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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.
31

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.
32

Behavioral Responses of Willow Flycatchers, <i>Empidonax traillii</i>, to a Heterogeneous Environment

Bakian, Amanda V. 01 May 2011 (has links)
Spatial heterogeneity impacts population and community-level dynamics including species-level dispersal patterns, the use and availability of refugia, predator/prey dynamics, and reproductive fitness. Understanding how wild animal populations respond to environmental heterogeneity is essential for their proper management and conservation. In this study, I examine the responses of Willow Flycatchers to spatial heterogeneity in the distribution of their food and habitat resources. Over the course of three breeding seasons, I radio- tracked Willow Flycatchers at Fish Creek in Manti-La Sal National Forest in Utah, recorded detailed behavior data at each radio location, and collected fecal, feather and insect samples. I formulated individual and population-level Bayesian spatial resource selection functions to model Willow Flycatcher foraging and vocalization behavior on multiple scales. These models indicate that vocalization and foraging behavior are spatially segregated within the home ranges of Willow Flycatchers. Further, Willow Flycatchers were found to use mature riparian habitat for vocalizing while they used a variety of habitat types for foraging. The insect samples were used to identify distinct carbon and nitrogen stable isotope signatures for the aquatic and terrestrial insect communities at Fish Creek. In conjunction with the fecal samples, I used the stable isotope signatures to determine the contribution of aquatic versus terrestrial insects to the Willow Flycatcher diet. Aquatic insects comprised a larger proportion of the diet of adult than nestling Willow Flycatchers. This suggests that adult flycatchers consume a diet that is distinct from the one they feed to their nestlings. Finally, I compared space use characteristics in two populations of Willow Flycatchers: a population of the endangered Southwestern Willow Flycatcher at Roosevelt Lake, Arizona and another belonging to a non-endangered subspecies of Willow Flycatcher at Fish Creek, Utah. Differences in space use were found largely among breeding flycatchers while space use characteristics in non-breeding Willow Flycatchers did not differ across populations. This suggests that space use patterns in non-breeding Southwestern Willow Flycatchers may be generalizable to non-breeding flycatchers from non-endangered populations. This study expands our understanding of how Willow Flycatchers respond to spatial heterogeneity while its key findings have management and conservation implications for the species.
33

Optimizing Monitoring Efforts of Kit Fox (<em>Vulpes macrotis</em>) in Utah

Richards, Kelsey Alina 01 November 2017 (has links)
The kit fox (Vulpes macrotis) is a species of conservation concern in western North America. Recent methods for monitoring populations of kit fox include using lures and remote cameras in an occupancy-modeling framework and habitat modeling to predict areas of occupancy. In chapter one, we tested the optimal lure and movement procedure for scent stations to maximize visits and detection of foxes, thereby improving estimates of occupancy. Between May 2015 and October 2016, we placed remote cameras at 522 random locations throughout nine study areas in the Colorado Plateau, Great Basin Desert, and Mojave Desert. Each location was randomly assigned one of three methods (Scented Predator Survey Disks, cotton swabs, or hollowed golf ball) to broadcast one of three lure types (Red and Gray Fox liquid lure, Willey liquid lure, and fatty acid lure). After seven nights, half of all stations were moved 100 meters within the same sample grid cell, while the others remained in the same location. Stations were then monitored for an additional week. We used Program MARK and AIC model selection to identify optimal lure types and broadcast methods and to estimate rates of occupancy. Detection of kit foxes differed by method of scent deployment; cotton swabs were associated with the highest rates of visitation. Detection of kit foxes did not differ by lure type. Relocating the scent station after one week did not influence detection probability. We suggest that the use of cotton swabs maximizes detection, and therefore, the precision of estimates of occupancy. For chapter two, we used resource selection functions to identify variables that best discriminated between locations where kit fox were detected and random locations. We then produced a habitat map that predicted the relative probability of kit foxes occurring across seven study areas throughout the state of Utah. We placed remote cameras at 458 randomly selected locations throughout the study areas in the Colorado Plateau, Great Basin Desert, and Mojave Desert. We detected kit foxes at 157 "use" points from these cameras between May 2015 and October 2016. We then compared the attributes of these "use" points to 14,742 available, randomly selected points located within the study areas using variables derived from a Geographic Information System (GIS). We used model selection and minimization of AIC values to determine key habitat characteristics that differentiated use and random locations. We identified slope, elevation, and soil type as significant variables (P < 0.05) in habitat selection of kit foxes. Kit foxes selected areas that were 1) less steep, 2) lower in elevation, and 3) classified as having silty soils. The identification of these specific variables from our modeling effort was generally consistent with kit fox ecology. Our study produced a habitat model that can serve as a foundation for future monitoring efforts of kit foxes in potential habitat across Utah.
34

