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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.
101

Ecology and conservation of the montane forest avian community in northeastern North America

DeLuca, William V 01 January 2012 (has links)
Montane forests provide habitat for unique assemblages of flora and fauna that contribute significantly to a region's biodiversity. Previous work indicates that montane forest ecosystems are exceedingly vulnerable to a host of anthropogenic stressors including climate change, atmospheric deposition, and recreation, to name a few. Montane forests and other high elevation ecosystems are considered to be among the first and most severely impacted by climate change. It is therefore, imperative to evaluate anthropogenic impacts on montane ecosystems and maintain reliable monitoring methods that are capable of tracking potential shifts in the distribution of species dependent on these systems. I surveyed birds at various distances from hiking trails in the White Mountain National Forest from 2006–2009 to determine whether existing monitoring programs, all of which are based on trail-centered surveys, are accurately reflecting bird abundance, abundance stability and recruitment. Contrary to previous studies, I found that recreational trails generally did not alter estimates of abundance, recruitment, abundance stability, and detection probability for five species of birds considered to be indicators of montane forest ecosystem integrity in northeastern North America. Therefore, trail-based monitoring programs for montane birds appear to accurately reflect dynamics of bird communities undisturbed by hiking trails. These conclusions were supported by my finding that the daily nest survival of a montane spruce-fir indicator species, blackpoll warbler (Steophaga striata), did not vary as a function of distance from trail. I then used data from the White Mountain National Forest's montane bird monitoring program from 1994 through 2009 to assess potential shifts in the elevational distribution of montane birds in conjunction with documented habitat shifts in the region. My results provide evidence that low elevation forest birds have expanded their upper elevational boundary while high elevation birds have expanded their lower elevation boundary. These results highlight the complicated relationship between habitat, climate, and other anthropogenic stressors such as atmospheric deposition and that even in the face of climate change other stressors may be playing a significant role in shifts of species distributions. Understanding how climate affects the reproductive ecology of montane organisms is an important step toward unraveling the potential mechanisms by which climate change will alter the distribution of these species. I used blackpoll warbler breeding data from the Green Mountains, VT from 1994 to 2003 to determine if temporal variation in climate influenced blackpoll nesting initiation and found that years with warm Mays and typical precipitation lead to earlier nest initiation. I also examined the effect of spatial variation in climate on blackpoll reproductive ecology and demography. I found a gradient in habitat quality associated with the spatial variation in climate along an elevation gradient. Blackpolls were less abundant, younger, had lower pairing success, lower daily nest survival, higher nest predator occupancy, and lower fecundity at lower elevations. The climatic conditions at these lower elevations represent the climatic conditions predicted to encompass increasingly larger portions of montane areas. Collectively, these findings contribute to filling in a dearth of knowledge regarding management and an understanding of how species dependent on montane ecosystems are responding to climate change.
102

The ecology and conservation of the eastern spadefoot (Scaphiopus holbrookii) in the province lands of Cape Cod National Seashore, U.S.A.

Timm, Brad C 01 January 2013 (has links)
The eastern spadefoot (Scaphiopus holbrookii) is an ephemeral wetland breeding amphibian that ranges from southern Florida north and westward to southeastern Missouri and northward along the Atlantic coastal plain to Massachusetts. This species is listed as either "threatened" or "endangered" in the four states (Connecticut, Massachusetts, New York, and Rhode Island) in the northeastern United States where it is known to exist. Population declines and extirpations throughout the region over the past century have been documented and are largely believed to be the result of habitat loss and/or alteration. Very limited empirical results exist on many life history attributes of S. holbrookii anywhere in its range, including movement patterns, upland habitat selection, and breeding habitat preferences. These are critical information gaps that must be filled in order to effectively conserve and manage for this rare species in the northeastern U.S. While S. holbrookii is extremely rare throughout most of the Northeast, it is locally common in specific areas of Cape Cod National Seashore, most notably in an extensive sand-dune ecosystem known as the Province Lands located at the northern terminus of the Cape Cod peninsula. During 2005 and 2006, we conducted larval trapping surveys at 102 wetlands in the Province Lands primarily to: 1) identify breeding wetlands and 2) to assess breeding habitat use and preferences of S. holbrookii with respect to a suite of selected abiotic and biotic covariates. We captured S. holbrookii larvae at 140/652 (~21.5%) trap locations and 41/102 (~40.2%) wetlands sampled. Model results identified a number of additional habitat covariates that exhibited a statistically significant relationship with larval S. holbrookii abundance including: the percent cover of 1) cranberry (positive relationship), and 2) woody shrub (positive relationship) at a 4m radius from the trap location; 3) percent woody shrub cover at the wetland-scale (negative relationship); 4) percent canopy cover at the wetland-scale (positive relationship); 5) wetland pH (positive relationship); 6) distance to the closest paved road (positive relationship); and the kernel density cover of 7) deciduous shrubland edge (positive relationship), 8) deciduous shrubland (negative relationship), 9) pine (positive relationship), and 10) open dune (positive relationship) in the uplands surrounding the study wetlands. During 2006 and 2008 we radio-tracked adult S. holbrookii in the Province Lands using surgically implanted radio-transmitters to: 1) describe movement patterns and estimate home range sizes, and 2) assess upland habitat preferences of S. holbrookii. We tracked 19/20 individuals (11 males and 8 females) and 12/20 individuals (7 males and 5 females) for at least the first 30 and 100 days post-surgery, respectively, during 2006. During 2008 we successfully tracked 15/25 individuals (10 males and 5 females) and 5/25 individuals (3 males and 2 females) for at least the first 30 and 100 days post-surgery, respectively. In addition to results obtained on a suite of movement attributes we identified a number of upland habitat preferences for S. holbrookii. Use locations were: 1) closer to the nearest deciduous shrub edge, 2) had a greater percent cover of ground-running pitch pine branches at a 1 m scale, 3) had a greater percent cover of deciduous shrubs at a 1 m scale, and 4) had a greater percent cover of reindeer lichen at a 5 m scale. Results from this research provide much needed empirical results on these critical life history attributes related to the movement and breeding ecology of S. holbrookii. These results will aid biologists and Park management staff at Cape Cod National Seashore in more effectively employing conservation and management strategies aimed at enhancing the long-term persistence probability of this regionally rare species in the Province Lands.
103

