贡嘎山麦吊杉群落优势种群的分布格局及相互关系

SPATIAL PATTERN AND RELATIONSHIP OF DOMINANT SPECIES IN A PICEA BRACHYTYLA COM- MUNITY ON GONGGA MOUNTAIN

本文对贡嘎山麦吊杉群落各优势种群的分布格局进行了分析，结果表明除麦吊杉和铁杉等大型针叶树种呈随机分布外，其余优势种群皆呈聚集分布。结合种群结构的分析表明，种群的分布格局随树龄的变化是个动态因子，并与微环境条件的变化有关。通过种间联结系数半矩阵的分析，对６２种乔木的种间联结、种群分布与生态幅度进行了描述，划分出麦吊杉群落中不同的生态组合，表明各种群间也有不同的竞争和结合关系，但总体上显示出各生态组合的适应共性。

The Gongga Mountain is located on the southeast edge of the Qinghai- Xizang(Tibet)Plateau and is in the middle of the Great Snowy Mountain Range of the Hengduan Mountain System. with its main peak being 7 556m above the sea level.Picea brachytyla mainly distributes on the east slope and its distributional range of altitude is between 2 300m to 2 800m. We used five methods to study the spatial pattern of different communi-ties dominant by Picea(brachytyla. The results show that most of the species were of clumped distribution type. However. the edificator. Picea brachyty- la. was of the random distribution type. Our studies on the spatial pattern of trees in different sublayers and the Morisita Index using plots of varying sizes have revealed that the spatial pattern changes as the community deve- lops. and is influenced by the formation of microhabitats. such as tree gaps.The factors responsible for the dynamic changes of the spatial pattern with forest age include self- thinning and alien-thinning caused by intra-and in- terspecific competitions in the community. The association coefficients and a 2 ×2 contingency table were used for the measurement of interspecific association. Based on the semi- matrix diag- ram of 62 tree species. we divided them into four closely linked natural groups. of which two groups are very clear. one is suitable for higher aItitu- de. and one has been invaded by broadleaf trees. The combination of spatial pattern analvsis with interspecific association measurement may be one of the approaches to explain the distributional range of species. population structure.community succession. as well as the difer- ence in their habitats.