Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Faculty of Health Sciences. Includes two articles published in the Journal of Zoo and Wildlife Medicine, 2007 v. 34 (4) p. 567-573 and March 17, 2008. Includes bibliographical references (leaves 273-312)

Thesis (Ph. D.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 173-195). Also available on the World Wide Web.

Thesis (M.S.) --Southern Oregon University, 2005. / "A thesis submitted to the Department of Biology and the Graduate School of Southern Oregon University in partial fulfillment of the requirements for the degree of Master of Science in Science." Includes bibliographical references (p. 69-75) Also available via Internet as PDF file through Southern Oregon Digital Archives: http://soda.sou.edu. Search Bioregion Collection.

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on July 8, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Ecology, Department of Biological Sciences, University of Alberta. Includes bibliographical references.

The invasive Indo-Pacific Lionfish Pterois volitans has been recognized as a severe threat to indigenous fish species on Caribbean reefs. Previous studies have identified an extensive variety of Caribbean fishes in the stomachs of lionfish, but few have tried to quantify the impact these invaders could have on endemic or threatened species. The threatened Labrid fish Halichoeres socialis has been identified as the primary component of lionfish diet in Belizean lagoonal reef systems. This study aims to answer two questions: what is the average maximum number of prey-fish a lionfish can consume in one sitting, and at what rate can these lionfish pass a meal of three prey fish completely? To test lionfish satiation, the subjects were fed as many Pseudohemiculter dispar (a commercially available surrogate) as they could eat within a fifteen-minute window. During the digestion rate experiment, lionfish were fed three similarly sized P. dispar and allowed to digest in 3, 6, 9, 12, 15, 19, and 24 hour blocks. From observing prey throughput under near optimal laboratory conditions, the maximum potential impact of lionfish on native populations of Caribbean reef dwelling fishes can be estimated. Given the volume and mass of prey items consumed in this study between 593 and 4658 individual H. socialis could be consumed by a single lionfish in one year. Coupled with further investigation into H. socialis stock numbers, lionfish (P. volitans) could be considered a potentially immanent threat to fishes that exhibit body morphometrics like those of H. socialis at any stage of their life-history.

Understanding the dynamics of functional genetic variability in small populations can have important implications in their conservation. I screened the variation of MHC II gene in Galapagos mockingbirds to evaluate the evolutionary forces that shaped the genetic variation. I found out that genetic drift affected the MHC variation together with a specific form of natural selection. Although the MHC is supposed to be under a pathogen-mediated selection I found no evidence for this theory in the mockingbird study system.

Magister Scientiae (Biodiversity and Conservation Biology) / Due to the critical status of Psammobates geometricus and the vulnerability of their habitat, there is a need to allocate areas for their protection. The aim of this study was to provide information on the space requirements and activity level of geometric tortoises to facilitate future conservation efforts. The thread-and-spool method was used to compare short-term movements, habitat utilisation, and activity patterns of male and female tortoises over 15 and 20 days respectively, in autumn and spring. Through radiotelemetry, the long-term movements of 10 male and 11 female tortoises were evaluated from April 2002 to April 2003. Locality data for the short-term and long-term studies were used to calculate the size of activity areas and home ranges as minimum convex polygons and fixed kernel estimates. Male and female geometric tortoises were active throughout the year, and maintained a high level of activity in autumn and in spring. However, females were more active than males were in spring. Females may require more resources, particularly food, in spring when they produce eggs. Although males and females travelled similar distances in autumn and in spring, males displaced further than females displaced in both seasons. The movement path for males was often linear, perhaps because this path may enhance their opportunities to encounter females. Geometric tortoise males were substantially smaller than females, which may explain why the distances that males moved and displaced in spring were negatively correlated to environmental temperature. In autumn, when temperatures were lower than in spring, the distance travelled by males was not correlated to temperature. However, in autumn female displacement showed a positive correlation with environmental temperature. Geometric tortoises showed large inter-individual variation in home range size, which may contribute to the fact that home range size did not differ among the three different habitat types: mature renosterveld, burned renosterveld and the old agricultural fields. Average home range size was 11.5 ha for 95% fixed kernel estimates, and 7.0 ha for minimum convex polygon estimates. Body size influenced the home range size of female geometric tortoises, but had no effect on the home range size of male tortoises. Females had larger home ranges than male tortoises had, possibly because females were larger, but reproductive requirements of females may have played a role. During the dry season, home range size increased when compared to the wet season. The larger home range during the dry season, which is associated with high temperatures, may be related to a reduction in resource availability. The fewer resources available, the greater the distance the tortoises would need to travel in order to acquire the necessary resources. The small home range in the wet season may indicate an abundance of resources, but it may also be that large pools of standing water restrict the movements of tortoises. Understanding the spatial and habitat requirements of P. geometricus will help to assess the viability of populations in disturbed and highly fragmented areas, and contribute to the conservation efforts for this endangered species. / South Africa