An evaluation of reclaimed coal strip mined land as wildlife habitat /

Riley, Charles Victor January 1952 (has links)
No description available.
104

Effects of drought and grazing on land bird populations in South Texas

Lipschutz, Maia Lynn 30 August 2016 (has links)
<p> Breeding bird surveys were conducted on 7 properties belonging to 2 ranches in South Texas. Using these data I calculated temporal trends, and tested the effects of total May&ndash;April precipitation and cattle stocking rate on avian abundance. Trends were calculated for each ranch, the East Foundation and King Ranch, individually due to different range and wildlife management practices. Total avian abundance increased significantly on the 3 East Foundation properties between 2008 and 2015. During 39 breeding bird surveys, 16,441 individual birds of 88 species were recorded. Non-breeding bird surveys were also conducted on East Foundation properties, an increasing trend in total avian abundance was also calculated from these data. Total breeding bird abundance was stable on the 4 King Ranch properties between 2005 and 2013. A total of 19,162 individual birds of 87 species were recorded during 40 breeding bird surveys. The combined effect of livestock use and precipitation had a significant effect on total avian abundance on all King Ranch properties, and on the abundance of some individual species and groups. </p>
105

An analysis of the demography and habitat usage of Roatan's spiny-tailed iguana, Ctenosaura oedirhina

Campbell, Ashley B. 10 September 2016 (has links)
<p> The Roat&aacute;n Spiny-tailed Iguana (<i>Ctenosaura oedirhina </i>) is endemic to the 146-km<sup>2</sup> island of Roat&aacute;n, Honduras. Harvesting for consumption, fragmentation of habitat, and predation by domestic animals threaten this lizard. It is currently listed as Endangered by the International Union for Conservation of Nature (IUCN), as threatened by the Honduran government, and is on Appendix II of the Convention on International Trade in Endangered Species (CITES). This species has been geographically fragmented and genetically isolated into small subpopulations that are declining in density. With data gathered from use/availability surveys, resource selection functions were used to identify habitats and environmental variables associated with their presence. Results indicate that protection from harvesting is the most important factor in determining their distribution. These high-density populations are currently restricted to &sim;0.6 km<sup>2</sup>. Organisms living in small, isolated populations with very restricted ranges are at higher risk of extirpation due</p><p> to various direct and indirect forces. Mark-recapture-resight surveys and distance sampling have been used to monitor the populations since 2010 and 2012 respectively. The data show that the high-density populations are declining. The current population size is estimated to be 4130-4860 individuals in 2015. A population viability analysis (PVA) was conducted to identify the most pressing threats and specific life history traits that are affecting this decline. The analysis estimates that if current trends persist, the species will be extinct in the wild in less than ten years. Adult mortality is a main factor and female mortality specifically characterizes this decline. In order for this species to persist over the next fifty years, adult mortality needs to be reduced by more than 50%. A lack of enforcement of the current laws results in the persistence of the main threat, poaching for consumption, thus altering the species distribution and causing high adult mortality. This is complicated by social customs and a lack of post primary education. Management changes could mitigate this threat and slow the population decline. Recommendations include an education campaign on the island, increased enforcement of the current laws, and breeding of <i>C. oedirhina in situ</i> and <i> ex situ</i> for release into the wild.</p>
106

