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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.
31

Influence de la dispersion endozoochore sur la composition des communautés végétales : une approche fonctionnelle basée sur trois ongulés sauvages / Influence of endozoochorous dispersal on the composition of plant communities : a functional approach based on three wild ungulates

Picard, Mélanie 16 December 2014 (has links)
La dispersion est un processus clé dans les dynamiques de populations. Chez les organismes à dispersion passive, dont les plantes, la dispersion de la banque de graines fait appel à un vecteur biotique ou abiotique. En particulier, la zoochorie influence les patrons spatiaux de distribution et de diversité des plantes à travers une interaction entre les traits écologiques du vecteur animal et de la plante transportée. Ma thèse vise à étudier l’effet de cette interaction sur la composition taxonomique et fonctionnelle des communautés floristiques. Je me concentre sur trois questions principales : (1) Comment les traits écologiques des plantes et des vecteurs influencent-ils le processus de dispersion endozoochore? ; (2) La zoochorie constitue-t-elle un filtre d’assemblage sur les traits fonctionnels des plantes dispersées? ; (3) La zoochorie imprime-t-elle un signal sur les patrons spatiaux de diversité? J’adopte à cet effet une approche expérimentale, en me concentrant sur la flore d’Europe de l’Ouest et sur les trois ongulés sauvages les plus communs dans cette région : le cerf (Cervus elaphus), le chevreuil (Capreolus capreolus) et le sanglier (Sus scrofa). Je montre que l’interaction entre les traits des plantes et des vecteurs influe sur les durées de rétention des graines, qui influencent les distances de dispersion. L’endozoochorie modifie la composition de l’assemblage d’espèces dispersé par rapport à la flore régionale en imposant un filtre fonction de l’habitat dans lequel se nourrit le vecteur animal, mais indépendant des traits morphologiques des graines. A échelle des communautés, l’effet de la zoochorie est cependant réduit relativement aux autres processus abiotiques et biotiques tels que les filtres liés à l’habitat ou l’herbivorie. Compte tenu de ces résultats, je propose de prendre en compte l’influence de la dispersion dans les modèles prédictifs de distributions des plantes, afin d’améliorer notre compréhension des dynamiques d’aires et leur prédiction en lien avec les scénarios de changements climatiques. Il apparaît en particulier nécessaire de mieux quantifier la contribution de la dispersion zoochore aux patrons de diversité et de composition des communautés végétales, relativement aux autres processus qui résultent d’interactions plantes-animaux et aux autres modes de dispersion des graines. / Dispersal is a key process shaping population dynamics. In passive dispersers like plants, the dispersal of the seed bank relies on biotic or abiotic vectors. Among the wide range of passive dispersal, zoochory influences spatial plant diversity and distribution patterns through an interaction between the ecological traits of dispersed plants and their animal vectors. In this work, I investigate the outcomes of this interaction on the taxonomic and functional composition of plant communities. I address three main questions: (1) How do the ecological traits of dispersed plants and their vectors influence the dynamics of endozoochorous dispersal? ; (2) Does zoochory affect the functional traits of dispersed species as a community assembly filter? ; (3) What is the imprint of zoochory on spatial patterns of plant diversity? I frame my work within an experimental approach focused on the West-European flora and on the three most common wild ungulates in this area: red deer (Cervus elaphus), roe deer (Capreolus capreolus) and wild boar (Sus scrofa). I show that interactions between plant and vector traits influence dispersal distances by modulating seed retention times. Endozoochory modifies the composition of dispersed plant assemblages as compared with that of the regional pool by filtering species according to the feeding habitats of the vectors. At a community level, zoochory has a limited influence relative to other abiotic or biotic processes including habitat and herbivory. On the basis of these results, I suggest to include dispersal in predictive models of plant distributions to improve our understanding of range dynamics and their prediction especially within the framework of current global changes. My results further suggest that the contribution of zoochorie to plant diversity and community composition patterns needs to be better quantified and compared with other plant-animal interactions and other dispersal modes.
32

Ecological Significance and Underlying Mechanisms of Body Size Differentiation in White-tailed Deer

