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- Title
- Diel movements of juvenile smalltooth sawfish (Pristis pectinata): Implications for defining the size of a nursery hotspot.
- Creator
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Huston, Cecily Ann, College of Arts & Sciences
- Abstract / Description
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Habitat use and movements of juvenile (1-year-old fish (1–3 years old), remained along the northern shoreline of the river in a protected cove. The younger age class remained closer (
Show moreHabitat use and movements of juvenile (<3 yr old) Critically Endangered smalltooth sawfish Pristis pectinata were studied in the Peace River in southwest Florida to estimate the size of a known nursery hotspot (high-use area). A total of 23 smalltooth sawfish were tagged during the peak recruitment period of April and May 2014 and were tracked until the end of September 2014 using passive acoustic monitoring. Active tracking was used to estimate positions of individuals relative to the shoreline and major habitat types. During the day, sawfish <1500 mm stretched total length (STL; n=11), representing <1 year old fish, and those measuring 1504 to 1881 mm STL (n=12), representing >1-year-old fish (1–3 years old), remained along the northern shoreline of the river in a protected cove. The younger age class remained closer (<25 m) to red mangrove-dominated shorelines than did the older age class. At night, both age classes moved away from the shoreline and away from the protected cove; the older individuals made the longest excursions (~5 km), toward the southern shoreline of the river. The discovery of these regular diel movements has led to the expansion of the boundaries of the single recognized nursery hotspot in the Peace River, which was previously defined solely by daytime catch data. These data are crucial for aiding the conservation of this Critically Endangered species and adding an extra layer of protection within its federally-designated Critical Habitat.
Show less - Date Issued
- 2017-06-13
- Identifier
- Huston_fgcu_1743_10259
- Format
- Document (PDF)
- Title
- Effect of Urbanization on Predatory Defense Mechanisms of Southern Ringneck Snake (Diadophis punctatus punctatus) Populations in South Florida.
- Creator
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Richards, Tesla, College of Arts & Sciences
- Abstract / Description
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The effect of urbanization on native wildlife is mostly negative. For example, the creation of urban habitats results in the loss of wild habitats, which can increase fragmentation, limit species dispersal and reduce access to resources. However, in some circumstances, urbanization can have positive effects on native wildlife. For example, some opportunistic and generalized species are able to tolerate urbanization by taking advantage of novel niches with reduced competition. Diadophis...
Show moreThe effect of urbanization on native wildlife is mostly negative. For example, the creation of urban habitats results in the loss of wild habitats, which can increase fragmentation, limit species dispersal and reduce access to resources. However, in some circumstances, urbanization can have positive effects on native wildlife. For example, some opportunistic and generalized species are able to tolerate urbanization by taking advantage of novel niches with reduced competition. Diadophis punctatus punctatus (Southern Ringneck Snakes) are a small, cryptic species found throughout the southeastern United States that thrive in both urban and wild habitats, indicating the snake’s tolerance to urbanization. Urbanization may have expanded D. p. punctatus’ niche. These snakes may be able to take advantage of the climate and landscape, availability of novel prey, and/ or refuge from predators within urban habitats. In this study, I examined if D. p. punctatus used urban habitats as refuge from predators by comparing the frequency of predator bite marks on clay snake models placed in urban and wild habitats. The snake models resembled different aspects of D. p. punctatus’ morphology and behavior. I also analyzed the placement of predator bite marks on the snake models to determine the function (i.e., aposematic, parasematic, or deimatic signaling) of D. p. punctatus’ tail-coiling display. The rates of predator attacks on the snake models were similar between urban and wild habitats, indicating D. p. punctatus used urban habitats for reasons other than a refuge from predators. In addition, this study supports the claim that D. p. punctatus’ tail-coiling display was an anti-predatory mechanism. Predators avoided the tail on snake models with red coloration and coiled tails, suggesting D. p. punctatus’ tail-coiling display may be used as a deimatic signal. Results of this study appear to contradict previous findings about the tail-coiling display. However, it is likely that the use of D. p. punctatus’ anti-predatory signal depends on the context. These snakes seem to show multi-modal signaling and flexible defense mechanisms, which may be important characteristics of urbanophiles.
Show less - Date Issued
- 2017-07-27
- Identifier
- Richards_fgcu_1743_10263
- Format
- Document (PDF)
- Title
- Environmental Factors Affecting Enterococcus and Fecal Coliform Bacteria in Beach Waters of Sarasota County, Florida.
- Creator
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Clemente, Jennifer Elaine, College of Arts & Sciences
- Abstract / Description
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The Florida Department of Health (FDOH) conducts sampling at recreational beaches for Enterococcus and fecal coliform bacteria, and posts advisories recommending against beach swimming when reported concentrations exceed 104 #CFU/100mL for enterococcus and 400#CFU/100mL for fecal coliform). County agencies select beaches to sample, and collect surf-zone samples once weekly. Bacteria concentrations fluctuate rapidly and over short distances, and beach advisories are posted up to four days...
Show moreThe Florida Department of Health (FDOH) conducts sampling at recreational beaches for Enterococcus and fecal coliform bacteria, and posts advisories recommending against beach swimming when reported concentrations exceed 104 #CFU/100mL for enterococcus and 400#CFU/100mL for fecal coliform). County agencies select beaches to sample, and collect surf-zone samples once weekly. Bacteria concentrations fluctuate rapidly and over short distances, and beach advisories are posted up to four days after high bacteria is first observed (field resampling and laboratory testing consume several days), seriously compromising FDOH's capability to protect beachgoers from exposure to harmful conditions. Precautionary measures could be improved if we could reliably predict conditions under which high bacteria concentrations are likely to occur. The objective of this research is to identify conditions statistically related to high bacterial concentrations using data from ten years of weekly sampling at 16 beaches in Sarasota County, FL. Previous studies in California, Miami FL, and elsewhere, analyzing the immediate vicinity of ocean stormwater outfalls, have identified modest relationships to factors including: magnitude and intensity of storm events that may mobilize bacteria from coastal watersheds; length of antecedent dry period before mobilizing storm, during which bacteria may propagate in conveyances; and tide/surf conditions that may either mobilize bacteria propagating in beach sand, break up bacterial colonies in the surf zone, or generate where bacteria may survive near the shore. The present study attempted multiple regression relating bacteria conditions to explanatory factors including: watershed rainfall in days prior to the sample date; total rainfall over several months, a surrogate for saturation of soils in the tributary watershed as well as for dry periods when bacteria may multiply in conveyances; seasonality, a surrogate for high air and water temperatures that promote propagation in the environment; and tidal stages and levels. Results found no correlation greater than 20%, for Sarasota County beaches in aggregate or for any beach individually, with the magnitude of bacteria measured in samples. Relationships are, however, identified between frequency of high-count bacteria samples and environmental conditions including flood level and stage, one-day antecedent rainfall, and seasonal rainfall (wet vs dry season). Results show the relationships are stronger for beaches influenced by stormwater outfalls, and less evident in beaches where no outfalls are nearby. This demonstrates that different mechanisms affect high-bacteria conditions on different beaches in this region, implying that prediction of potentially unhealthful bacteria conditions may be possible on a site-specific basis but may not be supported for a uniform set of environmental parameters across multiple sites, even for a group of beaches in close proximity with similar precipitation, tidal, and seasonal characteristics
Show less - Date Issued
- 2017
- Identifier
- Clemente_1743_10253
- Format
- Document (PDF)