31 |
Vliv rozšíření, populační dynamiky a krajinné genetiky, a preference druhů kořisti na ochranu levharta sněžného v Nepálu / Implication of snow leopard distribution, population dynamics and landscape genetics, and prey preference for its conservation in NepalShrestha, Bikram January 2021 (has links)
This thesis deals with an endangered large mammal species - snow leopard, its distribution, population dynamics, landscape genetics and connectivity, trophic ecology and human-snow leopard conflicts in the Nepalese Himalaya (Sagarmatha National Park (SNP), Lower Mustang (LM) and Upper Manang (UM) in the Annapurna Conservation Area, during Wet and Dry seasons in 2014-2016. In the case of snow leopard study, we used data obtained from camera traps, scat's genetic analysis and monitoring of fresh pugmarks and scrapes while direct count method was used to study for its main prey, blue sheep and Himalayan tahr. In study 1, we assessed the determinants of habitat suitability of snow leopards using MaxEnt model and mapped the distribution of suitable habitat for snow leopards in Nepal. Altitude and Annual mean temperature are important common factors contributing to snow leopard habitat suitability within the area studied, which is indicated by both the percentage contribution of environmental variables and Jackknife test from MaxEnt model. Some other uncommon factors also seem to play a role, as they were important in at least one of the analyses. These were: distance from road, and precipitation of driest month but their importance has to be considered with caution. In study 2, we present our...
|
32 |
The behavioural thermoregulation and ecophysiology of the leopard tortoise (Geochelone pardalis) in the Nama-Karoo.McMaster, Megan Kay. 30 May 2014 (has links)
The leopard tortoise (Geochelone pardalis) is the largest of the southern African tortoise
species and has a wide distribution range. However, there is a lack of ecological and
physiological information about the species, especially arid and semi-arid regions. The
Nama-Karoo, an arid region of South Africa, is subject to large fluctuations in rainfall, food
availability and ambient temperatures (Ta). This study focused on the thermal behaviour,
thermoregulatory, digestive and metabolic plasticity of the leopard tortoise within the Nama-
Karoo biome.
Seasonal changes in activity patterns and body temperature (Tb) were investigated in
free ranging leopard tortoises in the Nama-Karoo. Leopard tortoises had unimodal daily
activity patterns in winter, bimodal in summer, and there were daily and seasonal differences
in the extent to which certain behaviours were practiced. Daily activity behaviours were
executed at lower Tb and at lower Ta in winter compared to summer. In summer, core Tb of
all tortoises oscillated on a daily basis well below maximum Ta, while core Tb of all tortoises
in winter oscillated well above the daily Ta range. Tortoises were therefore able to maintain
their Tb independently of Ta. Differences in Tb as measured from various positions on the
tortoises body was investigated in relation to Ta. There was a strong seasonal and temporal
influence on the relationship between various Tb’s, with the skin and external shell
temperatures being more variable in response to fluctuating Ta’s compared with cloacal and
core Tb. Cloacal temperatures were significantly different to other Tb measurements
suggesting that it should be treated with circumspection as an exclusive measure of Tb.
Heating and cooling rates of leopard tortoises were investigated in the field and under
controlled laboratory conditions to determine if the tortoises maximise operational daily
activity periods, and to determine the effect of behaviour and size on the rate of heat flux. In
the laboratory, cooling rates were faster than heating rates in summer and winter for all size
classes and decreased with increasing body mass. Leopard tortoises had significantly faster
heating and cooling rates in winter than in summer. Free-ranging leopard tortoises had faster
heating rates than cooling rates and their heat flux was largely independent of Ta. Heating
and cooling rates were dependant on body mass and surface area-to-volume ratio of
individuals. Under experimental conditions, tortoises physiologically adjusted their rate of
heat flux, while free-ranging tortoises used physiological and behavioural mechanisms to
minimise the risk of overheating, to aid thermal inertia and maximise operative activity time.
