Predation critically threatens reproductive success of sea turtles and shorebirds at many of Florida's beaches. We examined the biological and bioeconomic results of predator management on two adjacent barrier islands, Cayo Costa and North Captiva, along Florida's west coast. Both islands suffered severe nesting losses due to predation and disturbance due to raccoons, while Cayo Costa also was impacted by a large population of feral swine. In 2006, our initial year of study, neither island received predator management and no least tern production occurred on either island, and sea turtle nest predation was 74% and 60%, respectively, for Cayo Costa and North Captiva. Predators were managed in 2007 on Cayo Costa while North Captiva served as an untreated reference island. North Captiva again had no least tern production and sea turtle nest predation was 84%. In contrast, Cayo Costa produced 31 least terns and sea turtle nest predation plummeted to 16%. Both islands received predator management in 2008 when Cayo Costa and North Captiva respectively produced 20 and 55 least terns and had 15% and 0% sea turtle nest predation. The entire costs for predator management by experts over the course of the study was $USD 39,636, while the returns in additional production of least tern young and hatchling sea turtles was valued over $USD 1.1 million for a resulting benefit-cost ratio of 27.8.Published by Elsevier B.V.
a b s t r a c tBeginning in the 1930s and continuing through the 1970s, rhesus macaques and patas monkeys were introduced to presumed secure locations, primarily coastal islets, in Puerto Rico. Escapes into the wild began almost immediately after introduction. Today the combined range of the two species covers approximately 600 km 2 of southwestern Puerto Rico, where serious conflicts with agricultural interests have resulted. The Puerto Rico Department of Agriculture surveyed about 90% of commercial farmers in the range of the monkeys to begin quantifying damage by monkeys and the associated economic losses during the years 2002-2006. During that time, total economic losses by commercial farmers to monkeys increased from $1.13 million USD to over $1.46 million per year. Of these amounts, the economic losses due to farmers avoiding monkey damage by switching from fruit and vegetable crops to less rewarding land use (primarily hay or pastureland) increased from $490,000 to $1.33 million per year. The losses reported from the survey represent only a portion of economic losses to the invasive monkeys. Subsistence and other smaller farms and agriculture were not included in the survey. We also discuss many other economic issues surrounding the impacts of the invasive monkeys, but for which sufficient data are not available for economic analyses. These include concerns such as destruction of native (especially endangered) wildlife, threat of disease spread, and property damage, all of which would also have to be considered to fully evaluate invasive monkey economic impacts in Puerto Rico.Published by Elsevier Ltd.
Diverse examples from managing invasive vertebrate species on inhabited islands of the United States" (2018).
Once established, invasive rodents cause significant impacts to island flora and fauna, including species extinctions.There have been numerous efforts to eradicate invasive rodents from islands worldwide, with many successes. For a number of reasons, many invasive vertebrates have become established in Florida, including several rodent species. We have implemented rodent eradication efforts on two Florida islands. Using the successful eradication strategy developed for Buck Island, U.S. Virgin Islands, we have attempted the eradication of roof rats from Egmont Key off Tampa Bay. We also are attempting to eradicate Gambian giant pouched rats from Grassy Key in the Florida Keys. On Egmont Key, we used a grid of bait stations containing diphacinone rodenticide bait blocks and hand tossing of bait blocks into thickets. On Grassy Key, we used a grid of bait stations containing a zinc phosphide bait along with intensive live-trapping. We discuss the eradication planning, efforts to minimize nontarget animal losses, and follow-up activities. We also discuss some of the difficulties encountered in each of these two different situations.
Bait stations for distribution of oral rabies vaccine baits are designed for rabies management in highly-developed areas where traditional distribution of oral rabies vaccine baits may be difficult. As part of national efforts to contain and eliminate the raccoon (Procyon lotor) variant of the rabies virus (raccoon rabies) in the eastern United States, the United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services program, distributed vaccine baits by bait stations experimentally and operationally in Massachusetts during 2006-present, and in Florida during 2009–2015. In Massachusetts, a rabies virus-neutralizing antibody (RVNA) response of 42.1% for raccoons captured in areas baited with high density bait stations during 2011–2015 was achieved, compared with 46.2% in areas baited by hand, suggesting the continuation of this as a strategy for the oral rabies vaccination (ORV) program there, and for similar locations. Non-target competition for vaccine baits is problematic, regardless of distribution method. In Massachusetts, bait station visitation rates for targeted raccoons and non-target opossums (Didelphis virginiana) were similar (1.18:1) during 2006–2009 (p > 0.05). Bait station modifications for reducing non-target uptake were tested, and in Massachusetts, reduced non-target bait access was achieved with two design alternatives (p < 0.001). However, no difference was noted between the control and these two alternative designs in Florida. Due to ongoing trials of new vaccines and baits, the bait station performance of an adenovirus rabies glycoprotein recombinant vaccine bait, ONRAB® bait (Artemis Technologies, Guelph, ON, Canada) and a vaccinia-rabies glycoprotein recombinant vaccine bait, RABORAL V-RG®bait (Merial Limited, Athens, GA, USA), was compared. While uptake of the ONRAB bait was greater in Massachusetts (p < 0.001) in this limited trial, both types performed equally well in Florida. Since bait station tampering or theft as well as potential human bait contacts has been problematic, performance of camouflaged versus unpainted white bait stations was analyzed in terms of internal temperatures and maintaining a stable bait storage environment. In Massachusetts, camouflaged bait station interiors did not reach higher average temperatures than plain white bait stations in partially- or fully-shaded locations, while in Florida, camouflaged bait stations were significantly warmer in light exposure categories (p < 0.05). As ORV operations expand into more heavily-urbanized areas, bait stations will be increasingly important for vaccine bait distribution, and continued refinements in the strategy will be key to that success.
