Current Search:  Wetland ecology -- Florida -- Everglades (x) » Gawlik, Dale E. (x)

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Factors Affecting Wading Bird Prey Concentrations in the Everglades During the Dry Season
Title
Factors Affecting Wading Bird Prey Concentrations in the Everglades During the Dry Season.
Creator
P. Brian Garrett, Gawlik, Dale E., Florida Atlantic University
Abstract/Description
One factor that potentially controls the distribution and density of wading bird prey within open-water marsh habitats during seasonal drying events is the amount of available aquatic habitat, which is partly a function of the amount of microtopographic relief at a given location. To determine how microtopographic relief affects prey concentrations during dry-downs a simulation model was developed and run using empirical microtopographic data collected from the Everglades. The simulation...
Show moreOne factor that potentially controls the distribution and density of wading bird prey within open-water marsh habitats during seasonal drying events is the amount of available aquatic habitat, which is partly a function of the amount of microtopographic relief at a given location. To determine how microtopographic relief affects prey concentrations during dry-downs a simulation model was developed and run using empirical microtopographic data collected from the Everglades. The simulation suggests that those locations within the marsh with higher levels of microtopographic relief concentrate prey earlier during the dry-down period and potentially to greater densities overall. In addition, a model selection analysis was performed on field data to determine which set of factors displayed the greatest effects upon prey concentrations during drydown events. When examining the best selected a priori model it appears that the amount of available aquatic habitat, water depth, and macrophyte density have the strongest affects upon concentrations of prey during a seasonal drying event.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000769
Subject Headings
Water birds--Florida--Everglades, Wetland ecology--Florida--Everglades, Bird populations--Climatic factors--Florida--Everglades
Format
Document (PDF)
Wading bird prey production and prey selection in a dynamic wetland
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)
Characteristics Affecting Prey Vulnerability and Avian Habitat Selection in the Florida Everglades
Title
Characteristics Affecting Prey Vulnerability and Avian Habitat Selection in the Florida Everglades.
Creator
Harris, Rachael L., Gawlik, Dale E., Florida Atlantic University
Abstract/Description
The vulnerability of prey to capture plays a fundamental role in determining overall prey availability for wading birds. Structural complexity can act to decrease prey vulnerability and influence foraging habitat selection. To determine how structural complexity can affect habitat selection I conducted a use vs. availability study throughout the Florida Everglades in 2005 and 2006. Results indicated that wading birds chose foraging sites that had less emergent vegetation and a thicker...
Show moreThe vulnerability of prey to capture plays a fundamental role in determining overall prey availability for wading birds. Structural complexity can act to decrease prey vulnerability and influence foraging habitat selection. To determine how structural complexity can affect habitat selection I conducted a use vs. availability study throughout the Florida Everglades in 2005 and 2006. Results indicated that wading birds chose foraging sites that had less emergent vegetation and a thicker flocculent layer relative to random sites. Submerged vegetation, and the height of emergent vegetation did not affect wading bird site selection. A difference in habitat selection between years was evident due to hydrological conditions. Ideal hydrological conditions are probably the most important parameter to wading bird success. Other factors affecting prey vulnerability became increasingly important in years of poor hydrology, probably because the penalty for choosing low quality foraging habitat would be greater than in years of more optimal conditions.
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Date Issued
2007
PURL
http://purl.flvc.org/fau/fd/FA00000754
Subject Headings
Everglades (Fla), South Florida Water Management District (Fla ), Wildlife management--Florida--Everglades, Bird populations--Florida--Everglades, Water birds--Florida--Everglades, Wetland ecology--Florida--Everglades
Format
Document (PDF)