【作者】 秦廷松；

【导师】 李登武；

【作者基本信息】 西北农林科技大学 ， 生态学， 2011， 硕士

【摘要】 为了探讨黄土高原地区黄龙山白皮松林的天然更新规律。本研究以种群生态学、植物分类学、植物群落学及生物统计学等多学科基础理论为依据,从白皮松林土壤种子库物种的组成、白皮松个体及地上植被更新的角度,通过样方调查和统计分析,研究该地区白皮松群落土壤种子库的组成和分布情况,分析地上植被与土壤种子库构成关系,阐明白皮松林天然更新的主导因素,主要结论如下:(1)白皮松林土壤种子库的组成和分布显现以下规律:全年土壤种子库共有物种44种,隶属34个属,26个科;黄龙山白皮松林土壤种子库萌发期和落种期两个不同物候期的物种结构相似;土壤种子库不同土壤层次间种子个体数和物种数差异极显著,均呈现上层(0～5cm)>中层(5～10cm)>下层(10～15cm)的趋势;受人为活动影响强烈的样地多样性指数明显低于远离耕作区的样地。(2)黄龙山白皮松林林隙地上植物与土壤种子库的关系是:在同一距离系数下,林隙地上植物种子个体分布与土壤种子库植物种子数量分布类型较为接近,聚类构型相似,灌木的Sorensen系数(0.12)<乔木(0.29)<草本(0.53);如果将地上植物按径级除去幼树,则乔木的Sorensen系数变为0.33,灌木的则变为0.30。草本的Sorensen系数仍是最高。(3)黄龙山白皮松母树土壤种子库在水平方向、垂直方向和不同方位都表现出一定的规律性:在水平方向上,随着距母树距离的增加,种子数量呈逐渐减少的趋势,差异较显著(p=0.031),种子的数量主要集中在母树树冠投影范围内;在垂直方向上,种子数量随土层深度的增加急剧减少,呈极显著性差异(p<0.01),大量种子集中在枯枝落叶层中;种子数量主要集中在东北方向,西南方向偏少,但差异性不显著。土壤种子库中具有活力的完好种子数量较少,仅占到总量的14.41%。(4)黄龙山白皮松林林缘更新在年龄结构上呈现为增长型,在年龄组成中,1～5龄的更新苗所占比例较其他龄级更新苗呈极显著差异(p<0.01);在分布类型上,黄龙山白皮松林林缘更新苗主要表现为随机分布形式,随着样带中样方离林分的距离增大,更新苗有明显的从集群分布向随机分布发展的趋势;从林缘形状来看,黄龙山白皮松凹型林缘的更新苗密度及延伸长度明显优于其他两种类型的林缘。更多还原

【Abstract】 Pinus bungeana relatively concentrated distributing in Huanglong mountain area of the Loess, and commonly mixed with Pinus tabulaeformis and Platycladus orientalis to form flora communities of high diversity, which also as mainly important habitats of Crossoptilon mantchuricum ranked as the First-grade state protected animal in China. Huanglong Mountain lies along the south part of the Loess, which is regard as a natural barrier against southwards sandstorm from Kuan-chung Plain. Therefore, the study of natural regeneration of Pinus bungeana forest land in this area is not only the important integral part of the Loess ecology research, but it would also play a significantly positive role in native forest diversity protection and agriculture production.Under the background of the basic theory of population ecology, descriptive botany, phytocoenology and biostatistics, from the point of the composition of soil seed banks, individual and vegetation regeneration of Pinus bungeana forest land, by investigating and analytic statistic, this study analyzed the process of natural regeneration of Pinus bungeana forest land, learned the distribution and composition of population in soil seed bank, in addition of the relationship between vegetation and soil seed bank, as well as illustrated the dominant factors of natural regeneration of Pinus bungeana forest land. Through the above work can draw the following conclusion:1) The composition and distribution of soil seed bank of Pinus bungeana forest land:The germination period was identical to the seed period in species structure. The soil seed bank contained 44 species belonging to 34 genera and 26 families in 2009. For individual seed number and species number, a significant difference (p<0.01) was found among soil layers with: 0-5 cm > 5-10 cm > 10-15 cm. Index averages were--Margalef abundance: 3.87, Shannon-Wiener diversity index: 3.63, and Pielou evenness degree index: 1.15. For regeneration and succession, P. bungeana had a stronger regeneration capability with seeds at 39.2% of all tree species. Also, the herbaceous plants were 19.00% more than the woody plants in seeds and 36.36% in species number. Our results show there are significant differences in the vertical distribution of soil seed banks, and the composition of species remained relatively stable in the Huanglong Mountain area.2) The relationship composition of vegetation and soil seed bank:Comparing with the relationship of the dominant species between soil seed bank and above-ground vegetation by similtude analyses, the result shows that the Sorensen index of shrub (0.12)<tree(0.29)<herb(0.53). In the soil seed bank tree and herb species dominant in seeds amount were both late-succession species, and the shrub species is pioneer species; According to the graph of cluster combining, the form of plants individual distribution above the ground vegetation is similar to the seeds distribution in soil seed bank; From the common species both in above-ground vegetation and soil seed bank, the percentage of tree species is 47.83%, which is more than shrub and herb species.3) Individual regeneration of the soil seed bank of Pinus bungeana:The distribution of Pinus bungeana performs regularly. The seeds concentrated under the canopy of their mother tree when they are mature Seed density declined with increasing distance from mother tree.Seed distribution varied with distance (P=0.031).Seed distribution varied with orientation is not significant. Meanly more seeds to the northeast of the mother tree, relatively small to the southwest. The distribution of Pinus bungeana seeds in soil was consistent.Seed density declined with increasing depth of soil(P<0.01).Most seeds were in the litter layer (84%).There were almost no seeds at soil depths greater than 10cm. viable seeds accounted for 14.41 percent 0f total seeds.4) The characteristics of regeneration near the forest edge of Pinus bungeana forest land:The forest edge orienting the northeast is best strongly regenerated of all directions, the northeast secondly. According to age structure, the natural regeneration of the soil seed bank of Pinus bungeana forest land totally shows in increasing development. Regeneration seedlings of 1-5 years is significantly different (p=0.000) from the others more than 5 years. A great loss of regeneration seedlings occurs in the transition of 1-5 to 6-10 years. The regeneration seedlings randomly distribute in the forest edge, increasing with the distance from central forest, three is a significant variation for generation seedlings distribution from contagiously to randomly. By investigating the shape of forest edge, the density and extension length of the regeneration seedlings in the concaved forest edge band in the Pinus bungean forest land.更多还原