Web Service Composition Under Resource Allocation Constraints

Karakoc, Erman 01 April 2007 (has links) (PDF)
Web service composition is an inevitable aspect of web services technology, which solves complex problems by combining available basic services and ordering them to best suit the problem requirements. Automatic composition gives us flexibility of selecting best candidate services at composition time, this would require the user to define the resource allocation constraints for selecting and composing candidate web services. Resource allocation constraints define restrictions on how to allocate resources, and scheduling under resource allocation constraints to provide proper resource allocation to tasks. In this work, web service composition system named as CWSF (Composite Web Service Framework) constructed for users to define a workflow system in which a rich set of constraints can be defined on web services. On the contrary many technologies and studies, CWSF provides a user-friendly environment for modeling web service composition system. The output of the framework is the scheduling of web service composition in which how and when web services are executed are defined. With this work, a language, CWSL is defined to describe workflow, resource allocation constraints, selection and discovery rules of web services and associated semantic information. An important property of CWSF system is converting web service composition problem into a constraint satisfaction problem to find the best solution that meet the all criteria defined by user. Furthermore, CWSF has ability to display other possible solutions to provides users flexibility. This study also includes semantic matching and mapping facilities for service discovery.
35

Distribution and habitat characterization of the Florida burrowing owl in non-urban areas

Mueller, Mark S 01 June 2006 (has links)
The full geographic distribution and habitat use of the Florida Burrowing Owl, a state "Species of Special Concern," is not well-understood, particularly in remote, non-urban areas. This thesis aimed to expand and improve knowledge about non-urban burrowing owls. We first compiled databases of historic sighting observations. Fieldwork verified and updated existing breeding observation point records and also yielded new breeding locations. Using a GIS, we characterized observed land use, landcover, relevant soil attributes, projected future land use and managed area status for selected points. We quantified landcover within biologically-determined buffer distances around burrows from our own field-verified records. Using standard resource selection methods, we compared observed and available proportions, calculated selection indices, and determined selection/avoidance for each landcover class. These empirical results were used in combination with expert opinion and literature review to finalize criteria for and map "suitable" landcover. Suitability of relevant soil attributes were also empirically-determined and used to further reduce the overall "suitable" area. The final suitable habitat maps appear to relate well to the overall distribution of known non-urban burrowing owl records and demonstrate that a great deal of potentially-suitable breeding habitat exists throughout Florida's central interior. Improved pasture, the most prevalent landcover class, also appears to be the most strongly selected in this study and may be of high importance to non-urban, breeding burrowing owls. Our results could be useful to wildlife officials managing this species. Recommendations include improving surveys and conservation efforts in non-urban areas and enhancing cooperation with landowners, particularly ranchers, as success on private lands seems critical to the long-term persistence of this species.
36

