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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.
11

Foraging Ecology of Mountain Lions in the Sierra National Forest, California

Nichols, Bradley C. 01 May 2017 (has links)
Studies of predator-prey and predator-predator interactions are needed to provide information for decision-making processes in land management agencies. Mountain lions (Puma concolor) are opportunistic carnivores that prey on a wide variety of species. In the Sierra National Forest, CA, they have not been studied since 1987 and their current interactions with their prey and other predators are unknown. Forest managers in this region are concerned with declines of fishers (Pekania pennanti) and studies have shown intraguild predation to be a leading cause of fisher mortality in this area. Managers are interested in learning more about mountain lion predation patterns with regard to prey preference, but also how lions traverse and use the landscape and how anthropogenic activities may be increasing lion predation risk on fishers. Using GPS radio-collar technology, we examined mountain lion kill rates and prey composition at 250 kill sites. We found mule deer (Odocoileus hemionus) to be their main source of prey (81%) with gray foxes (Urocyon cinereoargenteus) comprising 13.2% of prey composition. We did not detect any fisher predation during our 2-year study; however, during our study, the Kings River Fisher Project experienced extremely low juvenile fisher survival. To gain a better understanding of seasonal resource selection by mountain lions, we developed resource selection functions (RSF) while they were moving through the landscape and when killing prey. We developed RSF models for all data across the study area, as well as, for a subset of data encompassing an area where LiDAR (Light Detection and Ranging) data had been collected. Within the LiDAR study area, we digitized unmapped roads and skid trails using a Bare Earth data set. We found mountain lion ‘moving’ locations showed selection for close proximity to streams during summer months and selection for ruggedness and steeper slopes during both summer and winter. With 3 of the 4 RSF models at kill sites showing high risk of predation within close proximity to either digitized roads/skid trails or mapped roads, we recommend managers map all anthropogenically created linear landscape features and consider restoring these linear features to pre-treatment landscape conditions following timber harvest.
12

Determining habitat preferences of the juvenile gopher tortoise (Gopherus polyphemus) using spatially modeled vegetation on a central Florida sandhill

Raymond, Kristan Marie Nicole 01 June 2007 (has links)
Public and private conservation areas are becoming increasingly important to the continued survival of the gopher tortoise, making it imperative that land managers know the specific habitat requirements of juvenile gopher tortoises because recruitment is key to species persistence. Little is currently known about environmental factors that underlie hatchling and juvenile survival and recruitment in gopher tortoise populations. Because of the short duration and distance of juvenile tortoise foraging journeys, food availability, thermoregulatory conditions, and refugia near the burrow may considerably affect juvenile growth and survival. This two-year study of a central Florida sandhill examines the spatial relationship between juvenile gopher tortoise burrows and the surrounding habitat. Gopher tortoise burrow positions, activity, and width were recorded in four complete surveys of the 4-hectare study area. Coincident with three of the burrow surveys, vegetation and structural habitat characteristics, such as forb and canopy cover, were surveyed in a uniform grid design. Vegetation cover was reclassified using habitat suitability functions (HSFs) derived from qualitative literature values and combined into habitat suitability indices (HSIs) to model the relationships between habitat variables and the likelihood of juvenile gopher tortoise presence. Chi-squared tests and spatial point pattern analysis were used to validate and identify well-forming models. In general, the best performing HSI models for the juvenile gopher tortoise were those that incorporated all three gopher tortoise life requisites in a compensatory relationship (geometric mean): thermoregulation (total high canopy, bare ground, or litter), predation (oak mid-canopy), and food (forb or wiregrass). The models could be improved by using the observed relative abundance of juvenile burrows in each vegetation cover class to modify the HSFs. These methods will help identify habitat characteristics associated with active juvenile gopher tortoise burrows that can be used by public and private land managers to improve existing tortoise habitat and to identify high-quality habitat for future preserves.
13

Habitat linkages and highway mitigation using spatially-explicit GIS-based models

