| This paper based on the theory of landscape ecology and cartography, and west Dongting lake forest resources inventory vector map as the data source. Upon the existing research results on landscape pattern, ascertain the dominating environmental sensitive factors as:geomorphology, slope, slopes, forest age structure, establish the dominant tree species stands for the vegetation factors of landscape partition. Combining the environment-based coupling degree between forest landscape types, with the circle of five times stand average height radius as its influence area, build west Dongting lake forest landscape elements classification system. With the ArcGIS platform, generate 9 classes forest landscape elements patch map and attribute database in research area. Based on this, use FRAGSTAT3.3 as analysis tool, choose 17 landscape pattern indexes as the area of metrics, edge index, shape index, diversity and distribution index of four aspects, respectively calculate the landscape index on patch level, landscape type level and landscape level of three levels.With the calculation results, analyse the west Dongting lake forest landscape pattern for the different landscape elements type and landscape patch characteristics. With the administrative divisions, distribute the west Dongting lake into 8 different areas, separately calculate the landscape pattern index, and horizontally compare the forest landscape distribution pattern. The main conclusions are as follows:(1) 9 classes forest landscape types of West Dongting lake have uneven distribution proportion. Differences exist in the forest landscape status of the whole range, such with economical class, pine class, and broadleaf class; In some areas some parts of forest landscape dominate the overall landscape, leading to low level of regional diversity. Slow-growing broadleaf class in Taoyuan county, economical class in Hanshou county and Dingcheng district, and pine class in Li county, hold larger proportion in each area separately.(2) 9 classes forest landscape types in west Dongting lake are all made up of small patches (< 10hm2),94.42% of the total number of patches. Small and medium patches are above 99% of the total number of patches, big patches are mainly distributed in the economic forests, slow-growing broadleaf class and bamboo; Large and giant patches are mainly distributed in the slow-growing broadleaf class and bamboo landscape. For age structure, pine class, broadleaf class, fir class of three landscape types are reasonable, belong to stable structure, most are mid-maturation forest; Slow and fast growing broadleaf class belong to grow structure, with most young forest.(3) The edge density of each forest types in west Dongting lake are not high in general, economical class, pine class and fir class are higher than other types, which have large edge survival proportion, intense human disturbance, so large natural patches are fewer; For shape index, the irregular degree of each landscape type from high to low as:economical class> pine class> fir class> slow-growing broadleaf class> fast-growing broadleaf class> bamboo> in broadleaf class> kashiwagi class. The degree of concentration (AI) of each forest landscape types in west Dongting lake from high to low as:bamboo> slow-growing broadleaf class> in broadleaf class> shrubs class> fast-growing broadleaf class> economical class> pine class> fir class> kashiwagi class. Distribution and parallel index (ILI) from high to low as:bamboo> in broadleaf class> shrubs class> slow-growing broadleaf class> pine class> economical class> fast-growing broadleaf class.(4) The comparation of each landscape shape index is biggest in Taoyuan county, with the most irregular patch shape. Dingcheng district, Li county and Hanshou county Rank in the following order. The landscape patch shape of Jinshi city, Anxiang county and WuLing district are more rules, the landscape shape index is low.(5) Taoyuan county has the largest area of forest landscape in west Dongting lake, far outweigh the other areas. Forest landscape area from large to small as:Taoyuan county> Dingcheng district> Li county> Hanshou county> Linli county> Jinshi city> Anxiang county> Wuling district; The main distribution of each forest landscape types are:slow-growing broadleaf class, fir class, and in broadleaf class are mainly distributed in Taoyuan county; Economical class and bamboo are mainly distributed in Taoyuan county, Dingcheng district and Hanshou county; Pine class is mainly distributed in Taoyuan county, Li county and Linli county; Shrubs class is mainly distributed in Taoyuan county and Li county; Fast-growing broadleaf class is mainly distributed in Dingcheng district, Hanshou county, Linli county and Li county; Kashiwagi class is sporadically distributed in Dingcheng district, Li county and Linli county.(6) In forest landscape level, west Dongting lake landscape structure composition is relatively complex, diversity is higher, but each landscape type area distribution is not so balanced, the same type of landscape is relatively concentrated, and there is a certain fragmentation trend. Comprehensive comparison shows that the landscape distribution pattern in Taoyuan county is the best of all areas, each landscape type area distribution is uniformity, with the highest heterogeneity, higher connectivity and stability; Followed by Dingcheng district, Hanshou county, LinLi county, Li county, Jinshi city, which have less dominant landscape types, and heterogeneity is lower than Taoyuan county; The similar landscape in Anxiang county and Wuling district are relatively consentrated, dominant landscape types are obvious, landscape relative homogeneous, and connectivity between different landscape types is poor.The Research analyse the present west Dongting lake forest resources structure on landscape scale,provide basic data and reference for space for forest patches optimize configure and structure optimization on landscape scale. |
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