Seasonal climatic cycles and fluctuating daily temperatures influence the oxygen
consumption (VO2) of reptiles, however the result of these effects on metabolism in
chelonians is poorly understood. The effect of seasonal and daily differences in Ta on VO2
was investigated. Leopard tortoises’ VO2 was slightly higher than reported for other
chelonians. There were significant differences in tortoise VO2 at different Ta’s during the day
and night and in different seasons. This metabolic plasticity is possibly an adaptive
mechanism to cope with unpredictable environmental conditions.
Unpredictable climatic conditions lead to unpredictable food and water availability.
Little is known how tortoises adjust dietary parameters in response to food type and water
availability, and if this affects body mass, energy and water balance. Therefore this study
also considered whether leopard tortoises adjusted food transit rate, food intake and water
loss to cope with a diet fluctuating in fibre and water content, and whether body mass, energy
and water balance were maintained. Leopard tortoises fed a high fibre, low water content diet
had lower food intake rates, longer food transit times, but lower daily energy assimilation
compared with tortoises fed a low fibre, high water content diet. Tortoises fed a high fibre,
low water content diet had lower urine osmolality, but similar total water loss to those fed a
high fibre, low water content diet. The results indicate that tortoises can adjust digestive
parameters according to diet composition and exercise some control over energy and water
balance.
It is concluded that leopard tortoises show a high degree of plasticity in their thermal
behaviour and physiology which allows survival in an unpredictable environment,
particularly where there are fluctuations in rainfall, food availability and Ta’s. Seasonal and
daily variation in thermoregulation, metabolic rate and the uptake of energy allows the
leopard tortoise to maximise the duration of operative temperature, to minimise energy loss
and to use variable and unpredictable seasonal resources. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.
|
33 |
Climate change, an additional factor for considering the threat level of the snow leopard (Panthera Uncia) / Klimatförändringar, en riskfaktor för snöleopardens fortlevnadFast, Adam January 2019 (has links)
The snow leopard lives in the high mountains of Asia. Threats currently facing the species are being poached for its high-valued fur and being killed by herders in retaliation for livestock predation. However, climate change also has an impact on the snow leopard’s mountain habitats as tree line height and the average temperature have increased in Asian mountains. This thesis analyzes the near-future threats from climatic changes against snow leopards and what impact human activities have on the species. Fragmentation of habitats have a huge effect on the survival of snow leopards because the connectivity routes may be reduced or lost. The general process of assessment by the IUCN was examined alongside the assessment of the snow leopard. Both anthropogenic activities and global warming lead to fragmented habitats and may isolate snow leopard populations from each other. An estimated 30 - 65 % of the snow leopard’s habitats may disappear in future scenarios. Climate change is not a threat by itself but creates new threats. Therefore, climate change needs to be taken into consideration in future assessments by IUCN due to its growing impact. The recently released IPBES report makes it apparent what destructive force human activities have on biodiversity.
|
34 |
Quantitative studies of flow in small blood vessels of the frog, Rana Pipiens, and of the hamster, Mesocricetus AuratusGrillo, Gene Patrick January 1964 (has links)
Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Quantitative relationships between blood flow velocity, vessel diameter, width of the peripheral plasma layer and induction of thrombus formation were studied in small blood vessels of the retrolingual membrane and intestinal mesentery of the frog, Rana Pipiens, and of the cheek pouch of the golden hamster, Mesocricetus auratus.
Blood flow velocity was measured by a modification of the technique described by Hugues (Arch. Int. de Physiol. 61: 565, 1953). Internal vessel diameters and widths of the total peripheral plasma layer were measured with an ocular micrometer. Thrombus thresholds were determined by graded electrical stimulation.
Determinations were made on 202 vessels in retrolingual membranes of frogs prepared by single pithing. In 95 arterioles (diameters from 10 to 40 microns), the mean flow velocity was 2.84 mm/sec. and the mean volume flow rate, 1.68xl0-3 cu mm/sec. The mean width of the total peripheral plasma layer was 3.6 microns and its ratio to mean vessel diameter was 1:6. In 107 venules (diameters from 10 to 50 microns), the mean flow rate was 1.20 mm/sec. The mean volume flow rate was 1.02x10-3 cu mm/sec. The mean width of the total peripheral plasma layer was 4.1 microns and its ratio to mean vessel diameter was 1:7.4. The ratios of mean arterial to mean venous velocity and volume flow were 1:2.3 and 1:1.6 respectively.
