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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.
41

HABITAT USE AND MOVEMENTS OF BLANDING’S TURTLES (EMYDOIDEA BLANDINGII) AND WOOD TURTLES (GLYPTEMYS INSCULPTA) IN A SHARED LANDSCAPE

Elizabeth A Cubberley (12884906) 16 June 2022 (has links)
<p>Blanding’s Turtles (Emydoidea blandingii) and Wood Turtles (Glyptemys insculpta) face population declines range wide, largely because of degradation and loss of habitat in the landscapes  they occupy. Studies of spatial ecology inform land managers of both the resource needs of animal  populations and provide insight on site specific conservation priorities. I examined movements  and habitat use of overlapping populations of Blanding’s Turtles and Wood Turtles at a site in  northern Michigan. I used radio telemetry to locate turtles of each species over the course of two  active seasons. I examined full active season and bi-weekly movement patterns and compared  activity between the species and sexes of each using one-way analysis of covariance (ANCOVA)  and repeated measures analysis of variance (RM ANOVA), respectively. Using multiple  commonly used spatial metrics, including range length, 100% minimum convex polygons (MCP),  95% MCP, 50% MCP, and 95% kernel density estimation (KDE), I estimated seasonal activity  ranges of turtles and examined site fidelity, making comparisons of species and sexes using two?way multivariate analysis of variance (MANOVA). Finally, I used Euclidean Distance Analysis  to examine habitat use at Johnson’s 2nd and 3rd orders of selection, making comparisons at different  levels using MANOVA. Movement analyses suggest that Blanding’s Turtles and Wood Turtles at  this site travel similar distances over the active season and during different seasonal periods,  though females of both species make slightly larger movements during the spring nesting season and male Wood Turtles move more than females in late summer. Activity ranges were individually  variable, but comparable among species and sexes. Wood Turtles do appear to exhibit site fidelity  at this site, occupying similarly sized and overlapping activity ranges year to year. Habitat  selection was evident at the 2nd order for Wood Turtles, indicating favorable use of creek, mid?canopy, and high-canopy upland habitat types and avoidance of river habitat. Blanding’s Turtles  also showed selection of habitat at the second order, with scrub-shrub and cut or burned areas  ranking highest among available habitat types. Neither Wood Turtles nor Blanding’s Turtles  showed evidence of habitat selection at the 3rd order, which may indicate an abundance of high?quality habitat available to these species at this site. Maintenance of corridors between high-use  habitat areas, and mitigation of threats especially during times of greater movement may be  advantageous to the conservation of Blanding’s Turtles and Wood Turtles at this site. </p>
42

Winter Ecology of Radiomarked Female Mallards In Mississippi's Alluvial Valley

Lancaster, Joseph David 04 May 2018 (has links)
Interactions between animal populations and their environment form the foundation of wildlife management, and provision of resources that enhance fitness produce effectual management. Hunting is a selective force that shapes behavior and other adaptations of harvested species and may subsequently impact diel habitat use. Moreover, linking habitat use to biological outcomes, such as survival, is needed to evidence habitat suitability because of equivocal relations among population density, habitat correlations, or energy availability to population dynamics. The mallard (Anas platyrhynchos) is among the most coveted and harvested waterfowl in North America and is a migratory species of ecological, economic, and social importance. The Mississippi Alluvial Valley (MAV) is an ancestral and continentally important wintering area for North American mallards despite significant anthropogenic wetland transformation. Through targeted objectives and consequence of soil and water conservation, financial assistance programs have expanded waterfowl habitat on private lands in Mississippi. I radiomarked 265 female mallards and tracked their diel habitat use in winters 2010-2015 to evaluate objectives related to their wintering ecology in the MAV of Mississippi. Specifically, I investigated whether waterfowl hunting influenced use of some habitats during hunting season, the effectiveness of financial assistance programs in providing habitat, and habitat suitability through habitat specific survival rates. Females made greatest use of forested and emergent wetlands diurnally and emergent wetlands and flooded cropland at night. Results suggested that mallards did not avoid flooded cropland or emergent wetlands diurnally during hunting season, but conclusions were complicated by significant use of inviolate sanctuaries. Mallards used numerous incentivized conservation program wetlands, but use was less than public and privately managed wetlands. Among conservation programs, those with large enrollment and a focus on restoration (i.e., Wetlands Reserve Program) were most used by mallards. Apparent survival was independent of diurnal habitat use suggesting that mallards use of wetland complexes leads to their winter survival. Restoration of forested wetlands should be a management focus and easement programs provide such inroads on private lands. Public wetlands are an important source of habitat and inviolate sanctuary should be considered where waterfowl hunting is a predominate activity.
43

Breeding and Brood Rearing Ecology of Mottled Ducks in the Ashepoo, Combahee, and Edisto Rivers Basin, South Carolina.

