<p> Size-at-age of Pacific Halibut (<i>Hippoglossus stenolepis</i>) has declined significantly since the 1980s. For instance, the average weight of a 20-year-old female declined from 55 kg in 1988 to 20 kg in 2014. The decline in size-at-age corresponds to a period of declining Pacific Halibut recruitment, spawning biomass, and reductions in catch limits for the directed commercial Pacific Halibut longline fishery. The causes of changes in Pacific Halibut size-at-age are poorly understood. Our project investigates several hypotheses related to declines in size-at-age, including the effects of environmental and ecological variability on growth, and the cumulative effects of harvest and size-selective fishing. Specific potential environmental covariates include the Pacific Decadal Oscillation, which is an index of basin-wide sea surface temperatures, and summer sea surface temperatures along the continental shelf of the Gulf of Alaska. Specific ecological variables include annual biomass estimates of Arrowtooth Flounder (<i>Atheresthes stomias</i>) and Pacific Halibut to investigate the potential role of inter- and intraspecific competition, respectively. We used a population modeling approach to simulate the effects of fishing on size-at-age. We found that the large increase in Arrowtooth Flounder biomass since the 1970s corresponds to declines in Pacific Halibut size-at-age. Our results also suggest that periods of high Pacific Halibut biomass relates to poor growth and low size-at-age. Finally, we found that harvest and size-selective fishing explains between 30 and 65% of observed declines since the 1980s in the Gulf of Alaska, and up to 100% of the declines in Southeast Alaska and British Columbia where harvest rates were high in the 1990s and 2000s. Our findings have implications for fisheries management, including balancing tradeoffs associated with size limits, and understanding how changes in environmental and ecological conditions can shift management reference points such as maximum sustainable yield.</p>

<p> I studied current educational efforts about urban wildlife in Tucson, Arizona using three main approaches: a) interviews with key informants, b) analysis of the dissemination of and reaction to informative booklets about urban wildlife, and c) a review of regionally-relevant news articles published online from 2013 to 2015. These triangulated research efforts provide a general snapshot of the relative effectiveness of urban wildlife education practices and result in suggestions for improvement with future efforts. Key informants provided insight into successful human-wildlife conflict resolution and avoidance techniques and successful education practices. An analysis of the dissemination of information on living with urban wildlife, revealed that 53% of the small participating businesses valued the effort and requested additional booklets for their clients. All 45 of the recipients of the educational booklet found them useful and 65% cited them as their only such source of information about wildlife. Thus, I recommend additional concerted dissemination of such materials towards improved education of the public about urban wildlife interactions. Analysis of online news articles revealed that 51% focused on human-wildlife conflicts and, of these, 30% contained information about conflict avoidance. By contrast, 35% of all articles reviewed were strictly educational and yet, of these, 74% addressed conflict avoidance. Thus, I recommend that future media efforts continue this focus on human-wildlife conflict avoidance and resolution strategies. The culmination of this work demonstrates that much work is being conducted towards urban wildlife education and revealed education projects and strategies that may be applied in the future to help facilitate an informed coexistence with urban wildlife.</p>

Despite the ubiquity of wildlife management, from reintroductions and supplemental feeding to culling and habitat destruction, very little is known of the effects of management practices on species’ social dynamics. Species’ social structure has the potential to affect not only behaviour and evolution but also the transmission of information or disease. Understanding the effects of population management on social behaviour and organisation is a key step in understanding these species’ ecology. This thesis examines the differences between individuals’ roles in the social structure and what this means for the transmission of disease. It demonstrates how similarity in movement behaviour scales with increasing social circles, how seasonality in movement and seasonality in association rates covary as well as detailing post-cull behavioural changes. It finds that there is the potential for certain individuals (most likely non-breeding individuals) to transmit infection far and wide. It reveals the similarities in movement behaviour and body condition that birds share with their pair and social group. It emphasises the importance of autumn and winter movement in the transmission of infectious disease and it follows the short- and long-term changes in social structure and movement behaviour following a cull. Cull survivors were observed to retain a higher proportion of associations with their previous associates and moved less far in the year following the cull than in the year preceding it. This is the first application of social network analysis to quantify social structure before and after culling. The findings suggest that culling an infected population may facilitate rather than constrain the transmission of disease.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 497-523). Available also in a digital version from Dissertation Abstracts.

<p> Identifying species occurrence in ecosystems of high conservation concern is especially important in the context of modern landscapes. This study investigated how stand-scale and landscape-scale factors affect priority birds associated with longleaf pine (<i>Pinus palutris</i>) ecosystems. Herein, I compared priority bird occupancy among 12 stand types throughout the historic range of longleaf pine. I found open pine stands positively influenced red-cockaded woodpecker (<i>Picoides borealis</i>) and Bachman&rsquo;s sparrow (<i>Peucaea aestivalis</i>) occupancy, but were not significantly linked to northern bobwhite (<i>Colinus virginianus</i>) and brown-headed nuthatch (<i>Sitta pusilla</i>) occurrence. Landscape- and stand-scale factors affected red-cockaded woodpecker, Bachman&rsquo;s sparrow, and brown-headed nuthatch occupancy. Northern bobwhite occupancy was influenced solely by landscape-scale factors. Red-cockaded woodpecker and Bachman&rsquo;s sparrow were positively influenced by metrics associated with longleaf pine ecosystems suggesting they are effective indicator species. My analysis indicates that using this multi-scale approach is valuable to identifying areas on the landscape of conservation and restoration priority.</p>