Jones, Andrew Charles 13 December 2012 (has links)
I identified suitable locations for highway wildlife crossing mitigations across the TransCanada Highway (TCH) in the area of Mount Revelstoke and Glacier National Park (MRGNP), British Columbia. Highways fragment natural landscapes leading to habitat loss, reduced ecosystem connectivity and direct wildlife mortality though motor vehicle collisions. Grizzly bears (Ursus arctos) are vulnerable to the effects of habitat and population fragmentation. Highway wildlife crossing mitigations improve ecosystem connectivity by increasing the permeability of transportation corridors to wildlife. I identified high-quality habitat patches using a resource selection function (RSF) based on 1,703 radio telemetry locations from 59 grizzly bears. Least-cost path analysis (LCP) among habitat patches identified 6 linkage zones across the TCH. Electric circuit theory was used to generate current maps that classify linkage zones as high-volume crossing areas or tenuous linkages. Linkage zones occurred where high-quality habitat aligned with physical features conducive to cross-valley wildlife dispersal.
14

The Influence of Land-cover Type and Vegetation on Nocturnal Foraging Activities and Vertebrate Prey Acquisition by Burrowing Owls (Athene cunicularia).

Marsh, Alan J Unknown Date
No description available.
15

Seasonal Habitat Selection by Resident and Translocated Caribou in Relation to Cougar Predation Risk

Leech, Heather 17 April 2015 (has links)
Mountain caribou, an arboreal lichen-feeding ecotype of woodland caribou (Rangifer tarandus caribou), have been extirpated from much of their historic range. Mountain caribou are federally listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and red-listed by the BC government. Habitat loss and fragmentation of old growth forest is the ultimate cause for population declines. Yet, predation, linked to apparent competition, is the proximate cause for high rates of mortality. One of the most imperiled populations resides in the Purcell Mountains of BC, which was experimentally augmented in 2012 with 19 northern caribou from northern BC. The caribou-predator literature predominantly focuses on the relationship between caribou and wolves (Canis lupus) in northern caribou populations. However, cougars (Puma concolor) have been identified as a major predator of Purcells-South (PS) caribou, yet caribou-cougar interactions remain largely unstudied. I evaluated cougar predation risk in space and time on resident and translocated caribou in the Purcell Mountains. To do so, I determined biologically relevant seasons for resident, donor (i.e. not translocated) and translocated caribou, and cougars. I then used these seasons to investigate seasonal patterns of movement and habitat use between the three groups of caribou and cougars. Next I used resource selection functions (RSFs) to estimate habitat based seasonal variation in predation risk. I used these RSFs to compare the seasonal habitat selection and risk to cougar predation between resident and translocated caribou. Five resident caribou seasons and two cougar seasons were defined. Translocated caribou displayed inconsistent movement behavior with no clear seasonal pattern. Resident caribou remained at high elevations year-round and selected for low risk cougar habitat during the calving season at the home range scale and year-round at the landscape scale. Translocated caribou displayed risky behaviour throughout the study period by traveling to mid to low elevations and habitats selected by cougars. Translocated caribou displayed the same general pattern of elevational movement as their northern conspecifics, spending the majority of their time at lower elevations than resident caribou. Of the 19 translocated caribou, 17 (89%) died during the study, six of which were preyed upon by cougars, two by wolves, and the remainder due to accidents or unknown causes. In summary, translocated caribou did not adopt the predator avoidance or habitat selection strategies of resident caribou. I recommend that future efforts to augment small caribou populations use donor caribou experienced with similar predators and that possess comparable seasonal habitat use to the recipient population. However, because most suitable donor populations are declining, a soft-release of captive-reared mountain caribou might be the best option for mountain caribou recovery efforts. / Graduate / 0366 / 0329
16

Using radio-telemetry to determine range and resource requirements of upland sandpipers at an experimentally managed prairie landscape