Barr, Brannon 05 1900 (has links)
Body size varies according to nutritional availability, which is of ecological and evolutionary relevance. The purpose of this study is to test the hypothesis that differences in adult body size are realized by increasing juvenile growth rate for white-tailed deer (Odocoileus virginianus). Harvest records are used to construct growth rate estimates by empirical nonlinear curve fitting. Results are compared to those of previous models that include additional parameters. The rate of growth increases during the study period. Models that estimate multiple parameters may not work with harvest data in which estimates of these parameters are prone to error, which renders estimates from complex models too variable to detect inter-annual changes in growth rate that this simpler model captures
33

Vegetation studies in the management of ungulates on the Bynespoort Game Park, Cullinan

Hauptfleisch, Morgan Lindo 20 June 2008 (has links)
Please read the abstract in the section, 00front, of this document / Dissertation (MSc (Botany))--University of Pretoria, 2008. / Plant Science / unrestricted
34

Relationships among Birds, Willows, and Native Ungulates in and around Northern Yellowstone National Park

Jackson, Sally Graves 01 May 1992 (has links)
Although the impacts of livestock and human activities on riparian zones and associated wildlife have been well documented, little is known about the impacts that browsing by large native ungulates such as elk and moose may have. In the northern Yellowstone area, some willow stands experience intense browsing by elk and moose whereas others experience medium or very low amounts of browsing. The objectives of this study were (1) to compare the species and densities of birds among willow stands that have experienced different intensities of browsing by native ungulates, (2) to measure the relationship between five species of birds and aspects of habitat structure, and (3) to develop and evaluate predictive models that relate presence or absence of the five species to habitat characteristics. In 1989 and 1990, I measured densities of nesting songbirds and aspects of habitat structure in eight large willow stands that have experienced different intensities of browsing. The densities of five focal species (Common Yellowthroat, Lincoln's Sparrow, Warbling Vireo, Wilson's Warbler, and Yellow Warbler) varied considerably among sites. Only two sites had all five species and only one species--the Lincoln's Sparrow'was found in all eight sites. The proportion of severely browsed willows in the eight sites ranged from 3.5% to 100%. The nonlinear relationship between total bird densities and frequency of severe browsing suggests that birds have a threshhold of tolerance for browsing, beyond which bird numbers and total numbers of species drop. Principal Components Analysis of 14 habitat variables indicates that the study sites varied in terms of distances between shrubs, shrub heights, height heterogeneity, foliage density at various height intervals, and frequency of severely browsed willows. Browsing does appear to affect the assemblages of breeding birds in these sites, but site- and landscape-level factors such as food abundance, willow species composition, hydrology, type and gradient of adjacent community, and riparian zone width and elevation also play important roles. such variables should be incorporated into future predictive models to improve model performance. (82 pages)
35

Fire Severity and Size Alter Quaking Aspen (Populus tremuloides) Regeneration and Defense Against Ungulate Herbivory

Wan, Ho Yi 01 March 2014 (has links) (PDF)
Human activities and rapid global climate change are altering fire regimes with potential threat to the stability of aspen ecosystems in North America. Aspen is an early successional species that plays an important role in post-fire forest reestablishment, but chronic browsing on juvenile aspen by large ungulate herbivores after fire can be detrimental and lead to regeneration failure. Although larger and more severe fires are expected to become more prominent, whether and how this may influence aspen and ungulate communities remains unclear. The objective of this research was to examine how the relationship between aspen and ungulate communities might be influenced by variation in fire severity and size. In 2012, we examined browse patterns, growth responses and defense chemistry (phenolic glycoside and condensed tannins) concentrations of regenerating aspen that experienced variable burn severity in the 2010 Twitchell Canyon Fire, Utah, USA. We found that greater light availability in higher severity burn environments enhanced aspen tolerance and resistance against herbivory by increasing growth potential and defense chemistry concentrations of aspen. These results suggest that burn severity influences plant-herbivore interactions through bottom-up and top-down forces, and that higher fire severity increases post-disturbance vegetation recruitment potential by increasing resilience to herbivory. In 2013, we characterized aspen and ungulate patterns of 25 fires that spread across five National Forests (Uinta-Wasatch-Cache NF, Ashley NF, Fishlake NF, Dixie NF, and Manti-La Sal NF) in the state of Utah. We identified interaction effects between fire size and severity that strongly influenced aspen and ungulate densities. Fire size and severity are important ecological filters that can interact to affect forest reestablishment and community response. This information is useful in developing decision-making tools for wildfire and ungulate management that can more effectively increase the long-term resilience of forests systems.
36

