This study attempted to determine whether ova are formed from the epithelial covering of the ovary during sexual maturity, and if so to determine how they are formed and to see if there is any relation between the formation and the breeding season.

Thesis (M.Sc.)--Acadia University, 2002. / Includes bibliographical references ( leaves 67-77). Also available on the Internet via the World Wide Web.

Almost half of the world�s mammal extinctions in the last two hundred years have occurred in Australia (Short and Smith 1994). The western barred bandicoot Perameles bougainville is one of a suite of species that is currently threatened with extinction, surviving only on two islands in Shark Bay, Western Australia. Reintroduction has been used as a tool in conservation biology to assist in the recovery of threatened species, such as the western barred bandicoot. The aims of this project were to 1) successfully reintroduce and establish a free-ranging mainland population of the western barred bandicoot at Heirisson Prong, Shark Bay, 2) contribute information on the biology of the species, its interactions with introduced species, and its likelihood of persistence as a reintroduced population in the longer-term, and 3) to provide recommendations to assist future reintroductions of the species. The first reintroduction of the western barred bandicoot from surviving remnant island populations to the mainland, some 60 years after its apparent mainland extinction, was from Dorre Island to Heirisson Prong in 1995. Animals were translocated initially to a predator-free refuge on Heirisson Prong, and then subsequently released to the 12 km2 peninsula where introduced predators (foxes Vulpes vulpes and feral cats Felis catus) had been controlled, but European rabbits Oryctolagus cuniculus had not. Despite a small founder number and high mortality of free-range bandicoots in the presence of a low-density feral cat population, the bandicoot population successfully established. The reintroduced population of western barred bandicoots provided an opportunity to study the biology of the species, and to compare it with the remnant island populations and other species of Australian bandicoot. Many population parameters were similar between the island and mainland western barred bandicoot populations, as well as between the western barred bandicoot and other bandicoot species, suggesting that the habitat at the reintroduction site is suitable for long-term persistence of the population. However, there were some notable differences. The western barred bandicoot is the smallest extant species of bandicoot, with fewer young per litter than recorded for other bandicoot species, adult sex ratios were closer to parity, animals reached sexual maturity later, and it is the only species of bandicoot where females are larger than males. Home range size is larger also than recorded for other species. Some of these differences may be explained in part by trade-offs between island dwarfism, lactational pressures, and nest defence. The nesting biology of the western barred bandicoot was studied at Heirisson Prong, including during periods of high and low densities of rabbits. Individuals of the species constructed and utilised nests in a similar fashion to other species of Australian bandicoot, nesting amongst litter underneath shrubs. The western barred bandicoot appeared to favour particular shrub species, especially when vegetation condition was poor due to rabbit damage, but displayed flexibility in being able to construct nests under a variety of shrub species where at least some surface litter was present. Grasses were used in nest construction only when rabbit density was low. Nests appear important for protection against temperature extremes and diurnal predators. Vegetation exclosures around three of the shrub species most commonly used by the western barred bandicoot for nest sites (Acacia ligulata, A. tetragonophylla and Melaleuca cardiophylla) were used to examine the impact of rabbits on vegetation on Heirisson Prong. A high-density rabbit population over the summer of 1997/98 caused in a decrease in canopy cover and the death of mature A. ligulata. Subsequent rainfall and low-density rabbit populations allowed A. tetragonophylla shrubs to recover their former structure, and M. cardiophylla to recover, but not to the same degree. The flexibility of western barred bandicoots in use of nest materials and their omnivorous diet may enable the species to survive in the face of habitat modification by rabbits. Population viability analysis was used to examine future options for the recovery of the endangered western barred bandicoot. Biological data from the Dorre Island and Heirisson Prong populations were input to the computer simulation program VORTEX. The western barred bandicoot populations were modelled under a variety of scenarios to examine the possible effects of changes in carrying capacity, founder population size, inbreeding depression, and the occurrence of drought and cat predation as catastrophes, on the probability of population extinction. This analysis highlighted the need for eradication of feral cats, above all other management actions. Cat predation was particularly potent when it acted through high loss of juveniles, as well as adult bandicoots. Predator control is considered critical for the long-term persistence of reintroduced populations of the western barred bandicoot. This study documents the first reintroduction of the endangered western barred bandicoot to mainland Australia. The population had been extant for four years at the completion of data collection for this thesis, in late 1999 and for over eight years at the finalisation of this thesis in July 2004. The knowledge gained from the reintroduction was used to discuss management recommendations and future options for the recovery of the species. The primary concern for reintroductions of this, and other species of bandicoots, remains the control of introduced predators. For long-term persistence of small, isolated populations, such as those of the western barred bandicoot at Heirisson Prong and the Arid Recovery Project at Roxby Downs in South Australia, and the eastern barred bandicoot Perameles gunnii at a range of sites in Victoria, the complete eradication of introduced predators is essential.