Kneece, Molly Rebecca 07 May 2016 (has links)
Mottled ducks (Anas fulvigula) are a non-migratory waterfowl species endemic to the western Gulf Coast, with a separate, genetically distinct subspecies (A. fulvigula fulvigula) occurring in peninsular Florida. Birds from Texas, Louisiana, and Florida were released in coastal South Carolina from 1975-1983, and banding data suggest an expanding population. I monitored 72 mottled duck nests and captured and radio-marked 196 pre-breeding and nesting females between 2010 and 2014 to study breeding ecology of these birds in the Ashepoo, Combahee, Edisto Rivers Basin. Nest success averaged 12% and varied with vegetation height and year. Indicated breeding pair surveys revealed breeding mottled ducks select managed wetland impoundments, predominately influenced by water depth. Future research should investigate ecology of nest predators of mottled ducks to devise successful habitat management strategies for breeding birds. Preliminary evidence suggests that managed wetland impoundments are important to breeding and brood rearing mottled ducks in coastal South Carolina.
44

Positional behavior and habitat use of Peters’ Angola black and white colobus monkey (Colobus angolensis palliatus) in structurally distinct areas of the Diani Forest, Kenya

Dunham, Noah T. 05 July 2013 (has links)
No description available.
45

Survival, Habitat Use, And Nest-Site Characteristics Of Wild Turkeys In Central Mississippi

Holder, Brad Douglas 13 May 2006 (has links)
Wild Turkey (Meleagris gallopavo) survival, habitat use, and nest-site characteristics were studied on Malmaison Wildlife Management Area, Mississippi, 2003-2004. Survival rates were 0.55, 0.0004, 0.26, and 0.30 for jakes, adult gobblers, juvenile hens, and adult hens, respectively for the entire study. Spring survival for all groups was 0.51 (95% CI 0.36, 0.65) and was least among seasons. Predation (65%) and harvest (21%) were major causes of mortality. Brood hens used bottomland hardwood stands, pine plantations, and old fields more than expected during the post-nesting period. Non-brood hens used bottomland hardwood stands more than expected during the pre- and post-nesting periods. Forbs were the predominant vegetation type at nests. Vegetation height was 0.3-0.6 m for all nest sites. Vertical screening cover for all nests was in the 21-40% obscurity category at 1 m and 41-60% category at 3 and 5 meters. Vine composition differed between successful (2%) and unsuccessful (20%) nests (P = 0.03).
46

Walleye Habitat Use, Spawning Behavior, and Egg Deposition in Sandusky Bay, Lake Erie

Thompson, Adam January 2009 (has links)
No description available.
47

Wild carnivore habitat use and community ecology in a biodiversity hotspot and human-wildlife conflict with pumas and dogs across Chile