Monitoring of Foraging Sites for Ungulates within Alpine Plant Communities and Establishment of Long-Term Monitoring Plots for Rare Castilleja parvula var. parvula in the Tushar Mountains, Utah

Shipp, Heather 14 April 2022 (has links)
The Tushar Mountains of Utah provide essential alpine habitat to a variety of flora and fauna, including 27 endemic plant species and several ungulates (mountain goats, deer, elk, cattle). These ungulates were observed throughout two growing seasons and field analyses were conducted to assess foraging selection. Overall, most ungulates, especially large nursery herds, tended to prefer foraging amongst alpine regions within the Bullion volcanic of the Tushars, which is characterized by denser vegetation than the Belknap volcanic region. Mountain goats and deer were most frequently observed foraging within the Tushar alpine habitat; however, elk and domestic cattle were also observed. Mountain goats preferred foraging at higher elevations than other ungulates and shared the most dietary overlap with deer. Out of the 27 plant species endemic to this region, only Castilleja parvula var. parvula, commonly known as the Tushar paintbrush, was encountered frequently utilized by ungulates. This plant species was also observed being eaten by a variety of rodents and lagomorphs. Long-term monitoring plots were established in four different populations of C. parvula var. parvula across the Bullion volcanic range of the Tushars. These plots were revisited on a yearly basis and used to ascertain demographic data, which will shed light on population trends over time. A variety of different measurements were used to better understand the biology and habitat requirements of this rare plant species. Although the four monitored populations share many similarities, they each have their own site characteristics, local densities, relative plant communities, and potential threats. Further monitoring is necessary to better understand trends and assess the level of the various threats to C. parvula var. parvula populations.
37

Anthropogenic effects on site use and temporal patterns of terrestrial mammals in Harenna Forest, Ethiopia

