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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

Emerging Factors Associated With The Decline Of A Gray Fox Population And Multi-Scale Land Cover Associations Of Mesopredators In The Chicago Metropolitan Area

Willingham, Alison N. 08 December 2008 (has links)
No description available.
12

Spatial Ecology of a Vulnerable Species: Home Range Dynamics, Resource Use, and Genetic Differentiation of Eastern Spotted Skunks in Central Appalachia

Thorne, Emily D. 28 April 2020 (has links)
The spatial distribution of a species is not random or uniform across all landscapes, nor is it independent of resource availability and risk of predation. A key aspect in the study of wildlife ecology is understanding how a species evaluates its surroundings and selects habitat that offers advantages to survival and reproductive success. In theory, an individual should select habitat that offers adequate resources to meet its biological requirements and allows it to adjust its use of resources based on a variety of abiotic and biotic habitat factors. Relationships between wildlife populations and habitat characteristics are difficult to assess, yet identification and characterization of these relationships can improve delineation of limiting habitat factors needed for effective conservation and management. The eastern spotted skunk (Spilogale putorius) is a small Mephitid (weasel family) that was once a fairly common furbearer throughout the central and southern United States, with annual range-wide harvests of over 100,000 individuals. In Virginia, the spotted skunk is classified as vulnerable, and anecdotal evidence suggests that this species has been rare or largely absent from the central and southern Appalachians over the last two decades. Limited knowledge of spotted skunk habitat associations in Virginia dictate the need for research on this species of concern. The aim of this study was to determine the associations of environmental characteristics ofwith spotted skunk habitat selection and genetic differentiation. I assessed first-order habitat selection by conducting an analysis of predicted occurrence at the landscape scale. Next, I assessed second- and third-order selection using resource utilization functions to determine habitat selection among, and within, home ranges. Further, I assessed fourth-order selection by identifying microhabitat selection and resource use at spotted skunk den site. Finally, I evaluated genetic diversity and population structure of spotted skunks in the Appalachian Mountains. I found that spotted skunk habitat is distributed in small, spatially disjunct patches and that movement, home range size, and resource selection are impacted by availability of habitat and the isolation and/or fragmentation of this suitable habitat. I found overall low genetic diversity and evidence of inbreeding within populations and geographic patterns of genetic differentiation with distinct subpopulations isolated by unsuitable landscape characteristics. Application of these results will contribute to more effective conservation of eastern spotted skunks throughout the Appalachian Mountains. / Doctor of Philosophy / Wildlife species do not occur throughout the landscape randomly or evenly, but rather choose their locations based on the availability of food, cover, and water. A key aspect in the study of wildlife ecology is understanding how a species chooses its natural surroundings and selects habitat that allows it to survive and reproduce. In theory, an animal should choose a location that offers enough resources, such as food, cover, and water to meet its biological needs and allows it to adjust based on access to these resources. By understanding the how the availability of these resources influences an animal's choice of location, wildlife managers can better determine the need for protection or management of the species in a given area. The eastern spotted skunk (Spilogale putorius) is a small, weasel-like animal that was once fairly common throughout the central and southern United States. In Virginia, the spotted skunk is a protected species, and experts suggest that it has been rare in the central and southern Appalachians for over several decades. Because there is limited knowledge of spotted skunk habitat needs in Virginia, research on this species is necessary. The goals of this study were to determine the type of habitat in which spotted skunks are choosing and how it affects the species genetic makeup. First, I determined in which general areas spotted skunks exist in Virginia. Next, I determined that the habitat for spotted skunks includes forests with ample bushy plants and rocks to hide from predators. I then examined the genetics of spotted skunks to determine relatedness among individuals and whether inbreeding was occurring. Finally, I compared the relatedness of pairs of spotted skunks to the distance between their locations and found that skunks that are located on the same mountain range are more closely related to each other than to skunks on different mountain ranges. These results will inform wildlife managers on how to provide spotted skunks with the habitat resources they need to survive and reproduce successfully, thus promoting skunk conservation.
13

Turtle nest sensory perception by raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) : an approach through discrimination learning of potential nest cues

