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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.
21

Classification of high-elevation, non-forested plant communities in coastal British Columbia. Full report.

Brett, Bob, Klinka, Karel, Qian, H., Chourmouzis, Christine 03 1900 (has links)
This report expands and clarifies previous classifications of non-forested plant communities from upper subalpine and alpine locations in coastal British Columbia. A total of 80 plots (releves) sampled specifically for this study were added to 202 releves from published and unpublished studies conducted since 1963. We used tabular and multivariate methods to synthesize and classify plant communities according to the Braun-Blanquet approach. Plant communities were classified into 37 vegetation units (associations or subassociations) which served as the basis of the resulting hierarchical classification. We describe the habitat and species composition of these vegetation units and their relationship to units recogized elsewhere in the Pacific Northwest. We then present eight generalized habitat types which we propose as the basic units for future ecosystem mapping. Each of these habitat types includes a predictable mosaic of vegetation units whose pattern occurs at too fine a scale to map individually.
22

The influence of environment and livestock grazing on the mountain vegetation of Lesotho.

09 December 2013 (has links)
The mountains of Lesotho form the catchments for the Lesotho Highlands Water Project (LHWP), which is presently under construction, and their condition will determine the longevity of the LHWP. The mountain rangelands also support an extensive livestock system. However, there is concern that grazing is negatively affecting the mountain vegetation to the detriment of both livestock production and catchment function. Therefore, the impact of environment and grazing on the vegetation was investigated to aid the development of management policy for the conservation of the grazing, floristic and water resources of the mountains. Vegetation surveys were conducted in the mountains in the east (Study Area 1: 2 625 - 3 350 m a.s.l.) and in the west (Study Area 2: 2 240 - 3 125 m a.s.l.). Indirect gradient analysis (IGA) and classification were used to investigate the influence of environment on vegetation pattern. Results of the IGA indicated that variation in species composition in the mountains is related primarily to topographic variation, in particular elevation and aspect. Five vegetation communities were identified in Study Area 1 and seven in Study Area 2. These communities occurred consistently in specific topographic positions in the landscape and were arranged along a temperate/subtropical grass species continuum which was associated with a gradient in elevation and aspect. In Study Area 1, the elevation boundary between the high-lying temperate grasslands and the lower subtropical grasslands corresponded with the generally recognised boundary between the Alpine and Subalpine vegetation belts (viz. c. 2 950 m a.s.l. on northerly aspects and c. 2 750 m a.s.l. on southerly aspects). This boundary was lower in Study Area 2 (viz. c. 2 800 m a.s.l. on northerly aspects and c. 2 300 m a.s.l. on southerly aspects). Vegetation-insolation relationships were investigated in Study Area 1 using a model for simulating solar radiation, temperature and potential evaporation patterns on sloping terrain (RADSLOPE). The spatial distribution of the identified vegetation communities and the ratio of temperate (C₃) and subtropical (C₄) grasses in the sward were related to solar irradiance patterns, as influenced by topography. Results suggest that exposure, which increases with altitude, is probably also an important determinant of vegetation pattern in the mountains. The influence of grazing on the vegetation was studied by examining changes in species composition and cover that were associated with gradients in grazing intensity that exist around cattleposts in the mountains. There was little evidence of a shift in species composition and cover under grazing in the Alpine Belt but there was an identifiable grazing gradient in the Subalpine belt. There, short dense grasslands, dominated by palatable species, degrade to a dwarf karroid shrubland with sparse cover under prolonged, intense grazing. The optimum position along the grazing gradient of the more abundant species was identified. It was proposed that the relative positions, or scores, of these species along the grazing gradient can be used in a weighted scoring procedure to provide an index for monitoring the response of the mountain vegetation to grazing. However, the species’ scores still require verification. The need for monitoring temporal changes in vegetation composition and cover in order to assess the possible effects of the LHWP and other development initiatives was noted. Such monitoring should be undertaken in conjunction with an overall programme to assess the dynamics of the socio-economy in the mountains. Therefore, interdisciplinary monitoring programmes are required to achieve this. These programmes should be focused in a few key study locations rather than spread over a wide area. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg.
23

Mountain habitat activity guide

Glock, Gina 01 January 1992 (has links)
No description available.
24

Altitudinal Effects on The Behavior and Morphology of Pygmy Tarsiers (Tarsius pumilus) in Central Sulawesi, Indonesia

Grow, Nanda Bess 16 December 2013 (has links)
Pygmy tarsiers (Tarsius pumilus) of Central Sulawesi, Indonesia are the only species of tarsier known to live exclusively at high altitudes. This study was the first to locate and observe multiple groups of this elusive primate. This research tested the hypothesis that variation in pygmy tarsier behavior and morphology correlates with measurable ecological differences that occur along an altitudinal gradient. As a response to decreased resources at higher altitudes and the associated effects on foraging competition and energy intake, pygmy tarsiers were predicted to exhibit lower population density, smaller group sizes, larger home ranges, and reduced sexually selected traits compared to lowland tarsiers. Six groups containing a total of 22 individuals were observed. Pygmy tarsiers were only found between 2000 and 2300 m, indicating allopatric separation from lowland tarsiers. As expected, the observed pygmy tarsiers lived at a lower density than lowland tarsier species, in association with decreased resources at higher altitudes. The estimated population density of pygmy tarsiers was 92 individuals per 100 ha, with 25 groups per 100 ha. However, contrary to expectation, home range sizes were not significantly larger than lowland tarsier home ranges, and average NPL was smaller than those of lowland tarsiers. The average home range size for the observed pygmy tarsiers was 2.0 ha, and the average nightly path length (NPL) was 365.36 m. Pygmy tarsiers exhibited a nonrandom, clumped distribution near forest edges. While insect abundance and biomass were found to decrease as altitude increased, insect abundance and biomass was higher along anthropogenic edges. Thus, tarsiers within the study area may mitigate the decreased availability of insects at high altitudes by remaining close to forest edges, which in turn may be related to smaller than expected home range sizes. Further, estimates of pygmy tarsier abundance may be inflated because of increased insect abundance along anthropogenic edges. Contrary to the prediction for smaller group sizes as a response to feeding competition, the observed pygmy tarsiers lived in relatively large groups with multiple adult males. However, in support of the prediction for energetic constraints on body proportions, the observed pygmy tarsiers did not exhibit sexually selected traits. The pygmy tarsiers exhibited low sexual dimorphism and small relative testes mass, a trend opposite from lowland tarsier species, which may indicate a constraint on the development of those traits. Considered together, these results suggest that the observed pygmy tarsiers have adapted to life in an environment with limited resources. Future studies should explore the possible contributing effects of seasonality and topography.

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