Gichuru, Phillys Njambi 22 March 2022 (has links)
There has been little research comprehensively documenting wildlife species in Harenna Forest within the Bale Mountains National Park of Ethiopia. This area is one of the few remaining afro-alpine biodiversity hotspots and is home to numerous endemic plants and animals and offers socio-economic benefits to the neighboring communities. Human population pressure, weak land protection policies, and uncertain land tenure rights have led to increases in farmland for subsistence and coffee farming, livestock grazing, and reduction of afro-alpine, shrubland and grassland habitats. Given these challenges, I used 48 camera trap stations to produce an inventory of wildlife species and to determine factors influencing occupancy (i.e., habitat use), detection, and temporal activity and overlap. I recorded 26 terrestrial and arboreal mammalian species and I had sufficient data to model occupancy for 13 species and temporal activity for 14 species. Occupancy and detection were generally higher for herbivores and omnivores (occupancy: 0.28-0.97; detection: 0.1-0.54) than carnivores (occupancy: 0.31-0.80; detection: 0.04-0.18). I found more evidence of positive anthropogenic impacts on herbivore and omnivore occupancy than negative, while detection was influenced by habitat or landscape features, rather than by humans. Carnivore occupancy was largely unaffected by anthropogenic or habitat variables, but detection was strongly, and mostly positively, influenced by anthropogenic impacts. Temporal activity analyses revealed that, for herbivores and omnivores, only tree hyraxes (Dendrohyrax arboreus) and crested porcupines (Hystrix cristata) were nocturnal, Menelik bushbucks (Tragelaphus scriptus meneliki) were crepuscular, and the remaining species ranged from diurnal to cathemeral. Neither similar body size nor similar diet affected overlap between species pairs. However, overlap with human temporal activity was low for Menelik bushbucks (Δ=0.45) and common duikers (Sylvicapra grimmia) appeared to become less active at stations with high human use. For carnivores, leopards (Panthera pardus) and honey badgers (Mellivora capensis) were crepuscular, and the remaining species were nocturnal. I found evidence that carnivores overlapped less when they were more similar in body size to other carnivores (average Δ=0.67-0.71) compared to species more dissimilar in body size (average Δ=0.75), although there was variation across species. In general, carnivores overlapped much less with humans (average Δ=0.20) than did herbivores (average Δ=0.52) and omnivores (average Δ=0.43). Spotted hyenas (Crocuta crocuta), in particular, appeared to alter activity to reduce overlap with humans. This study provides baseline information on presence, distribution, and activity of large- and medium-sized terrestrial and arboreal mammals in an understudied biodiversity hotspot. My findings are concerning for biodiversity conservation as rare and endangered species (e.g., mountain nyalas (Tragelaphus buxtoni), Ethiopian wolves (Canis simensis)) were rarely or never photographed, and larger carnivores (e.g., lions (Panthera leo), leopards, jackals), generally had low capture rates. The species with higher capture rates, occupancy, and activity tended to be those that can tolerate or take advantage of human activity and disturbance. Species sensitive to human disturbance eventually may be lost unless measures can be put in place to reduce human impacts. This baseline knowledge is important for future studies examining trends in mammalian wildlife populations, such as site extinction and colonization, or changes in overlap with humans, in a landscape that is continuing to experience human-caused, landscape change. / Master of Science / Harenna forest, which is located in Bale Mountains National Park, Ethiopia is an important habitat to both wildlife and people. However, it faces a number of challenges as a result of population growth leading to increased coffee farming and livestock grazing resulting in reduced habitat for wildlife species. I used 48 cameras located across the forest to record presence of terrestrial mammals and document their distribution and daily activity across the landscape. I also used data such as vegetation indices, elevation, and distances to human-disturbed areas to determine what influenced wildlife species. Cameras recorded 26 species of mammals. I had enough data to determine distribution for 13 species and daily activity for 14 species. I found that presence across the landscape and activity of herbivores and omnivores was generally higher than that of carnivores. Additionally, I found that human activity or disturbance often had a positive influence on herbivore and omnivore distribution, but my ability to detect species in camera traps was primarily influenced by habitat or landscape features. Carnivore distribution on the landscape was not influenced much by humans or habitat, but their detectability was often positively influenced by presence of humans. In addition to daily activity, I also analyzed overlap in activity between species pairs and between species and humans, to determine whether wildlife changed their temporal activity to overlap less with similar sized competitors or in response to high human use. For herbivores and omnivores, I found that tree hyraxes and crested porcupines were active at night, Menelik's bushbucks were active at sunrise and sunset, and cape bushbucks, common duiker, olive baboon, bushpig, and giant forest hogs were active either during the day or throughout the day and night. I found little evidence that the herbivores or omnivores avoided each other temporally and only the Menelik bushbuck and duiker appeared to avoid humans. For carnivores, I found that leopards and honey badgers were active early morning and evening, and the common genet, African civet, white-tailed mongoose, and spotted hyenas were all active at night only. Carnivores generally overlapped less with humans than herbivores and omnivores. I found some evidence that carnivores more similar in body size had lower temporal overlap with each other and that spotted hyaenas appeared to avoid activity during times of day when humans were active. My study not only provides baseline information on terrestrial and arboreal mammals present in Harenna forest, Ethiopia, but is also necessary for understanding how wildlife species use the landscape and particularly how presence of humans influences wild animal behavior. My findings are concerning for biodiversity conservation because I had few to no photographs, respectively, of the endangered mountain nyala and Ethiopian wolf. In fact, most of the species with a wide distribution on the landscape, or with high activity, were common or smaller species that are tolerant of, or could take advantage of, human disturbance. Without concerted effort to curtail the current landscape change caused by humans, the area is likely to lose species less tolerant of humans, and biodiversity will ultimately decline.
38

From antelopes to zebras: which factors explain inter- and intraspecific variation in ungulate cognition?

