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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Evaluating the Use of Surrogates of Marine Mammal Species Representation in Biodiversity Conservation Planning

January 2019 (has links)
abstract: Biodiversity is required to guarantee proper ecosystem structure and function. However, increasing anthropogenic threats are causing biodiversity loss around the world at an unprecedented rate, in what has been deemed the sixth mass extinction. To counteract this crisis, conservationists seek to improve the methods used in the design and implementation of protected areas, which help mitigate the impacts of human activities on species. Marine mammals are ecosystem engineers and important indicator species of ocean and human wellbeing. They are also disproportionally less known and more threatened than terrestrial mammals. Therefore, surrogates of biodiversity must be used to maximize their representation in conservation planning. Some of the most effective surrogates of biodiversity known have only been tested in terrestrial systems. Here I test complementarity, rarity, and environmental diversity as potential surrogates of marine mammal representation at the global scale, and compare their performance against species richness, which is the most popular surrogate used to date. I also present the first map of marine mammal complementarity, and assess its relationship with environmental variables to determine if environmental factors could also be used as surrogates. Lastly, I determine the global complementarity-based hotspots of marine mammal biodiversity, and compare their distributions against current marine protected area coverage and exposure to global indices of human threats, to elucidate the effectiveness of current conservation efforts. Results show that complementarity, rarity, and environmental diversity are all efficient surrogates, as they outcompete species richness in maximizing marine mammal species representation when solving the minimum-set coverage problem. Results also show that sea surface temperature, density, and bathymetry are the top environmental variables most associated with complementarity of marine mammals. Finally, gap analyses show that marine mammals are overall poorly protected, yet moderately exposed to hotspots of cumulative human impacts. The wide distribution of marine mammals justify global studies like the ones here presented, to determine the best strategy for their protection. Overall, my findings show that less popular surrogates of biodiversity are more effective for marine mammals and should be considered in their management, and that the expansion of protected areas in their most important habitats should be prioritized. / Dissertation/Thesis / Doctoral Dissertation Biology 2019
412

A Multi-scale Evaluation of Pygmy Rabbit Space Use in a Managed Landscape

Wilson, Tammy L. 01 May 2010 (has links)
Habitat selection has long been viewed as a multi-scale process. Observed species responses to resource gradients are influenced by variation at the scale of the individual, population, metapopulation, and geographic range. Understanding how species interact with habitat at multiple levels presents a complete picture of an organism and is necessary for conservation of endangered species. The main goal of this dissertation is to evaluate distribution, relative abundance, and habitat selection of a rare species, the pygmy rabbit Brachylagus idahoensis, at multiple scales in order to improve management and conservation for this species. At the broadest scale, pygmy rabbit occurrence and relative abundance were modeled in the Duck Creek allotment of northern Utah using a hierarchical spatial model. Pygmy rabbits are not easily observable, and the model used two levels of indirect detection to make statistically rigorous spatial predictions. We found that the model predicted the general pattern of rabbit occurrence and abundance within the study area, and that there was spatial heterogeneity in the probability of pygmy rabbit occurrence within a study domain that was known to be occupied. The resulting model framework could be used to develop a long-term monitoring program for pygmy rabbits and other species for which hierarchically nested levels of indirect observation are collected. The mid-scale analysis evaluated pygmy rabbit home range placement and movement with respect to sagebrush removal treatments using null models based on an optimal central place foraging behavior. While placement of home-range centers did not appear to be affected by the treatments, within-home range movements were farther from treatments than expected by the null models for two rabbits (of eight), and rabbits that approached treatment edges were less likely to enter treatments than expected by chance. Rabbits are not extirpated from sites that have been treated, but the observed reluctance to enter treated patches calls for caution when conducting sagebrush removal treatments near occupied pygmy rabbit burrows. At the finest level of resolution, the spatial ecology of pygmy rabbit use of burrows was evaluated. Both the placement of burrows in general and pygmy rabbit use of burrows were clustered. While the habitat gradients experienced by each of the rabbits evaluated affected the modeled habitat selection responses, some generalities were observed. Selection of high cover suggests that pygmy rabbit use of burrows may be linked to predator avoidance behavior. Additionally, pygmy rabbit use of clustered burrows affects management actions including: habitat modeling, monitoring, and species introduction. Explicit attention to resource distribution will improve efforts to predict species responses to management actions.
413

