【作者】 宋百敏；

【导师】 王仁卿； 于长青；

【作者基本信息】 山东大学 ， 生态学， 2008， 博士

【摘要】 随着经济的发展和现代化程度的提高,人类对矿产资源的开发利用也与日俱增,开山采石一方面极大地满足了人们物质生产的需求,另一方面造成对景观和自然生态系统的严重破坏,加强对废弃矿区受损生态系统的恢复与重建,已经成为生态学的重要研究课题。本研究以北京市西山（门头沟区）废弃采石场为例,运用空间代替时间的方法,在前期调查的基础上,选择了4个代表不同自然恢复时期的典型样地及1个未受采石影响对照样地,对自然生态恢复过程中土壤特性、植被变化规律、土壤种子库以及群落演替过程中早期物种的消退原因等进行了研究,以丰富恢复生态学的理论和指导生态恢复的实践。通过对废弃采石场自然生态恢复过程中土壤特征和植被特征研究发现:随着生态恢复的进行,土壤厚度、土壤有机质不断积累,土壤粒径、土壤容重、土壤pH值逐渐变小,土壤含水量、土壤全N、土壤全P、土壤全K以及速效N、速效P、速效K的含量逐渐增加,土壤理化性状逐渐得到改善。Pearson相关分析结果显示,群落的物种多样性、物种丰富度和地上生物量分别与其生境中土壤的含水量、容重、粉粒含量、粘粒含量、pH、有机质、全N、全P、全K、速效N、速效K之间存在显著相关（p＜0.05）,其中,与土壤容重、pH分别呈负相关,其余为正的相关。该结果表明,土壤性状的变化与群落结构动态相对应。土壤与植被的相互作用,共同推动着群落的演替。在生态恢复的不同阶段,组成群落的优势物种发生变化,在恢复1年、5年、15年和32年的样地中,优势植物分别为牛筋草（Eleusine indica）、狗尾草（Setariaviridis）、虎尾草（Chloris virgata）和狗尾草、荆条（Vitex negundo var.heterophylla）。随着群落演替的进行,植物群落物种组成、分科及生活型功能群结构也在改变。组成群落的物种数量总体呈增大趋势,在生态恢复过程中科的数目在不断增加,群落组成更加复杂化和多样化。随着生态恢复的进行,一年生植物的重要值逐渐减小,多年生植物和灌木的重要值逐渐增大。乔木在生态恢复的后期虽有零星出现,但所占的比重始终很小,这说明在当地矿区进行生态恢复时仅凭自然力几十年内难以恢复成森林生态系统,要想恢复成生态功能更强的森林生态系统,一定的人工措施是必要的。群落物种多样性、物种丰富度随着演替时间的延长先增加而后保持相对稳定,而植被总盖度和地上生物量呈不断增大趋势。相关分析表明,在不同恢复阶段的样地中,地上净初级生产力与Shannon-Wiener多样性指数及Margalef丰富度指数显著相关（p＜0.01）,在恢复1年的样地中,地上净初级生产力和生物多样性的关系呈线性负相关,恢复5年、15年的样地,地上净初级生产力随着生物多样性的增加呈现出线性递增的关系,到恢复的后期（大于32年）,地上净初级生产力和物种多样性之间的关系为单峰曲线。这说明,在生态系统中,一定物种数量对生产力是必要的,但生态系统功能的维持,即初级生产力,主要是由群落中的优势种或功能群所决定的。研究样地自然生态恢复的状况表明:（1）北京西山采石废弃地在初期可以借助自然力实现初步的恢复,在自然恢复过程中,草本植物和灌木对采石场裸露废弃地表土的稳固和生态系统结构与功能的维持起着重要的作用,但在整个自然生态恢复过程中（包括大于50年的未受采矿影响的对照样地）乔木所占的比重始终很小,说明在当地的山地阳坡单靠自然力恢复很难形成森林群落,必须适当进行人工辅助。（2）一定数量的物种对维持态系统的功能是必要的,但对生态系统功能起关键作用的是功能群及优势物种,在生态恢复的实践中,要更加注重群落中植物功能群的组成和构建以及优势物种的选择和应用。通过对不同恢复阶段采石场废弃地种子库的研究,得到以下结果:从物种组成来看,本研究的土壤种子库共记录了35种植物,分属11个科,其中禾本科、菊科、马鞭草科和豆科占到总科数的69.23%-92.86%。在恢复1年的样地中,一年生草本占76.9%,随着恢复的进行,一年生草本的种数逐渐减少,多年生草本、半灌木灌木的种数逐渐增加。在所研究的不同恢复阶段的样地中,均未在种子库中发现乔木的种子。土壤种子库的密度随恢复时间的变化而变化,变动范围为269-5002粒.m^-2。随着生态恢复地进行,种子密度在恢复15年的样地中达到最大,然后呈减小趋势。土壤种子库的垂直分布特点是种子数随着土层深度的增加而降低,表现为0-3cm＞3-6cm＞6-10cm。土壤种子库物种多样性的变化表现为,随着演替的进行,优势度指数逐渐减小,而丰富度指数、均匀性指数和Shannon-Wiener多样性指数逐渐增大,恢复到32年时达到最大。土壤种子库和地上植被之间具有较大相似性。地上植被密度73%的变异可归结为土壤种子库密度的变异。在生态恢复过程中,土壤种子库和地上植被的3种相似性系数（Ochiai、Dice和Jaccard）具有相同的变化规律,3种相似性系数的变化范围分别为0.5-0.73、0.49-0.73和0.33-0.57。在恢复1年的样地中最小,恢复到15年时达到最大,以后随着恢复时间的延长又呈现下降的趋势。这说明在采石矿区生态恢复的过程中,土壤种子库对地上植被具有重要影响,在恢复的后期,植被成分主要受群落之间物种的相互作用决定,受种子库的影响降低。对不同恢复阶段样地的土壤种子库研究表明:（1）北京门头沟不同恢复阶段的采石场废弃地中含有相当数量的种子,并且在适宜的条件下能够萌发,可以为采石场废弃地初步的生态恢复提供的种源。（2）土壤种子库和地上植被在物种组成、密度、生物多样性以及相似性系数方面均具有较高的相似性。通过土壤种子库可以形成相对稳定的草本及灌丛群落,因此,在废弃采石场的生态恢复的初期,可以考虑利用土壤种子库的自然恢复力,如保留表土,这是一种经济而且有效的生态恢复措施。（3）土壤种子库中没有发现乔木物种,说明单纯依靠种子库难以在采石场废弃地上形成森林群落,采石场废弃地要想进一步恢复形成当地潜在的稳定森林群落,应当适当借助人力。对不同恢复阶段狗尾草（Setaria viridis（L.）Beauv.）生物量分配策略研究的研究结果表明:随着恢复时间的延长,茎、叶生物量及总生物量均增加,其中,茎的增加幅度最大,超过30%。而根、穗的生物量随着生态恢复的进行逐渐变小,其中穗的减幅最大,从恢复15年的样地,到恢复32年的样地,穗的生物量降低了37.6%。随着群落演替的进行,狗尾草显著提高了对茎的生物量分配,显著降低了对生殖构件和根的分配比率,对叶的分配虽有增加,但变化幅度较小。随着生态恢复的进程,狗尾草的地下/地上比值及根茎比逐渐减小,而茎叶比逐渐增大,并且各比值在不同样地间呈现出显著差异。相关分析结果显示,狗尾草茎生物量分配与根、叶、穗构件生物量分配间存在负相关关系,表明茎生物量分配与其他构件生物量分配间存在协调关系。通过狗尾草的生物量配置研究发现:在群落演替的后期,狗尾草为争夺光照而加大了对茎的生物量投资,减少了对生殖器官的投资比例,并最终造成狗尾草种子的减少,这可能是导致狗尾草退出演替序列的内在原因。总之,通过本研究发现,北京门头沟不同恢复阶段的采石场废弃地中含有相当数量的草本和灌木种子,并且在适宜的条件下能够萌发,可以为矿区的初步生态恢复提供种源,但要想进一步恢复形成当地潜在的稳定森林群落,必须采取适当的人工辅助措施。更多还原