Schaffer, Alina 16 October 2024 (has links)
Cognition is the mechanism by which animals acquire, process, store, and act on information from the environment, including perception, learning, memory, and decision-making (Shettleworth 2009a). Comparative cognition aims to investigate how cognitive skills are distributed across taxa, and thus find the socio-ecological challenges that might explain this distribution (Healy et al. 2009; MacLean et al. 2012). As a result, comparative cognition allows researchers to find variations in problem-solving abilities, better understand the processes that lead to the emergence of complex cognition, and understand the evolutionary challenges that are linked to the emergence of specific skills (Barrett et al. 2002; Bueno-Guerra and Amici 2018; Dunbar 1992; Harcourt et al. 1988; MacLean et al. 2012; Shettleworth 2009a). In their natural environment, animals face a variety of ecological and social challenges. Theories of cognitive evolution suggest that these challenges have favoured the emergence of cognitive skills that allow individuals to better cope with the requirements they encounter in their ecological niches, like foraging or interacting with conspecifics (Ashton et al. 2018; Holekamp 2007; Tomasello and Call 1997). Therefore, cognitive skills usually evolve when individuals face specific problems, either in a physical context (i.e., cognitive processes used to solve physical problems) or in a social context (i.e., cognitive processes used to interact with social partners). In my thesis, I focus on physical cognition and object understanding, which includes how animals deal with inanimate objects and what they understand about their spatial, temporal, and causal relations. One reason why some species may have evolved different cognitive abilities is that they face specific ecological challenges which the evolution of complex cognition, and thus greater behavioural flexibility, allows to overcome more efficiently. These ecological challenges include, for example, dietary breadth or domestication. Moreover, social challenges may also constitute a strong selection pressure for the evolution of enhanced cognitive abilities. When social life is complex, individuals must use flexible cognitive strategies to recognize other individuals, keep track of their relationships, and predict, coordinate and manipulate their behaviours. Unlike objects, social partners are reactive, unpredictable and respond with different behaviours to one's actions; therefore, social complexity would present high cognitive challenges and strong selection pressures for the evolution of cognition. Social challenges include, for example, living in large groups, frequently engaging in social interactions, or showing fission-fusion dynamics. Apart from interspecific variation, cognition also varies across conspecific individuals, depending on factors such as sex, age, rank, social integration or early life experiences. In addition to these characteristics, personality traits (i.e., interindividual behavioural differences that are consistent over time and across contexts) may also influence performance on cognitive tasks. In this project, I used ungulates as a model to directly test socio-ecological hypotheses about the evolution of cognition. Ungulates are an ideal model to test cognitive abilities from a comparative perspective. First, they show an impressive diversity of socio-ecological traits, which allows for a reliable contrast of different evolutionary hypotheses. Second, there are very few studies that have examined the relationship between cognition and socio-ecological traits in ungulates, and the largest majority have used neuroanatomical proxies for cognitive skills. Third, although ungulates are economically important for humans, we still know little about their cognition, and about the cognitive enrichments that might be used to improve their welfare. This thesis aimed to test variation in different cognitive skills across several ungulate species, to assess the ecological, social and individual factors that best explain inter- and intra-specific variation in their cognitive abilities. I used well-established experimental procedures to test individuals´ object permanence, short-term memory, causality, understanding of object properties, gravity and quantity discrimination skills. Further, I tested individuals´ neophobic reactions to new objects. All tests were carried out on captive individuals in the zoos of Leipzig (Germany) and Barcelona (Spain), and partially in other European zoos. I tested the following species in one or more studies: goats (Capra aegagrus hircus), llamas (Lama glama), guanacos (Lama guanicoe), Grevy’s zebras (Equus grevyi), Chapman’s zebras (Equus burchelli chapmanni), rhinos (Diceros bicornis michaeli), giraffes (Giraffa camelopardalis rothschildi), European bisons (Bison bonasus), Forest buffalos (Syncerus caffer nanus), oryx (Oryx dammah), dromedaries (Camelus dromedarius), red deer (Cervus elaphus), barbary sheep (Ammotragus lervia), Przewalski horses (Equus ferus przewalskii), and sheep (Ovis aries). In summary, 15 different ungulate species were tested in well-established experimental procedures to test individuals´ object permanence, short-term memory, causality, understanding of object properties, gravity and quantity discrimination skills. Further, individuals´ neophobic reactions to new objects were tested. In the first paper on neophobia, I tested neophobic responses to novel objects in different ungulate species and found differences both within and across species. In particular, more socially integrated individuals were more neophobic than less central ones, showing a higher latency to approach food that was closer to a novel object. Further, Barbary sheep were less neophobic than all the other species and spent a higher proportion of time close to novel objects. In the second paper, I tested whether higher levels of fission-fusion dynamics predict better cognitive skills. I found Grevy´s zebras (which are characterized by higher fission-fusion dynamics) to perform better than Chapman´s zebras in tasks requiring inference and quantity discrimination skills. In the third paper, I tested the cognitive skills of ungulates in different object-understanding tasks and showed that all species were able to understand that objects continue to exist even when they are out of sight, remember the location of objects after delays of up to 60 seconds (short-term memory), and infer the location of the food from the presence or lack of sound produced when shaking containers. I found that subjects, across species, had some understanding of object properties and gravity, being able to locate food behind one of the two occluders based on their shape and inclination, and searching for falling food in the correct location. In the fourth paper, individuals performed above chance levels in most conditions of the Numerosity and Size tasks, in which they had to rely on item number and size to maximize food intake. Overall, I detected inter- and intra-specific variation across the cognitive tasks performed. The socio-ecological factors that explained the inter-specific variation were domestication (i.e., species that have been selected for living in close relationships with humans), group size (i.e., the actual size of the tested group) and fission-fusion dynamics (i.e., individuals living in groups frequently splitting into subgroups of varying size and composition). Apart from inter-specific variation, I could also detect inter-individual variation, with socially more integrated individuals being more neophobic. Taken together, the results of my thesis show that different inter- and intra-specific factors lead to variation in cognitive skills between ungulate species.
39

