• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 4
  • 4
  • 2
  • 1
  • Tagged with
  • 28
  • 10
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 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

The susceptibility of leopards Panthera pardus to trophy hunting : the trophy hunting of leopards

Braczkowski, Aleksander Ryszard January 2013 (has links)
The trophy hunting of African leopards Panthera pardus pardus may generate revenue to help foster their conservation. However, leopards are sensitive to hunting and populations decline if overharvested. The practice therefore requires careful management grounded in robust estimates of population density/status. Camera-trap surveys are commonly used to establish leopard numbers, and may guide harvest quotas. However, such surveys are limited over wide spatial scales and many African governments lack resources to implement them. In this thesis I explore the potential use of a harvest composition scheme applied to puma Puma concolor in North America, to monitor leopards. The method hinges on the susceptibility of different leopard cohorts to hunting and if this varies, then predictions can be made about harvest composition. Susceptibility is likely to be governed by space use, encounter rates with bait lures (a common method used to attract leopards to hunting hides) and hunter selectivity. Thus in this thesis I explore leopard susceptibility to these factors using a protected leopard population in northern Zululand, South Africa. In my first chapter I examine using scent lures in camera-trapping. Against a backdrop of a passive survey I show adult males, females and sub-adults are captured at similar rates compared to a passive survey using lures. The use of lures does not appear to violate closure assumptions or affect spatio-temporal patterning, but their use appears limited as density estimate precision is not improved. My second chapter examines ecological (likelihood of encountering a hunter) and anthropogenic (attractiveness to hunters) susceptibility of leopards to trophy hunting. I show that adult males are the most susceptible cohort to hunting (sub-adults least susceptible). I then take the incident rates from ecological and anthropogenic models and create a theoretical harvest composition using population parameters of protected leopards. My third data chapter departs from hunting susceptibility and examines determinants of leopard trophy package price across Africa. I show that factors such as trophy quality, outfitter leopard hunting reputation and hunt success have little impact on price determination. Instead, overall outfitter reputation and the number of charismatic species in a package are positively correlated with price. These results have important consequences on several sustainable leopard hunting schemes proposed in the literature.
12

Effect of a Temporary Hunting Ban on the Demography of African Lions (Panthera Leo) Using a Protected Area

Mweetwa, Thandiwe, Mweetwa, Thandiwe January 2016 (has links)
Large carnivores are in decline throughout their range primarily due to anthropogenic influences. This is a concern because these species have high social, economic and ecological value. African lion (Panthera leo) populations are in decline in most parts of the continent and this has been attributed largely to habitat loss, habitat fragmentation, wire snare poaching, black market trafficking in lion parts, retaliatory killings, and poorly regulated trophy hunting. In order to implement effective lion conservation actions, the effect of each factor on lion demography or population dynamics must be well understood. In the past, most studies have used indirect methods to quantify the effects of hunting on lion demography. The temporary ban on lion hunting in Zambia allowed me to study directly how removing a key source of mortality, for males in particular, changed the demography. Using data collected from 2008-2015, I studied how the lion population in and around South Luangwa National Park, Zambia responded to a 3-year moratorium on lion trophy hunting implemented in 2013. For the duration of the study ban, I monitored 386 known individuals in 19 prides and 15 male coalitions. Reproductive activity as represented by cub production appeared to improve after the hunting ban and the number of individually identifiable lions in the study area steadily increased from 88 in 2008 to 197 in 2015. Using a Cormack-Jolly-Seber model, I found that apparent annual survival increased in the absence of hunting for all adult male age classes. The temporary ban on hunting was lifted in 2016 and I recommend that quotas remain conservative in order to allow more time for the population to recover, particularly in the adult male age classes. Better monitoring protocols should also be implemented to promote compliance with hunting regulations.
13

Best of

Aleck, Nimer I, II 26 April 2011 (has links)
The majority of modern popular trophies seem to act as memorials to small victories. Foiled plastic figures sitting atop extruded tubes of holographic tape are given for everything from internationally recognized achievement to participation in regional events. These architectural sculptures are icons of success. This thesis explores the themes, processes, and contexts that inform the ways that we perceive value. Using the iconography of the popular modern trophy, this thesis and the artwork associated with it examines the constructs of value within visual culture. My goal is to display and understand the way we appreciate and define that which implies worth.
14

Přehled obchodu s exempláři nosorožců / Overview of the trade in specimens of rhinoceros