Galois, Patrick. January 1996 (has links)
Egg predation may be the most important mortality factor for North American turtles. This predation can destroy 50-90% of nests in an area. The major predators are striped skunks (Mephitis mephitis) and raccoons (Procyon lotor). Despite differences in their habits and diet, these species appear equally efficient in turtle egg predation, even though these eggs represent a very small portion of their annual food intake. Sight, olfaction, touch and hearing could be used by these predators to find the nests. The aim of this study was to document intra and inter-specific differences in the perception of possible nest-cues used by raccoon and striped skunk. Choice-tests based on food-conditioning were carried out with two visual cues (dark and smooth surface), one olfactory cue (turtle urine) and one tactile cue (soil compaction). Subject performances (number of trials to obtain 80% success rate in the different tests) were compared to assess intra and inter-species, and skunk inter-age differences in sensory perception and learning abilities. As expected raccoons learned the tactile cue discrimination faster than the visual cue discriminations. The tactile cue discrimination was learned as fast as the olfactory cue. As expected skunks learned the olfactory cue discrimination faster than other cue discriminations. When compared, the olfactory cue appeared to be as important for both species even though raccoons had faster learning rates than skunks in all the tests except for one visual test. Juvenile skunks learned faster than adult skunks with four out of six juveniles performing better in the olfactory test. Olfaction may play an important role in nest localization by raccoons and skunks, and sight may also play a role for raccoons. Learning turtle nest cues while with their mother could facilitate their future ability in locating turtle nests.
14

Turtle nest sensory perception by raccoon (Procyon lotor) and striped skunk (Mephitis mephitis) : an approach through discrimination learning of potential nest cues

Galois, Patrick. January 1996 (has links)
No description available.
15

Utbredningen av den invasiva växten skunkkalla (Lysichiton americanus Hultén & St. John 1931) i Fylleån

Robak Enbratt, Emelie January 2019 (has links)
Invasive alien species is one of the biggest threats to biodiversity worldwide. American Skunk-cabbage (Lysichiton americanus) is an invasive alien plant originating from North America. It has become naturalised in several European countries, including Sweden. American Skunk-cabbage is a threat to other plants as it forms dense stands and outcompetes native vegetation by shadowing. It is believed that the biggest population of Skunk-cabbage in Sweden is along Fylleån in Halland. The aim with this report is to map the distribution of Skunk-cabbage in a section of the stream and to examine different methods for control and eradication of the weed. A survey was performed along a section of the stream between the dates 30th April – 8th May 2019. The survey was executed from Ryaberg to Torsaberga (13 km). The search area was comparted into 6 locations. The highest point where Skunk-cabbage was found upstream in Fylleån was at location 6. A total of 4157 individual plants were found along a stretch of 6km and 34 km of the stream is believed to be affected by the invasion. A majority of the plants grows in marshland. Both mechanical and chemical control are used when eradicating Skunk-cabbage. The most common method is digging by hand. This is also the method that I recommend in the event of an eradication campaign in Fylleån. No eradication efforts will be performed in Fylleån during 2019 due to restricted economical resources. Different projects are under development for the purpose of future eradication of Skunk-cabbage in Halland. / Invasiva främmande arter är ett av de största hoten mot biodiversiteten globalt. Gul skunkkalla (Lysichiton americanus) är en invasiv främmande växt från Nordamerika. Arten är naturaliserad och etablerad i flera europeiska länder, däribland Sverige. Skunkkalla har en förmåga att konkurrera ut andra arter genom skuggning. Den bildar täta och stora bestånd och tränger på så vis undan annan växtlighet. Sveriges största bestånd av skunkkalla förmodas finnas längs med Fylleån i Hallands län. I bevarandeplanen för Natura 2000-området Fylleån finns en punkt om att man behöver ta ställning till de stora bestånden av skunkkalla i ån. Den här rapporten behandlar både utbredning och kartläggning av skunkkalla i en utvald del av Fylleån, samt bekämpningsmetoder för arten. Kartläggning av utbredningen har skett genom en inventering längs med ån. Inventeringen utfördes mellan Ryaberg och Torsaberga (13km) mellan datumen 30/4 – 8/5 2019. 4157 plantor av skunkkalla hittades längs en sträcka av 6km mellan Ryaberg och Fröbökekvarn. Fyndplatserna delades in i 6 lokaler. Lokal 6 är den högsta fyndplatsen av skunkkalla i Fylleåns lopp. 3,4 mil av ån bedöms vara påverkad av invasionen. Den vanligaste växtplatsen längs med ån bedöms vara sumpmark. I bekämpning av skunkkalla använder sig av både mekanisk och kemisk bekämpning. Den vanligaste använda bekämpningsmetoden visade sig vara bortgrävning för hand. Det är också den metoden jag förespråkar vid en eventuell utrotning i Fylleån. På grund av brist på ekonomiska resurser kommer inte någon utrotning att ske i Fylleån 2019. Olika projekt är nu under konstruktion för framtida bekämpning i länet.
16