Forest carnivores such as the fisher have frequently been the target of conservation concern due to their association with older forests and assumed sensitivity to landscape-level habitat alteration. Although the fisher has been extirpated from most of its former range in the western U.S., it is still found throughout much of northwestern California. However, fisher distribution is still poorly known in the majority of this region where surveys have not been conducted. In order to predict fisher distribution across the region, a multiple logistic regression model was created using data from 682 previously surveyed locations and a GIS vegetation coverage created from satellite imagery. A moving-average function was used to derive landscape level indices of vegetation variables from the GIS layer. Moving averages of canopy closure, tree size class, and percent conifer were found to have strong correlations with fisher presence. Regional gradients as represented by either precipitation or a trend surface derived from spatial coordinates were also significant predictors in the model. The model was validated with new data collected from 240 survey locations and proved to be accurate in predicting fisher presence in unsurveyed areas. The model was used to generate hypotheses as to the mechanisms controlling habitat selection and the scales at which these operate and to evaluate the representation of fisher habitat in existing protected areas. These insights may be valuable in designing conservation reserve networks that insure the long-term viability of forest carnivore populations. / Graduation date: 1998

Thesis (Ph. D.)--Oregon State University, 1971. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

I studied the population delineation, hierarchical habitat selection, home range requirements, and denning habits of barren-ground grizzly bears (<i>Ursus arctos</i>) in Canada's central Arctic. To meet study goals, I tracked 81 bears equipped with satellite radio-collars in a study area of approximately 235,000 km2, centred 400 km northeast of the city of Yellowknife, Northwest Territories. I identified three populations of grizzly bears in the study area using multivariate cluster analysis of movement data and population range analyses. High exchange among population units for both females and males, however, suggest that identified grizzly bear population units cannot be managed independently from one another. I documented highly selective patterns of habitat selection by grizzly bears in a central, 75,000 km2 portion of the study area. Using resource selection functions, I examined habitat selection at the level of the home range (second order selection). Coverage of habitat was determined from Landsat Thematic Mapper scenes. The general pattern was for bears to possess home ranges, relative to the study area, that contained preferential amounts of esker habitat, tussock/hummock successional tundra, lichen veneer, birch seep, and tall shrub riparian areas over other habitat types. I also examined habitat selection at a finer level of selection (third order selection), whereby habitat use was determined from individual satellite telemetry locations and compared to the availability of habitats within home ranges of individual animals. Overall, esker and riparian tall shrub habitats were the most preferred habitats by bears throughout the year. Annual ranges of males ('X' = 7,245 km2) were significantly larger than the annual ranges of females ('X' = 2, 100 km2). Annual ranges are the largest ranges yet reported for grizzly bears in North America. Multiple regression revealed that ranges increased in size as the proportional amount of poor bear habitat in the environment, supplying constant amounts of quality habitats. Compared to the proportional availability of habitat types in the study area, esker habitat was selected more than expected by chance. The majority of bears emerged from their dens in the first week of May. Den entrance occurred primarily in the last two weeks of October.

Thesis (Ph.D.)--University of Oklahoma, 1998. / Includes bibliographical references (leaves 131-139).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 94-106).

No description available.

Of all the marine taxa, marine mammals seem to have benefited the most from a paradigm shift from exploitation to conservation. This thesis provides the first quantitative assessment for marine mammals of (1) global, publicly available population-level abundance data, (2) abundance trends, (3) the relationship between decline and recovery, and (4) critical factors to recovery. I compiled a database of 143 population abundance time series. Using robust linear regression, I found approximately one third (35%) were significantly increasing and recovering. For populations with historical estimates (n=47), I also found a negative relationship between decline and recovery. With the significant population trends (n=43), I used a variety of modeling approaches—classification trees, generalized linear models (GLMs) and generalized additive models (GAMs) —to assess the relationship between hypothesized intrinsic and extrinsic critical factors and recovery. The results suggest the ongoing importance of wildlife proximity and accessibility to humans in determining population recovery.