Mong, Tony Wayne January 1900 (has links)
Master of Science / Department of Biology / Brett K. Sandercock / The native grasslands of North America are highly fragmented, and remaining tracts are intensively managed for grazing. Loss of tallgrass prairie and changing land management practices has caused many grassland birds that rely on these areas for breeding to decline in population numbers. To investigate resource selection and area use requirements of the upland sandpiper, we outfitted birds with radio transmitters at the experimentally managed Konza Prairie Biological Station in northeast Kansas. Two logistical challenges for wildlife telemetry projects are: minimizing the impact of radios on survival and movement, and optimizing the duration of transmitter attachment. We compared 4 methods of radio attachment for upland sandpipers under field conditions at breeding sites in tallgrass prairie. The daily probabilities of radio retention (DRR) for our 4 attachment methods were: 0.9992 (SE = 0.0005, n = 85) for a leg loop harness, 0.9801 (SE = 0.0099, n = 11) for radios glued to clipped feathers, 0.9627 (SE = 0.0085, n = 25) for radios glued directly to feathers and 0.8538 (SE = 0.0322, n = 20) for radios glued to plucked skin. The expected duration of radio attachment ranged from 1290 days for the leg loop harness, and 6 to 50 days for the glue attachment techniques. Survival rates of males (DSR = 0.9987, SE = 0.0009, n = 53) and females (DSR = 0.9988, SE = 0.0008, n = 71) were similar, and the probability of surviving the 90-day breeding season was about 0.90 in both sexes. We recommend attaching radios with glue to clipped feathers for short-term telemetry studies and a leg loop harness if longer retention is desired. The unique landscape of Konza Prairie allowed us to investigate specific tallgrass management strategies, and their impact on the range and habitat requirements of a bird that relies on the prairie for breeding. We found that upland sandpipers have large home ranges during the breeding season (male: = 199.0 ha ± 40.5 SE, n = 21, female: = 247.7 ha ± 51.7 SE, n = 23). Male home ranges were twice as large during brood-rearing ( = 200.8 ha ± 69.1 SE, n = 9) than during the nesting period ( = 67.02 ha ± 11.84 SE, n = 14, 1 = 5.14, P = 0.023). Upland sandpipers selected home range sites that had been burned the same spring (n = 44, ²3 = 31.65, P < 0.001), but did not show preference for certain habitat types within their home range ( ²3 = 1.49, P = 0.685). During brood rearing upland sandpipers used sites with higher percentages of bare ground, herbaceous and short woody vegetation, and low amounts of vegetative litter. Management strategies for the upland sandpiper should seek to preserve large contiguous tracts of tallgrass prairie that receive a heterogeneous mix of burning and grazing.
17

VITAL RATES AND HABITAT SELECTION OF BULL ELK (<em>CERVUS CANADENSIS NELSONI</em>) IN SOUTHEAST KENTUCKY

Hast, John Tyler 01 January 2019 (has links)
Globally, male ungulate species are heavily managed for their sporting and trophy qualities. North American elk (Cervus canadensis) are typically managed using a male-biased harvest regime, placing increased chances of mortality on males in these hunted populations. To manage for trophy quality animals that typically represent older age classes, wildlife managers have implemented many age-biased harvest regulations, including spike-only tags and antler point restrictions. Many of these age-biased harvest regulations have fallen short of their desired goal of producing older bull elk. Consequently, the consensus has evolved to center on an overall reduction in harvest pressure. The state of Kentucky began an elk restoration project in 1997, with 1,553 elk released through 2002. As with other modern elk restoration projects, the male demographic received little research attention in the years immediately post restoration. The difficult logistics surrounding the transport of adult male elk and the reluctance of source states to part with potential trophy animals, led to few adult male elk receiving tracking collars to monitor this demographic. Hunter success rates indicated a growing male component to this population in light of the lack of a radio-marked cohort. With overall population numbers increasing in step with predictive models, so too did hunting tag numbers and hunting pressure. This rise in hunting pressure likely forced elk to become more cryptic, giving rise to the perception of a decline in the elk population, especially older age class male elk. This research represents the first in-depth look at the survival rates and habitat selection of adult male elk in Kentucky. Recent improvements in field methodology have allowed for the more efficient acquisition of a robust sample of adult male elk. I conducted a radio-telemetry study of adult male elk within southeast Kentucky to investigate the following: (1) survival and cause-specific mortality factors, (2) survival during the fall hunting period, (3) changes in survival following the implementation of a limited entry area (LEA) enclosing our study area, and (4) the associations of morphometric characteristics with the survival of adult male elk. Given the lack of information on the habitat use of male elk, a cohort of global positioning system (GPS) equipped elk were captured to investigate: (1) seasonal habitat use of male elk, (2) quantification of availability of male elk in readily viewable habitats, (3) changes to the percent of open land within the fall home range of adult male elk, and (4) the influence of open land on survival rates. To investigate the dispersal of male elk, I compared genetic relatedness to space use. Finally, in an attempt to better understand our existing capture methodologies, I analyzed drug induction and reversal metrics for the immobilization drug Carfentanil citrate. Survival analysis resulted in a 16.9% (CI = 12.2 – 23.7) three-year survival rate for adult male elk. An improvement in survival rate (p = 0.077) was noted after the implementation of an LEA system that limited the number of hunters in the study area. No morphometric characteristics were observed to have an association with survival, indicating that hunters indiscriminately harvest male elk. Predictive, habitat use models for male elk indicated a preference for grass habitats and use of habitats near grass patches. Seasonal variation in habitat use was observed with the greatest daily use of grass habitats occurring in the winter season. Adult male elk selected for open land at greater rates than is available across the study area. Over the course of three hunting seasons, elk were found to reduce their use of open land during daylight hours, and we anecdotally believe this to be a response to hunting pressure. A reduction in survival probability of male elk was directly related to use of open land in the final year of the project. Little home range overlap was observed between related male elk, indicating some level of dispersal and intra-specific competition. Predictive models for Carfentanil immobilization indicated an increase in efficacy of a shoulder injection as opposed to a hindquarter drug injection. Future management of elk in Kentucky should center on promoting the persistence of healthy grassland areas within the elk restoration zone and meeting hunter expectations. Hunter expectations should be gathered and management tailored to meet their desires and the objectives of the management agency. This research indicates that hunters harvest male elk regardless of trophy characteristics, yet we are not sure of the underlying reasons. The interaction of habitat and survival is complex and further complicated by the reclaimed coal mines that Kentucky elk live upon. Habitat management priorities should focus on a heterogeneous, yet healthy habitat that meets the needs of all species residing on these once-exploited lands.
18