La chasse aux trophées : conséquences comportementales, démographiques, et évolutives chez les populations d'ongulés : l’exemple des ongulés des savanes africaines / Trophy hunting : behavioral, demographic, and evolutionary consequences in ungulate populations : the example of the ungulates of African savannahs

Crosmary, William Georges 11 May 2012 (has links)
La chasse aux trophées peut contraindre les ongulés à ajuster leur comportement pourréduire le risque de mortalité. De plus, comme cette chasse est basée sur des critères detaille, et biaisée en faveur des mâles, elle peut causer des changements morphologiquesvers des individus plus petits, et altérer la structure et la dynamique des populations. Lachasse aux trophées est l’un des modes de conservation des habitats naturels. Son potentielde conservation est encore incertain parce qu’il y a peu d’études en dehors des parcsnationaux, notamment en Afrique. Cette thèse examine les effets de cette chasse sur lesongulés africains, i.e. sur leur comportement, la longueur des cornes, la proportion de mâlesadultes, la taille de groupe, et la densité des populations. J’ai travaillé à partird’observations comportementales et de données populationnelles de suivis à long terme.Pour plusieurs espèces (surtout l’impala Aepyceros melampus, le grand koudouTragelaphus strepsiceros, et l’hippotrague noir Hippotragus niger), j’ai comparé lecomportement, la structure et la densité des populations entre le Parc National de Hwangeet les zones de chasse adjacentes, Zimbabwe. Dans les zones de chasse, j’ai analysé lestendances de longueur des cornes au cours des 30 dernières années. Les ongulés venaientdavantage de nuit aux points d’eau, et étaient plus vigilants dans les zones de chasse quedans le parc national. L’amplitude de ces ajustements en revanche, était limitée par lebesoin en eau, et par le risque de prédation naturelle. La longueur des cornes a décliné, plusparticulièrement pour les espèces prisées des chasseurs et subissant une pression de chasseélevée. Il n’y avait pas de différence significative de la proportion de mâles adultes, ou dela taille de groupe, entre les populations du parc national et des zones de chasse. Au coursdes 30 dernières années, les densités de population ont globalement davantage diminuédans le parc national que dans les zones de chasse. Ceci suggère que la chasse aux trophéesn’a eu qu’un effet minime sur les densités de population par rapport à d’autres facteurscomme les précipitations, ou possiblement la prédation naturelle et l’éléphant. Malgré lesajustements comportementaux, le déclin de la longueur des cornes, et le prélèvement biaiséen faveur des mâles adultes, les densités d’ongulés étaient aussi élevées dans les zones dechasse que dans le Parc National de Hwange. Cette étude illustre comment les zones dechasse aux trophées, lorsque rigoureusement gérées, peuvent jouer un rôle dans laconservation des ongulés africains. / Like predation, trophy hunting may constrain ungulates to adjust their behaviour todecrease mortality risk. Moreover, because this removal is size selective and male-biased, itmay induce morphological changes towards individuals with smaller traits, alter populationstructure and dynamics. Trophy hunting is one of the conservation modes of naturalhabitats, particularly in Africa. However, its conservation potential is still unclear becausethere are few studies outside National Parks. This thesis aimed to investigate the subtleeffects of trophy hunting on African ungulates, i.e. on their behaviour, horn length ofharvested males, proportion of adult males, group size, and population densities. I workedfrom behavioural observations, and from population data of long-term surveys. For severalspecies (mainly impala Aepyceros melampus, greater kudu Tragelaphus strepsiceros, andsable antelope Hippotragus niger), I compared behaviour, population structure, anddensities between Hwange National Park and adjacent hunting areas, Zimbabwe. In huntingareas, I analysed trends in horn length of harvested males over the past 30 years. This thesisshows that ungulates drank more often at night, and were more vigilant in hunting areasthan in the national park. However, the amplitude of these adjustments was constrained bythe need of surface water, and by natural predation risk. Trophy hunting caused a decline inhorn length, particularly for species that experienced high hunting pressure and were ofhigh value for hunters. Trophy hunting tended to decrease proportion of adult males,though not significantly, and did not affect group size. Moreover, during the last 30 years,ungulate densities generally declined more in the national park than in neighbouringhunting areas. This suggests that trophy hunting played a minor role on densities comparedto other factors, i.e. rainfall, and possibly natural predation and elephant densities. Despitebehavioural adjustments induced by hunting risk, decline of horn length, and harvestskewed towards adult males, ungulate densities in hunting areas adjacent to HwangeNational Park remained comparable to densities within the national park. This studyillustrates how trophy hunting areas, when rigorously managed, may play a significant rolein the conservation of ungulates in Africa.
40

