【作者】 赵勇；

【导师】 范国强； 樊巍；

【作者基本信息】 河南农业大学 ， 森林培育， 2007， 博士

【摘要】 恢复生态学是生态学研究领域中最年轻的分支之一,也是现代生态学领域的研究热点。太行山低山丘陵区属平原与山地的生态过渡带,由于长期人为的过渡开发利用,现有植被处在不同的退化阶段,植被表现出以天然植被稀疏、低矮、部分地段裸露并镶嵌类型各异的人工植被为主要特点。导致植被改善环境的能力减退。而环境改善和稳定的根本是森林生态系统的恢复、发展和保护。为此,阐明太行山低山丘陵区退化生态系统自然恢复过程的生态学特征,探求自然恢复机理、对植被恢复过程进行正确评价和预测,既能丰富恢复生态学的内容,同时也为人工加快植被恢复进程和实现该区域资源的可持续发展提供科学的依据。通过研究,导致太行山低山丘陵区植被退化和恢复进程较慢的关键问题是人为的干扰和区域气候变化的结果。本论文在对研究区植被恢复阶段分类的基础上,从土壤、植被和群落演替分析入手,深入地剖析了恢复演替过程中群落的物理、化学和生物学变化特征,找到了群落演替过程中生态特征利环境特征变化规律;建立了研究区的群落演替模型;通过采取植被恢复预测模型的手段,对植被演替和恢复时间进行了初步探索,提出了研究区各群落植被恢复经历的时间;构建了植被恢复过程的评价指标体系,对植被恢复进程进行了有效的评价。通过研究,本论文取得主要结果:（1）导致研究区植被退化的主要原因是人为干扰,其次是气候原因。气温的年际变化具有6a、3.5a的周期规律;降水量变化具有8.5a、4.3a的周期性规律。研究区气候特点是平均湿度的减少和平均气温的升高,未来气候将更暖、更干燥。蒸发蒸腾量（ET₀）值将会持续升高。（2）随植被恢复进程,土壤容重和毛管孔隙度大小排序为草本恢复阶段＞乔木恢复阶段＞灌丛恢复阶段,灌丛和乔木恢复阶段容重差别不大。裸地阶段土壤容重最大,而孔隙度最小。土壤自然含水量大小顺序为乔木阶段＞草本阶段＞灌丛阶段＞裸地。从裸地到乔木阶段,随着植被恢复进程,土壤理化指标逐渐提高。石砾含量降低,粘粒含量增加,粉粘比减小。土壤粘粒与有机质、全氮、速效氮呈显著正相关关系。（3）植被降温效应和增湿效应随植被恢复进程而增强。气温日变化特征呈不对称的单峰曲线,植被恢复程度越高,气温变化幅度越小,群落调节气温的作用越显著。空气相对湿度的日变化呈不规则“U”型变化,与温度的日变化呈负相关。（4）研究区植物成熟绿叶中的N素含量在1.568%～5.011%之间;枯叶中N素含量变化在0.82%～3.890%之间。植物叶片中N素与土壤有机质含量、土壤含水量等指标相关性显著。植物N素回收效率（NRE）平均值为28.8%,都属于低回收率植物。乔木的NRE表现为最低,灌木的NRE最高。NRE与叶片中N素含量呈负相关,与土壤N含量、有机质含量、速效氮和土壤水分呈现负相关关系。（5）植物种类随植被恢复进程增加较快,物种丰富度也呈升高的态势;土壤湿度、土壤厚度与H′、D₁、PIE等多样性指数之间呈极显著的正相关;土壤有机质、速效氮、速效磷等养分指标与多样性指数（H′、D₁）有显著的正相关;乔木、灌木群落多样性指数H′与群落生物量表现为正相关;乔木林群落多样性指数（Jsw、H′）与恢复时间呈正相关;栓皮栎群落恢复时间每增加10a,群落物种数平均增加6种;物种多样性指数（H′）与灌木的盖度和高度呈较好的线性关系;草本群落的高度和盖度与物种丰富度指数（D₂）呈显著的负相关关系。（6）随恢复进程,群落生物量呈增加趋势,二者呈现幂函数关系;栓皮栎群落总生物量最大,刺槐次之,侧柏群落生物量最低。乔木群落生物量结构都表现为树干最高,根次之的规律;灌木群落地上部分的生物量明显大于地下部分的生物量,其比值在2.30～3.825之间;草本群落以魁蒿群落总生物量最高,白草群落最小。（7）乔木群落的凋落量要显著高于灌木群落;群落的凋落量随季节而变化,一般凋落量随季节变化规律为秋季＞春季＞冬季。凋落物持水量与植被恢复阶段有显著关系,最大吸水率为刺槐群落;最大持水量为20a生栓皮栎群落。刺槐的分解速率最快,理论上完全分解时间需要8.83a:40a生栓皮栎林凋落物分解速度最慢,理论分解时间为26.63a。同一群落中,30a生栓皮栎群落凋落物分解速度最快。灌木群落凋落物分解时间整体上较快,酸枣凋落物理论完全分解期是9.66a;荆条凋落物理论完全分解期为12.35a。随着演替的发展,群落的枯落层和腐殖质层厚度均不断增加,呈现乔木群落＞灌木群落＞草本群落。表明复杂的群落结构具有更强的物质循环能力。（8）研究区生态系统总碳贮量随恢复进程而增加。由草本阶段到乔木群落增加约4.5倍。土壤碳总贮量也呈上升状态,但土壤碳贮量占生态系统总贮量的比重却呈下降趋势;植物碳贮量所占比例逐渐增高,植被在恢复过程中的作用越来越大。（9）植被演替呈现出草本群落--灌木群落--乔木群落发展的趋势。草本群落逐渐由一年生草本占主导地位发展到多年生草本、半灌木及灌木占据群落主体。草本群落演替到10a时,逐渐形成以酸枣、荆条为建群种的单优群落。栓皮栎为优势种的群落是研究区的气候演替项极。刺槐群落在自然演替条件下,它将逐渐为栓皮栎群落所替代,但是由于人为的干扰,刺槐成为研究区一个偏途演替顶级群落。侧柏群落演替进程虽然缓慢,但却表现出了由针叶纯林向针阔混交林发展的趋势。（10）在研究区,从裸地开始植被演替到顶极群落最快也需要80a时间;但是达到相对稳定的森林群落则只要40a左右。草本植物恢复的时间大约是7～8a。其中土壤中物理结构恢复较慢;群落生物量恢复时间最长。灌木群落恢复时间大约是12～14a。栓皮栎林经过60～84a的时间才能演替到顶级群落。刺槐群落演替时间大致为60～73a;侧柏群落演替时间最长,需要95～110a。演替时间表现为阴坡小于阳坡;缓坡小于陡坡;其中坡度对植被恢复时间的影响最显著。（11）按照聚类结果,研究区群落恢复进程可分为4个阶段,分别为恢复初期、恢复进展期、恢复中期、恢复稳定期。根据不同恢复阶段,从地理环境、小气候、群落结构、土壤等4个方面选取指标,构建了小浪底山地退化生态系统恢复综合评价指标体系,运用层次分析法,用生态恢复指数对小浪底山地退化生态系统的恢复程度进行了评价。更多还原

【Abstract】 Restoration ecology is one of the new branches in ecology, and one of issues on which many ecologists focus. Restoration and reconstruction of degraded ecosystems have become one of the major subjects of modern ecology. The hilly area in Taihang mountains is an ecotone between the plain vegetation and the mountainous vegetation. As a result of the over-exploitation to vegetation for a long time, ecosystems in the research areas have degraded seriously, which are characterized by natural vegetation with lower coverage ,lower height, even bare land in some parts, and mosaic with different types of artificial vegetations. The ecological protection functions of the vegetations have been declined. Forest ecosystems play an important role for improving and stabilizing agriculture environment in hill areas of Taihang mountains. For this reasons, this dissertation deals mainly with studies on the natural restoration process and their mechanism of degraded forests in order to find out the limit factors of vegetation restoration and promote the natural restoration and forest sustainable development.The ecological mechanisms and ways for vegetation restoration in the hilly areas of Taihang mountains have been analyzed in this study. The degradation of studied ecosystem is mostly caused by disturbance and climatic change. Based on the methods of classifying restoration stages, Starting from analyze soil physical—chemical properties, vegetation and succession and much previous research, The physical ,chemical and biologic