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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.
21

The Impacts of Three Common Mesopredators on the Reintroduced Population of Eastern Wild Turkeys in Texas

Melville, Haemish 1972- 14 March 2013 (has links)
Early in the 20th century wild turkeys (Meleagris gallopavo) in North America were on the brink of extinction. Conservation and reintroduction efforts ensured that this species recovered throughout most of its historic range. Efforts to reintroduce eastern wild turkeys (Meleagris gallopavo sylvestris) to the Pineywoods of east Texas have achieved limited success. Previous research suggested that predation may have confounded this reintroduction. My aim was to quantify the influence of mesopredators on the wild turkey population in the Pineywoods. Raccoons (Procyon lotor), bobcats (Lynx rufus) and coyotes (Canis latrans) occur sympatrically in east Texas and are thought to prey on wild turkeys, their nests and poults. I fitted bobcats, coyotes and raccoons with both GPS and VHF collars and used location data and GIS applications to estimate home ranges, home range overlap and habitat selection for these mesopredators. I used scat analysis to determine diet of mesopredators and to establish whether they preyed on wild turkeys. I used capture mark recapture (CMR) techniques to investigate small mammal population dynamics at annual and seasonal bases. I used spotlight counts and track plates to assess seasonal relative abundance of eastern cottontail rabbits (Sylvilagus floridana). I used artificial nests to identify likely nest predators of wild turkey nests. I found that mesopredators in the Pineywoods had larger home ranges than elsewhere in the Southeast. Bobcat and coyote home ranges varied seasonally, being largest in fall. Raccoon home ranges did not vary seasonally. Bobcats and coyotes shared space more than did raccoons with bobcats or coyotes. There was differential habitat selection between species, but mature pine and young pine were important to the mesopredators and as nesting habitat for eastern wild turkeys. I found no evidence of wild turkey remains in scat samples. White tailed deer (Odocoileus virginianus), lagomorphs and small mammals occurred in the diets of all three mesopredators. Small mammal numbers varied seasonally, declining from spring to summer, in synchrony with mesopredator diet diversification, and wild turkey nesting and brood rearing. Lagomorph abundance did not vary seasonally. Bobcats were predominantly carnivorous while coyotes and raccoons were omnivorous, consuming seasonal fruit and insects. American crows (Corvus brachyrhynchos) and raccoons were the primary artificial nest predators. Crows depredated most artificial nests, except in summer, when raccoons depredated the most nests. I concluded that the impact of mesopredators on wild turkeys was not as severe as suggested by previous research. I suggest a combination of video monitoring live wild turkey nests to identify nest predators, improvement of nesting habitat to reduce mesopredator / wild turkey nest encounters, and a program of conditioned taste aversion to reduce any nest predation by mesopredators and crows.
22

Developing, Demonstrating, and Validating a Vehicle Test Bed to Extend the Capabilities of a Chassis Dynamometer Test System

Murphy, Robert T. 29 December 2008 (has links)
No description available.
23

GNSS Inter-Constellation Time Offset Determination in Low Earth Orbit

Peters, Brian C. 03 June 2021 (has links)
No description available.
24

Assessment of the Lactation Index for Managing White-Tailed Deer Populations

Campbell, Kamen Lee 11 August 2012 (has links)
I analyzed precision and accuracy of lactation data to reflect actual fawn recruitment for various levels of fecundity, neonatal mortality, harvest intensity, and hunter selectivity. I evaluated and developed a correction equation to adjust for harvest date effects on lactation detectability. I compared metrics of site-specific fawn recruitment (e.g., lactation rates, hunter observation fawn-to-doe ratios, and post-season fawn-to-doe ratios) among themselves, and to site-specific indices of carnivore abundance, for 18 properties across Mississippi and Alabama. Accuracy of lactation rates are compromised due to variation at minimal harvest intensity and insensitivity to change in fetal rate or neonatal mortality. Lactation data can be corrected for harvest date effects on lactation detectability. Hunter observation data are variable and poorly represent fawn recruitment. Lactation data are related to fawn recruitment and can be used to roughly estimate fawn recruitment. Carnivore abundance had neither a significant nor consistent effect on fawn recruitment.
25

