where water-level fluctuations shape trophic interactions. Anthropogenic manipulation of water-level fluctuation threatens the integrity of these systems worldwide. Wading birds, a group of species sensitive to landuse changes and fluctuating habitat conditions, serve as important indicators for wetland health. I used wading birds in the Everglades, as a model system to address the challenges of environmental restoration within an ecosystem heavily impacted by anthropogenic activities. Specifically, I 1) identified the nesting response of Great Egret (Ardea alba), White Ibis (Eudocimus albus), and Wood Stork (Mycteria americana) to hydrologically-mediated changes in food availability and 2) quantified spatiotemporal foraging-habitat selection of Great Egrets, White Ibis, and Wood Storks to fluctuating hydrologic conditions. Collectively, model selection results suggest food availability, generated through dynamic hydrological conditions, is a strong predictor of the abundance of nesting birds in a given year. Great egret and white ibis produce the highest nests numbers in years when the frequency of days of rising water is low. Wood stork nest numbers are the highest in years with high prey production coupled with continuous prey availability. My study of resource selection indicated wading birds select foraging sites based on similar hydrologic parameters, but the response varies by species. Wood storks are more likely to forage in shallow cells (< 10 cm) drying with high recession rates (0.5-1.5 cm/day), and long time since last drydown (600 days). White ibises selected foraging cells with relatively shallow water depths (0-15 cm), intermediate recession rates (0.5-1.0 cm/day), and long time since drydown (600 days). Great egrets selected foraging cells with a wider range of water depths (0-20 cm) where recession rates were lower (0.5 cm/day). All species are more likely to forage in cells where water has not increased by more than 3 cm in the previous two weeks. These differences in resource selections correspond to morphological and behavioral differences in the species, whereby wood storks were more constrained hydrologically and would be more affected by water-level manipulation.
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Date Issued: 2017
PURL: http://purl.flvc.org/fau/fd/FA00004852
Subject Headings: Wetland biodiversity conservation--Florida--Everglades., Wetland conservation., Water birds., Wood stork., White ibis., Egretta alba.
Format: Document (PDF)

Title: REPRODUCTIVE RESPONSES OF THREE HERON SPECIES TO VARIABLE FORAGING CONDITIONS AND NESTING ISLAND TYPE IN A MANAGED LAKE ECOSYSTEM.
Creator: Evans, Jacquelyn D., Gawlik, Dale E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: The relationship between water-level fluctuations and wading bird nest numbers and nesting location is well documented, yet species-specific reproductive responses of wading birds to environmental drivers and nesting habitat type is poorly understood. Here, I compared the reproductive responses of two ecologically similar species, Snowy Egret and Tricolored Heron, to foraging conditions influenced by water management and examined the effect of nestling island type on the reproductive success...
Show moreThe relationship between water-level fluctuations and wading bird nest numbers and nesting location is well documented, yet species-specific reproductive responses of wading birds to environmental drivers and nesting habitat type is poorly understood. Here, I compared the reproductive responses of two ecologically similar species, Snowy Egret and Tricolored Heron, to foraging conditions influenced by water management and examined the effect of nestling island type on the reproductive success of three wading bird species. Reproductive responses to foraging conditions were broadly similar between Snowy Egrets and Tricolored Herons, however this study revealed specific-specific differences that could lead to different population dynamics in response to management over the long-term. I also found that these two species had lower productivity at spoil islands than marsh colonies, whereas Great Egret productivity did not vary by colony type. This study demonstrates the importance of establishing species-species relationships between productivity and environmental conditions
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013550
Subject Headings: Herons--Ecology, Reproduction, Nesting behavior, Okeechobee, Lake (Fla), Species
Format: Document (PDF)