Osorio Popiolek, Christian Thomaz 21 May 2021 (has links)
Habitat loss and fragmentation and human-wildlife conflicts, often resulting in retaliatory killing in response to livestock predation, are one of the main threats to wild felids worldwide, including pumas (Puma concolor). However, mesocarnivores are more abundant than large carnivores, live closer to human settlements, and drive community structure and processes in similar or different ways from large predators. Understanding both large and small carnivores' habitat use is key to their conservation and management. Thus, there is need to explore the ecological roles of predators (including invasive ones like free-ranging dogs [Canis lupus familiaris] and cats [Felis catus]) to examine how ecological context modulates the ecological roles of carnivores . This is especially important in my study area, which was severely burned by a catastrophic mega-wildfire in 2017. I used dynamic occupancy modeling of human-wildlife conflict (HWC) across 52 provinces for 8 years in Chile and found that free-ranging dogs outpace pumas in livestock depredation, killing substantially more livestock than pumas. Occupancy models show that HWC occurrence for both dogs and pumas increased with sheep density. Unexpectedly, dog HWC decreased with anthropogenic habitat degradation indicating that dogs may travel far to prey on livestock. The emergence of puma HWC in a site where it did not occur in the previous year was positively associated with anthropic disturbance. Countrywide, dogs HWC occurrence probability was higher than pumas in 43 out of the 49 provinces where both species occurred. I discuss livestock vulnerability, management strategies, and policy to mitigate HWC, and also highlight threats that free-ranging dogs pose to biodiversity conservation and even human public health. I also used single-species, single-season occupancy models fit to camera-trap data to investigate the patterns of site occupancy and response to mega-wildfires of native mesocarnivores in southern-central Chile: guignas (Leopardus guigna), culpeo foxes (Lycalopex culpaeus) and chilla foxes (Lycalopex griseus). I found that vulnerable guignas avoided burned sites, preferring sites with native, dense vegetation while culpeo foxes were intermediate in being able to use plantations, but avoiding burned sites. Chilla foxes were most tolerant to landscape change with no response to burns and were found closer to human habitation and rivers. Finally, I used two-species, single season occupancy models, and Kernel Density Estimation on circular data, to investigate the spatial and temporal dynamics, and overlap of native and exotic carnivores. I found that feral cats are a potential threat to pumas, guignas, and native foxes given they overlap extensively in time of activity with these species. Also, feral dogs had the widest distribution of all species indicating that their effects could be ubiquitous on the landscape. Thus, exotic species are damaging to wildlife, to livestock industry, and even to public health. I urge dialog between government authorities, wildlife managers, and scientists to generate a legal and public policy framework to properly managing habitat and HWC in southern-central Chile. / Doctor of Philosophy / Landscape transformation and human-wildlife conflict (HWC), which often result in retaliatory killing of wildlife in response to livestock predation, is one of the main global threats to wild cats, including pumas (Puma concolor). Medium-sized carnivores (mesocarnivores or mesopredators) are more abundant than large carnivores, live closer to human settlements and, like large predators, impact ecosystem structure and function significantly. Understanding habitat use of these carnivores is key to their conservation and management and to biodiversity preservation. Thus, there is need to investigate the ecological roles of carnivores (including invasive ones like free-ranging dogs and cats) to determine how interactions with other carnivore species and with the physical environment influence ecological roles of such species. This is especially important in my study area, which was severely burned by a catastrophic mega-wildfire in 2017, and for which there is scant information on wildlife responses to the mega-fire. I determined the distribution and causes of HWC across 52 provinces for 8 years in Chile and found that free-ranging dogs accounted for higher livestock depredation than pumas, killing substantially more livestock. Occurrence of HWC for both dogs and pumas increased with the sheep density of the province. Unexpectedly, dog HWC increased in less degraded habitats, indicating that dogs may travel far to prey on livestock in remote areas. The emergence of puma HWC in a site where it did not occur in the previous year increased with human-caused disturbance. Countrywide, dog HWC was higher than pumas in 43 out of the 49 provinces where both pumas and dogs occurred. I discuss livestock vulnerability, management strategies, and policy changes to address HWC, and discuss the threats that free-ranging dogs pose to biodiversity conservation and even to human public health. I also used remotely-triggered, camera-trap records to explore distribution of three mesocarnivores (guignas, culpeo foxes and chilla foxes across the landscape and in response to mega-wildfires in southern-central Chile. I found that guignas, a small and vulnerable wild cat, avoided burned sites, preferring sites with native, dense vegetation while culpeo foxes were intermediate in being able to use plantations, but avoiding burned areas. Chilla foxes were most tolerant to landscape change with no response to burns, and they were found closer to human settlements and rivers. Finally, I examined overlap in space and time of day between native species pairs and native and exotic species pairs. I found that dogs were the most widely distributed species across the landscape, but were mostly diurnal while native species were primarily nocturnal. Cats however had high temporal overlap with guinas and chilla foxes, highlighting the potential for competition between them.. Thus, exotic species are damaging to wildlife, livestock and even human health. I discuss the management implications and urge dialog between government authorities, wildlife managers, and scientists to generate a legal and public policy framework to properly managing habitat and HWC in southern-central Chile.
48