Disturbance and habitat factors in a small reserve : home range establishment by black rhinocerous (diceros bicornis minor)

Odendaal, Karen 18 January 2012 (has links)
MSc., Faculty of Science, University of the Witwatersrand, 2011 / Black rhinos are being moved to small protected areas in an attempt to expand their range; and factors commonly found within these small protected areas could influence black rhino ecology. From the literature we understand how biological factors affect rhino resource selection but not in the context of small reserves. This study investigates the home range establishment of black rhinos and those factors commonly associated with small reserves that affect rhino habitat-use as well as weigh the relative importance of each of them. The factors considered were human disturbances such as residences, lodges, roads and fences, slope, elevation, perennial water, burnt areas and vegetation type. Minimum convex polygon, 50% core and 95% local convex hull (LoCoH) was used to generate home ranges from sightings data collected for 17 individuals. The mean 95% LoCoH home range was 3.77 km² (95% CI: 2.92- 4.63, n=17), and is comparatively small in relation to the adaptive kernel home ranges of previous studies. A use-availability resource selection function showed that black rhinos avoided areas close to residences, lodges, camps, and perennial water, and these variables played a bigger role than their selection for thicket vegetation. These factors have a highly significant effect on rhino resource selection, and this effect is magnified due to the density of human disturbances and water points commonly found in small reserves. It is essential that this knowledge be applied in the management of reserves protecting black rhinos.
107

Monitoring population size, structure and change in Bechstein's bat (Myotis bechsteinii) : combined approaches using molecular and landscape ecology

Wright, Patrick January 2018 (has links)
The Bechstein’s bat, Myotis bechsteinii, is known as one of Britain’s most elusive mammals. Critical information on the species is lacking, hindering evidence-based conservation and management in a human-dominated landscape. In this thesis, I used a combination of molecular and landscape approaches to assess the genetic health and population genetic structure of M. bechsteinii and understand how the British landscape affects the species habitat and its connectivity. I also aimed to develop new molecular tools, such as non-invasive genetic sampling and molecular ageing, which could then be used to better monitor the species. Data from nuclear markers (microsatellites) showed high levels of genetic diversity and little inbreeding across the species range, though genetic diversity was slightly lower in Britain than in mainland Europe. Bayesian and spatial Principal Components (sPCA) analysis showed a clear separation between British and European populations. This analysis also revealed that in Europe the Italian population south of the Alps was found to constitute a different group from other sites. In Britain, there was genetic structuring between the northern and southern part of the species range. Despite there being little genetic divergence in mitochondrial DNA (mtDNA) sequences throughout most of Europe, the mtDNA patterns in Britain confirmed this separation of northern and southern populations. Such genetic structuring within Britain — in the absence of any obvious physical barriers — suggested that other features such as landuse may limit gene-flow. To better understand how the species interacts with 4 the British landscape, I used a landscape genetic approach, habitat suitability modelling using presence-only data and a landscape connectivity analysis. The negative association of M. bechsteinii presence with distance from woodland was identified as the main variable determining habitat suitability, while the landscape genetics results highlighted the importance of woodlands for gene flow. M. bechsteinii habitat was highly fragmented and only showed good connectivity if the species was able to disperse over 5,000 m. These results subsequently highlight the importance of woodlands not only for providing suitable habitat, but also in maintaining genetic connectivity between populations. Then, I investigated the use of non-invasive capture-mark-recapture (CMR) and demographic history models to estimate the population size and changes of M. bechsteinii. Bat droppings were collected below roosting sites of a single colony. After species identification, the 123 droppings belonging to M. bechsteinii were genotyped at nine DNA microsatellite loci in order to differentiate all individuals. All microsatellites showed very low amplification rates indicating low quality samples. However, at a larger scale, the use of population demographic models to assess effective population size variation using a dataset of 260 bats of the British population gave an estimate of the effective population size of 6,569 (CI: 5,307-8,006) and suggested that the British population of Myotis bechsteinii is stable and possibly expanding. Finally, I developed an epigenetic assay to estimate the age of individual bats. For this, I measured DNA methylation on bats of known age at seven CpG sites from three genes. All CpG sites from the tested genes showed a significant relationship between DNA methylation and age and provided reliable age estimates. 5 The findings presented in this thesis show that despite exhibiting high levels of genetic diversity throughout its range, the genetic structure, habitat and connectivity of M. bechsteinii populations is highly influenced by woodlands. It also offers a novel method to monitor the species by developing an assay which can provide information on the age structure of an entire colony from a single sampling session. Such approaches are much needed in the field of conservation and could in the future help preserve a wider range of species.
108

The Effects of Beach and Species Management Actions on the Nesting and Incubation Environment of Sea Turtles in the Northern Gulf of Mexico