Title: RESPONSES OF WOOD STORKS TO HUMAN-INDUCED LANDSCAPE CHANGE IN SOUTH FLORIDA.
Creator: Evans, Betsy A., Gawlik, Dale E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description: There is a strong conservation need to understand traits of native species that adapt to urban environments, but results have been equivocal. Wetland birds have shown a strong phylogenetic signal towards urban tolerance; however, these species have largely been ignored in urban studies. I used Wood Storks (Mycteria americana) to determine how a wetland species of conservation concern responded to human-induced landscape change in South Florida. Specifically, my study investigated 1) resource...
Show moreThere is a strong conservation need to understand traits of native species that adapt to urban environments, but results have been equivocal. Wetland birds have shown a strong phylogenetic signal towards urban tolerance; however, these species have largely been ignored in urban studies. I used Wood Storks (Mycteria americana) to determine how a wetland species of conservation concern responded to human-induced landscape change in South Florida. Specifically, my study investigated 1) resource selection of storks in roadway corridors, 2) factors influencing stork prey biomass in roadside created wetlands, 3) dietary flexibility of storks in response to human-induced landscape change, and 4) the impact of urban food subsidies on natural food limitations and stork productivity. I found that storks preferred canals and roadway corridors within the urban landscape. At a finer scale, storks selected for more natural wetland vegetation even within the urban landscape cover type. These results suggest that roadway corridors even within a highly urbanized area may provide adequate foraging habitat for storks. Factors influencing stork prey biomass in roadside created wetlands varied depending on created wetland type. I found that landscape-level vegetation and the physical properties of a created wetland were more influential in permanently inundated created wetlands whereas local-scale vegetation and hydrologic conditions were most influential in ephemeral created wetlands. Storks also selected prey that were more similar to the larger-bodied fishes in created wetlands than the smaller fishes in natural wetlands. Urban nesting storks selected prey that were more characteristic of created wetlands whereas storks nesting in natural wetlands selected prey that was more characteristic of prey found in natural wetlands. These results suggested that storks may have behavioral plasticity in foraging habitat and prey selection to adapt to some degree of human-induced rapid environmental change. Additionally, storks nesting in both urban and natural wetlands had narrow diet breadths and high productivity during optimal natural wetland conditions; however, during suboptimal natural conditions, urban stork diet expanded to include anthropogenic items, leading to increased productivity. Overall, this research provides a mechanistic understanding of how a wetland species persists, and even thrives, in an urban environment.
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Date Issued: 2020
PURL: http://purl.flvc.org/fau/fd/FA00013554
Subject Headings: Wood stork, Mycteria americana, Human influence on nature, Nature conservation--Florida, Urban environment
Format: Document (PDF)

Title: The Associations of Little Blue Heron Prey and Vegetation Communities in Two Subtropical Coastal Ecosystems.
Creator: Kohler, Emilie R., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: 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...
Show moreShallow 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.
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013156
Subject Headings: Herons--Ecology, Egretta, Great White Heron National Wildlife Refuge (Fla), Florida Bay (Fla), Coastal ecology--Florida
Format: Document (PDF)