Habitat Characteristics and Occupancy Rates of Lewis's Woodpecker in Aspen

Vande Voort, Amy M 01 May 2011 (has links)
Lewis‘ woodpeckers (Melanerpes lewis) are generally associated with open ponderosa pine (Pinus ponderosa), open riparian, and burned pine habitats in the West; however, this species has recently been found to nest in aspen (Populus tremuloides) stands in Utah. This study describes the habitat characteristics of Lewis‘ woodpecker nest sites in aspen and investigates how well aspen stand characteristics predict Lewis‘ woodpecker occupancy. I surveyed for Lewis‘ woodpeckers at previously occupied nesting locations in aspen and took habitat measurements at nest sites. In addition, nest-centered Forest Inventory and Analysis (FIA)-type plots provided stand-level habitat characteristics. I used logistic regression to determine which stand-level habitat variables were associated with nest locations; significant variables were then used to select FIA plots in Utah that contained predicted suitable nesting habitat. Criteria used to select FIA plots were aspen type stands, percent canopy cover less than 46%, and average tree diameter at breast height greater than 27.9 cm (11 inches). I then conducted occupancy surveys at FIA plots predicted to contain “suitable” and “non-suitable” Lewis’ woodpecker habitat to field validate the predictive model. No predicted non-suitable plots (n=26) were occupied and only one predicted suitable plot (n=49) was occupied. My results indicated that Lewis’ woodpeckers are rare throughout Utah in aspen stands even though there seems to be abundant nesting habitat available. My results also indicated that variables measured by FIA do not, in isolation, provide sufficient capability to predict Lewis’ woodpecker nesting habitat or actual use, and that more data are needed to accurately predict Lewis’ woodpecker nesting habitat, such as distance to, age, and severity of fires.
414

Sexual conditioning in the dyeing poison dart frog (Dendrobates tinctorius)

Gaalema, Diann E. 15 January 2010 (has links)
Amphibian populations worldwide are currently in decline. One approach to preventing extinction of some of the affected species is to create assurance colonies. These sustainable captive populations might some day be used to reestablish wild populations. One issue with creating assurance colonies is successful breeding; often difficulties arise when attempting to breed exotic animals in captivity. Sexual conditioning, a form of Pavlovian conditioning, has been shown to improve breeding behavior. In this project the efficacy of sexual conditioning to improve breeding behavior in the dyeing dart frog (Dendrobates tinctorius) was tested. The frogs were trained with a stimulus that was either predictive of or independent of exposure to a member of the opposite sex. The group trained with the predictive stimulus showed shorter latencies to a variety of breeding behaviors and produced more eggs than the control groups. The sexual conditioning procedure also increased expression of various breeding behaviors allowing for careful examination of calls and visual signaling within this species.
415

Habitat fragmentation, livelihoods and conservation : implications for Tarangire National Park.

Porokwa, Jacob T. January 2003 (has links)
This study set out to investigate habitat fragmentation and its implications for wildlife conservation. It focused on Emboreet Ward in the Arusha region of Tanzania, which is in close proximity to the Tarangire National Park. This area, traditionally occupied by the Maasai pastoralists, has undergone several changes, not least of which are changes in the local livelihoods in response to a need for cash and deterioration of state support for animal health care. Dominating these changes is a shift in livelihood strategies from pastoralism to a mix of pastoralism and cropping. Increasingly, land is being cultivated and agricultural opportunities are changing lifestyles, livelihoods and habitat integrity for wildlife. Fragmentation of habitats outside the national park has serious implications for the future of pastoralism and conservation, especially since some species of wildlife migrate seasonally between this park and the adjoining plains. It also has significance for the Maasai whose approach to domestic livestock management is deeply rooted in a culture that does not comfortably accord with the market economy. The study adopted a case study approach, was mainly qualitative, and relied on both primary and secondary data sources. Interviews played a critical part in sourcing primary data from the respondents. Documentary analysis was critical to gathering secondary data. The study shows the future of Tarangire National Park to be intricately woven into the complex and dynamic interaction between the changing economy, the responses of the Maasai whose culture separates them from the market economy, migrants into the area, and the government agencies whose intentions appear to be neither clearly expressed nor interpreted. The study concludes that empowerment lies at the heart of the envisaged change. This is shown to be a necessity for all stakeholders operating within a proposed integrating structure. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
416