JEŽKOVÁ, Věra January 2015 (has links)
The subject of this thesis was focused on the analysis of international trade with selected specimens of rhino species (trophies, horns, live rhinos, carvings, horn carvings, derivatives) in 2004 - 2013. The trade at the European Union, taking into accounts the position of the Czech Republic, and the global worldwide trade were evaluated in term of importer and exporter and source, purpose and origin of specimens. Evaluation was based on data from the Cites Trade Database which was further processed via contingency tables and graphs. It was found that there was a decrease of import and export in 2013. The most imported specimens were live rhinos in the world (40,5%) and trophies in the European Union, the most exported specimens were trophies in the world (39,4%) and carvings (80,7%) in the European Union. The largest importer was USA in the world (16,6%) and Spain in the European Union (3%). The largest exporter in the world was South Africa (73,9%) and United Kingdom in the European Union (4,6%). The Czech Republic was imported 0,8% of total import and exported 0,2% of total export. Imported specimens came mostly from the wild (62,1%), the country of origin was not completed and were imported mainly as hunting trophies (33,4%). Exported specimens came mostly from the wild (76,3%), the country of origin was not completed (82,2%) and were exported primarily as hunting trophies The results indicate an overall downward trend in the legal trade but also confirm the considerable interest in horns in Asia. Therefore, it is necessary to continue to monitor all transactions.
15

Vliv rybníků a rybničních soustav na složení bentosu horní Lužnice / Effect of ponds and pond systems on the composition of the benthos in horní Lužnice

SVAČINA, Petr January 2013 (has links)
The work is focused on monitoring changes in benthic communities in the longitudinal gradient of the river Lužnice. The river flows through to the pond area Třeboňsko and the largest pond of the Czech Republic - Rožmberk. It is examine affect of pond on benthic communities. The work involves collecting benthos according to the PERLA method on four profile in four seasons, the analysis of chemical parameters and data processing. The values of SI (saprobiological index) in the longitudinal gradient were from SI 1.8 to SI 2.6. SI values were at the outflow of Rožmberk higher than at inflow. The lowest values were in the first profile Suchdol (SI 1,8 ? SI 2,1) and higher values were in the last profile Vlkov (SI 2,4 ? 2,6). The chemical parameters at outflow were observed increased values of BOD5, TOC, NL105, NL505, chlorophyll and total P but lower values of nitrogen forms (Ntotal,NH4, N-NO3-). On the each profile was the significant change in the incidence or absence of certain groups. Profiles Suchdol and Hlína were diferent than Lužnice and Vlkov especially in the presence of stoneflies, dragonflies, beetles, and individuals generally indicates good water quality. Profiles at outflows from Rožmberk (Lužnice and Vlkov) showed a continued presence of bloodsuckers and more species indicating high organic pollution. NMDS method confirmed impact of sites in communities rather than period (R2 = 0.6 at significance level of p = 0.001).
16

Reported & Reported: differences among local and international game hunting data and potential reasons on the example of South Africa

Johanisová, Lucie January 2020 (has links)
The South African wildlife tourism industry is based on trophy hunting and together with international wildlife trade it can represent a major treat to biodiversity conservation. Annually, thousands of hunters participate in hunting activities in South Africa and thousands of trophy items are traded across international borders. This research is a result of comprehensive quantitative analysis in how far data of trophy hunting kills and data of trophy export are consistent on the example of South Africa. Data were extracted from 2 different sources: trade data reported under the CITES Trade Database on export of trophy items from South Africa within the year 2018; South African Professional Hunting statistics (SAPHs) containing trophy kills information for each species and the country of origin of the hunter. In the year 2018, a total of 3,126 hunting trophy items of 28 endangered taxa were exported out of South Africa to 37 countries that contributed to trophy hunting trade in South Africa. However, 64 countries participated in trophy hunting of endangered taxa in South Africa and a total of 4,726 trophy kills of 28 trophy-hunted endangered taxa were reported. Therefore, the level of inconsistence in data of trophy hunting kills and data of trophy hunting export is significant and differs to varying degrees across the countries contributing to trophy hunting and CITES-listed trophy-hunted species. This research provides possible reasons for the inconsistency and propose recommendations for improving the CITES reporting system. / <p>2020-06-10</p>
17

Určení zdrojů fosforu a stanovení nápravných opatření eutrofizované Hornoveské nádrže / Determination of phosphorus sources and determine of corrective measures of Hornoveské eutrophic reservoir

Čech, Dalibor January 2012 (has links)
The aim of the present master's thesis is to assess the problem of eutrophication in the reservoir named Hornoveská reservoir near the city of Fryšták. The main goal of this thesis is to do a search report on the topic of eutrophication of surface waters, to do practical measurement and make samples in the Hornoveská reservoir, and then evaluate results from these actions and determine the source of phosphorus in the reservoir. Last goal is to suggest actions which can improve the condition of reservoir by limitation the occurrence of algae and cyanobacteria in the summer period.
18

The influence of hunting activity on African elephant (Loxodonta africana) movements