【Abstract】 The exploitation of natural resources has been increasing rapidly along with the development of economy and the modernization. The quarry is necessary to provide stones for the human beings, but it will destroy the landscape and natural ecosystem greatly. So, the restoration and reconstruction of damaged ecosystem caused by the quarry has become a hot topic of restoration ecology.The ecosystem restoration was studied in an abandoned quarry in Xishan Mountain in Beijing （Mentougou District） using ecosystems in different restoration stages to substitute the temporal restoration stages. Based on the pilot study, four typical plots and one comparison plot were selected to represent the different temporal restoration stages. The soil properties, the changes of the vegetation, the soil seed bank and the mechanisms of the community succession were studied to test and enrich the ecological theories and direct the ecological restoration practice.The studies on the soil properties and the vegetation characters in the abandoned quarry in Xishan Mountain found that: The soil particle size, soil bulk density and soil pH decreased along with the natural restoration, while the soil thickness, soil water content and soil nutrients increased along with the natural restoration. The increased soil nutrients include soil organic matter, total N, total P, total K, available N, available P, available K. The physical and chemical characteristics of soil were ameliorated significantly. The Pearson correlation analysis found that the species diversity, species richness and the aboveground biomass were correlated negatively with the soil bulk density and soil pH, while correlated positively with soil water content, percentage of fine sand （2-20μm）（%）, percentage of clay （<2μm）（%）, soil organic matter, total N, total P, total K, available N, available P, available K. These results showed that the changes of soil properties were corresponding to the changes of community structure. The interaction between the soil and vegetation may promote the community succession together.The dominant species of the communities changed with the ecological restoration. The Eleusine indica, Setaria viridis, Chloris virgata and Setaria viridis, Vitex negundo van heterophytla are the dominant species in the plots after one year, five years, fifteen years and thirty two years of restoration, respectively. Along with the community succession, the structure of the community changed significantly in terms of the composition of species, family and life forms. The number of species showed the trends of increase while the number of families increased gradually, which made the community more complex and diverse along with the succession time. The important value of annuals decreased, while the important value of perennials and shrubs increased gradually along with the restoration time. Only sporadic trees were found in the late of the restoration and their important value are small in the all the plots, which suggested that the natural restoration itself cannot restore forest ecosystems in 32 years and the human activities were needed to promote the restoration towards the forest ecosystems with more ecosystem services.The species diversity and species richness increased with the succession time at first and then tended to stabilize. The vegetation coverage and aboveground biomass increased along with the restoration stages in the study. The correlation analysis showed that the net aboveground primary production was correlated significantly with the Shannon-Wiener diversity index and Margalef richness index （p < 0.01）. In the plots after one-year restoration, the net aboveground primary production was correlated negatively with the