【作者】 刘颖；

【导师】 苏志尧； 翁殊斐；

【作者基本信息】 华南农业大学 ， 风景园林硕士（专业学位）， 2017， 硕士

【摘要】 苔藓植物是森林生态系统中重要的组成部分,对维系森林生物多样性,促进水分、养分循环等方面发挥着重要的生态功能。本文以东源康禾自然保护区为研究地点,以苔藓植物为研究对象,对4 hm~2样地进行植被和土壤调查,采用半球面影响技术测定冠层叶面积指数。通过多种统计软件来分析环境因子对苔藓植物的影响,揭示环境因子对苔藓植物分布及多样性的影响机理,并确定特定环境因子强度下的苔藓植物指示种。主要的研究结果如下:(1)康禾自然保护区4 hm~2固定样地中共记录到苔藓植物23科34属40种(含变种),其中苔类植物7科11属14种,藓类植物16科23属26种。对本区苔藓植物物种组成分析得出,本区苔藓植物优势科、种具有明显的热带、亚热带性质。同时,样地内存在较多的单种科,说明研究样地苔藓植物具有明显的特殊性和复杂性。(2)以乔木胸径为依据,运用TWINSPAN将研究样地划分为4个木本群落类型,不同群落间苔藓植物最大盖度和均匀度指数无显著差异,苔藓植物总盖度级、物种数、Shannon-Wiener指数和Simpson指数差异极显著(P﹤0.01)。其中群落4的苔藓植物总盖度级、最大盖度级、物种数、均匀度指数、Shannon-Wiener指数和Simpson指数均最大。(3)Mantel检验结果显示,苔藓植物物种组成和冠层树种物种组成有极显著的相关性(P﹤0.01)。苔藓植物最大盖度级与冠层叶面积指数呈显著负相关(P﹤0.01);均匀度指数与冠层叶面积指数呈极显著正相关(P﹤0.01);物种数、Shannon-Wiener指数以及Simpson指数与冠层叶面积相关性不显著;而总盖度级与冠层叶面积显示出边际性显著相关(P=0.0583)。(4)苔藓植物多样性与土壤因子的关系通过非参数Spearman R进行分析,结果表明,土壤因子与苔藓植物最大盖度级和均匀度均无显著相关;总盖度级与全钾有显著的正相关关系(P﹤0.05);Shannon-Wiener指数和Simpson指数与土壤容重、全磷呈显著的正相关(P﹤0.05);苔藓植物物种数与土壤容重、全磷、全钾有显著的正相关关系(P﹤0.05),而与有机质呈现显著的负相关关系(P﹤0.05)。(5)对各土壤因子划分梯度后,用Kruskal-Wallis检验分析苔藓植物多样性在各梯度下的差异性,结果表明,不同土壤自然含水量、容重、全氮梯度间的苔藓多样性指标无显著差异;不同土壤有机质梯度下总盖度级、Shannon-Wiener指数、物种数以及Simpson指数差异显著(P﹤0.05);苔藓植物均匀度在不同土壤全磷梯度下有显著差异(P﹤0.05);不同土壤全钾梯度下只有苔藓植物总盖度级和最大盖度级有显著的差异(P﹤0.05)。(6)随机森林分析表明,群落生境类型对苔藓植物总盖度级、物种数、Shannon-Wiener指数和Simpson指数的影响最大;土壤p H对苔藓植物最大盖度均有较大影响;而土壤全磷则对苔藓植物均匀度影响最大。说明土壤养分含量的变化对苔藓植物的分布起到主要的作用,而林下生境异质性对苔藓植物多样性的影响起到主导作用。(7)指示种分析(ISA)表明,环境因子与苔藓植物分布具有密切的关系,研究样地内共有23种苔藓植物对群落类型及土壤等环境因子有指示作用,且不同梯度的环境因子均有对应的指示种。反映了苔藓植物对单一环境因子、多种环境因子以及群落生境类型有指示作用。更多还原

【Abstract】 Bryophytes are important components of forest ecosystems which play an important role in maintaining the biodiversity of forest and promoting the cycling of water and nutrients.We surveyed the canopy trees,bryophytes,and soils in a 4-ha permanent forest plot.The leaf area indices(LAI)of the canopy trees were determined using hemispherical photography.We examined the effects of environmental factors on the distribution of bryophytes diversity and the potential underlying mechanisms,and detected the indicative bryophyte species of the specific environmental factors.The main results were as follows:(1)We recorded 40 bryophyte species(including varieties)from 23 families and 34 genera by conducting a survey in a 4-hapermanent forest plot established in Kanghe nature reserve in Dongyuan city,Guangdong province.There were 14 liverwort species from 11 genera of 7 families and 26 moss species from 23 genera of 16 families.The analysis of the species composition of bryophytes in this area showed that the dominant families and species of bryophytes in this area belonged to tropical and subtropical flora.There were a large number of single families in the sample plot,which indicated high habitat specificity of the bryophytes in this area.(2)Based on tree DBH of the overstory trees,all subplots within the 4-ha permanent plot are divided into 4 community types by performing TWINSPAN.The results of Kruskal-Wallis test showed no significant differences among community types in maximum cover class and evenness index of bryophyte,but highly significant differences(P < 0.01)in the total cover class,number of species,Shannon-Wiener diversity index,and Simpson diversity index of bryophytes.The total cover class,maximum cover class,species number,evenness index,Shannon-Wiener diversity index and Simpson diversity index of bryophyte were the highest in community 4.(3)The results of Mantel test showed a significant correlation between bryophyte species composition and species composition of canopy tree(P < 0.01).The leaf area index of the canopy trees was highly significantly and negatively correlated with the maximum cover class of bryophytes,but highly significantly and positively correlated with the evenness index of bryophytes and not significantly correlated with number of species,the Shannon-Wiener index,the Simpson index,and the total cover class of bryophytes(P<0.05).(4)The Spearman’s Rank correlation,a non parametric method,showed no significant correlation between the soil factors and the maximum cover class,and evenness of bryophytes;The total cover class was significantly and positively correlated with the soil total K(P < 0.05);both Shannon-Wiener diversity index and Simpson diversity index were significantly and positively correlated with soil bulk density and the soil total P(P < 0.05);Number of species of bryophytes was significantly and positively correlated with the soil bulk density,the soil total P and total K(P < 0.05),but significantly and negatively correlated with organic matter(P < 0.05).(5)The Kruskal-Wallis test showed no significant differences in bryophyte diversity index along the soil moisture,bulk density,and total nitrogen gradients,respectively;The Shannon-Wiener diversity index,number of species,Simpson diversity index,and the total cover class significantly differed along a soil organic matter gradient(P < 0.05);Bryophytes evenness significantly differed along a soil total P gradient(P < 0.05);Both the total cover class and the maximum cover class significantly differed along a soil total K gradient(P < 0.05).(6)The results of Random Forest showed that community types was the most important driver of the total cover class,number of species,Shannon-Wiener diversity index,and Simpson diversity index of bryophytes,while the soil total P exerted the greatest influence on the bryophyte evenness;The soil pH exerted a great influence on the maximum cover class.The results indicated that the change of soil nutrient content played a major role in the distribution of bryophytes,and the heterogeneity of forest communit y played a leading role in the diversity of bryophytes.(7)Indicator Species Analysis(ISA)showed that the bryophytes were highly associated with environmental factors.Twenty-three bryophyte species were detected as indictors of the community types and soil factors,with the corresponding indicator species for each environmental factor gradient.The results showed that indicator species were indicative of specific environmental conditions.更多还原