Wolf responses to spatial variation in moose density in northern Ontario

Anderson, Morgan 02 May 2012 (has links)
Forty-four wolves in 3 boreal forest sites in Ontario were monitored via GPS radiotelemetry during 2010 and 2011 to examine spatial responses to variation in prey density. Home ranges were defined using a Brownian bridge utilization distribution, and a resource utilization function was calculated for each pack in winter and summer, based on habitat, topography, and prey density. Wolf territories were smaller where moose density was higher. Third order selection (within home range) varied by pack and season. Wolves generally selected for sloping areas, areas near water, and stands with deciduous or regenerating forest, but selected against areas with dense conifer cover. Roads were most important in summer, especially in those territories with large road networks. Habitat use in a mild winter was similar to habitat use in summer. Variable resource selection among packs emphasizes the adaptable, generalist nature of wolves even in the relatively homogenous the boreal shield. / National Science and Engineering Research Council, Ontario Graduate Scholarships, Ontario Ministry of Natural Resources - Wildlife Research and Development Section, Center for Northern Forest Ecosystem Research, Ontario Ministry of Natural Resources, Canadian Forest Service, Forest Ecosystem Science Cooperative
37

Foraging ecology of brown bears in the Mackenzie Delta region, NWT

Barker, Oliver Unknown Date
No description available.
38

Woodland Caribou Conservation in Alberta: Range Delineation and Resource Selection

Slater, Simon C Unknown Date
No description available.
39

Grain-dependent habitat selection in white-tailed deer (Odocoileus virginianus)

2014 October 1900 (has links)
A fundamental problem in ecology is determining what factors affect the distribution of organisms across a landscape. Landscapes are by their nature heterogeneous and different habitat types confer different fitness benefits and costs to organisms that inhabit them. Ecologists are now aware of the importance of examining multiple spatial scales when designing studies quantifying animal resource selection. Scale of analysis has been shown to be important, since ecological pressures relating to the establishment of a home range differ from those relating to the use of resources within the home range. Most studies that examine multiple spatial scales examine the effect of modifying extent. Here, I examine the role of grain, an underappreciated component of scale, on our interpretation of habitat selection patterns and functional response. The goal of this thesis was to examine how grain size affects the interpretation of animal resource selection and functional response across multiple habitats. The perceptual range of an individual is known to change with habitat, therefore I hypothesized that resource selection and functional response would be both grain- and habitat-dependent, and that resource selection functions computed using different grains for different resources would be more predictive than models computed using only a single grain. I used GPS-collared white-tailed deer (Odocoileus virginianus) to quantify resource selection functions at various grains and used generalized linear mixed effects modelling and multi-model inference techniques to examine how resource selection patterns changed with spatial scale across habitat types. I used selection ratios to examine functional response across grains. Model coefficients changed with grain and the strength of selection varied by habitat type. Multi-grain resource selection functions had lower AIC values and better cross-validation scores than single grain models. Functional response varied with scale and habitat type, displaying a unique relationship for each habitat. My results suggest that spatial memory and habitat-dependent perceptual range play an important role in resource selection. I conclude that the examination of multiple grains in the study of animal habitat selection and functional response represents a step forward in our ability to understand what drives the distribution and abundance of organisms.
40

Foraging ecology of brown bears in the Mackenzie Delta region, NWT

Barker, Oliver 06 1900 (has links)
The Mackenzie Delta region, NWT, has a short growing season and highly seasonal climate, and brown bears (Ursus arctos) there face many challenges obtaining their nutritional requirements. Consumption of meat by brown bears is linked to increases in population density, fecundity, growth and body size. I examined the use of Arctic ground squirrels (Urocitellus parryii), and broad whitefish (Coregonus nasus) as meat sources by Mackenzie Delta brown bears. As a preliminary step, I built an Arctic ground squirrel habitat model, using field-surveyed ground squirrel burrow locations. Using this model, I examined bears selection for Arctic ground squirrel habitat as a population, by sex and as individuals, and linked this to results of stable isotope analysis and site investigations. Bears showed little evidence of Arctic ground squirrel use at the population and sex level, but some individual bears appeared to prey heavily on ground squirrels, particularly during hyperphagia. I also described observations of a brown bear using broad whitefish in autumn, and used telemetry locations to show that other bears may also feed heavily on broad whitefish during hyperphagia. My research provides prey-specific evidence for intrapopulation niche variation among Mackenzie Delta brown bears. / Ecology

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