Measurements were made on 100 mesenteric vessels of frogs prepared by single pithing. In 50 arterioles (diameters from 15 to 45 microns), the mean velocity was 3.77 mm/sec. The mean volume flow was 3.05xlo-3 cu mm/sec. The mean width of the total peripheral plasma layer was 2. 7 microns and its ratio to mean vessel diameter was 1:11.5. In 50 venules (diameters from 20 to 50 microns), the mean velocity was 1.55 mm/sec. and the mean volume flow rate, 1.76x10-3 cu mm/sec. The mean width of the total peripheral plasma layer was 6.7 microns and its ratio to mean vessel diameter was 1:5.3. The ratios of mean arterial to mean venous velocity and volume flow were 1:2.3 and 1:1.7 respectively.
A total of 109 mesenteric vessels were studied in frogs anesthetized with urethane. In 55 arterioles (diameters from 15 to 45 microns), the mean velocity was 3.28 mm/sec. The mean volume flow was 2.87x10-3 cu mm/sec. The mean width of the total peripheral plasma layer was 3.2 microns and its ratio to mean vessel diameter was 1:9.3. In 54 venules (diameters from 20 to 50 microns), the mean flow rate was 1.61 mm/sec. and the mean volume flow, 1.83x10-3 cu mm/sec. The mean width of the total peripheral plasma layer was 5.6 microns and its ratio to mean vessel diameter was 1:5.9. The ratios of mean arterial to mean venous velocity and volume flow were 1:2.0 and 1:1.5 respectively.
In these three series of studies in the frog, no relationship was clearly apparent between velocity and either vessel diameter or width of the peripheral plasma layer in arterioles. Suggestions of a direct relationship between velocity and peripheral plasma layer in veins, however, were evident. In all cases, and in both arterioles and venules, vessel diameter and peripheral plasma layer were clearly and directly related.
The effects of flow velocity changes on width of the total peripheral plasma layer in individual vessels were studied in 26 arterioles of the hamster cheek pouch. Blood flow was varied by means of a cuff described by Copley (Biorheology 1: 3, 1962). A direct relationship between velocity and width of the peripheral plasma layer was clearly demonstrated.
Thrombus thresholds were determined in mesenteric vessels of the frog. In 103 arterioles (diameters from 20 to 140 microns), the mean strength of stimulus necessary to produce a platelet thrombus was 24.8 volts with an amperage of 0.18 milliamperes. In 100 venules (diameters from 20 to 140 microns), the mean strength of stimulus necessary was 20.7 volts with an amperage of 0.12 milliamperes. Possible relationships of thrombus thresholds to flow velocity in mesenteric arterioles and venules are discussed. / 2031-01-01
|
35 |
PLANNING THE REINTRODUCTION OF THE CLOUDED LEOPARD (NEOFELIS NEBULOSA) TO TAIWAN: AN ASSESSMENT OF ATTITUDES AND POTENTIAL SUPPORTGreenspan, Evan 01 December 2018 (has links)
Large felid populations are in decline globally and wildlife managers have increasingly used reintroductions as a conservation tool, yet few studies have assessed public attitudes towards potential large felid reintroduction candidates prior to release. The clouded leopard was recently declared extinct in Taiwan; however, a reintroduction effort is ecologically feasible and success largely depends on resident attitudes towards clouded leopards and support for its reintroduction. In 2017, 263 semi-structured interviews with indigenous locals were conducted in southern Taiwan and an internet questionnaire was distributed to 500 urban residents for comparison. Rural and urban attitudes were 67% and 76% positive toward clouded leopards, respectively. Males, younger respondents, and residents with more clouded leopard knowledge exhibited more positive attitudes among rural respondents. In addition to these predictors, urbanites with more household children were more positive. Rural support for reintroduction to the Tawushan Nature Reserve was 48% positive, 31% neutral, and 21% opposed, while urban support was 71% positive, 22% neutral, and 7% opposed. Environmental group membership, increases in attitudinal positivity, and lower levels of risk perception and knowledge influenced support for reintroduction in both samples. Although support is substantial among urbanites, a knowledge-based education campaign that targets women and older residents living adjacent to the reintroduction site would benefit reintroduction efforts.
