大兴安岭兴安落叶松林下植被多样性及土壤养分季节分布特征

Seasonal Dynamics of Understory Vegetation Diversity and Soil Nutrients in Larix gmelinii Forests of Great Xing'an Mountains

研究了内蒙古大兴草类—兴安落叶松林(HLV)、杜香—兴安落叶松林(LLV)、藓类—兴安落叶松林(MLV)下植被多样性及土壤养分季节分布特征。结果表明:(1)3种林地植被丰富度指数、多样性指数、优势度指数、均匀性指数随着季节的变化呈先增加后降低趋势,以秋季最高;相同季节,3种林地植被丰富度指数、多样性指数、优势度指数、均匀性指数基本表现为HLV>LLV>MLV,局部有所波动。(2)3种林地土壤温度、土壤湿度和土壤电导率随着季节的变化呈先增加后降低趋势,土壤pH值随着季节的变化呈先降低后增加趋势。(3)3种林地土壤有机碳、全氮、全钾和土壤酶活性(纤维素酶、脲酶、酸性磷酸酶、蔗糖转化酶和过氧化氢酶)随着季节的变化呈先增加后降低趋势,在秋季达到最高,春季最低,土壤有机碳、全氮和全钾基本表现为HLV>LLV>MLV,局部有所波动,全磷没有明显的变化规律。(4)3种林地土壤养分和土壤酶活性均表现为腐殖层>沉淀层,其中土壤全磷在腐殖层和沉淀层没有显著差异(P>0.05)。(5)偏相关分析表明影响草类—兴安落叶松林(HLV)植被多样性的主要因子是土壤有机碳、酸性磷酸酶和转化酶;影响杜香—兴安落叶松林(LLV)植被多样性的主要因子是土壤pH值、有机碳、全氮、转化酶和过氧化氢酶;影响藓类—兴安落叶松林(MLV)植被多样性的主要因子是土壤有机碳、全氮和纤维素酶。(6)主成分分析表明土壤有机碳、全氮和过氧化氢酶是兴安落叶松林土壤养分的主要影响因子。

In order to study the seasonal diversity dynamics of understory vegetation and soil nutrients in Larix gmelinii forests of Great Xing＇an Mountains,3forest types including herbage-Larix gmelinii forest（HLV）,Ledum palustre-Larix gmelinii forest（LLV）and moss-Larix gmelinii forest（MLV）were selected in Great Xing＇an Mountains where the investigations were carried out by 3consecutive years（from 2012—2014）.The results showed that：（1）The richness index,diversity index,dominance index and evenness index of understory vegetation in 3forest types increased at first and then decreased with the procession of the seasons,which were the highest in autumn.In the same season,the understory vegetation diversity of 3kinds of forests generally listed in the following order：HLV〉LLV〉MLV,with local fluctuations.（2）The soil temperature,soil moisture and electric conductivity of 3forest types increased at first and then decreased with the procession of the seasons,while soil pH showed the opposite trend.（3）Soil organic carbon,total nitrogen,total potassium and soil enzyme activities（cellulase,urease,acid phosphatase,invertase and catalase）in 3forest types increased at first and then decreased with the procession of the seasons,which were the highest in autumn and the lowest in spring.In the same season,soil nutrient contents and soil enzyme activities of 3kinds of forests generally listed in the following order is HLV〉LLV〉 MLV,with local fluctuations.（4）Soil nutrient contents and soil enzyme activities of 3kinds of forests were all higher in humus layer than in sediment layer,and soil phosphorus had no significant difference in humus layer and sediment layer（P〉0.05）.（5）Partial correlation analysis showed that the most important factors affecting HLV understory vegetation diversity were soil organic carbon,acid phosphatase and invertase,while the most important factors affecting LLV understory vegetation diversity were soil pH,organic carbon,total nitrogen,invertase and catalase,and the most important factors affecting MLV understory vegetation diversity were soil organic carbon,total nitrogen,and cellulase.（6）Principal component analysis showed that soil organic carbon,total nitrogen and catalase were the main effecting factors of the soil nutrients of 3forest types.