甘肃文县珙桐群落的组成结构数量特征

The Quantitative Characters of Davidia involucrata Communities in Wen County of Gansu Province

甘肃文县为珙桐分布的北部边缘地带。对其群落的组成结构、数量特征研究分析认为，在沿摩天岭北坡自东向西的不同地段，水热条件优越程度下降，群落组成及优势种有所差异，群落多样性指数依次减小，分别为３．８８３０，３．３５８８，３．３５４５，生态优势度有升高的趋势，分别为０．０８８９，０．１１３９，０．１４８６，群落稳定性依次下降。中部地段的珙桐群落均匀度偏高，可能是人为活动干扰所致。

Wen county of Gansu province is the northern border of Davidia involucratadistribtition.It was indicated in this paper based on studying the quantitative characters ofD. involucrata communities that,with the decreased water and heat conditions superiority de-gree in the sections along Motianling northern hillside from east to west,the compositionsand dominans of the communities were different.Species diversity index decreased with thevalues of 3.8830,3.3588 and 3.3545,dominance showed an increase tendency with the valuesof 0.0889,0.1139 and 0.1486,the stability of the communities reduced.The higher evennessof the D.involucrata community in middle section might results from the human activities.