characteristics of main communities in hilly areas of Taihang mountains are investigated . The ecological and environmental feature during vegetation succession has been revealed. The succession models of communities have been set up. The succession times of different communities have been put forward by using the method of modeling for vegetation restoration. The evaluating index structure of vegetation succession period have been established. Which are also well-assessment to vegetation restoration.Major conclusion are summarized as follows:1) The present findings suggested that nature and human activity factors would lead to degraded vegetation for studied ecosystem. The degradation of vegetation is mostly caused by human disturbance and destruction. The lower air moisture and higher air temperature is climatic feature in studied areas. In the future, the climate will be more worm and dry. The ET₀ would be progressive increase. Analysis of climatic functional spectrum indicates that changes temperature and precipitation among years present the distinct periodic fluctuation, of which the former changes with 6a, 3.5a periods and the later changes with 8.5a, 4. 3a periods.2) With the development of vegetation restoration, different restoration stages result in different soil bulk density and such as in order as follows: herbs stage>trees stage>shrub stage. The soil bulk density between shrub stage and trees stage are no significantly different. The capillary moisture capacity and porosity of soil was the lowest in bare land, and the soil bulk density is reversed, soil nature moisture becomes lower in the order from the trees stage, herbs stage, shrub stage and bare land. With progressive vegetation succession, the gravel content decreased; while the indicators increase gradually. The content of clay grain is significantly positive with the soil organic matter and total nitrogen and available nitrogen contents of soil.3) The effect of lowering air temperature and increasing air humidity of vegetation increased with vegetation succession. Daily changes of air temperature in every restoration community stage presented a anisomerous curve of single apex. The air temperature and their fluctuation declined with the development of the community. That showed the effect of adjusting air temperature was better and better. Daily changes of air relative humidity in every restoration community stage had anomalous change presenting "U", which was contrary related to daily changes of air temperature change.4) Nitrogen concentration in green leaves varied widely among species from 1.568% to 5.011% and from 0.82% to 3.89% in senescing leaves. A significant correlation was found between N concentrations in leaves and soil organic matter ,soil moisture. N concentration in green leaves （Ng） and N concentration in senecing leaves （Ns） increased with increasing soil organic matter, total soil N and soil moisture. NRE in these species ranged from 17.4% to 50.1%, with an average of 28.8%, depending upon the species and the life-form. The results show that most of species examined in this study can be categorized as incomplete N resorption plants. The pattern of NRE in different life-forms followed the order of herbs>shrubs>trees. NRE was positively related to soil organic matter, total soil N and soil moisture, meaning that the higher soil organic matter was due to low plants NRE.5) The species numbers and richness had significant increased with vegetation succession, some species diversity indices, such as H’, D₁ and PIE had a significantly positive correlation with moisture and thickness of soil, others diversity indices H’ and D₁ have positively correlation with soil organic matter, available N, available P. The biomass of shrubs and trees had a significantly correlated with H’. There are no relation between H’ and biomass of herbs. The vegetation restoration period was positively correlated with species diversity indices Jsw and H’, but not PIE, D₁ and D₂. The species numbers increased by six averagely during 10 years of vegetation restoration. H’ had significantly positive correlation with coverage and height of shrubs. There was a clear negative correlation between species richness indices and height and coverage of herbs, and no significant correlation with H’. 