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

<p>The Golden-winged Warbler (Vermivora chrysoptera) is an imperiled songbird that breeds in early-successional plant communities of eastern North America. Conservation efforts on the breeding grounds have become a priority because population declines are understood to be driven chiefly by the loss/degradation of breeding habitat. Although the species is known to use a variety of upland and wetland habitat types, most previous research on the species has been conducted solely in uplands. I studied Golden-winged Warbler use and habitat characteristics in the Poconos region of Pennsylvania. Density estimates suggest that both timber harvests and wetlands support similar densities of Golden-winged Warblers. Microhabitat occupancy models revealed that those wetlands I surveyed with high densities of 1-2 m tall shrubs (>2x as many shrubs) supported fewer Golden-winged Warblers whereas wetlands with more saplings (>2x as many saplings) and sedge cover (~1.3x as many sedge observations) supported more warblers. Finally, I found that macro-scale habitat variables that I quantified did not predict species occupancy of wetlands, likely due to the homogeneous nature of the study area. My study suggests that both wetlands and timber harvests have similar capacity to support Golden-winged Warblers. Further, wetlands in the Poconos should be evaluated at the microhabitat-scale for vegetative attributes that meet Golden-winged Warbler habitat requirements, rather than at the macro-habitat scale.

<p> Sea-level rise is a concern for the future of coastal marsh obligate species such as the Clapper Rail (<i>Rallus crepitans</i>). Clapper Rails possess the potential to indicate changes to marsh ecological state due to population variation related to habitat features exhibited in previous study. Estimates for Clapper Rail survival are among the key missing parameters to create predictive models for Clapper Rail populations. I estimated Clapper Rail survival using data collected from six automated telemetry towers located in two Mississippi marshes. Thirty adult rails were harnessed with radio transmitters around telemetry towers to provide evidence of a rail&rsquo;s status, alive or dead. Using survival estimates in conjunction with existing empirical data, I created an individual-based model that incorporated existing Sea-level Affecting Marsh Models, which predict changing land cover. These models showed that Clapper Rails will likely persist, though at decreased populations, through changes in habitat due to sea-level rise.</p><p>

<p> Historically, black bears occurred throughout Mississippi but by 1932, &lt;12 bears remained. Repatriation in neighboring states and conservation efforts in Mississippi have led to the recolonization of at least 2 subspecies (<i>U. a. luteolus</i> and <i>U. a. americanus</i>) of black bears in the state. I compiled available data to provide a synthesis of the history, current status, and management of black bears in Mississippi. Additionally, I used global positioning data collected from radio collared bears to determine the influence of distance to source population, cover type, distance to roads, distance to water, wetland reserve program areas, and human population density on black bear resource selection at various spatial scales. I studied characteristics of space use and resource selection of recolonizing bears in the Mississippi Alluvial Valley (Delta). I assessed the influence of environmental parameters at the female core annual home-range (using 50% kernel density estimator) and male and female seasonal and annual home-ranges (95% kernel density estimator). Distance to source population and distance to roads had significant influence at the core female home-range scale. I found a sex-based difference in annual and seasonal home-ranges. I also found that bears exhibited response to and selection for specific resources with an affinity toward hardwood stands, particularly young-aged hardwoods. My research illustrates the importance of analyzing resource selection at multiple scales to gain a full understanding of parameters that influence the recolonization of a bear population.</p><p>

<p> Rails (Family: Rallidae) are among the least studied birds in North America, in large part due to their elusive nature. As a wetland-dependent species, understanding the timing of their migration and their habitat needs during migration is especially important since management needs to be timed to balance the needs of many species. I developed and verified a new distance sampling based nocturnal ATV spotlight survey because traditional call-broadcast surveys are not effective during autumn migration because of the drop off in call rate after the breeding season. These surveys allow us to ask point-level questions about what habitats rails select during migration and how it changes over time. Through these standardized surveys from 2012-2016 across 11 public properties in Missouri, USA, I documented the migratory timing and habitat use of migratory rails. Sora (Porzana carolina) have a wide migratory window, beginning in early August and continuing through the end of October with a peak in late September. Virginia Rail (Rallus limicola) and Yellow Rails (Coturnicops noveboracensis) have shorter migratory periods, from late September through the end of October. Rails, especially Sora, migrate earlier than waterfowl, which can create a mismatch of habitat needs. We performed a 3 year experiment to examine the response of Sora and waterfowl to early autumn wetland flooding. Sora responded positively without a negative impact on waterfowl. I used monitoring data to create species distribution models to inform estimates of migratory connectivity for all three species using stable hydrogen isotopes. Sora and Yellow Rails were estimated to migrate generally north-south, with Virginia Rails coming from a wider east-west range. Through better understanding the migratory connectivity, timing and habitat use of rails in the autumn I provide a foundation to inform conservation and management of these fascinating and elusive birds. We provide a description of all variables used (Appendix II), GPS data of survey tracks and detection points (Appendix III), data sets of bird observation points, survey data, and vegetation information (Appendix IV), data sets of stable hydrogen isotope data (Appendix V), data sets of species distribution models (Appendix VI).</p>