Bobcat and coyote management scenarios: evaluating the flexibility of management preferences in probable scenarios

Stanger, Melissa Eileen 26 October 2022 (has links)
No description available.
26

Factors Affecting White-tailed Deer Recruitment in Virginia

Aubin, Gisele Rosalie 12 June 2020 (has links)
Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. On the other hand, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Many areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with changes in landscape, deer harvest strategies, and increasing and expanding black bear (<i> Ursus americanus </i>) and coyote (<i> Canis latrans </i>) populations. Most studies have addressed this problem at small spatial and temporal scales and in areas where predation was assumed to be limiting population growth. We evaluated white-tailed deer fawn recruitment both directly and indirectly at relatively broader spatial and temporal scales. We studied fawn survival on Marine Corps Base Quantico in Virginia, USA from 2008–2019. We used the Kaplan-Meier estimator, and Cox-proportional hazards models to assess annual survival and factors that influence hazard risk such as sex, weather, landscape composition and configuration and food availability. On Marine Corps Base Quantico, we found an increase in red oak mast abundance increases survival and probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also found that predation was the leading source of mortality. We assessed recruitment using lactation status from hunter harvest data collected by the Virginia Department of Game and Inland Fisheries during a 22-year period in 30 counties in the Appalachian Mountains of western Virginia. We predicted lactation status as a function of landscape composition and configuration, oak mast abundance, weather, age, and predator detection rates using generalized linear mixed models. We found land cover diversity index positively and black bear detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that are heterogeneous. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Another potential option which needs further research, would be to reduce predator efficiency by increasing hiding cover for fawns. / Master of Science / Deer (<i> Odocoileus </i> spp.) are an important cultural and economic resource. They are the most popular game species in the United States and the number one driver of conservation funding. Conversely, they also cause damage to resources including to the agricultural industry, private property and to humans via deer vehicle collisions. Some areas in eastern North America have experienced a decline in white-tailed deer (<i> Odocoileus virginianus </i>) populations over the past twenty years concurrent with the colonization of coyotes (<i> Canis latrans </i>) as well as changes in habitat. Therefore, we aimed to determine white-tailed deer fawn survival rates and factors affecting recruitment across a large spatial and temporal scale. Recruitment is when an individual becomes part of the reproductive population. However, for harvestable populations, recruitment is when individuals can be legally harvested for the first time. On Marine Corps Base Quantico from 2008–2019, in Virginia, USA we found that probability of fawn survival was higher during the first interval of the study (2008–2010; 0.71 [0.52–0.96]; survival probability [CI95%]) than the last three intervals (2011–2013; 0.46 [0.30–0.70]; 2014–2016; 0.48 [0.35–0.66] and 2017–2019; 0.50 [0.39–0.63]). We also discovered predation was the leading cause of death and probability of survival increased with increasing red oak mast abundance. Over a large spatial (30 counties) and temporal (22 years) scale we examined fawn recruitment by predicting lactation status of female harvested white-tailed deer in the Appalachians Mountains of western Virginia. We found land cover diversity index positively and black bear (<i> Ursus americanus </i>) detection rate negatively influenced recruitment. Age also predicted lactation status with middle-aged females (3.5–4.5 years old) having a higher lactation probability than mature (≥5.5 years old) age and young (2.5 years old) age class deer. Based on these findings, recruitment is likely to be greater in areas that have a mixture of land cover types. Therefore, if an increase in recruitment is desired silvicultural practices such as fire and timber harvest could be used to permanently change land cover types. These silvicultural practices could also be used to increase the number of oaks on the landscape, and augment production of mature oaks as red oak mast abundance influenced fawn survival. Also reducing predation by manipulating predator densities could improve recruitment. Overall, we found diversity of land cover types, food availability, predators, and age influences population dynamics of white-tailed deer.

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