【作者】 王博；

【导师】 周志勇；

【作者基本信息】 北京林业大学 ， 生态学， 2020， 硕士

【摘要】 兴安落叶松是我国重要的林区资源,对维持大兴安岭地区生态平衡具有重要作用。由于大兴安岭地区是林火高发区,本研究以不同恢复时期的兴安落叶松林作为研究对象,研究分析不同恢复期森林群落的物种组成和土壤生物化学性状,探讨了地上植被与土壤功能的演变规律,采用Pearson相关性分析分析了不同恢复时期土壤化学性质、微生物量和酶活性和地表植被物种多样性指数的相关性,采用冗余分析法分析不同恢复时期灌木草本物种土壤影响因子,为林火干扰后兴安落叶松林群落功能的重建提供了理论基础。研究结果表明:(1)火烧干扰后短期内土壤养分含量较低,灌草群落阶段短期内林火显著影响土层0～5cm酸碱度、碱解氮、易氧化碳、全氮、DOP、微生物量和酶活性。白桦林阶段至落叶松林阶段树种更替影响土层0～5cm有机碳、酸碱度和碱解氮。(2)不同恢复时期火烧迹地土壤微生物量影响因子不同,相关性分析表明土壤氮素是不同恢复时期土壤酶活性主要影响因子。灌草群落阶段土壤上下层微生物量受土壤碳、氮元素的限制。白桦林阶段土壤上下层微生物量受土壤碳、磷元素的限制。落叶松林阶段土壤上下层微生物量受土壤氮素的限制。(3)不同恢复时期火烧迹地物种多样性和生物量发生改变,灌草群落阶段林火短期内降低了灌木草本物种多样性,且对白桦、落叶松幼苗影响显著,白桦幼苗占据优势。白桦林阶段到落叶松林阶段,落叶松幼苗占据优势,但林火促进灌木生物量的增加,降低草本多样性和生物量。(4)不同恢复时期林下植被物种多样性土壤影响因子不同。灌草群落阶段火烧迹地土壤上下层灌木多样性影响因子为土壤碳氮含量。白桦林阶段火烧迹地土层0～5cm灌木多样性影响因子为TN、MBP。落叶松林阶段火烧迹地土壤上下层灌木多样性影响因子为土壤碳磷元素含量和土壤微生物量。白桦林和落叶松林阶段草本多样性主要受土壤酸碱度、LAP酶活性的影响。(5)不同恢复时期林下植被具有相同的土壤影响因子。土层0～5cm灌木物种主要影响因子为p H,土层5～20cm灌木物种主要影响因子是碱解氮。更多还原

【Abstract】 Larix gmelinii was an important forest resource in China,it played an important role in maintaining ecological balance in the Greater Hinggan Mountains.The Greater Khingan Mountains area was a high incidence of forest fires.Our research object was the Larix gmelinii forest of different restoration stages.We researched soil chemical characteristics,soil microbial biomass,soil enzyme activity,species diversity and biomass in the burn area of different restoration stages,influence factors of soil microbial biomass and influencing factors soil enzyme activity were analysed by Pearson correlation analysis,influencing factors of shrub and herb species were analysed by RDA,it provided a theoretical basis for the Larix gmelinii community reconstruction in the burn area of the Greater Hinggan Mountains.The results show that:(1)The soil nutrient content of burn areas was kept at a low level in a short period.In the chronosequence of shrub and herb,forest fire influenced significantly the depth of 0～5cm soil layer p H,available nitrogen,ROC,TN,DOP,microbial biomass and enzyme activity in a short period.From the chronosequence of Birch to the chronosequence of Larix gmelinii,tree species replacement influenced the depth of 0～5cm soil layer p H,SOC and available nitrogen.(2)The influencing factors of soil microbial biomass were different in different restoration stages.In the chronosequence of shrub and herb,correlation analysis showed that the enzyme activity was limited by soil nitrogen in different restoration stages,the microbial biomass in 0～5cm and 5～20cm soil layer was limited by soil carbon and nitrogen.In the chronosequence of Birch,the microbial biomass in 0～5cm and 5～20cm soil layer was limited by carbon and phosphorus nutrients.In the chronosequence of Larix gmelinii,the microbial biomass in 0～5cm and 5～20cm soil layer was limited by soil nitrogen nutrients.(3)The species diversity and biomass changed in different restoration stages.In the chronosequence of shrub and herb,Birch seedlings were dominant species.The species diversity index of shrub and herb decreased in a short period.Forest fire influenced significantly Birch seedlings and Larch seedlings.From the chronosequence of Birch to the chronosequence of Larch,Larch seedlings were dominant species,forest fire increased the biomass of shrub,but the species diversity and biomass of herb decreased.(4)The influencing factors of species diversity were different in different restoration stages.In the chronosequence of shrub and herb,influencing factors of shrub species diversity in 0～5cm and 5～20cm soil layer were soil carbon and nitrogen content.In the chronosequence of Birch,influencing factors of shrub species diversity in 0～5cm soil layer were TN and MBP.In the chronosequence of Larch,influencing factors of shrub species diversity in 0～5cm and 5～20cm soil layer were soil carbon content,phosphorus content and microbial biomass.In the chronosequence of Birch and Larch,influencing factors of herb species diversity in 0～5cm and 5～20cm soil layer were p H and LAP.(5)The influencing factors of shrub and herb species were the same in different restoration stages Influencing factors of shurb species in 0～5cm soil layer were p H.In 5～20cm soil layer,influencing factors of shurb species were available nitrogen,and influencing factors of herb species were soil nitrogen content.更多还原