Bobcat Abundance and Habitat Selection on the Utah Test and Training Range

Muncey, Kyle David 01 December 2018 (has links)
Remote cameras have become a popular tool for monitoring wildlife. We used remote cameras to estimate bobcat (Lynx rufus) population abundance on the Utah Test and Training Range during two sample periods between 2015 and 2017. We used two statistical methods, closed capture mark-recapture (CMR) and mark-resight Poisson log-normal (PNE), to estimate bobcat abundance within the study area. We used the maximum mean distance moved method (MMDM) to calculate the effective sample area for estimating density. Additionally, we captured bobcats and estimated home range using minimum convex polygon (MCP) and kernel density estimation (KDE) methods. Bobcat abundance on the UTTR was 35-48 in 2017 and density was 11.95 bobcats/100 km2 using CMR and 16.69 bobcats/100 km2 using PNE. The North Range of the study area experienced a decline of 36-44 percent in density between sample periods. Density declines could be explained by natural predator prey cycles, by habituation to attractants or by an increase in home range area. We recommend that bobcat abundance and density be estimated regularly to establish population trends.To improve the management of bobcats on the Utah Test and Training Range (UTTR), we investigated bobcat (Lynx rufus) habitat use. We determined habitat use points by capturing bobcats in remote camera images. Use and random points were intersected with remotely sensed data in a geographic information system. Habitat variables were evaluated at the capture point scale and home range scale. Home range size was calculated using the mean maximum distance moved method. Scales and habitat variables were compared within generalized linear mixed-effects models. Our top model (AICc weight = 1) included a measure of terrain ruggedness, mean aspect, and land cover variables related to prey availability and human avoidance.
19

Spatial determinants of habitat use, mortality and connectivity for elephant populations across southern Africa

