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珍稀濒危植物南方红豆杉种群数量特征的研究

The Research on Population Quantitative Characteristics of Precious and Endangering Plant-Form.Taxus Chinensis var.mairei

【作者】 王新功

【导师】 洪伟; 吴承祯;

【作者基本信息】 福建农林大学 , 生态学, 2003, 硕士

【摘要】 南方红豆杉属国家—级保护植物,也是我国珍稀濒危植物。本文从南方红豆杉种群生态学的角度、主要应用数学生态学的方法探讨南方红豆杉种群的数量特征,包括南方红豆杉种群年龄结构、种群空间格局(探讨分布格局动态规律与生境相互关系)、不同立地条件下种群优势度增长趋势、生态位宽度、生态位相似比例、生态位重叠、空间占据能力及种间竞争等,分析其目前现状及濒危原因,期望为南方红豆杉野生资源的保护和扩大、营造人工林及可持续利用提供理论基础,也为濒危植物种群生态学的研究提供参考。 由于南方红豆杉无解析木,因而以“空间推时间”、“横向导纵向”方法,将林林依胸径大小分级,以立木级结构代表年龄结构,采用分段匀滑技术,对两个不同生境的南方红豆杉种群编制特定时间生命表,绘制存活曲线,结果表明不同生境的南方红豆杉种群的存活曲线均趋于Deevey-Ⅲ型,两地差异较小,幼苗死亡率极高,不同生境的幼苗死亡率均达到96%以上。南方红豆杉种群固有的生态生理特征决定了其生命表和存活曲线的类型,从种群发展的角度来看,早期较高的死亡率严重限制了南方红豆杉种群的扩展,是南方红豆杉濒危的重要原因。南方红豆杉种群天然更新过程的动态,是通过南方红豆杉不同龄级的株数分布波动表现的,种群动态的谱分析表明,南方红豆杉种群表现出明显的大周期内有小周期的多谐波迭加特征,这种周期性的波动与林分更新有关,有利于南方红豆杉种群自我稳定性的维持。 种群空间格局及其变动的趋势是影响种群数量发展的主要因素,本文采用6种典型聚集度指标及IwaoM—(?)回归分析法研究了南方红豆杉林中南方红豆杉幼苗、幼树、中龄树和成树的分布格局及动态,并分析格局形成原因,结果表明,各样地南方红豆杉种群幼苗均成聚集分布,幼树的分布格局偏向于随机分布,而中龄树与成树则为随机分布,从幼苗到成树,随机扩散的趋势十分明显。南方红豆杉幼苗表现为较强的聚集分布,除与种子的散布有关外,生境条件的差异是重要原因之—,其它发育阶段表现为明显的随机分布,表明它在自然群落中分布的概率很小,反映了南方红豆杉珍稀濒危的生态生物学特性和特征。 以胸高断面积代替种群生物量,分别采用Logistic常规模型及刘金福提出的Logistic改进模型对南方红豆杉种群的增长动态进行研究,运用改进单纯形法对模型进行优化,拟合结果表明改进模型比Logistic常规模型更符合南方红豆杉种群的增长趋势,南方红豆杉种群的最大增长速度出现在第10龄级,即胸径为68~76cm时期。运用改进模型对南方红豆杉种群在不同海拔梯度的种群优势度增长进行了探讨,表明海拔790m处的南方红豆杉具有较大的环境容纳量,但增长速度不快,海拔990m处的南方红豆杉种群环境容纳量不高,但具有较大的增长速度,这可能与群落的发育阶段不同有关,两地海拔均为南方红豆杉适宜的生长海拔高度,相比而言,海拔790m的珍稀濒危植物南方红豆杉种群数量特征的研究高度更宜于南方红豆杉种群的生长。 对多数植物而言,尤其是阳性树种,植物种群个体占据林分空间的大小是决定此个体存在及发展的重要条件,在南方红豆杉占据似划准的群落中,通过绘制高度级结构图和存活曲线并采用动态分析方法,定量分析南方红豆杉种群的高度级结构及动态变化,结果表明南方红豆衫种群高度结构近拟为塔型,高度存活曲线为中间微凸而近于直线,种群失稳率为正且值较大,综合二者认为南方红豆杉种群趋于缓慢增长型,这与南方红豆杉具有较大的幼苗库有关,幼苗数量占91.48%、其次为高度为5~7m的中树,占2.27%。分析南方红豆杉种群高度结构变化的原因认为,种间和种内对资源的竞争是引起其种群结梅粼七的主要原因,随着高度增长,物种间不唯琳内对生存空间的竞争加剧,形成南方红豆杉种群世代不同大,J、个体的高度结构。 在对种群高度结构研究的基础上,运用分形理论,彩月三种不同的尺度寸剖示:冠幅、底面积、体积,分别测度南方红豆杉树冠的分形维数,对南方红豆杉种群树冠空间占据程度及利用生态空间的能力进行分析,同日士付用改进单纯形法月滋性回归求解分维数与双对数线性回归求解进行比较,结果表明,南方红豆杉三种尺度指标树冠的分形维数均不高,分维数D分别为0.68似、02721、0.1442,南方红豆杉林内南方红豆杉对空间的占据能力不强,在与其它优势种群的竞争中并不占优势地位,分维数不同的求解方法表明用改进单纯形直接非线除粼不叫赌那斑的效果。 将群落的取附址线抬看作一维的资源状态,采用定量分析方法,对南方红豆杉林乔木层12个主要种群生粉彭翻于了钡淀,包括生态位宽度、生态位捌必性比例、生态位重叠.结果表明:组成南方红豆杉群落的优势种群大多数为广生态位,对资源具有一定的共享性,种群之间的生态位相似性比例较高,生态位相似性比例大于0.5的种对占全部物种对的56.1%;南方红豆杉、毛竹生态位宽度较大,南方红豆衫与生态位较宽的树种重叠值较大,表明南方红豆杉、毛川如醚招洲落生境,分布较广,利用资源较为充分,且易于与生态位较宽的物

