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China Forestry Science Academy (2009)

Study on the Assessment and Remote Sensing Classification Technique of Shrub in Tibet


Titre : Study on the Assessment and Remote Sensing Classification Technique of Shrub in Tibet

Auteur : 张超;

Grade : Doctoral Dissertation 2009

Université : China Forestry Science Academy

Résumé partiel
As an important part of forest in Tibet, shrub plays an irreplaceable role in regional ecological security maintenance and regional economic and social development. However, shrub has been limited both in forestry production and scientific research because of the incorrect understanding and less attention for a long time. In this paper, based on the review of shrub population and community characteristics, spatial structure and distribution of shrub, as well as remote sensing classification techniques, the research was carried out as following by taking the shrub in Tibet which accorded with the special regulation of national as the research object : (ⅰ) the community characteristics of shrub in Tibet were analyzed ; (ⅱ) the populations niche of shrub in Tibet were measured, and the adaptability and interspecific competitions of shrub populations were studied ; (ⅲ) the spatial structure of shrub types was studied through the landscape pattern analysis, spatial autocorrelation analysis, and spatial scaling effects analysis ; (ⅳ) interactional relationship between environmental factors and distribution of shrub was analyzed, and the spatial distribution of shrub types was studied ; (ⅴ) the remote sensing classification technique of shrub in Tibet was discussed, including the process of assistant classification based on spatial distribution characteristics and re-classification based on spectral characteristics.The inventory was carried out and the community characteristics were analyzed. The results show that, the main family compositions of shrub in Tibet are Rosaceae, Papilionaceae and Ericaceae. Species composition in shrub communities is single, and species richness and diversity are at low level. Dominant species in the communities occupy a main proportion, and as a result, stable original or secondary communities with single dominant specie are dominated. Mostly, the coverage of the shrub communities is larger than 0.4, and it is remarkable different in districts and shrub types. Being affected by the plateau environment and shrub species ecology characteristic, the tree height distributes between 0.1 m and 6.0 m, and the ground diameter distributes between 1 cm and 5 cm. The power function curves of H-D of some shrub types show prominent relativity.Niche breadth and overlap indexes were measured at the environmental space including altitude, aspect, position and slope. The result shows that the environmental adaptability is different among environmental factors through the measurement of the population niche characteristics from the four-dimensional environment space. The populations show flexible width to different environmental factors, and it makes the habitat resources useable for each species from different aspects.

Mots clés : Shrub; Assessment; Niche; Spatial Structure; Spatial Distribution; Remote Sensing Classification; Tibet;

Présentation (CNKI)

Page publiée le 16 mai 2018