diversity indices; In the plots after five-year or fifteen-year restoration, the net aboveground primary production was correlated positively with the diversity indices; In the late restoration stages （ >32a ）, a unimodal relationship was found between the net aboveground primary production and the diversity indices. The study suggested that the richness of species has the trend to promote the primary productivity of the ecosystem, but the relationship between them is not simple. In the ecological restoration, the restoration is of species richness is needed for the primary productivity, but the functional group and dominant species may play more important role in the function of the ecosystem.The studies on the vegetation in different restoration stages suggested that: （1） The abandoned quarry in Xishan Mountain could be restored by nature forces in the early stages. The restored herbs and shrubs could protect the topsoil and maintain the structure and function of the ecosystems. The important values of trees are small in the all the plots （including the comparison plot after more than 50 years of natural restoration）, which suggested that the natural restoration itself cannot restore forest ecosystems in the studied sun-facing slopes and the human activities were needed to promote the restoration. （2） The richness of species is needed in maintain the function of the ecosystem, but the functional group and dominant species may play more important role in the function of the ecosystem. So, the composition of the functional group and the selection and build up of the dominant species may be more important in the ecological restoration.Based on the studies on the soil seed bank in abandoned quarry in the different restoration stages, 35 plants species belonging to 11 families were found in the soil bank. The number of species belonging to Poaceae, Compositae, Verbenaceae and Leguminosae amount to 69.23%-92.86% of all the species across different restoration stages. In the plots after one-year restoration, the annuals amount to the 76.9% of all the species. Along with the restoration time, the number of annual species decreased gradually, while the number of perennial and shrub species increased significantly. No seeds of trees were found in the seed bank of the studied plots in all the restoration stages.The density of soil seed bank varied significantly (from 269 to 5002 grain m^-2)between the plots in different restoration stages. The density of soil seed in the plotafter 15-year restoration was the biggest, and then decrease gradually. The number ofseeds in soil bank decreased with the depth of the soil, the pattern is that 0-3cm > 3-6cm> 6-10cm. Along with the restoration stages, the dominance index decreased while the species richness index, evenness index and Shannon-Wiener diversity index increased gradually and come to the highest value in the plots after 32-year restoration. The soil seed bank and vegetation are similar in the study. 