| With special ecological structures and functions, alpine timberline, a kind of ecotones highly sensitive to disturbances and environmental changes, has become one of the major concerns in global climate change studies. Quantitative explanations and analyses to landscape patterns are bases of further research into Forest-Grassland Ecotone systems' changes and progresses, and they're also significant for the further analyses to patterns' changes and managements. Taken Rike River——a small watershed in the upper Dadu River as a case, this paper studied the landscape patterns and their dynamics.The results of landscape patterns' analyses show that: (1)Under the influence of topographic and geomorphic features, the distribution of heat and water has determined the present patterns of major landscape types and floristics' distribution. Coniferous forests, in most of which is Picea purpurea, are in the north-facing slope, as large boundary zones consisting of Rhododendron spp. and Salix spp., the shrubs exist beyond treeline, meadows distribute higher than shrubs and closed to shrubs. There are much less shrubs in the south-facing slope, but much more meadows distribute beyond treeline, and coniferous forests here consist of Sabina spp. We can conclude that the landscape patterns here in Rike River present as typical Forest-Grassland Ecotone.(2)Most of the area here is covered by meadows and forests, it leads to low total diversity and high dominance; in this area, the concentration of patches of same landscape types made them disturbed by few facts, as a result of this situation, with low isolation, landscape fragmentation is not evident, and high fractal dimension and shape indices of landscape patches show that the stability in this area is low. The landscape patterns here are influenced by topographic and geomorphic features, consequently, the landscape patterns in Forest-Grassland Ecotone are naturally unstable, and sensitive to disturbances from both nature and people.(3)The situation of changes and results from investigations show that, from 1967, the changed landscape types are L1, L2 and L4, at the same time, L6 and C4 appeared after 1967 for the first time. The natural factors which posed these changes are fire as well as plant diseases and insect pests, they affected Sabina spp forests and Picea purpurea forests separately. Plant diseases and insect pests effected Sabina spp forests so seriously that a new landscape type appeared with a large area of 0.369 km~2.(4)Deforestation and restoration of Picea purpurea, and grazing are the disturbances from people. Picea purpurea forests are the object of deforestation, therefore, they are the very landscape type which are influenced most directly by people's activity, and they changed most over the past 40 years. Their areas declined from 24.262％in 1967 to 15.646％in 2006, and this decline ranged from 3450m to 4000m. Picea purpurea here own the highest diversity index, but it declined year after year, with the rising of fragmentation, fractal dimension and shape coefficient indices, this promote the instability in this area. C4 and L4 developed from clear-cutting forestland of Picea purpurea, which are ranging from 3450m～4000m. Their area, number of patches, diversity, shape, fractal dimension and fragmentation indices are rising. Rike River watershed is an underpopulated area, so the grazing is light and only changed the composition of Meadows species, however, this kind of change can't be compartmentalize to different landscape types under the scale of 1:50000, in a word, grazing affect Rike River's landscape patterns little.
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