Climate is a long-term driver of ecological change, but the rapidity with which climate is projected to change over the next century may push the limitations of ecological adaptability, to the detriment of biodiversity. Given their typically small populations, limiting biological traits and exposure to external stressors, species currently classified as “at risk” may be among the most vulnerable to climate change and least capable of adapting naturally. A screening level assessment of the impacts of climate change on endangered species in Canada was conducted by integrating knowledge of the current status and characteristics of each endangered species with projections of climate change and climate change impacts. It was determined that climate change may have a potential overall negative influence on more than half of all endangered species in Canada. However, while relatively few species were predicted to respond in an overall positive or neutral manner to climate change, a large portion of endangered species were classified as having insufficient information to generate a decision on the net influence of climate change; in many cases, these species were located at the northern extent of their range in warmer regions of Canada and have the potential to experience at least some benefits under climate change provided that other stressors are sufficiently mitigated. These results, as well as the inherent vulnerability of species at risk to environmental change, the potential for species at risk distributional shifts and the likelihood of increasing rates of species imperilment, demonstrate the need for greater consideration of the implications of climate change in species at risk management and policy. Canada’s Species at Risk Act (SARA) does not explicitly address the issue of climate change and limitations exist in SARA’s time-sensitive definition of wildlife species eligible for protection in Canada and in the interpretation of SARA’s mandates in the context of anthropogenically driven climate change. It is recommended that climate change be systematically considered in all species at risk assessments, recovery strategies and management plans and that SARA’s definition of a wildlife species be revaluated in light of shifting species distributions under climate change. Further recommendations to identify “values” that will assist in prioritizing species for conservation, to reassess the concept of an invasive species under climate change and to implement strategies that focus more broadly on the conservation of biodiversity and ecological integrity rather than individual species may require ethically complex discussions and decisions on the part of species at risk managers and policy makers. Future research should focus on informing species at risk management and policy by improving modeling capabilities at the species level, conducting in-depth analyses of priority species, and building knowledge of alternative species conservation strategies such as assisted colonization.

Climate is a long-term driver of ecological change, but the rapidity with which climate is projected to change over the next century may push the limitations of ecological adaptability, to the detriment of biodiversity. Given their typically small populations, limiting biological traits and exposure to external stressors, species currently classified as “at risk” may be among the most vulnerable to climate change and least capable of adapting naturally. A screening level assessment of the impacts of climate change on endangered species in Canada was conducted by integrating knowledge of the current status and characteristics of each endangered species with projections of climate change and climate change impacts. It was determined that climate change may have a potential overall negative influence on more than half of all endangered species in Canada. However, while relatively few species were predicted to respond in an overall positive or neutral manner to climate change, a large portion of endangered species were classified as having insufficient information to generate a decision on the net influence of climate change; in many cases, these species were located at the northern extent of their range in warmer regions of Canada and have the potential to experience at least some benefits under climate change provided that other stressors are sufficiently mitigated. These results, as well as the inherent vulnerability of species at risk to environmental change, the potential for species at risk distributional shifts and the likelihood of increasing rates of species imperilment, demonstrate the need for greater consideration of the implications of climate change in species at risk management and policy. Canada’s Species at Risk Act (SARA) does not explicitly address the issue of climate change and limitations exist in SARA’s time-sensitive definition of wildlife species eligible for protection in Canada and in the interpretation of SARA’s mandates in the context of anthropogenically driven climate change. It is recommended that climate change be systematically considered in all species at risk assessments, recovery strategies and management plans and that SARA’s definition of a wildlife species be revaluated in light of shifting species distributions under climate change. Further recommendations to identify “values” that will assist in prioritizing species for conservation, to reassess the concept of an invasive species under climate change and to implement strategies that focus more broadly on the conservation of biodiversity and ecological integrity rather than individual species may require ethically complex discussions and decisions on the part of species at risk managers and policy makers. Future research should focus on informing species at risk management and policy by improving modeling capabilities at the species level, conducting in-depth analyses of priority species, and building knowledge of alternative species conservation strategies such as assisted colonization.