Title: Wading bird prey production and prey selection in a dynamic wetland.
Creator: Klassen, Jessica A., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Anthropogenic impacts, such as habitat destruction and spread of exotic species, are contributing to the sixth major extinction event in Earth’s history. To develop effective management and conservation plans, it is important to understand the ecological drivers of at-risk populations, assess the ability of a population to adapt to environmental change, and develop research methods for long-term ecosystem monitoring. I used wading birds nesting in the Florida Everglades, USA as a model system...
Show moreAnthropogenic impacts, such as habitat destruction and spread of exotic species, are contributing to the sixth major extinction event in Earth’s history. To develop effective management and conservation plans, it is important to understand the ecological drivers of at-risk populations, assess the ability of a population to adapt to environmental change, and develop research methods for long-term ecosystem monitoring. I used wading birds nesting in the Florida Everglades, USA as a model system to address the challenges of managing and monitoring populations within an ecosystem greatly impacted by anthropogenic activities. Specifically, my project investigated 1) the prey selection of wading bird species, and the role of prey and foraging habitat availability on annual nesting numbers, 2) the ability of using diet change to predict species adaptability to a rapidly changing environment, and 3) the use of sensory data to provide low-cost, long-term monitoring of dynamic wetlands. I found that tricolored herons, snowy egrets, and little blue herons consumed marsh fish larger than those generally available across the landscape. Additionally, number of nests initiated by tricolored herons, snowy egrets, and little blue herons was strongly correlated with the annual densities of large fish available within the Everglades landscape. Conversely, number of nests initiated by wood storks, great egrets, and white ibises was more correlated with the amount of foraging habitat availability across the nesting season. Wood stork diets changed considerably since the 1960’s, consisting of mainly sunfish and exotic fish as opposed to marsh fishes dominant in historical diet studies. Storks also consumed more exotic fish species than they did historically. This diet plasticity and the species’ ability to exploit anthropogenic habitats may be conducive to maintaining population viability as storks experience widespread human-induced changes to their habitat. Sensory-only data models generated complementary results to models that used site-specific field data. Additionally, sensory-only models were able to detect different responses between size classes of fish to the processes that increase their concentrations in drying pools. However, the degree to which sensory variables were able to fit species data was dependent upon the ability of sensors to measure species-specific population drivers and the scale at which sensors can measure environmental change.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004716
Subject Headings: Charadriiformes -- Habitat -- Florida -- Everglades, Ciconiiformes -- Habitat -- Florida -- Everglades, Everglades National Park (Fla.) -- Environmental conditions, Predation (Biology), Wetland ecology, Wildlife conservation
Format: Document (PDF)

Title: Wading Bird Reproductive and Physiological Responses to Environmental Disturbance in a Managed Lake Ecosystem.
Creator: Chastant, Jennifer E., Gawlik, Dale E., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Wetlands are some of the most diverse and productive ecosystems on earth. Water-level fluctuations determine the ecological function of shallow lakes and wetlands. Currently, anthropogenic modification to water-level fluctuations is the leading source of ecological degradation in lake and wetland ecosystems worldwide. I used wading birds nesting in Lake Okeechobee, as a model system to address the challenges of environmental restoration within an ecosystem greatly impacted by anthropogenic...
Show moreWetlands are some of the most diverse and productive ecosystems on earth. Water-level fluctuations determine the ecological function of shallow lakes and wetlands. Currently, anthropogenic modification to water-level fluctuations is the leading source of ecological degradation in lake and wetland ecosystems worldwide. I used wading birds nesting in Lake Okeechobee, as a model system to address the challenges of environmental restoration within an ecosystem greatly impacted by anthropogenic activities. Specifically, I 1) identified environmental factors most important for predicting the number of wading bird nests, 2) tested the assumptions of both the match-mismatch and the threshold hypothesis by modeling the relationship between nesting success and prey density with foraging habitat availability, and 3) measured the stress response of Great (Ardea alba) and Snowy Egrets (Egretta thula) to hydrologically-mediated changes in food availability. Collectively, the results suggest that the number of nests was greatest when area of nesting substrate was high and water-levels were moderate (3.9 - 4.4 m). Nest numbers dropped when either nesting substrate or foraging habitat was limited. My investigation into the predictions of the match-mismatch and threshold hypotheses found that indeed, prey density can reduce or intensify the effects of a mismatch event. The interaction of prey density and foraging habitat availability was significant and positive in both models. Saturation thresholds existed for both fledging success (147 prey (m^2)^-1) and total productivity (189 prey (m^2)^-1), above which high concentrations of prey could sustain nesting when foraging habitat availability was low. Finally, my studies of the stress response support the hypothesis that hydrologic factors associated with prey availability play an important role in regulating nesting patterns, although the level of food limitation the birds experience at the lake was not as severe as expected. Model selection identified foraging habitat availability as most influential to the nestling Great Egret stress response, whereas foraging habitat availability and prey density both influenced nestling Snowy Egret stress response. Moreover, the Snowy Egret stress response was more sensitive to changes in prey availability than was the Great Egret stress response. Temperature and foraging conditions influenced yolk corticosterone concentrations for both egret species.
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Date Issued: 2016
PURL: http://purl.flvc.org/fau/fd/FA00004779
Subject Headings: Wetland ecology., Estuarine ecology., Water birds--Habitat., Predation (Biology)
Format: Document (PDF)