Densities, habitat-use, and mesopredator release of the ocelot in Belize

Davis, Miranda L. 09 June 2009 (has links)
The mesopredator release hypothesis suggests that small carnivore populations are negatively affected by competition with larger carnivore species; this could hinder the conservation of mesopredators in areas where large top-carnivores are prioritized. I investigated the ecology of ocelots in Belize and examined the role of mesopredator release in the neotropical carnivore guild to determine if ocelots are limited by competition with jaguars and pumas. I conducted remote camera surveys and sampled habitat within four protected areas: three broadleaf sites and one pine forest site. I measured ocelot activity and habitat-use with respect to the activity of jaguars and pumas at one broadleaf site and one pine forest site; additionally, I calculated estimates of ocelot and jaguar densities within those two sites. Ocelot presence was positively related to jaguar activity in the pine forest and to both jaguar and puma activity in the broadleaf forest. There were few relationships with habitat characteristics; however, in the broadleaf site, ocelot activity was positively related to road width and large avian prey activity. Both jaguar and ocelot densities were low in the pine forest and higher in the broadleaf site. Preliminary findings from the remaining two sites suggest that future results may be similar to those from the first two sites analyzed. I conclude that ocelot populations are not negatively affected by jaguars and that a negative effect of pumas is unlikely. Results imply that mesopredator release does not limit ocelot populations in these areas. / Master of Science
49

Human and environmental influences on the distribution and abundance of arapaima in river floodplains of the Lower Amazon

Richard, Jordan Conner 17 November 2016 (has links)
Understanding the factors influencing the abundance and distribution of tropical floodplain fishes is an important component of fisheries management plans to support future sustainable resource use. This thesis uses a multi-scale approach to understand the habitat factors controlling the distribution and abundance of arapaima (Arapaima spp.) in river floodplains of the lower Amazon River, near the municipality of Santarém, Para State, Brazil. In chapter 1, a study of eight environmental variables in 13 dry season floodplain lakes demonstrates that lake depth, relative depth, conductivity, and transparency were significantly related to the probability of arapaima presence at individual locations within lakes. Further, the study revealed that smaller arapaima were more likely to be found near macrophyte coverage than in open water locations. In chapter 2, a landscape scale approach was used to examine the interactions between management systems, landscape habitat coverage, and spatial arrangement on arapaima population sizes in 73 floodplain lakes. Results showed that all three influences were important in explaining variability in arapaima abundances. Management and habitat variables contributed equally in controlling arapaima abundances. Both had strong patterns of spatial arrangement and overlapped significantly, suggesting that analysis of either management systems or landscape habitats without the other would lead to overestimations of the strength of their influence. Findings from both chapters support the notion that future sustainable use of arapaima populations requires a dualistic approach combining habitat conservation with fisheries management techniques enacted at a local scale. / Master of Science
50

Differential stability of spawning microhabitats of warmwater stream fishes

Smith, Ryan Kennerly 05 June 1999 (has links)
I investigated streambed stability in spawning microhabitats of warmwater fishes in the upper Roanoke River, Virginia. Spawning microhabitats used by four reproductive guilds (egg-clusterers, mound-builders, egg-buriers, and pit-builders) were identified and ranges of 15 microhabitat variables used by each guild were compared to available microhabitat conditions to investigate habitat selection. Habitat usage by egg-clusterers was most characterized by selection for spawning rocks in the cobble size range, substrate roughness elements in the cobble to boulder size range, high roughness Reynolds number and moderate water column velocity. The mound-building bluehead chub (Nocomis leptocephalus) was distinct in its selection of substrate in the small gravel range, low water velocity and non-turbulent flow. Egg-buriers were the least distinct of the four guilds, exhibiting much variation in habitat use among the component species. However, all species used areas with small substrate (sand to gravel range), high velocity, and high turbulence. The pit-building central stoneroller (Campostoma anomalum) was distinct in its usage of areas with high velocity and turbulence, gravel sized substrate, and low embeddedness. Stability of each guild's spawning microhabitats was empirically evaluated through analysis of tracer particle movement and repeated surveying of bed elevation along stream transects. Logistic regression equations developed from tracer particle data predicted that microhabitats selected by egg-clusterers are among the most stable of all available habitats during high flows. Microhabitats utilized by mound-builders, egg-buriers, and pit-builders are predicted to be less stable. Repeat transect surveying corroborates model predictions in that egg-burier habitats experienced changes in bed elevation in high flows, while egg-clusterer habitats did not. / Master of Science

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