Biomechanics of the Mammalian Tongue: Kinematic Analysis of Tongue Movements and Deformations during Feeding and Drinking

Olson, Rachel A. 24 September 2020 (has links)
No description available.
17

Mekanisk uppgrävning: ett effektivt verktyg mot den invasiva främmande arten gul skunkkalla (Lysichiton americanus) : En utredning av behandlingsmetoder

Kekäle, Oscar January 2023 (has links)
Den biologiska mångfalden minskar globalt och ett av de största hoten utgörs av invasiva främmande arter. Natura-2000 området Fylleån, Halland, huserar en av de största svenska populationerna av gul skunkkalla (Lysichiton americanus). Arten utgör ett hot mot de naturvärden som finns i Fylleån och är subjekt för extensiva behandlingsarbeten i området för att motarbeta växtens effekt på ekosystemet. Det finns i dagsläget ingen evidens för att behandlingsmetoderna som presenteras av Naturvårdsverket och Havs- och vattenmyndighetens metodkatalog har effektivitet i svenska vattendrag. Målet med min studie är att undersöka effektiviteten av mekanisk uppgrävning samt ytlig hetvattensbehandling som behandlingsmetoder för gul skunkkalla. Jag undersöker även lämpligheten för användandet av övriga metoder presenterade av metodkatalogen och metoderna hetvattensbehandling och fröställningsborttagning som inte listats i metodkatalogen men som testas av myndigheter i viss utsträckning. Den första delen av studien genomförs som jämförelsestudie mellan områden som behandlats i olika grad med mekanisk grävning och hetvattenbehandling för att bestämma metodernas effektivitet. Den andra delen av min studie var att genom en litteraturgenomgång med metodkatalogen som utgångspunkt avgöra lämpligheten på och reflektera över metoderna samt reflektera över metodernas lämplighet att användas civilt. Min slutsats är att mekanisk grävning ger minskande populationer och signifikanta skillnader i individantal, förutsatt att behandlingen utförs rätt och konsekvent. Jag resonerar att andra behandlingsmetoder kan påverka mer organismer än vad man avsett och att de därför är olämpliga att bruka i Fylleån. Jag diskuterar vad jag anser är rimligt idéellt arbete i nuläget samt framtida potential och behovet av information i rätt kanaler. / Biodiversity is decreasing globally and one of the biggest threats is invasive alien species. The Natura-2000 area Fylleån, Halland, houses one of the largest Swedish populations of the American skunk cabbage (Lysichiton americanus). The species poses a threat to the natural values ​​found in Fylleån and is subjected to extensive treatment to counteract the plant's effect on the ecosystem. There is currently no evidence for the effectiveness of the treatment methods presented by Naturvårdsverket and Havs- och vattenmyndighetens method catalog in Swedish watercourses. The goal of my study is to investigate the effectiveness of mechanical excavation and superficial hot water treatment as treatment methods for American skunk cabbage, along with hot water treatment and seed stand removal which are not listed in the method catalog but are tested by authorities to a certain extent. Through a comparative study between areas treated to varying degrees with mechanical digging and hot water treatment, I determine the effectiveness of the methods. The second part of my study was to try to determine the suitability of and reflect on the methods, as well as reflect on the suitability of the methods for civilian use through a literature review using the method catalog as a starting point. My conclusion is that mechanical digging produces declining populations and significant differences in found individuals, provided the treatment is carried out correctly and consistently. I reason that other treatment methods can affect more organisms than intended, and that they are therefore unsuitable for use in Fylleån.

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