6) Biomass is significant increase with the succession stages. Which is relationship of power function. The biomass of the Quercus variabilis was the highest, whilst the Platycladus orientalis was the lowest, and the Robinia pseudoacacia was in the middle. The roots biomass of trees community was lower than that of stem. The ground biomass of the shrubs community was higher than that of underground, the biomass ratio between ground and underground ranged from 2.3 to 3.82. The biomass of Artemisia princeps was the highest, and whilst the Pennisetum flaccidum was lowest.7) The litterfall amount of trees community is significant more than that of shrubs. The quantity dynamical of litterfall is obviously along with the seasonal variation, The sequence is that: autumn >spring>winter. The water content of litterfall was close relationship with vegetation restoration stages. Water retention rate of Robinia pseudoacacia is the highest. Water absorption rate of Quercus variabilis in 20 years old is the lowest. Litter decomposition rate of Robinia pseudoacacia is fastest, which will just take 8.83years to almost decompose litterfall. Loweast by 40 years old Quercus variabilis, 26.63 years. Litter decomposition rate of 30 years old Quercus variabilis in same community is the fastest. Litter decomposition rate of shrubs has faster than other community. It will take 9.66 years to almost decompose litterfall by Ziziphus jujube, and 12.35 years by Vitex negundo.8) total carbon storage of ecosystem and soil increased with progressive succession. It increased 4.5times form herbs stage to trees stage, the ratios of soil carbon storage / ecosystem carbon storage show decreased. And the ratios of carbon storage in vegetation increased gradually by progressive succession. So that, The vegetation played an important role in degraded ecosystem restoration process.9) Vegetation successional processes show the trend form herbs to shrubs and trees. With the progressive succession, the community would turn from annual grass species dominance into a multiple-community dominated perennial herbaceous genus , semi-shrubs, shrubs. When the herbs successes 10 years, Ziziphus jujube and Vitex negundo formated mono-dominant community, the community of Quercus variabilis dominance is climax community. Robinia pseudoacacia under natural succession will been taken by Quercus variabilis community. Robinia pseudoacacia might be a dis—climax community under the human disturbance. Platycladus orientalis successes slowly. But the community would turn from mono-dominant coniferous forests into a broadleaf/coniferous mixed stand.10)The successive times will take almost 80 years at fastest speed form bare land to climax-community.but it take about 40 years to reach the sustainable community. The restoration time is about 7-8 years for herbs, and 12-14 years for shrubs. Restoration time of soil is slower than that of community. Physical character index of soil recovered the slowest, biomass restoration take the longest. Quercus variabilis community will reach the climax-community after 60-80 years. The slope effect on restoration process obviously. The restoration time in shade slope is faster than that in sunny slope. And restoration time in steep slope is faster than that in gentle slope. The restoration time is 60-73 years in Robinia pseudoacacia, 95-110 years in Platycladus orientalis, which is longest.11) As a results of cluster analysis, The vegetation in the researching areas can be classified into 4 types, including initial restoration stage （IRS） , progressive restoration stage （PRS）, middle restoration stage（MRS）, stable restoration stage（SRS）. According to different restoration, the index , valued degraded ecosystem ,which included environment , micro-climate , community structure and soil had been setup. The degraded ecosystem at hilly areas in Taihang mountain was assessed by using method of analytic hierarchy process and eco-restoration indices.更多还原