Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 102-104). Also available via the Internet.

There is a need for a refined understanding of large carnivore prey preference and carrying capacity (K). To date, K estimates for large carnivores have been developed from predictions of carnivore diet at a prey and predator species-level. These predictions therefore assume that all social classes within a carnivore species display similar prey preferences and that all demographic classes within a prey species are equally preferred or avoided. The objective of this study was to investigate the importance of including prey demographics and carnivore social class in carnivore diet descriptions and thereby K estimates, using cheetah Acinonyx jubatus as a study species. It was predicted that prey sex, prey age and cheetah social class influence cheetah prey preferences, when they influence the risk and ease of prey capture, and that their inclusion in a K model would improve its predictive strength. Based on an analysis of 1290 kills from South Africa, male coalition cheetah were found to prefer a broader weight range of prey than solitary cheetah. Prey demographics further influenced cheetah prey preference, when it corresponded to differences in prey size and the presence of horns. The current species-level K regression model for cheetah is based on preferred prey and thus omits highly abundant antelope that often comprise the majority of the diet, an artefact of the way in which preferences are calculated. A refinement of the species-level K regression model, to account for prey demographic- and cheetah social class-level differences in diet and the biomass of accessible prey (defined in this study as all non-avoided prey) instead of just preferred prey, doubled the predictive strength of the K model. Because group-hunting enabled predation on a broader weight range of prey, cheetah K was influenced by the ratio of male coalition cheetah to solitary cheetah in the population. The refined K regression model is derived from ecosystems supporting an intact carnivore guild. A mechanistic approach to estimating K, based on Caughley‟s (1977) maximum sustainable yield model, therefore better predicted cheetah K in systems devoid of lion Panthera leo and African wild dog Lycaon pictus, which were found to suppress cheetah density. This study improves our understanding of the relationships between prey demographics, cheetah social classes and intra-guild competition in determining cheetah prey preferences and K. This study therefore paves the way for similar work on other large carnivores.

Investigations were made into the trapping biology of the pitchers of Nepenthes rafflesiana (Jack), Family Nepenthaceae, in Brunei, Borneo. The plant produces two distinct pitcher forms, upper and lower, which were found to differ in their prey spectra. Although ants were the most important prey in both forms, the upper form caught more anthophilous insects than the lower. High contrast U/V patterns on the upper pitchers were found to contribute to the attraction of some anthophilous insects, as was the fragrance of upper pitcher fluid. Increased height above ground was also found to increase the numbers of anthophilous insects caught. Upper pitchers possessed features of several pollination syndromes, but may have been mutualistic rather than mimetic, as certain criteria for mimesis were not met. Evidence for mutualism is strongest for ants, in which both pitcher forms were found to be specialising, although the involvement of lower pitcher 'wings' in such a relationship, was discounted. The loss of wings from the upper pitcher form may have occurred to reduce strain on the upper pitcher-tendril attachment. Reduction of fluid volume, and strengthening of the attachment in upper pitchers, support this idea. The possession of upper pitchers was found to allow N.rafflesiana access to populations of anthophilous insects that were not as easily available to the sympatric Nepenthes gracilis (Korth). There was found to be a shift in the prey spectrum of lower N.rafflesiana pitchers, as pitcher size increased. Production of lower pitchers was found to increase when upper pitchers were rendered non-functional. This may allow the plant to regenerate after stem damage. Although covering of pitchers failed to produce a decrease in either male flowering success, or &'37 age of viable seeds produced by female plants, pre-flowering pitcher counts suggested that pitchers were an important factor in reproductive fitness.

Thesis (Ph. D.)--University of Queensland, 2003. / Includes bibliographical references.