Nobrega, Catherine Elizabeth Pinho January 2015 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Masters of Science (Environmental Sciences). September 2015. / African elephants (Loxodonta africana) are still being poached and hunted and this could potentially affect their movement. As a keystone species, crucial to maintaining ecosystem function and therefore food webs, it is important to understand the effects hunting may have on their movements. This study was undertaken in the Associated Private Nature Reserves adjacent to the Kruger National Park, where elephants are hunted. I looked at changes in daily displacement distance and distance from hunting and natural mortality events to determine if elephants were affected by hunting events, up to what distance, and to determine whether elephants reacted in the same way to hunting and natural mortality events. I found that elephants are only affected by hunting events when within 1 km of the event, which is consistent with the literature. When considering natural mortality events, they actually diverted movements towards the event location, which is also consistent with literature. These results, however, are based on a very small sample size. In addition, the time of day of the events was not recorded by the wardens of the reserve, and this provided a further limitation for the data analysis and interpretation.
19

Bioarchaeological Analysis of Isolated Crania from the Elizabeth Site in the Lower Illinois River Valley

Jones, Daniel 09 May 2015 (has links)
This thesis explores the life history of six isolated skulls interred in Mound 3 of the Elizabeth site, a Middle Woodland site in the lower Illinois valley. This study employs analyses of osteological features, stable and radiogenic isotopes, and biodistance for a cross-section of the Mound 3 population (n=15), including the isolated crania. Isotopic results reveal significant variation in lead isotope ratios in enamel, and interpretively meaningful variation in strontium values. However, bone carbonate oxygen values are not significantly different. Carbon isotope values from bone carbonate revealed only sex-based dietary differences. Biodistance data indicate relatively genetic homogeneity at the site, although significant variation was present in two of the isolated crania. Ultimately, data indicate that two of the six isolated skulls likely originated from elsewhere in the valley, but that the population likely resided in the Elizabeth site vicinity in the decade preceding death, and were not outsiders.
20

Etude des effets de l'arsenic et du cuivre sur un macrophyte aquatique, Myriophyllum alterniflorum D.C. : évaluation des biomarqueurs pour la détection précoce de pollution / The effects of arsenic and copper on an aquatic macrophyte Myriophyllum alterniflorum DC : evaluation of biomarkers for early detection of pollution

Krayem, Maha 15 December 2015 (has links)
L’utilisation des plantes aquatiques comme indicateurs de la qualité des eaux de rivière a débuté dès le XXème siècle. Parmi les macrophytes utilisés, le myriophylle à fleurs alternes, Myriophyllum alterniflorum a démontré dans plusieurs études sa capacité bioaccumulatrice des métaux et son intérêt en tant que bioindicatrice de qualité de l’eau. L’objectif de cette étude est d’identifier chez cette espèce des biomarqueurs sensibles pour la détection précoce de pollution d’une rivière par un métal, le cuivre et un métalloïde, l’arsenic. Pour atteindre cet objectif, un milieu synthétique dont la composition est représentative de la qualité des eaux de la rivière Vienne, a été préparé (milieu Vienne). Une fois les conditions opératoires maîtrisées, le développement du macrophyte est suivi dans trois milieux : un milieu témoin, un milieu contaminé en cuivre et un autre en arsenic avec des concentrations d’exposition au polluant de 100 µg/L pendant 21 jours. Durant cette période, des biomarqueurs physiologiques (activités respiratoires et photosynthétiques, potentiel osmotique), biochimiques (les concentrations en chlorophylle a, b et en caroténoïdes, les teneurs en malondialdéhyde, les phytochélatines) ont été analysés. Ces suivis ont été réalisés en système fermé dans des boites de culture de 400mL in vitro en tenant compte de la trophie du milieu (condition eutrophe et oligotrophe), puis en système recirculé dans des aquariums de 150 L, toujours dans le milieu Vienne, mais cette fois en se plaçant dans différentes conditions hydrodynamiques (zones turbulente, laminaire à une vitesse de 3 cm/s et calme). / Alternate watermilfoil, Myriophyllum alterniflorum is an aquatic macrophyte presented in the rivers of the Limousin region in France whose potential for bioindication of metal pollution has been demonstrated. The objective of this study is to identify in this species sensitive biomarkers for the early detection of pollution in a river by a metal copper, and a metalloid, arsenic. To achieve this goal, a synthetic medium whose composition is representative of the water quality of the river Vienne, was prepared (Vienne medium). The composition of the medium studied is verified by ICP-MS and ion chromatography (IC). The development of the macrophyte was followed in a control medium, a copper contaminated medium and another contaminated with arsenic at a concentration of 100 µg/L for 21 days. During this period, the respiratory and photosynthetic activities of Myriophyllum alterniflorum, the concentrations of chlorophyll a, b and carotenoids, levels of malondialdehyde, osmotic potential, and phytochelatins were recorded. This monitoring has been made in a closed system (400mL culture boxes) taking into account the trophy of the medium (eutrophic and oligotrophic conditions), and then in a recirculating system (aquariums of 150 L) taking into account the hydrodynamic conditions (turbulent, laminar and quiet areas).

Page generated in 0.028 seconds