The ecology and conservation of Mackinder's eagle owls (Bubo capensis mackinderi) in central Kenya in relation to agricultural land-use and cultural attitudes /

Ogada, Darcy L. January 2007 (has links)
Thesis (Ph.D. (Zoology & Entomology)) - Rhodes University, 2008.
417

Developing Behavioral Indices of Population Viability: A Case Study of California Sea Lions in the Gulf of California, Mexico

January 2012 (has links)
abstract: Despite years of effort, the field of conservation biology still struggles to incorporate theories of animal behavior. I introduce in Chapter I the issues surrounding the disconnect between behavioral ecology and conservation biology, and propose the use of behavioral knowledge in population viability analysis. In Chapter II, I develop a framework that uses three strategies for incorporating behavior into demographic models, outline the costs of each strategy through decision analysis, and build on previous work in behavioral ecology and demography. First, relevant behavioral mechanisms should be included in demographic models used for conservation decision-making. Second, I propose rapid behavioral assessment as a useful tool to approximate demographic rates through regression of demographic phenomena on observations of related behaviors. This technique provides behaviorally estimated parameters that may be applied to population viability analysis for use in management. Finally, behavioral indices can be used as warning signs of population decline. The proposed framework combines each strategy through decision analysis to provide quantitative rules that determine when incorporating aspects of conservation behavior may be beneficial to management. Chapter III applies this technique to estimate birthrate in a colony of California sea lions in the Gulf of California, Mexico. This study includes a cost analysis of the behavioral and traditional parameter estimation techniques. I then provide in Chapter IV practical recommendations for applying this framework to management programs along with general guidelines for the development of rapid behavioral assessment. / Dissertation/Thesis / M.S. Biology 2012
418

Two Essays on the Trade-Offs Between Multiple Policy Objectives of Environmental Management Efforts

January 2012 (has links)
abstract: Environmental agencies often want to accomplish additional objectives beyond their central environmental protection objective. This is laudable; however it begets a need for understanding the additional challenges and trade-offs involved in doing so. The goal of this thesis is to examine the trade-offs involved in two such cases that have received considerable attention recently. The two cases I examine are (1) the protection of multiple environmental goods (e.g., bundles of ecosystem services); and (2) the use of payments for ecosystem services as a poverty reduction mechanism. In the first case (chapter 2), I build a model based on the fact that efforts to protect one environmental good often increase or decrease the levels of other environmental goods, what I refer to as "cobenefits" and "disbenefits" respectively. There is often a desire to increase the cobenefits of environmental protection efforts in order to synergize across conservation efforts; and there is also a desire to decrease disbenefits because they are seen as negative externalities of protection efforts. I show that as a result of reciprocal externalities between environmental protection efforts, environmental agencies likely have a disincentive to create cobenefits, but may actually have an incentive to decrease disbenefits. In the second case (chapter 3), I model an environmental agency that wants to increase environmental protection, but would also like to reduce poverty. The model indicates that in theory, the trade-offs between these two goals may depend on relevant parameters of the system, particularly the ratio of the price of monitoring to participant's compliance cost. I show that when the ratio of monitoring costs to compliance cost is higher, trade-offs between environmental protection and poverty reduction are likely to be smaller. And when the ratio of monitoring costs to compliance costs is lower, trade-offs are likely to be larger. This thesis contributes to a deeper understanding of the trade-offs faced by environmental agencies that want to pursue secondary objectives of protecting additional environmental goods or reducing poverty. / Dissertation/Thesis / M.S. Biology 2012
419