|
36 |
Natural history and evolution of a color polymorphism in Rana pipiens, the northern leopard frogHoffman, Eric Adam 09 June 2003 (has links)
A primary goal of population genetics is to identify the role of
microevolutionary forces in producing observed patterns of molecular and phenotypic
variation. I conducted four studies in the northern leopard frog, Rana pipiens, to
determine just how mutation, migration, genetic drift, and selection influenced,
genetic structure of mitochondrial DNA (mtDNA), nuclear DNA, and a single locus
polymorphism that determines dorsal coloration. In the first study, I surveyed the
literature concerning color and pattern polymorphisms in anurans. I conclude that
anuran polymorphisms remain a rich but largely unexploited system for studying the
evolution of phenotypic variation in nature.
In the second study, I compared mitochondrial DNA variation from 35
populations distributed across the species' range. A phylogenetic analysis indicated R.
pipiens is split into two deeply divergent mtDNA groups, a western group and an
eastern group. Phylogeographic and demographic analyses indicated that although
restricted gene flow with isolation by distance explained the majority of the processes
influencing current genetic structure, population bottlenecks and expansions also
played an important role.
In the third study, I investigated mtDNA and microsatellite variation in Pacific
Northwest populations of R. pipiens, where a recent range contraction had occurred.
I found that peripheral populations had reduced levels of genetic variation compared to
more interior populations. Moreover, I found that historic samples from peripheral
population already had reduced levels of genetic variation. Therefore, low diversity in
the remnant populations could not be ascribed to the recent range contraction.
In the fourth study, I compared genetic structure from a suite of putatively
neutral molecular markers with that derived from the color polymorphism locus.
Genetic structure at the color locus, assessed both spatially and temporally, was
indistinguishable from structure at neutral loci. This study exemplifies the importance
of investigating for evidence of selective maintenance before studies attempt to
measure the selective mechanisms maintaining a polymorphism.
Overall, my research helps to elucidate how biogeographic and
microevolutionary forces influence a wide-spread North American species, R. pipiens. / Graduation date: 2004
|
37 |
The Predators of Junnar: Local Peoples' Knowledge, Beliefs and Attitudes towards Leopards and Leopard ConservationShingote, Ramaa Jhamvar 2011 May 1900 (has links)
Conflicts between humans and leopards have intensified in the Junnar Forest Division (JFD), India due to a combination of factors: loss of natural habitats, increasing rural human densities, and increasing leopard populations. These rural and agrarian communities that have large sugarcane plantations are vulnerable to these conflicts in the form of livestock depredation and attacks on humans, which decrease the tolerance of locals towards leopards and may undermine local wildlife conservation activities. This study used structured interviews to explore local resident's views, knowledge, beliefs, attitudes and behavioral intentions towards leopards and their conservation. The mean attitudes and behavioral intentions of respondents (N = 154) was found to be positive towards leopards and their conservation. To understand behaviors towards leopards and their conservation, a socio-psychological theory, Theory of Reasoned Action (TRA), was used. Results indicate a stronger attitudinal influence on locals' behavioral intention towards leopards and leopard conservation. Although several socioeconomic and demographic variables were found to be statistically significant in relation to attitudes, this study revealed the existence of social, psychological, and cultural variables that shape the locals' perceptions of leopards and their conservation. The current study shows that local peoples' attitudes toward leopards are complex, with the view held by the same person often being characterized by both negative and positive aspects. This study does reveal positive dimensions to the local peoples' perceptions of leopards, which are relevant to conservation of this animal and serve as a foundation for recommendations regarding regulatory interventions and educational and management strategies for the future.
