微尺度景观格局是景观生态学的一个研究热点.干旱河谷是横断山区一类特殊的生态系统类型,生态脆弱,生态退化潜在风险大.选择四川茂县两河口典型样地干旱河谷微尺度景观格局进行研究.研究表明,样地上分布的景观类型多样,斑块类型有19个,植被景观总斑块达3 383个,以基质分布为主,植被斑块状镶嵌其中,主要以中生性耐旱植物为主,植被覆盖度为42.25％.植被景观类型大部分为豆科类灌丛景观,整个景观由川甘亚菊、刺蓬、瓦松、茂汶韭、狗尾草、小角柱花、侧柏、臭椿、滇柏、卷柏、元宝枫、岷江柏景观斑块控制.植被景观分布特征为,帚菊斑块面积最大且分布均匀,小马鞍羊蹄甲斑块最大且聚集度最高,狗尾草斑块破碎化程度最大,蚊子草斑块多样性程度最大,小角柱花多样性程度最小且分布最散.通过空间自相关性分析,研究区植物分布呈现较高的正相关性和空间聚集性,在尺度2m×2m空间自相关值最大,未来干旱河谷区微尺度空间格局研究尺度在这个尺度较适宜.%The dry Minjiang river valley is a special kind of cross-sectional type of ecological system, with its ecological fragility, the potential risks of degradation. We analyzed land cover categories(20 m ×20 m of extent and 1 mm of resolution) and images of vegetation index in MAO county. This study showed that the landscape diversity in the experimental plots are significant with 19 patch types and total 3 383 patches of vegetation. The regional distribution was matrix-based, patchy mosaic of vegetation in which endogenous drought-tolerant plants predominated. The vegetation coverage is 42. 25%. Most of the vegetation in the landscape are shrub legumes, the vegetation types include Pertya phylicoides, Sophora viciifolia Hance ,Ajania potaninii, Herba Euphorbiae Milii, W. Stnophylla, Iudigofera lenticellata,Orostachys fimbriatus,Bauhiniafaberi var. Microphylla,Allium tuberosum,Filipendulapalma-ta,Setaria viridis (L. ) Beauv. ,Ceratostigmaminus Stapf,Platycladus orientalis (Linn. ) Franco,Ailanthus altissima ( Mill) Swingle, Cupressus duclouxiana hickel, Selaginella tamariscina ( Beauv. ) Spring, Acer truncatum Bunge, Cu-pressus chengiana. It is shown that the largest number of vegetation patches is for Filipendula palmata patches, the largest patch is for the Pertya phylicoides; the maximal single patch is for Bauhinia faberi, the minimal single patch is for the Setaria viridis (L. ) Beauv. And Setaria viridis (L. ) Beauv. Has the maximum degree of the fragmentation ; Filipendula palmata has the most patch diversity, Vice versa for Ceratostigmaminus Stapf. Pertya phylicoides patch is relatively evenly distributed, Ceratostigmaminus Stapf is most scattered patches. By spatial autocorrelation analysis, the study area showed the distribution of plants with high positive correlation and spatial aggregation; in size of 2 m x 2 m, the spatial autocorrelation value is the largest, suggesting the future spatial pattern of 2 m × 2 m was the appropriate fine scale for landscape and vegetation analysis in dry Minjiang valley.
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