大兴安岭北部植被对高胁迫冻土环境及干扰的响应

The Responses of Vegetation on Northern Part of Mt. Daxinganling to Strongly Enforced Permafrost Environment and Environmental Disturbances

本文以Ｓｉｍｐｓｏｎ指数，测定了大兴安岭阿木尔林区火灾后植物群落的生态优势度。通过与冻土环境的比较分析得出，植物群落的生态优势度与多年冻土的发育程度之间呈正相关、与物种多样性之间呈负相关。并进而提出，多年冻土对该区兴安落叶松林的生长具有直接的高胁迫作用和间接的保护其生物竞争力的双重作用；森林植被则在此高环境压力下采取耐胁迫对策，对干扰也产生双重的响应方式。依此可指导我们在营林实践中有效地利用干扰的正效应而减轻森林的冻土环境压力，促进森林的生长和持续的利用。

An ecological dominance was measured of plant communities after the forest fire onAmur of Mt,Daxinganling, by means of Simpson Index. By comparing them with thepermafrost environment, we conclude that the ecological dominanee is positively corelatedwith the degree of permafrost growth, and negatively corelated with the species diversity. Fur-ther more, we point out that there are two opposite effects from permafrost on the growth ofLarch forest,directly strong enforcement and indirect protection of the biological competi-tion. The forest responses accordingly under such environment, and also there are two oppo-site responses to the disturbances. Therefore in our practice of forest management,we cantake advantage of the positive effect of disturbances to reduce the enforcement on permafrostenvironment,and promote the forest growth.