Evaluation of wildlife food plot seed mixes for Kansas

Tajchman, Alan J. January 1900 (has links)
Master of Science / Horticulture, Forestry, and Recreation Resources / Peg McBee / Three wildlife seed mixes were tested, Perfect Plot (BioLogic), Rack Force (Evolved Harvest), and Bird and Buck Whitetail and Gamebird mix (Star Seed). Two methods of research were conducted, (1) a food plot monitoring field study, and (2) a seed germination laboratory test. Food plots were planted in northwest (Jennings) and northeast (Manhattan) Kansas. Single season occupancy models from Program MARK were used to determine plot usage and preference of the seed mixes. Feeding patterns were analyzed from two locations targeting white-tailed deer (Odocoileus virginianus). Camera trap data were also analyzed for raccoon (Procyon lotor), wild turkey (Melagris gallopavo), and coyote (Canis latrans). During the summer 2014, the Bird and Buck mix retained the greatest amount of desirable vegetation, compared to the Rack Force and Perfect Plot mixes, which exhibited intermediate and relatively poor stand condition, respectively. White-tailed deer were documented at 100% occupancy using all (i.e., 100%) plots of all three mixes in Manhattan and Jennings, Kansas. In Manhattan, a significant increase in feeding events was observed for the months of July (45% of days) and August (50% of days) compared to the month of June (34% of days; p < 0.02). In contrast, deer feeding events in Jennings declined from 67% and 55% of days in June and July, respectively, to only 18% of days in August (p < 0.001). After initially having establishment issues among all three mixes, a laboratory study was initiated comparing the germination rates of each seed mix. Ten 1-gram random samples of each seed mix were tested in complete darkness at a constant 25-30°C for 25 days. When comparing daily germination rates of the seeds in the mixes, peak germination for all mixes (p < 0.0001) occurred on days 5-10 and 12-14. A single expected germination rate of similar plant types (i.e. alfalfa, clover, chicory, grasses) was computed from the seed tag, and then compared to the observed proportion of total seeds sampled that germinated. Bird and Buck recorded the highest germination, 79%, only 0.5% less than the expected overall germination. Perfect Plot and Rack Force recorded germination rates of 49% and 52%, which respectively, were 7% and 11% less than was expected.
420

Landscape ecology, survival and space use of lesser prairie-chickens

Robinson, Samantha January 1900 (has links)
Master of Science / Biology / David A. Haukos / The lesser prairie-chicken (Tympanuchus pallidicinctus) has experienced range-wide population declines and range contraction since European settlement. Due to ongoing declines, lesser prairie-chickens were listed as threatened under the Endangered Species Act in 2014; however, uncertainty regarding the legal status of the species has developed following a judicial decision to vacate the listing in September 2015. Regardless, new research is required for conservation planning, especially for understudied portions and temporal periods of the occupied range. I evaluated nonbreeding lesser prairie-chicken survival using known-fate models, and tested for the influence of environmental, landscape and predator effects on weekly survival. I estimated nonbreeding home-range size using fixed kernel density estimators and Brownian Bridge movement models for VHF and Satellite tagged lesser prairie-chickens, and measured habitat use during the 6-month nonbreeding period (16 September – 14 March). I also determined the influence of lek location on space use intensity within home ranges using resource utilization functions. Female survival was high (0.75, SE = 0.05) and consistent across nonbreeding seasons, but not explainable by selected variables. Mean home range size for birds with GPS transmitters (955 ha, SE = 128.5) was 215% larger than for individuals with VHF transmitters (303 ha, SE = 24.1) and 136% greater during the 2014-2015 nonbreeding season than the 2013-2014 season. Males and females were tied to leks throughout the nonbreeding season, and this relationship was not variable across the months of the nonbreeding season. Proportions of habitat used differed among study sites, but temporal trends were not evident. Lesser prairie-chickens exhibited consistency among ecoregions for home-range, space use, and survival; however, with differing habitat use among regions, management should be on the regional scale. Agriculture and energy development have caused fragmentation of the landscape where lesser prairie-chickens evolved. I used known fate survival models to test if landscape composition or configuration within sites caused survival to differ by site, as well as within home ranges to determine if functional relationships exist between weekly survival and landscape configuration or composition. I used Andersen-Gill models to test whether distance to anthropogenic features affected hazard rates. Differences in survival rates between sites, with survival rates 50% greater in Clark County, Kansas compared to Northwestern, Kansas, corresponded to differences in the amount of grassland habitat on the landscape, but study-site configuration was not measurably different. Increasing the number of patch types within home ranges increased survival, indicating positive effects of heterogeneity. In addition, as distance to fences decreased, lesser prairie-chickens experienced greater risk. Overall, further breakup of grassland landscapes that lesser prairie-chickens occupy should be avoided, to avoid habitat loss and fragmentation thresholds that could further affect survival rates. Additionally, fences should be removed or avoided around active leks.

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