How does the ungulate community respond to predation risk from cheetah (Acinonyx jubatus) in Samara Private Game Reserve?

Makin, Douglas Ferguson January 2012 (has links)
Predator reintroductions are becoming increasingly more common for multiple reasons, including assisting with the conservation of a predator species, the restoration of ecosystem functions and the economic benefits of their reintroduction for ecotourism ventures. There remains however, little knowledge on prey species responses to these predator reintroductions. As such, the reintroduction of cheetah (Acinonyx jubatus) into Samara Private Game Reserve provided an opportunity to investigate prey responses to predator reintroduction across a range of spatial and temporal scales. More specifically, the aim of this study was to investigate the effect of cheetah predation risk on habitat use and behavioural responses of the resident ungulate community. Samara is divided into “predator present” and “predator absent” sections, providing the opportunity to conduct a comparative study investigating the effect of cheetah on prey responses. It was hypothesized that different ungulate species would respond differently to the presence of cheetah, depending on differences in perceived vulnerability to cheetah predation. To address this, shifts in habitat use, and behavioural responses of the ungulate community reflected at landscape and patch scale were investigated. Overall, ungulate species have not shifted habitat use since cheetah reintroduction, this was possibly related to life history strategy constraints and the need for individuals to obtain suitable forage and therefore remain in specific habitats. While no shift in habitat use was observed for the majority of ungulate species, a shift in behaviour was observed for kudu (Tragelaphus strepsiceros) at a landscape scale, where kudu dedicated more time to vigilance and less time to foraging within the predator section. In addition, individuals within smaller kudu groups were observed to be more vigilant than individuals within larger groups of kudu within the predator section. Although the other three ungulate species monitored did not increase time spent vigilant within the predator section, they still maintained relatively high levels of vigilance, potentially as a means of social monitoring. At a patch level, ungulate species responded strongly to a predator cue as a proxy for cheetah proximity, and increased time spent vigilant with a trade-off of lower foraging effort. This vigilant response was strongest for kudu. Differences in perceived predation risk were reflected within eland (Tragelaphus oryx) and kudu species demographic classes, with juvenile eland and kudu, adult female kudu and subadult female kudu spending more time vigilant within manipulated patches than respective males of each species. Kudu were also observed adopting fine-scale behavioural responses to minimize predation risk within patches. The asymmetrical prey species response to perceived predation risk from cheetah supports the hypothesis that different species respond differently to the presence of a predator. Furthermore, this study illustrated the importance of measuring prey responses to predation risk across multiple scales and highlighted the need to replicate this study for a number of different sites where predators have been reintroduced, to better understand the range of factors influencing these predator-prey interactions.

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