| Using GIS, remote sensing and spatial statistics, this thesis explores some spatial patterns in ecology, at a variety of levels and scales, through three case studies. The fundamental, but frequently obscure, role of physical factors in governing the spatial patterns and dynamics at different spatial scales and across different levels is emphasized.; The spatial pattern of coniferous and deciduous forest patches in the agricultural landscape is first investigated. The analyses reveal quite different spatial and dynamic forest patch patterns from the ones in natural landscapes. Results show that the role of landscape physical factors on forest patch pattern has been modified by land use. Physical factors only indirectly influence the forest pattern because they strongly influence the land-use practices.; The role of physical factors on land-use patterns in the same study area is then further investigated. Results show that there are clear relationships between land-use types and surface deposit types during the period of time studied. At the landscape level, crops are dominant on marine deposits, while forests are the dominant land use on moraine.; In case study three, the analyses not only further confirm the important role of physical factors at the species and community level, they also allow an in-depth analysis of the role of individual edaphic factors on the spatial structure of halophytic communities. Results show that there are two distinct vegetation gradients, one of which is determined by soil moisture, and the other by soil salinity.; From all three case studies, it can be concluded that no matter the location on the earth surface, the organisational level or the spatial scale, the ecological patterns have a physical basis. In addition, the relative importance of physical factors changes with scale, level and patch type. (Abstract shortened by UMI.)... |