Unknown Date (has links)
Sandy beaches are unique environments which offer billions of dollars’ worth of ecosystem services, including among others: storm protection, sediment storage and transport, habitat space for beach-dwelling and nesting species, nutrient cycling, and tourism. Management of coastal systems tends to be anthropocentric – adjusting the coastal environment to suit the needs of human development and use. However, management actions can have important consequences for the natural functioning of these systems, particularly on the species who live or breed on sandy beaches. It is crucial that future management actions balance the economic, aesthetic, and recreational value of these ecosystems to coastal communities and their ecosystem services. Sea turtles offer an excellent case study in this balance. Changes to nesting or incubation conditions from anthropogenic alterations (e.g., artificial lighting, beach renourishment, marine debris) can result in the abandonment of nesting, suffocation or drowning of the embryos, increased feminization or hyperthermia, or death from exhaustion, desiccation, or predation. Understanding how the nesting and incubation environment may change under different beach- or species management actions is critical to ensuring their appropriate use in sea turtle population recovery. This dissertation investigated how two management actions affect the nesting and reproductive output of sea turtles: 1) sea turtle nest relocation (Chapter 2) including the assessment of inundation risk (Chapters 3 and 4) and 2) Leave No Trace ordinances (Chapter 5). Nest relocation is a common approach used to reduce losses due to inundation, erosion, poaching, and other terrestrial threats; however, there are concerns that this strategy may alter the incubating environment of the developing embryos, and thus affect proper hatchling development and fitness. In Chapter 2, I examined potential differences in inundation exposure, sand temperature, moisture content, and grain size between paired original-relocated nest sites as well as hatchling production between in situ and relocated nests. The incubating environment between original-relocated pairs were comparable, though relocation offered a minimal net benefit as it decreased emergence success and did not reduce the likelihood of inundation. More nests were being moved than are necessary, indicating additional information is needed to identify high-risk nesting sites. To better identify nests at-risk of wave exposure which are suitable for relocation, a wave runup model was developed using historical beach elevation, offshore wave, and tide data (Chapter 3). Wave runup modeling proved effective at identifying washed over nesting sites (83%). The best choice of beach slope used in the assessment varied depending on whether the user was interested in presence of wash-over or the frequency of wave wash-over at a site. An updated digital elevation model (DEM) was not necessary as the time-averaged DEM performed better than, or comparable to, those using the most recent LiDAR survey. A more complete understanding of sea turtle embryonic tolerance to inundation would improve high-risk site identification. HOBO U20L-04 water level loggers were tested in situ to evaluate their potential to provide this inundation tolerance information versus existing PVC-based equipment at paired experimental sites and when deployed adjacent to nests (Chapter 4). The HOBO loggers could provide high resolution observations of inundation frequency, duration, and severity which can inform nest productivity; however, their high cost will limit the scale of their deployment. In a complementary role, the low-cost PVC-based design can be mass-produced and deployed across a wide spatial scale but at a reduced data resolution – the balance between the use of these equipment will depend on the resources of the monitoring agency and the specific research question. Sea turtle population recovery is predicated not just on our ability to reduce losses of developing embryos, but on the continued availability of suitable nesting habitat itself. Leave No Trace ordinances are increasingly being used to combat the issue of marine debris including abandoned beach equipment (Chapter 5). Nesting success and obstructed crawl frequency were compared before and after the implementation of the ordinance at control and treatment beach segments in a BACIPS design. The ordinances had mixed success – though obstructed crawls did decline after the ordinance in Gulf Shores and Orange Beach, the presence of an obstruction did not influence a turtle’s decision to nest and nesting success declined after the ordinance across the study area due to natural variation. More time and/or increased compliance may be necessary for improvements in nesting success to materialize. These management actions appeared to have only small effects on sea turtle hatchling production and population growth rates in the northern Gulf of Mexico. But as charismatic megafauna and valuable ecosystem service providers, their continued conservation based on the provision of suitable environmental conditions serves as an important example of the need to balance anthropocentric coastal zone management with ecosystem function. / A Dissertation submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2019. / March 29, 2019. / endangered species conservation, inundation, Leave No Trace, marine debris, nest relocation, sea turtle / Includes bibliographical references. / Mariana M. P. B. Fuentes, Professor Directing Dissertation; Thomas E. (Tom) Miller, University Representative; Jeffrey P. Chanton, Committee Member; Scott Burgess, Committee Member; Dean Grubbs, Committee Member.
109

Efficacy of biological corridors

Rosenberg, Daniel K. 18 November 1994 (has links)
Graduation date: 1995
110

International wildlife law and the geography of the commons /

Giordano, Mark. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2002. / Typescript (photocopy). Includes bibliographical references (leaves 70-79). Also available online.

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