|
38 |
Effects of embryonic temperature, gonadal sex, and sex steroids on behavior and neuroendocrine phenotype in leopard gecko, Eublepharis macularius /Rhen, Turk Eleazar, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 153-164). Available also in a digital version from Dissertation Abstracts.
|
39 |
Life-History Trade-offs in Northern Leopard Frog (Lithobates [Rana] Pipiens) Tadpoles: Interactions of Trace Metals, Temperature, and RanavirusLeduc, Joël 19 March 2014 (has links)
Emerging infectious diseases, pollution and climate change are associated with amphibian extinction
events worldwide; however, direct causation is often obscured by the interactions of these stressors.
Elucidating the possible synergies between metal contamination and disease is, therefore, critical in
advancing our knowledge of the co-evolutionary mechanisms in host-pathogen systems and helping with
the ability to better forecast the spread of diseases in metal-stressed environments. Additionally,
increasing ecotoxicological research has improved our understanding of the complex influence trace
metals may have on the physico-chemical nature of aquatic systems; however, the discrepancy in
concentration-response within the toxicological literature makes it difficult to accurately define the range
of toxicity, often due to the variability in media used in experimentation. The first chapter of this thesis
reports an evaluation of copper, nickel and copper/nickel concentrations on several Northern Leopard
Frog (Lithobates [Rana] pipiens) larvae life history traits within field collected smelting effluent water.
Overall, results indicated that copper had a stronger negative impact on survival than nickel. However,
tadpoles exposed to copper displayed increased growth and developmental patterns while those exposed
to nickel demonstrated opposing life history traits. These results indicate that tadpoles are displaying
different fitness strategies, in terms of survival and life history, in the presence of increased copper and/or
nickel stress.
|
40 |
Habitat quality effects on the ecology of leopard on a small enclosed reserve.Owen, Cailey. January 2013 (has links)
Although the leopard (Panthera pardus) is one of the more successful large carnivores, challenges for leopard conservation emulate those of other more endangered carnivores, and they are a model species for investigating issues affecting carnivore persistence worldwide. This thesis represents a six year study of leopard on the Karongwe Game Reserve, South Africa, which provided a unique opportunity to observe various aspects of behavioural ecology in the absence of prey availability
constraints or human persecution. Small, enclosed reserves such as Karongwe make up 16.8% of the total land in South Africa and undertaking sound ecological research in these areas provides valuable data for evidence-based conservation and management. The leopard is notoriously shy and difficult to study and I used free darting and habituation to enhance visual observation, in order to understand the ecological processes influencing leopard reproductive success and survival. My results show that
leopard in the high prey area studied, consume almost double the number of ungulates as leopard in similar habitats elsewhere. This generalist predator improved its hunting success by selecting vulnerable prey and selectively hunted in habitats of intermediate density, where preferred prey were most abundant. Ample nutrition played a key role in reproductive health and reduced the duration of reproductive parameters below that previously recorded in the literature. Any additional nutritional input could not translate into increased population growth as females were already reproducing optimally. Female territorial size and habitat selection were determined by the availability of riparian habitat and resources of their preferred prey. Territoriality however was governed by prey biomass. Neighbouring leopards were territorial, sharing little space (average 11% territorial overlap) and
hunting five times more often in the core than in the rest of their territory. During periods of prey richness, females became more territorial and there was a positive “bottom up” effect through subadult recruitment. Density-dependent intraspecific and interspecific competition for limited space regulated the population around carrying capacity, and constrained population growth. These results
provide fundamental baseline data about leopard in the absence of human disturbance, or prey constraints. They highlight that, although the influence of optimal nutrition is important in the reproductive health and territoriality of leopard, habitat quality and quantity are ultimately what
govern leopard carrying capacity and population size. I provide baseline reproductive, carrying capacity and territorial data for agencies developing policy, and for setting priorities in conservation and management, as well as habitat protection and restoration, for not only this species but other threatened species as well. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2013.
|
Page generated in 0.0257 seconds