The Reticulated Flatwoods Salamander, Ambystoma bishopi, is an inhabitant of longleaf pine forests in the southeastern United States. Historically distributed across southern Alabama, Georgia, and the Florida panhandle west of the Apalachicola-Flint Rivers, the range of this species has been drastically reduced. It is currently listed as federally endangered under the Endangered Species Act (ESA). Population viability analyses (PVAs) represent a key component of many recovery plans for threatened and endangered species. Here we use 10 years of mark recapture data collected from two breeding populations of A. bishopi to construct a demographic model that can be used to evaluate future extinction risk. In chapter one, we quantify population sizes through time, and estimate the impact of annual variability in numbers on genetic viability. This species exists in small (< 500) breeding populations and exhibit annual fluctuations in abundance characteristic of pond-breeding amphibians. In chapter 2, we adopt a modified version of the von Bertalanffy equation to construct size-at-age curves for A. bishopi that include the metamorphic transition. Individuals exhibit rapid growth in the larval stage such that they emerge as metamorphs at 60% of their final body size. In chapter 3, we employ a Cormack-Jolly-Seber model, modified to include continuous covariates, to generate size-dependent survival curves. Survival of A bishopi exhibits dramatic annual and seasonal variability, but is always positively correlated with body size. Lastly, in chapter 4, we combine the elements of all previous chapters to construct an Integral Projection Model (IPM). Given the prevalence of complete recruitment failure in these populations, and their relatively small size, extinction probabilities under a business-as-usual model were high. Increasing the frequency of successful recruitment drastically reduces extinction risk; however, adult survival exerts the greatest influence on long-term population growth. To assure the recovery of A. bishopi, management must consider all elements of the life-history when allocating resources and effort. More generally, both aquatic and terrestrial habitats must be protected for amphibian conservation to be effective, making them ideal candidates for 'umbrella species' status. Amphibian conservation would also benefit from an increase in systematic, long-term data collection. / Doctor of Philosophy / The southeastern United States is the global salamander hotspot, representing a crucible for diversity. Longleaf pine forests, the predominant ecosystem in the southeast, have been reduced to 3% of their former range, with dire consequences for the animals that inhabit them. The Reticulated Flatwoods Salamander, Ambystoma bishopi, is endemic to the region, and currently listed as federally endangered owing to recent population declines. A recovery plan for the species therefore, is required by law, under the Endangered Species Act (ESA). A salient component of modern recovery plans are population forecasts that evaluate future extinction risk. Such forecasts can then be used to assess alternative management strategies proposed to improve the species' long-term prospects. By studying two of the last remaining populations of A. bishopi from 2010-2019, we were able to collect the data required to construct a demographic model that can be used to run population projections. In some regards, A. bishopi is a typical amphibian, in that their populations show dramatic fluctuations in numbers through time, and they exhibit rapid growth in the aquatic larval stage, achieving 60% of their maximum body size in the first three months of life. Flatwoods salamanders breed in ephemeral wetlands, that often dry before successful metamorphosis can occur. The frequency of pond-drying results in a high probability of extinction for a single population, but survival of breeding individuals was equally important when considering long-term persistence. To assure the recovery of A. bishopi, management must consider all elements of the life-history when allocating resources and effort. More generally, both aquatic and terrestrial habitats must be protected for amphibian conservation to be effective, making them ideal candidates for 'umbrella species' status.

Minnows and darters are the most imperiled freshwater fish species in North America as a result of habitat degradation and restricted ranges, which often results in isolated populations. The Candy Darter Etheostoma osburni was recently listed as Endangered and may represent a suite of other imperiled fishes in terms of their ecology, life-history traits, and conservation needs. I examined the effects of microhabitat features, sampling effort, species abundance and morphology on riffle-dwelling species. My results confirm many of the well-known influences on detection, while adding to the knowledge of species-specific attributes that can influence detection of common riffle species. Using physical marking and molecular methods, I describe movement patterns and provide insight into the spatial distribution of related pairs and reproductive contribution of the endangered Candy Darter. Minimum detected movements of adults were greater for molecular methods than for visual markings. Indirect movements inferred from the spatial extent between related pairs indicated that parents and offspring move along their entire 18.8-km distribution in Stony Creek, while individual parents and offspring in Laurel Creek move throughout half of their 4.25-km distribution. Additionally, I provide evidence that the lifetime reproductive contribution of Candy Darter is greater than previously described. Using microsatellite DNA markers, I describe population genetic structure and estimate effective population sizes of the four extant populations of Candy Darter in Virginia and provide insight into which populations may be successful as sources for reintroduction or translocation efforts. The four extant populations in Virginia are demographically isolated, but results also suggest historical connectivity. Effective population estimates for all populations were less than the recommended 500 to maintain evolutionary potential, but three populations numbered > 130, indicating they may be viable options for source populations for translocations. My results suggest that all populations may benefit from translocations to overcome genetic drift and inbreeding and to safeguard the historical genetic variation of the species. / Master of Science / Minnows and darters are the most imperiled freshwater fish species in North America as a result of habitat degradation and restricted ranges, which often results in isolated populations. The Candy Darter Etheostoma osburni was recently listed as Endangered and may represent a suite of other imperiled fishes in terms of their ecology, life-history traits, and conservation needs. I examined the effects of microhabitat features, sampling effort, species abundance and morphology on riffle-dwelling species. My results confirm many of the well-known influences on detection, while adding to the knowledge of species-specific attributes that can influence detection of common riffle species. Using physical marking and molecular methods, I describe movement patterns and provide insight into the spatial distribution of related pairs and reproductive contribution of the endangered Candy Darter. Minimum detected movements of adults were greater for molecular methods than for visual markings. Indirect movements inferred from the spatial extent between related pairs indicated that parents and offspring move along their entire 18.8-km distribution in Stony Creek, while individual parents and offspring in Laurel Creek move throughout half of their 4.25-km distribution. Additionally, I provide evidence that adult Candy Darter successfully reproduce over a greater number of years than previously described. Using microsatellite DNA markers, I describe population genetic structure and estimate the number of individuals contributing the gene pool of the four extant populations of Candy Darter in Virginia and provide insight into which populations may be successful as sources for reintroduction or translocation efforts. The four extant populations in Virginia are reproductively isolated, but results also suggest historical connectivity. The numbers of individuals contributing to population-specific gene pools were less than the recommended 500 to maintain evolutionary potential, but three populations numbered > 130, indicating they may be viable options for source populations for translocations. My results suggest that all populations may benefit from translocations to overcome genetic drift and inbreeding and to safeguard the historical genetic variation of the species.

No description available.