The literature of disturbance ecology reveals that, under present climatic conditions, non-native plants have little or no role in high arctic tundra revegetation. Rather, it has been suggested that indigenous flora, especially long-lived perennial graminoids, are crucial to recovery. However, few long-term data are available on past impacts within productive sedge-meadows in the High Arctic, and none which consider the non-vascular flora. / This thesis combines biogeographical and patch dynamics perspectives to focus on $ geq$21 yr of natural and assisted recovery of vegetation and soils from a wide range of dated anthropogenic surface disturbances at three Canadian Arctic sites. Empirical, experimental and archival investigations were made among climatically similar, but widely disjunct, coastal lowlands of contrasting geologies on Baffin, Devon, and Cornwallis Islands. These data encompass minerotrophic and oligotrophic wetlands in which the vascular floras show minimal differentiation yet the sampled bryofloras share only 31.8% of their total taxa. The occurrences chosen for study are representative of the most widespread, small-scale human impacts in the North, including vehicular, pedestrian, construction, and pollution disturbances. / It was determined that rutting from even a single passage of a tracked vehicle in summer resulted in significant reductions in species richness and biomass. On slopes $ geq$2$ sp circ$, these same small ruts have drained large areas of peatlands, a serious cumulative impact. Long-term effects of drainage include the local extinction of populations of Sphagnum spp. and rhizomatous vascular aquatics, and changes in the chemistry and thermal regime of drained mineral soils. Other effects include significant changes in biomass and the concentrations of macronutrients in the leaves of dominant species. These effects were magnified in peatlands drained where multi-pass vehicle movements occurred. / Species richness displayed an inverse relationship with trampling intensity and the soils of heavily trampled ground remained severely compacted after 21 years. These patches were dominated by dense swards of ruderal grasses. Nutrient concentrations in the leaves of the latter and other colonizing and surviving species tended to increase with trampling intensity. Trampled patches and archaeological sites appeared selectively grazed by several herbivores. Although humans initiated the disturbances within these patches, it is the animals which are responsible for many of the dynamics of patch change over the long-term. / Classification and ordination procedures revealed linkages between the floristic associations of trampled meadows on Baffin Island and archaeological sites on Devon and Cornwallis Islands. One critical implication is that even low levels of human impact may give rise to ruderal plant communities which are extremely persistent. These patches are poor in terms of species richness, but contribute to habitat heterogeneity at the landscape level and comprise preferred forage for local vertebrate herbivores. / Archaeological excavation and restoration revealed that at least some stores of viable seed exist in both mesic and wet tundra soils and point to the importance of initial floristic composition (sensu Egler 1954). From a long-term perspective, the data establish that mesic tundra vegetation and soils are easily disturbed and recover much more slowly than their low arctic counterparts under similar disturbance regimes.

Thesis (M.A.)--George Mason University, 2007. / Title from PDF t.p. (viewed Jan. 21, 2008). Thesis director: Paula Ruth Gilbert. Submitted in partial fulfillment of the requirements for the degree of Master of Arts in Foreign Languages. Vita: p. 119. Includes bibliographical references (p.112-118). Also available in print.

Thesis (M.A.) - Carleton University, 2002. / Includes bibliographical references (p. 235-254). Also available in electronic format on the Internet.

Alternatives are required to replace the dominant paradigm of modernization if the residents and communities of Canada's Northwest Territories are to benefit fully from northern development activities. One such alternative is a bottom-up, community-based development process wherein communities engage in active planning to control and manage the resources of their regions. The purpose of this study is to investigate the implications of staple theory, a model of economic growth based on the export of primary resources, and community development approaches for development in the Northwest Territories. The thesis is that an Anarchist formulation of staple theory provides a theoretical foundation for an alternative, community-based approach to northern regional development. The study describes the contexts of development theory, Canadian regional development, and the dependent nature of northern development. Staple theory, in a basic descriptive form, is then introduced. The prescriptive interpretations of staple theory posited by W.A. Mackintosh, H.A. Innis, and W.L. Gordon and M.H. Watkins are discussed. The study then compares staple theory's prescriptions with those indicated by the Anarchist approach to regional development and community development literature. The combined prescriptions are placed within the context of northern development. The study concludes by outlining the implications of staple theory and community development approaches for regional planning theory and practice in the Northwest Territories. In the context of northern development, the study recommends the adoption of a community-based development policy and a reconnection of regions to their resources as suggested by both the staple theory and community development approaches. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

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Microbial mats exist in freshwater pools atop the Ward Hunt and Markham ice shelves in the Canadian high Arctic. In this study, culture-dependent and culture-independent techniques were used to describe the microbial diversity and activity of these mat communities.Bacterial and archaeal 16S rRNA gene clone libraries were constructed from Markham and Ward Hunt mat samples. Bacterial libraries from both mats had high diversity, though the Markham library appeared more diverse than the Ward Hunt library. Over 95% of sequences in both bacterial libraries, and all isolates from both mats, grouped within the phyla Bacteroidetes, Proteobacteria, and Actinobacteria. Archaeal diversity appeared low in both mats. Only one phylotype, potentially representing a novel Euryarchaeota, was observed in both archaeal libraries. Populations in both communities showed activity at subzero temperatures, with growth of isolates at -5°C and detectable metabolic activity at -10°C, measured by radiorespiration assays of mat microcosms.

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Thesis (Ph. D.)--York University, 1999. Graduate Programme in Physics and Astronomy. / Typescript. Includes bibliographical references (leaves 166-174). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL:http://gateway.proquest.com/openurl?url_ver=Z39.88-2004 & res_dat=xri:pqdiss & rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation & rft_dat=xri:pqdiss:NQ39262.