Wildlife management

Invasive species are one of the major threats to biodiversity and understanding the effects any one invasive species has on members of its new ecosystem can help land managers decide how to best use their limited resources. This study attempted to show the effect Cuban Treefrogs (Osteopilus Septentrionalis) were having on native Florida hylids. For a year, Cuban Treefrogs were removed from three cypress domes and monitored in three other cypress domes, a change in the native population in the experimental domes was the eventual desired effect. Due to weather issues and low native hylid numbers no effect was shown, however due to environmental constraints an effect could not be ruled out either.

This dissertation examined the natal origins, home-range, and in-situ foraging behavior of an aggregation of sub-adult hawksbill turtles (Eretmochelys imbricata) found off the coast of Palm Beach County, Florida. Surveys were conducted on approximately 30 linear km of reef between 15 and 30 m in depth. Tissue samples were retrieved from 112 turtles for mtDNA haplotype determination. GPS-linked satellite transmitters were deployed on six resident sub-adults, resulting in both minimum convex polygon (MCP) and 95%, 50%, and 25% kernel density estimates (KDE) of home-range size. A foraging ethogram was developed, and sequential analysis performed on thirty videos (141 total minutes) of in-situ foraging behavior. Seventeen total haplotypes were identified in this aggregation, the majority (75%) of which represented rookeries on Mexico’s Yucatan Peninsula. Other sources, from most to least important, include Barbados, Costa Rica, Puerto Rico, Antigua, and the U.S. Virgin Islands.

This research examines tensions between Latino/a farmworkers, who rely on the seasonal harvest of saw palmetto (Serenoa repens [W. Bartram] Small) berries for increased livelihood security, and conservationists and land-managers who view harvesting as detrimental for wildlife. Informal harvesting occurs on public and private lands, sometimes without permission. Berries, though ubiquitous on the landscape, have become a contested resource. The rapid conversion of rural wildlife habitat into suburban development has increased State urgency to bring natural areas into protection along the Florida Ecological Greenways Network. Habitat infringement and associated pressures on wildlife by development has led to the promotion of the state-wide Florida Wildlife Corridor, based on the FEGN. This corridor would connect isolated Florida black bear (Ursus americanus floridanus) populations and Florida panthers (Puma concolor coryi) with other populations. The scale of the commercial berry industry is unknown, but is estimated at millions of pounds annually. State and wildlife conservationists are increasingly concerned with the perceived scale of the harvest and its possible associated effects on wildlife, particularly Florida black bears.

Commercial longline fishing results in large amounts of incidental bycatch of elasmobranch fishes (sharks, skates, and rays). Teleost species lack electrosensory systems and development of technologies which target the ampullary organs of sharks provides an avenue to selectively deter elasmobranchs without affecting the catch rate of target teleosts. Electric field measurements and a controlled scientific longline study were conducted testing whether the lanthanide metal neodymium or zinc/graphite might reduce elasmobranch catch per unit effort (CPUE). Baited longline hooks were treated with neodymium and zinc/graphite and catch rates were compared to that of controls. Shark CPUE decreased by 60% on neodymium treated hooks and 80% on zinc/graphite treated hooks. The effectiveness of both treatments varied among species with significant reductions shown for Atlantic sharpnose sharks (Rhizoprionodon terranovae) but less dramatic differences for others. Zinc/graphite is potentially a viable tool for reduction of shark bycatch in a commercial longline fishery.

Successful foraging by avian predators is influenced largely by prey availability. In a large-scale experiment at the Loxahatchee Impoundment Landscape Assessment project within the Arthur R. Marshall Loxahatchee National Wildlife Refuge, I manipulated two components of prey availability, water depth and vegetation density (submerged aquatic vegetation and emergent vegetation), and quantified the response by wading birds in terms of foraging habitat selection and foraging success. Manly's standardized selection index showed that birds preferred shallow water and intermediate vegetation densities. However, the treatments had little effect on either individual capture rate or efficiency. This was a consistent pattern seen across multiple experiments. Birds selected for certain habitat features but accrued little benefit in terms of foraging success. I hypothesize that birds selected sites with shallow water and intermediate vegetation densities because they anticipated higher prey densities, but they did not experience it here because I controlled for prey density.

Wading bird foraging success is influenced by many different factors. From January to March 2008, I conducted a small-scale experiment with three captive Scarlet Ibis (Eudocimus ruber) at the Palm Beach Zoo, in West Palm Beach, Florida. Prey density and the presence of conspecifics were manipulated to test for a response by ibis in terms of prey capture rate. Mixed model analysis, when one prey type was available, showed that capture rate increased significantly with prey density and decreased with the presence of conspecifics. When two prey types were available, prey density and the presence of conspecifics had no effect on the capture rates of either prey type. Selectivity analysis revealed that ibis always selected for crayfish in mixed treatments. I hypothesize that the number of prey types available in a treatment played an important role in determining how fish density and the presence of conspecifics affected ibis foraging success.

Upper Respiratory Tract Disease (URTD) is a highly contagious illness, caused by the bacterium Mycoplasma agassazii. URTD has affected the gopher tortoise population in the Abacoa Greenway, and is believed to have a high mortality rate. In this study, 18 samples of tortoise blood were collected from this location. Fifteen of the 18 samples were collected from previously tested individuals. Comparisons between the previously tested tortoises were made. According to this study there is no documented mortality rate with URTD in Abacoa. Results show that four tortoises have continued to test positive for the antibodies for several years, suggesting a chronic state of the disease. Four other tortoises have gone from positive results to negative results indicating that their immune systems' production of antibodies has tapered off, suggesting the ability to recover from the disease.

Habitat fragmentation causes the isolation of groups of individuals within species by producing a new landscape that is uninhabitable for many species, including birds. I surveyed the John D. MacArthur campus of FAU in the Fall of 2005 and Spring of 2006 to assess the use of the campus by birds. Throughout the campus trees are lined in rows along the sidewalks and around buildings, in contrast to the pine flatwoods environment that existed prior to development. The birds observed were found performing various activities on the campus, including foraging, perching, and building nests. Individuals were concentrated around or near buildings with the most diverse vegetation. Through assessing these campus uses I suggest that there are ways we can help increase bird diversity in promoting their use of urban environments. Such solutions can help decrease the number of individuals and species lost to the destructive force of habitat fragmentation.

Throughout the course of North American history, wolves have been persecuted with a vengeance. Negative wolf perceptions have in the past created and continue to create controversial policies and views towards wolves. While most of these attitudes are geared towards gray wolves, as gray wolves are the most common and prominent, unfavorable perceptions have also extended to the less well-known red wolf. This study compares two red wolf reintroduction programs, one in the Tennessee-Kentucky area and the other in North Carolina, as well as the Yellowstone Gray Wolf Reintroduction program. After analyzing these three programs, it can be concluded that the perceptions towards wolves regardless of the type of wolf or location remain largely negative and that wolves continue to face persecution.

The gopher tortoise, Gopherus polyphemus, is a threatened species native to the southeastern United States. The breeding season of G. polyphemus is reportedly from April to June. However, out of season hatchlings in Jupiter, Florida, suggest that in South Florida, the very southernmost part of the gopher tortoise's range, the warmer climate allows a longer period of reproduction or a year-round breeding season. My research sought to find evidence for an extended breeding season and to collect fecundity data on the South Florida tortoises by capturing female tortoises and X-raying them at different times of the year to check for the presence of eggs. Although I found no conclusive proof of an extended breeding season, I present additional circumstantial evidence for it, as well as information regarding the fecundity of tortoises in the spring.