Efforts to eliminate the raccoon variant of the rabies virus (raccoon rabies) in the eastern United States by USDA, APHIS, Wildlife Services and cooperators have included the distribution of oral rabies vaccine baits from polyvinyl chloride (PVC) bait stations in west-central Florida from 2009 to 2015. Achieving sufficient vaccine bait uptake among urban raccoons is problematic, given limitations on aerial and vehicle-based bait distribution for safety and other reasons. One or three bait stations/km2 were deployed across four 9-km2 sites within rural and urban sites in Pasco and Pinellas Counties, Florida. Based on tetracycline biomarker analysis, bait uptake was only significantly different among the urban (Pinellas County) high and low bait station densities in 2012 (p = 0.0133). Significant differences in RVNA were found between the two bait station densities for both urban 2011 and 2012 samples (p = 0.0054 and p = 0.0031). Landscape differences in terms of urban structure and human population density may modify raccoon travel routes and behavior enough for these differences to emerge in highly urbanized Pinellas County, but not in rural Pasco County. The results suggest that, in urban settings, bait stations deployed at densities of >1/km2 are likely to achieve higher seroprevalence as an index of population immunity critical to successful raccoon rabies control.
R i c h a r d E n g e m a n , R . E r i k M a r t i n , J o h n W o o l a r d , M a r g o S t a h l C h a r l e s P e l i z z a , A n t h o n y D u f f i n e y and B e r n i c e C o n s t a n t i n Abstract We examined impacts from effective predator management on nesting success of marine turtles in an exceptional nesting year at Hobe Sound National Wildlife Refuge, Florida, USA, a beach with a high density of nesting marine turtles that has a history of severe nest predation. Historically up to 95% of nests were predated, primarily by raccoons Procyon lotor and, more recently, armadillos Dasypus novemcinctus. Predator control was identified as the most important conservation tool for marine turtle reproduction. Predator management by refuge staff as ancillary duties typically only held predation levels to c. 50%. However, when experts in predator control were employed predation was substantially reduced. An extraordinary opportunity to evaluate the biological and economic benefits of this management approach occurred in 2008, a year with exceptionally heavy nesting. Loggerhead turtle Caretta caretta nesting resurged, green Chelonia mydas and leatherback Dermochelys coriacea turtles nested in record numbers, producing twice or more than their median number of nests, and the first Kemp's ridley Lepidochelys kempii nest was observed. Overall predation was 14.7%, resulting in an estimated . 128,000 additional hatchlings emerging compared to estimates had no predator management been in place and historical predation rates occurred, and . 56,000 hatchlings more than expected had predator management been conducted as ancillary duties rather than by experts. The USD 12,000 investment for expert predator management equated to only USD 0.09 spent for each additional hatchling produced compared to the scenario of no predator control and only USD 0.21 compared to the scenario of predator control as ancillary duties.
Having entered into its second century, the eradication program for bovine tuberculosis (bTB, caused by Mycobacterium bovis) in the United States of America occupies a position both enviable and daunting. Excepting four counties in Michigan comprising only 6109 km2 (0.06% of US land area) classified as Modified Accredited, as of April 2022 the entire country was considered Accredited Free of bTB by the US Department of Agriculture for cattle and bison. On the surface, the now well-described circumstances of endemic bTB in Michigan, where white-tailed deer (Odocoileus virginianus) serve as a free-ranging wildlife maintenance host, may appear to be the principal remaining barrier to national eradication. However, the situation there is unique in the U.S., and far-removed from the broader issues of bTB control in the remainder of the country. In Michigan, extensive surveillance for bTB in deer over the last quarter century, and regulatory measures to maximize the harvest of publicly-owned wildlife, have been implemented and sustained. Prevalence of bTB in deer has remained at a low level, although not sufficiently low to eliminate cattle herd infections. Public attitudes towards bTB, cattle and deer, and their relative importance, have been more influential in the management of the disease than any limitations of biological science. However, profound changes in the demographics and social attitudes of Michigan’s human population are underway, changes which are likely to force a critical reevaluation of the bTB control strategies thus far considered integral. In the rest of the U.S. where bTB is not self-sustaining in wildlife, changes in the scale of cattle production, coupled with both technical and non-technical issues have created their own substantial challenges. It is against this diverse backdrop that the evolution of whole genome sequencing of M. bovis has revolutionized understanding of the history and ecology of bTB in Michigan, resolved previously undiscernible epidemiological puzzles, provided insights into zoonotic transmission, and unified eradication efforts across species and agencies. We describe the current status of bTB eradication in the U.S., how circumstances and management have changed, what has been learned, and what remains more elusive than ever.
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