【作者】 范玮熠；

【导师】 王孝安；

【作者基本信息】 陕西师范大学 ， 生态学， 2006， 硕士

【摘要】 黄土高原由于强烈的水土流失其生态系统正处于极度退化的状态,加速该地区退化生态系统的恢复与重建势在必行。地处子午岭南端的马栏林区是黄土高原目前保存比较完整的天然次生林区,是黄土高原中部地区重要的生态公益林。子午岭植被对调节陇东及陕北地区的区域气候、维护生态平衡、促进生态和经济的可持续发展都有举足轻重的作用,研究子午岭马栏林区的植被群落演替对黄土高原退化生态系统的恢复和重建具有重要的生态意义。 本论文在综合国内外研究进展的基础上,对马栏林区植物群落的演替系列、主要植物种的生态位特征、林隙的主要特征和干扰状况以及辽东栎(Quercus liaotungensis)和油松(Pinus tabulaeformis)的林隙更新状况进行了研究,结果如下: 1 黄土高原子午岭马栏林区是由处于不同演替阶段的植物群落所组成的。通过DCA排序能够较好地反映植物草本群落→灌木群落→乔木群落的演替系列。结合数量分类和排序,将演替系列划分为9个阶段,呈现草本群落→灌木群落→乔木群落的演替过程。其中,自然恢复演替以辽东栎林为演替顶极,而人工油松林可能是人为干扰下的一种相对较稳定的群落类型。在演替系列上,群落的科、属、种均呈现较明显的增长趋势,表现为乔木群落>灌木群落>草本群落,群落的物种多样性和复杂性在演替进程中都得到了很好的恢复。随着演替的进程,植物生活型功能群组成逐渐复杂,物种丰富度逐步增加,其组成比例也随着恢复时间的延长趋于稳定。群落枯落层和腐殖质层厚度均呈加速增长,二者组成比例由于枯落物性质的不同在各群落类型间存在一定差异。 2 在森林群落演替系列中,乔木种生态位宽度的平均水平小于灌木种,建群种的生态位宽度小于主要伴生种:生态位宽度较大的种与其它各物种间生态位重叠的平均值较大,生态位宽度较小的种则相反,甚至没有重叠。由于物种生物生态学特性的不同和环境的异质性,物种间的生态位重叠情况各异,而同属植物种对间生态位重叠较大。 3 马栏林区以中小林隙为主,大林隙较为少见;中期林隙在该地区占主导地位:林隙形成木中掘根风倒的最多,其次是干基折断、砍伐树桩和枯立,最少的是干中折断;林隙绝大多数由1～3株形成木形成;构成林隙形成木的主要树种是辽东栎和油松,白桦(Betula platyphylla)、山杨(Populus davidiana)等森林演替早期或中期树种由于在林冠层的分布有限,成为林隙形成木的几率也相对较小。更多还原

【Abstract】 It is imperative under the situation to accelerate the recovery and restoration of degenerative ecosystem on loess plateau because the ecosystem is seriously degraded due to soil and groundwater depletion. Malan forest area, in the south of Ziwulin area, is a relative intact natural secondary forest on loess plateau and is important for loess plateau central area. Ziwulin area has crucial effect for maintaining regional climate and as a base for ecologically sustainable economic development in east Gansu and north Shaanxi provinces. So, the research of plant community successional series has significant ecologic meaning for recovery and restoration of degenerative ecosystem.In this dissertation, the studies of plant community successional series in Malan forest area, niche characteristics of common plant species, characters of gaps, disturbance status and gap regeneration of Quercus liaotungensis and Pinus tabulaeformis are carried on and got the results as follow:1. Malan forest area was composed with various plant community successional stages. The plant community successional series were divided into nine stages in this area with a trend over time from herb- to shrub- to tree-dominated communities with DCA analysis. The climatic climax was a Q. liaotungensis community. Artificial P. tabulaeformis community was a relative stable community under human disturbance. Over time, the number of families, genera and species increased. The species richness of every life form group increased and the compositional proportion became more consistent over time. Litter and humus thickness increased over successional time, however, the ratio of litter to humus differed among successional stages.2. In the forest successional series, the niche breadths of common tree species were smaller than that of common shrub species, and some companion species had larger niche breadths than dominant species. Species with large niche breadths tended to overlap with other species highly and vice versa, even those with smaller niche breadths sometimes had no overlap at all. Because of the distinction of species bio-ecological characteristics and environmental heterogeneity, some species with large niche breadths had low niche overlaps with each other and some narrow niche specieshad high niche overlaps with each other. High niche overlaps also occurred between species in the same genera.3. Medium and little gaps were majority in Malan forest area whereas great gap was rare. Metaphase gap was dominant in this area. Uprooting treefall was most in the Gap maker, and truncal basal breakage, fell stub, standing die were less. The least was middle-truncal breakage. Gap was mainly constituted with 1-3 gap makers including Q. liaotungensis and P. tabulaeformis. The probability of Betula platyphylla> Populus davidiana to become gap maker was less since distribution in canopy was limited. Most Diameter class of gap makers was under 30cm.4. The status of Q. liaotungensis renewal in Malan forest area was well but P. tabulaeformis was inferior. The mean density of Q. liaotungensis seedling and sapling was bigger than P. tabulaeformis while livability of P. tabulaeformis seedling was higher than Q. liaotungensis. Response rules of Q. liaotungensis and P. tabulaeformis regenerations for gap size and age had obvious difference that related to bioecology traits, mean coverage of shrub and herb in gap. Otherwise, gap regeneration ways of Q. liaotungensis and P. tabulaeformis in different forest community types were distinguishing. In the mass, Q. liaotungensis seedling had more capability for inhabiting in gap than P. tabulaeformis, further more, the trend that Q. liaotungensis may diffuse in P. tabulaeformis was observed. Gap appearance, development and dynamic cycle change with surroundings were possibly important microcosmic mechanism for plant community succession in Malan forest area.In our study, plant community secondary successional series were mainly natural recovery accompanied by human disturbance in Malan forest area on loess plateau. Recovery level of P. tabulaeformis pure forest represented for artificial forest was lower than that of Q. liaotungensis represented for natural secondary forest. Although in the natural recovery of degraded ecosystem, especially at initial stage, artificial forest could accelerate succession, species planted by human didn’t show superior adaptability. Hence, the further investigation emphases were the degree of community recovery with natural force, species of artificial assistance planting, and species quantity with appropriate ways.更多还原