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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.
1

Intraguild interactions between native and domestic carnivores in central India

Vanak, Abi Tamim. Gompper, Matthew Edzart. January 2008 (has links)
Title from PDF of title page (University of Missouri--Columbia, viewed on March 17, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Matthew E. Gompper. Vita. Includes bibliographical references.
2

Resource partitioning between two sympatric Australian skinks, Egernia multiscutata and Egernia whitii

Bellamy, Stephen. January 2006 (has links)
Thesis (Ph. D.)--Flinders University, 2006. / Title from PDF t.p. (viewed on Mar. 11, 2007). Includes bibliographical references.
3

Adaptive radiation and the evolution of resource specialization in experimental populations of Pseudomonas fluorescens

MacLean, Roderick Craig January 2004 (has links)
Understanding the origins of biological diversity is a fundamental goal of evolutionary biology. A large body of theory attributes ecological and genetic diversification to divergent natural selection for resource specialization. This thesis examines adaptive radiation in response to selection for resource specialization in microcosm populations of the asexual bacterium Pseudomonas fluorescens. The general protocol for these experiments is to introduce a clonal population of Pseudomonas into a novel environment and to allow evolution to occur through the spontaneous appearance of novel genotypes carrying beneficial mutations. Adaptation can then be quantified through direct comparisons between evolved populations and their clonal ancestors. These experiments show that resource heterogeneity generates divergent natural selection for specialization on alternative resources, irrespective of the spatial structure of the environment. Adaptive radiation is possible in sympatry because of genetic trade-offs in the ability to exploit different resources, but these trade-offs are often not the result of antagonistic pleiotropy among loci that determine fitness on alternative resources. The rate of phenotypic diversification declines during adaptive radiation, apparently because the ecological opportunities required to support specialist lineages disappear as a consequence of initial diversification. The ultimate outcome of repeated instances of adaptive radiation is the evolution of a community of ecologically equivalent specialists that share similar adaptive traits, despite differences in the underlying genetic basis of specialization in replicate radiations. Comparisons with the literature on experimental evolution in microbial populations illustrate the results of this thesis are well-supported by experiments in a wide range of microbial microcosms.
4

Coexistence in a chirostoma species flock niche analysis and the role of water-level fluctuation on the structure and function of the zooplanktivorous guild /

Moncayo-Estrada, Rodrigo. Lind, Owen T., January 2009 (has links)
Thesis (Ph.D.)--Baylor University, 2009. / Includes bibliographical references (p. 104-117).
5

Sexual dimorphism, resource partitioning and intraspecific aggression in Caprella californica Stimpson

Campbell, Ian D. 01 January 1979 (has links)
The Caprellidae are a specialized suborder of Amphipoda, which are highly modified for a semisessile life. Caprellids exhibit direct development and brood their young. The suborder is exclusively marine and commonly found on filamentous algae, sea grasses and fouling communities. Most published works on caprellids have been primarily concern~d with systematics (Caine, 1974; Dougherty, 1943; Laubitz, 1970, 1972; McCain, 1968, 1975), although a few recent studies have dealt with ecology and ethology (Bynum, 1978; Caine, 1977; Keith, 1969, 1971; Lewbel, 1978; Saunders, 1966). This study examines·spatial and temporal variations in distribution, abundance and population structure as well as describing intraspecific aggressive behavior of Caprella californica Stimpson. ~- californica is dioecious and has marked sexual dimorphism in both its size and secondary sex characteristics. It is found from San Diego to the South China Sea (Laubitz, 1970), and is the dominant caprellid in the Zostera marina beds of the local bays and is a major diet item for many of the eel grass associated fishes. There is a preponderance of females in the population as well as a size-specific distribution of the proportion of the sexes.
6

Adaptive radiation and the evolution of resource specialization in experimental populations of Pseudomonas fluorescens

MacLean, Roderick Craig January 2004 (has links)
No description available.
7

Can the potential for tick infestation influence patterns of resource use by Eland (Taurotragus oryx)?