Lethal carnivore management, aimed at reducing carnivore impacts, threatens the persistence of carnivores globally. The effects of killing carnivores will depend on their life histories and social structures. Smaller canids, like black-backed jackals (Canis mesomelas), are highly adaptable and display variable population-level responses to mortality sources, which may contribute to their success in fragmented landscapes. Jackals, the dominant predator of livestock in South Africa, are widely hunted to reduce this predation. This hunting is heterogeneous across the landscape, focussed on livestock and game farms, with nature reserves acting as refuges. The aim of this research was to investigate the ecology and population dynamics of jackals in response to heterogeneous anthropogenic mortality. I hypothesized that the spatial variation in hunting results in the formation of a source-sink population structure, which contributes to the persistence of jackals. I addressed this hypothesis by evaluating two criteria, essential for the formation of a source-sink system in larger mammals. Firstly, I confirm that hunting pressures result in the formation of distinct subpopulations with asymmetrical dispersal (i.e. compensatory immigration) from unhunted reserves to neighbouring hunted farms. Secondly, I show that jackal subpopulation display asynchronous demographics, with farm populations displaying a relatively younger age structure and an associated increase in reproductive output (i.e. compensatory reproduction). This confirms the formation of a hunting-induced source-sink system. additionally, I show that jackals have a catholic diet, which confers a level of adaptability to direct (anthropogenic mortality, prey provisioning) and indirect (alteration in prey base) habitat modifications. This dietary flexibility allows jackals to obtain the appropriate resources to achieve reproductive condition. The relatively better body condition of younger jackals in sink habitats allows for compensatory reproduction which contributes to the success of jackals on hunted farms. Based on my findings, I hypothesize that the compensatory life history responses of jackals to anthropogenic mortality may be ascribed to two interconnected mechanism. Dispersal is presumably driven by density-dependent interference competition, as dominant territorial pairs outcompete subordinates in high-density reserve areas, forcing them to disperse onto low-density farms (i.e. ideal despotic model). Additionally, farms likely represent attractive habitats, owing to a reduction in conspecifics and a concomitant increase in resource availability (including anthropogenic resource provisioning). Therefore, dispersing subordinates presumably select for farms which are perceived as good quality habitats, as the high risks of anthropogenic mortality cannot be perceived by dispersing individuals. This results in the formation of an attractive sink or ecological trap. These compensatory processes will continue to counter population management actions as long as recruitment from unmanaged areas persists. This hypothesis provides a conceptual framework for future research directions in understanding jackal persistence and management (i.e. specifically focussing on controlling dispersal) of jackal populations.

Utricularia is the only genus in Lentibulariaceae of Taiwan. The morphology of Utricularia is highly diverse due to the habitats variation, which results in the difficulty to identify the species of this genus. This study emphasizes the morphology of Utricularia, and combines with the information of field observation and the cultivation, to ensure the influence of environmental change on external morphology, especially the characters of stolons, rhizoids, leaves, flowers, fruits, pollens, seeds, and traps. Further, the taxonomic value of trap glands between species is discussed. There are seven species recognized in Lentibulariaceae of Taiwan; namely, U. aurea Lour., U. australis R. Br., U. bifida L., U. caerulea L., U. gibba L., U. striatula Sm., and U. uliginosa Vahl. In addition, U. minor L. and U. inflata Walter are treated as doubtful species.

Thesis (doctoral)--Ludwig-Maximilians-Universität München, 2003. / Includes bibliographical references (p. 226-236). Also available via the World Wide Web: http://edoc.ub.uni-muenchen.de/archive/00001078/01/Meimberg_Harald.pdf

Determining carnivore diets and how they may change over time is important if the management of large carnivores is successful in an enclosed reserve. Carnivore diets are known to shift over time in response to a variety of factors. These factors include prey availability and climatic conditions (rainfall patterns). The re-introduction of lions (Panthera leo) and spotted hyaena (Crocuta crocuta) to Addo Elephant National Park (AENP), South Africa provided the opportunity to study diet trends of lions and spotted hyaena in an enclosed system. The study focused on the diets and overlap of lions and spotted hyaena and how their prey selection changed since their re-introduction in 2003 to 2010. The database included scats collected over a seven year period. A total of 195 spotted hyaena scats and 217 lion scats were analysed using scat analysis. Prey items estimated from scat samples were coupled with prey availabilities to determine preferred prey items. Additionally, from determined carnivore diets, lions and spotted hyaena diet overlap was estimated over time. Lions preferred prey items which included zebra (Equus quagga) and eland (Tragelaphus oryx) during the early portion of the study. Over time preference shifted to include buffalo (Syncerus caffer), bushbuck (Tragelaphus scriptus) and grey duiker (Sylvicapra grimmia). Spotted hyaena preferred zebra and eland in the earlier part of the study, then over time, shifting their selection to grey duiker, buffalo, red hartebeest (Alcephalus busephalus) and bushbuck. Lions and spotted hyaena had a similar diet which increased in overlap during the study (67 percentage - 91 percentage). Our findings suggest that lions and spotted hyaena had a degree of diet specialization; both carnivores avoided and preferred certain prey items relative to their abundance. Their preference excluded the most abundant prey items, thus causing a decline in abundance of rarer species over time. Lions and spotted hyaena did not respond by shifting their diets to consume abundant prey items when their preferred prey items declined in availability. However, this study may be a snap-shot of carnivore’s diet trends. Thus further monitoring of the large carnivore diets should be researched in order to determine which factors drive their prey selection. Additionally, lions and spotted hyaena diet overlap increased overtime. The high diet overlap may be a result from spotted hyaena scavenging off lion kills, thus spotted hyaena diets may be facilitated by lion kills. Finally our data suggests that re-introduced large carnivores in AENP are likely to change the composition of the overall mammal community, potentially eliminating rare but preferred prey species in an enclosed reserve.