The purpose of this study was to determine how manatees use Swallow Caye, Drowned Cayes, and Gallows Reef, three distinct habitat types within the Belize Barrier Reef lagoon system near Belize City. Data were collected using boat-based point scan methods with the assistance of volunteers. Presence/absence and photo ID methods ensured consistency of data collection despite a changing pool of volunteer researchers. Results confirmed the mangrove and seagrass ecosystem between the Belize Barrier Reef and Belize City as important manatee habitat. Inconsistent with the prevailing "seasonal distribution hypothesis" for manatees in Belize, the probability of encountering manatees at Swallow Caye and in the Drowned Cayes was equal between dry and wet seasons. However, manatees were only observed at Gallows Reef during the wet season. Swallow Caye had the highest probability of encountering manatees, confirming traditional knowledge held by local tour operators, which led to the establishment of Swallow Caye Wildlife Sanctuary in 2002. In contrast to previous studies, my data suggest that at least 44% of the manatee population carry scars from non-lethal boat strikes. The proportion of scarred animals did not vary as a function of habitat type, season, or year. The probability of encountering manatees did not change between years, despite an exponential increase in cruise ship tourism. Marine Protected Areas (MPAs) and wildlife protection laws indicate that Belize is working to meet obligations under international agreements. However, there is still cause for concern. Manatees do not remain inside designated refuge boundaries; governmental agencies depend on co-management agreements with local non-governmental organizations for enforcement of rules inside MPAs; regulations governing human behavior outside MPAs are lacking; funds for monitoring and evaluation of MPAs are lacking. Manatee conservation strategies should be integrated into a system of riverine, coastal, and marine protected areas supported by additional tactics such as required manatee training for boat captains, slow zones at hot spots outside MPAs, and continued educational outreach. With few modifications and increased enforcement and monitoring, the Belize model for manatee conservation could lead to a shared "triumph on the commons" for the manatees and the user groups that shared their habitat.

The goal of my dissertation was to describe the dynamics of a group of Houston toads located at the Griffith League Ranch (GLR), Bastrop County, Texas. My research included using statistical modeling to predict activity and abundance, mark-recapture techniques to estimate survivorship, and simulation modeling to explore the impacts of the difference in age at first reproduction and to project the future dynamics of the population at the GLR. From 2001 – 2005, 225 individual Houston toads (199 M : 26 F) were captured using two methods: breeding pond surveys and drift fences. Houston toads were neither caught equally among capture methods, nor across years. Toad activity was mostly confined within their breeding season, and activity was not continuous. A logistic regression indicated activity depended on time of year, mean precipitation, mean minimum daily temperature, and mean percent lunation as well as two-way interactions with moon-phase and other variables. Abundance depended on time of year, current precipitation, minimum temperature, and two-way interactions between time of year and the other two variables. Twenty-one of the 199 males (10.5%) and no females were recaptured among years. The probability of male survival was estimated using program MARK. Eight of 16 candidate models were supported and all but one contained precipitation as a covariate, indicating precipitation is important for Houston toad survival. Survivorship estimates varied from 0.1 to 0.41. The sex ratio was significantly male-biased. The odds of catching females in traps were 3.5 greater than capturing females in a pond, while the odds of capturing males in a trap were 0.28 compared to ponds. Results from a simulation model indicated the sex ratio is biased because of the difference in maturation times between males and females, coupled with high juvenile mortality. Results from an individual-based, spatially-explicit, stochastic simulation model, indicated a relatively low probability (~ 0.013) of B. houstonensis going extinct at the GLR within the next 10 years. Emergent properties of the model were similar to results observed in the field or reported in the literature. The model also identified that dispersal of Houston toads should be a future research priority.

The Lower Keys marsh rabbit (LKMR, Sylvilagus palustris hefneri), a subspecies of marsh rabbit endemic to the Lower Keys, Florida, is threatened with extinction due to extensive coastal development of salt marsh habitats. LKMR recovery is limited by habitat loss and degradation from brush encroachment, predation by freeroaming cats (Felis catus) and raccoons (Procyon lotor), sea-level rise, and hurricanes. This study sought to determine local and landscape factors that influence LKMR metapopulation ecology and dynamics and to evaluate strategies for their recovery. I evaluated the influence of patch and landscape characteristics on LKMR densities, extinction, and colonization rates following Hurricane Wilma, and the response of LKMRs and salt marsh habitats to prescribed fire. I used estimates of population change based on annual monitoring data to validate vital rates, constructed a spatially explicit demographic model to evaluate various levels and spatial configurations of recovery scenarios implemented throughout the LKMRs range, and validated expected changes in parameter estimates using measures of habitat degradation and raccoon activity from known LKMR populations. I found LKMR densities were higher in patches with greater numbers of bunchgrasses and forbs and less edge and lower in patches with higher measures of raccoon activity. In response to a hurricane, I found the distance between LKMR patches and the coast had a negative influence on extinction probability; the distance between an extirpated and occupied LKMR patch had a negative influence on colonization probability and patch size had a positive influence. Adult LKMRs increased as woody cover <0.5 m decreased, herbaceous cover <0.5 m increased, and food availability increased in at least one site following prescribed fire. Model results indicated habitat management actions that improve carrying capacity of local rabbit populations and juvenile survival and control raccoon populations to increase rabbit reproductive rates are effective population recovery strategies. In total, my results provide a conservation planning tool that can be used to select recovery strategies and locations that will maximize benefits to LKMRs, thus improving their viability and recovery.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 162-168). Also available on the Internet.

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (p. 121-138). Also available via the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 155-180). Also available on the World Wide Web.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2009. / Härtill 5 uppsatser.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references. Also available on the Internet.