73% of the variance of the vegetation can be attributed to the variance of the soil seed bank. The indices of similarity （Ochiai, Dice and Jaccard） between the soil seed bank and vegetation have similar change trend. The three indices of similarity varied from 0.5 to 0.73, from 0.49 to 0.73, from 0.33 to 0.57, respectively. The indices of similarity in the plots after one-year restoration are the smallest and that in the plots after fifteen-year restoration are biggest After 15 years of restoration, the indices of similarity may tend to decrease along with the time. The results showed that the soil seed bank contributed significantly to the vegetation. In the late restoration stages, the composition of community was more influenced by the interactions between the plant species and the influences of seed bank may decrease gradually.The studies on the seed bank of different restoration stages suggested that: （1） There were abundant seeds that could germinate in suitable conditions in the abandoned quarry in Xishan Mountain in Beijing, which can provide seed resources for the elementary restoration. （2） The soil seed bank and vegetation are similar in terms of species composition, density, the indices of the diversity and similarities. The seed bank contributed to the formation of relatively stable communities of herbs and shrubs. So, the natural restoration using the soil seed bank should be considered first in the elementary restoration of abandoned quarry and preserving the topsoil to utilizing the soil seed bank is the economic and effective measure. （3）. No seeds of trees were found in the seed bank of the studied plots in all the restoration stages, which suggested that the seed bank cannot restore forest ecosystems in the studied sun-facing slopes and the human activities were needed for the restoration towards the potential forest ecosystems.The studies on the biomass allocation of green foxtail （Setaria viridis （L.） Beauv.） in different restoration stages found that: Along with the restoration stages, the total biomass and the biomass of stems and leaves both increased. The biomass of stems increased the most, which is up to 30%. But, the biomass of roots and reproduction decreased gradually. The biomass of reproduction in the plots after 32 years of restoration decrease 37.6% comparing with that in the plots after 15 years of restoration.Along with the community succession, the green foxtail increased the percentage of biomass to the stems significantly while decreased the allocation to the reproduction and roots. The biomass to the leaves increased only a little. The ratio of belowground biomass to the aboveground biomass and the ratio of root to stem both decreased significantly along with the community succession, while the ratio of stems to leaves increased significantly. The correlation analysis found that the allocation of biomass to stem was negatively correlated with the allocation of biomass to other organs including roots, leaves and reproduction, which suggested the there was a tradeoff between the allocation of biomass to stems and to other organs.The studies on the biomass allocation found that the green foxtail increased the allocation of biomass to the stems while decreased the allocation to the reproduction in the late of the community succession, which is an adaptive response to scrabble for light resources. But this allocation pattern will passively decrease the seed production and may cause the green foxtail fade from the community succession.In conclusion, the study found that there were abundant seeds of herbs and shrubs that could germinate in suitable conditions in the abandoned quarry in Xishan Mountain in Beijing, which can provide seed resources for the elementary restoration. But the human activities were needed for the restoration towards the potential forest ecosystems.更多还原