大兴安岭冻土活动层对兴安落叶松生长及林下植物影响

Effects of Permafrost Activity on Growth and Undergrowth of Larch in The Greater Hinggan Mountains

以内蒙古大兴安岭冻土区的兴安落叶松为研究对象,通过2年的野外调查数据,分析不同冻土活动层兴安落叶松胸径生长率、兴安落叶松林下生物多样性指数变化特征。结果表明:1)随活动层增加,冻土活动层相对较深地区兴安落叶松胸径生长率较高,冻土区比非冻土区均有降低;2)随活动层的增加,冻土区中各活动层样地的Shannon多样性指数与丰富度指数,出现升高趋势,均比非冻土区样地有所降低;土壤中有机质含量、全氮和全磷含量表现出增加趋势,比非冻土区有所减少,全钾含量表现出减小趋势;3)RDA分析结果显示,冻土土壤因子中,冻土地表地温因子和活动层厚度因子影响兴安落叶松胸径生长率、林下植物物种多样性。

Based on two years′field survey data,the DBH growth rate of larch in different permafrost layers in the Greater Hinggan Mountains,Inner Mongolia and the variation characteristics of biodiversity index under larch forest were analyzed.The results showed as follows:1)With the increase of active layer,the DBH growth rate of Larix Xing′an was higher in the relatively deep permafrost area,and was lower in the frozen area than in the non-frozen area;2)With the increase of the active layer,the Shannon diversity index and richness index of the active layer samples in the permafrost region increased,which were lower than those in the non-permafrost region.The contents of organic matter,total nitrogen and total phosphorus in soil showed an increasing trend,while the contents of total potassium showed a decreasing trend compared with those in non-frozen soil area.3)The results of RDA analysis showed that among the permafrost soil factors,the surface temperature and active layer thickness significantly affected the DBH growth rate and understory plant species diversity of Larix Xing′an.