Title: Wading bird use of geographically isolated wetlands in the southeastern U.S. Coastal Plain.
Creator: Herteux, Camille E., Gawlik, Dale E., Smith, Lora L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description: Geographically isolated wetlands (GIWs) within the southeastern U.S. Coastal Plain have been increasingly recognized for their importance in providing ecosystem services. These wetlands serve as valuable foraging and breeding habitat for wetland-dependent species, including wading birds. I quantified wading bird presence in GIWs in southwestern Georgia and determined the relative importance of factors influencing their use of these wetlands. I also examined the diet of a nesting colony of...
Show moreGeographically isolated wetlands (GIWs) within the southeastern U.S. Coastal Plain have been increasingly recognized for their importance in providing ecosystem services. These wetlands serve as valuable foraging and breeding habitat for wetland-dependent species, including wading birds. I quantified wading bird presence in GIWs in southwestern Georgia and determined the relative importance of factors influencing their use of these wetlands. I also examined the diet of a nesting colony of Little Blue Herons; a species experiencing population declines throughout most of the Southeast. I found that wetland-specific parameters were important factors in predicting wading bird use of GIWs, and wading birds utilized agricultural and natural wetlands differently depending on hydrological seasonality. Little Blue Herons were primarily consuming large anurans and anuran larvae, which are characteristic of agriculturally modified wetlands. The seasonal process of receding water levels in GIWs and subsequent concentration of
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Date Issued: 2018
PURL: http://purl.flvc.org/fau/fd/FA00013012
Subject Headings: Wetlands--Georgia, Wading birds, Herons--Ecology
Format: Document (PDF)

Wading birds (4)	+ -
Herons--Ecology (3)	+ -
Predation (Biology) (3)	+ -
Okeechobee, Lake (Fla.) (2)	+ -
Water birds -- Habitat (2)	+ -

Wetland ecology (2)	+ -
Wildlife conservation (2)	+ -
Wood stork (2)	+ -
Acoustics (1)	+ -
Adaptation (Biology) (1)	+ -
Birds -- Florida -- Lake Okeechobee -- Geographical distribution (1)	+ -
Charadriiformes -- Habitat -- Florida -- Everglades (1)	+ -
Ciconiiformes -- Habitat -- Florida -- Everglades (1)	+ -
Coastal ecology--Florida (1)	+ -
Ecological modelling (1)	+ -
Ecology (1)	+ -
Egretta (1)	+ -
Egretta alba. (1)	+ -
Estuarine ecology -- Florida -- Lake Okeechobee (1)	+ -
Estuarine ecology. (1)	+ -
Everglades (Fla.) (1)	+ -
Everglades National Park (Fla.) -- Environmental conditions (1)	+ -
Florida Bay (Fla) (1)	+ -
Great White Heron National Wildlife Refuge (Fla) (1)	+ -
Habitat selection (1)	+ -
Herons (1)	+ -
Herons--Ecology. (1)	+ -
Human influence on nature (1)	+ -
Lacustrine ecology (1)	+ -
Lake ecology--Florida. (1)	+ -

Charles E. Schmidt College of Science (14)	+ -
Florida Atlantic University (14)	+ -
Botta, Richard A. (1)	+ -
Calle, Leonardo (1)	+ -
Chastant, Jennifer E. (1)	+ -

Essian, David A. (1)	+ -
Evans, Betsy A. (1)	+ -
Evans, Jacquelyn D. (1)	+ -
Herteux, Camille E. (1)	+ -
Klassen, Jessica A. (1)	+ -
Kohler, Emilie R. (1)	+ -
Larson, Rachel C. (1)	+ -
Martinez, Marisa Takada (1)	+ -
May, Jenna C. (1)	+ -
Milton, Sarah L. (1)	+ -
Petersen, Michelle L. (1)	+ -
Shlepr, Katherine R. (1)	+ -
Smith, Lora L. (1)	+ -

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