Roever, Carrie Lynn 13 February 2013 (has links)
Southern Africa contains 58% of the world’s savannah elephant population, yet 72% of their range occurs outside of protected areas. It is, therefore, important to develop management guidelines that satisfy the needs of both elephants and people while maintaining environmental heterogeneity and ecosystem processes. Managing elephants as a metapopulation may provide the solution. The goal of this thesis was then to use a habitat-based approach to identify landscape characteristics which could contribute to the functionality of a metapopulation for elephants. Using resource selection function models, I identified habitat suitability for elephants across southern Africa and used these models to evaluate whether current habitat configurations allow for the assumptions of connectivity and asynchronous population dynamics required by a metapopulation. I found that water, tree cover, slope, and human presence were important predictors of elephant habitat selection. Furthermore, functional responses in habitat selection were present across space and time for water and tree cover, showing the adaptability of this generalist species to resource heterogeneity. Using habitat selection along with circuit theory current flow maps, I then found a high likelihood of connectivity in the central portion of our study area (i.e. between the Chobe, Kafue, Luangwa, and Zambezi cluster). Main factors limiting connectivity were the high human density in the east and a lack of surface water in the west. These factors effectively isolate elephants in the Etosha cluster in Namibia and Niassa clusters in Mozambique from the central region. Models further identified two clusters where elephants might benefit from being managed as part of a conservation network, 1) northern Zambia and Malawi and 2) northern Mozambique. Incorporating information on elephant mortalities in northern Botswana into habitat selection estimations, I found that source habitats for elephants occurred within the central Okavango Delta region and sink habitats were associated with periphery of the study area where human use was highest. Eighty percent of elephant mortalities occurred within 25 km of people. The protected designation of an area had less influence on elephant mortality than did the locations of the area in relation to human development. To exacerbate human-elephant conflicts, people tended to settle in areas of high-quality elephant habitats, creating resource competition between elephants and people. Consequently, elephant mortality near humans increased as a function of habitat suitability, and elephants responded by using less suitable habitats. While humans occupied only 0.7% of the study area, mortality and behavioural effects impacted 43%. Based on the habitat factors examined here, elephants in southern Africa could be managed as a metapopulation if (1) connectivity is maintained and encouraged and (2) spatial heterogeneity in resources and risks serves to stabilize elephant demography. This habitat-based system of management could serve to alleviate unstable elephant populations in southern Africa and create more natural, self-sustaining regulatory mechanisms. / Thesis (PhD)--University of Pretoria, 2013. / Zoology and Entomology / unrestricted
20

The Effects of Shed Antler Hunting on Ungulate Movement, Space-Use and Resource Selection

Bates, Steven B. 02 June 2021 (has links)
Shed antler hunting has increased in popularity during the past decade, but little is known about how this recreational activity affects ungulate movements and space use. We placed geographic positioning system (gps)-collars on 133 bighorn sheep (Ovis canadensis), bison (Bison bison), and mule deer (Odocoileus hemionus) to quantify their movements, space use, and resource selection during shed antler hunts on Antelope Island Utah, USA, from 2012 to 2015. In Chapter 1, we calculated means and 95% confidence intervals for distance moved during 90-minute segments (16 points/day); pre-event (control, seven consecutive days prior to event), event (one to two days), and post-event (seven consecutive days after event) for shed hunts and helicopter surveys. We also compared each species use of space during these events. Female bighorn sheep did not increase distance moved or substantially change space use during shed hunts and helicopter surveys. Male bighorn sheep increased distance moved 41% on average during shed hunts and by 2.02 times during helicopter surveys but did not change space use during those events. Female bison increased distance moved 15% on average during shed hunts and 30% during helicopter surveys. Mule deer increased distance moved and altered space use the most during shed hunts; females increased distance moved 97%, and 54% of females moved a mean distance of 742 ± 642 (SD) m outside of their home ranges during those hunts for a mean of 9.2 ± 9.4 hours (range = 1.5 to 41 hr). Male mule deer increased distance moved by 2.10 times on average during shed hunts, and 82% of males moved a mean distance of 1,264 ± 732 m outside of their home ranges during those hunts for a mean of 12.6 ± 7.6 hours. In Chapter 2, we analysed 177,138 gps locations to quantify space use and movements of 12 mule deer and 25 bighorn sheep in response to shed hunting. Twenty-five percent of mule deer and 44% of bighorn sheep responded differently to shed antler hunting across two years. We tracked four mule deer for three and four consecutive years, and all those deer responded to shed hunting differently across subsequent years. Mule deer increased movement (paired t-test = -3.9, p < 0.001) during shed hunts compared to pre-event movement. Bighorn sheep increased movement (paired t-test = -6.9, p < 0.001) during shed hunts compared to pre-event movement. In Chapter 3, we placed gps-collars on 27 mule deer and 29 bighorn sheep to quantify habitat selection during shed hunts compared with resources selection seven days prior and seven days following these hunts. Mule deer (n = 6) remained in the same area (response 1), moved to another area within their home range (n = 7; response 2), or moved beyond their home range boundaries (n = 14; response 3). Bighorn sheep (n = 17) remained in the same area (response 1), moved to another area within their home range (n = 11; response 2), or moved beyond their home range boundaries (n = 1; response 3). Shifts in resource selection by mule deer and bighorn sheep were detected during shed hunts regardless of the initial response of the individual animal during those hunts.

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