McCulloch, Douglas John 10 May 2016 (has links)
A research report submitted to the Faculty of Science, University of Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science (Resource Conservation Biology). Johannesburg, 2015 / The vegetation of the Kgaswane Mountain Reserve, in North West Province, South Africa, was mapped according to seven vegetation structure types, based on tree density and height, and grass height. Free-living ticks were collected by drag-sampling the vegetation from each structure type in November 2014, prior to the onset of the summer rains, and February 2015, once most of the seasonal rains had fallen. Eland (Taurotragus oryx) location information was recorded from four GPS collared cows over the two sample periods. Tick abundance was consistently lower in shorter, open, more exposed vegetation structure types, and higher in more sheltered types. Position higher up in the landscape nullified the positive impacts of trees on beneath-canopy microclimate in tall open woodlands, as indicated by comparatively lower tick numbers than in more sheltered woodland types. Tick abundance is influenced by vegetation structure and the availability of hosts. The majority of ticks trapped during both periods were larvae, with nymphs mostly present in November and adults mostly present later in the season, indicating the seasonal nature of tick cohort recruitment. Eland calving behaviour centred on areas with low adult tick abundance. Eland did not respond to total tick abundance during either sampling period. They did select areas with low adult tick abundance, and avoided areas with high adult tick abundance. This corresponded with an improvement in upland forage quality, which allowed them to avoid foraging in areas with high adult tick abundance. It is plausible that the potential for infestation by adult ticks may be a supplementary influence driving the use of space by eland.
8

Resource partitioning in a spring spawning freshwater fish assemblage dominated by catostomids (Catostomus commersoni, C. catostomus)

Dion, René January 1992 (has links)
For three consecutive years, I monitored the spring stream residency and spawning of five species of fishes using a tributary stream of the Gouin Reservoir (north central Quebec). Timing of spawning of the distantly related species was different whereas the spawning activity of the closely related suckers overlapped in time and space. Intra- and inter-specific egg predation by the two sucker species was observed as well as predation by lake whitefish (Coregonus clupeaformis) on sucker eggs. Synchronisation of the spawning of the suckers may allow them to "swamp" egg predators with drifting eggs. Abundance of spawning fish was affected by water management practices in the reservoir. When water levels were low, fewer fish of all species had access to the stream possibly because of the development of rapids. / The courtship behavior of the two sucker species was described and compared in the same period, to determine if behavioral isolating mechanisms which prevented hybridization existed.
9

Interspecific competition between Blue and Great tits

Minot, Edward O. January 1980 (has links)
Great tits (Aves: Passeriformes; Parus major) and blue tits (Parus caeruleus) nested in boxes in Wytham Woods near Oxford. The breeding densities of both species were limited by the availability of nest sites. The larger great tits were dominant in obtaining nest boxes. This was most important where breeding sites were scarce. The two species did not maintain interspecific territories or interfere with interspecific nest site spacing beyond the immediate vicinity of the nest. Blue and great tit numbers fluctuated in parallel where nest sites were not limiting resources. Annual changes in breeding numbers of great tits were negatively related to blue tit breeding density but great tit density did not seem to affect changes in the blue tit population. Overlap in the feeding sites of blue and great tits was greatest during the summer and interference competition was lowest at this time. The nestling diets of the two species were very similar. Despite an apparent abundance of food for nestlings, adults were pressed to feed large broods. Food for nestlings was probably a limiting and depletable resource. The date of clutch initiation of great tits, but not blue tits, was retarded at high densities of blue or great tits. The clutch sizes of both species were probably negatively affected by high breeding densities of congeners but the results were not clear cut. Heavy great tit fledglings are most likely to survive to breed. Great tit fledglings were heavier at low densities of blue tits. An experiment in which blue tit young were removed from a section of the Woods, showed that great tit nestlings were heavier and developed faster, and that female condition was better, than in a control section or section where blue tit broods were supplemented. In terms of resource competition, blue tits were the better scramble competitors and great tits the better interference competitors.
10

Niche partitioning among fur seals /

Page, Brad. January 2005 (has links)
Thesis (Ph.D.) -- La Trobe University, 2005. / Submitted in total fulfilment of the requirements for the degree of Doctor of Philosophy to the Zoology Dept., School of Life Sciences, Faculty of Science, Technology and Engineering. Research. Includes bibliographical references (leaves 133-152). Also available via the World Wide Web.

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