【Abstract】 Form.Taxus chinensis var.mairei is protecting plant in the first class, which is a precious and endangering plant in China In this paper, the quantitative characterics of Form. Taxus chinensis vsr.mairei population including age structure, spatial distribution pattern, growth dynamics of tree basal area, niche characterics, fractal dimension and competition between specises were studied using methods of mathematics ecology from the angle of population ecology of Form.Taxus chinensis var.mairei, then the prent state and the endangering causes were analysed. This research offers gist to protecting and enlarging the crude resourse of Form.Taxus chinensis vsr.mairei population, afforesting plantation and sustainable utilize for us. The research can offer some important references to the population ecology of endangerous plant, too.Based on the dates of two different circumstances, two standard life tables of Form.Taais chinensis var.mcarei population are founded by mathematical technique according to premising with "space deducing time", and the curves of survival rate, mortality rate and killing power were drew. The results showed both of the survival curves of population appeared to be a type of Deevey-III and the high mortality of seeding is one of the important reasons which caused Taxus chinensis var.mairei to be endangered, which badly limited the enlargement of Form.Taxus chinensis var.mcarei population. The spectral analysis of the population showed that there was a marked regularity of periodic in the process of natural regeneration of Taxus chinensis var.mairei, and it availed to the stabilazation of Form.Taxus chinensis var.mairei population.This paper presents the spatial distribution pattern and dynamics of Form. Taxus chinensis var.mairei population in Form.Taxus chinensis var.mairei community using six aggregate indices(C,I,I M, PAI,CA,), then analyze the causes of evolved pattern. The results indicated that the distribution pattern of seedling were all clumped in every plot, however, the distribution patterns of sapling, media tree and mature tree were mostly random. The trend of diffuse of Form. Taxus chinensis vsr.mairei population is very oblivious from seeding stage to mature tree stage. The patterns were consistant with the ecological and biological characteristics of Form.Taxus chinensis var.mairei which were valuable and rare and in severe danger.In this paper, Logistic model and Liu-Logistic model were proposed to approach thegrowth dynamics of tree basal area of Form.Taxus chinensis var.mairei population. The method of modified simplex was applied to optimize the models, and the fitting results show that Liu-Logistic model was more suitable than Logistic model to the actual growth trend of Form.Taxus chinensis var.mairei population, and the highest growth rate of basal area was the tenth age class, namely the phase when breast diameter was 68~76 cm. The growth dynamics of tree basal area of Form.Taxus chinensis var.mairei population in different altitude were discussed using the Liu-Logistic model, and the results showed that the altutide of 790 meters is more suitable to the survive of Form. Toms chinensis var.mairei population than 990 meters.Plot sampling was selected and dynamic analysis was used to study the height structure of Taxus chinensis var.mairei population, and the quadrate picture of height structure and the curve of survival rate were drew. The results showed the height stucture wsa "revere-J" and the survival curve was likely a linear with a little protruding. It was belonged to stable type. The seeding accounted for 91.48% of total number, and the mature tree of H: 5~7m class for 227% whose density was just next to the seeding class. The results of intraspecific and interspecific competion formed the different individual height of Taxus chinensis var.mairei population.The fractal dimension of Taxus chinensis vsr.mairei were calculated on three indices : crown breath, base area, volume. At the same time, the relativities of linear regression and nonlinea

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