在全国范围划分水蚀、风蚀和冻融侵蚀三大侵蚀类型区基础上,提出进一步划分水蚀风蚀交错区的必要性及重要意义.黄土高原的强烈侵蚀中心出现在水蚀风蚀交错区,该区为黄河粗泥沙的主要来源区,生态环境脆弱,自然灾害频繁.该区又为世界级大型煤田蕴藏地,将建成我国21世纪的能源重化工基地.强化水蚀风蚀交错区综合治理,对治黄及西部地区开发具有重大意义.

Based on the vegetation survey on 18 sampling plots in Wuqi County of Shaanxi Province, and by using the methods of substituting space series for time series and of contrastive analysis, the dynamics of plant community species diversity in the process of ecological rehabilitation in the County was analyzed from the aspects of succession time, rehabilitation mode, and slope direction. The results showed that in the 25 years natural succession series, the natural restoration community on previous cropland experienced the sequence of Salsola collina, Artemisia scoparia, Lespedeza davurica, Artemisia sacrorum, and Bothriochloa ischcemum, with the dominant species tended to be changed from annual to perennial and from low-class to high-class. The variations of species number, Margalef index, Simpson index, Shannon-Wiener index, and Pielou index in the succession process could all be described by a quadratic function y = at2 + bt + c, suggesting that after the outside pressure removed, the degraded ecosystem in loess area could naturally restore to an advanced and steady state, but the restoration rate would be very slow. With the same site factors and restoration periods, the Margalef index, Shannon-Wiener index and Pielou index of herb layer decreased in the order of naturally restoring on previous cropland (Ⅰ)＞converting cropland to grassland (Ⅱ)＞converting cropland to forestland (Ⅲ)＞afforestation on barren hills (Ⅳ), while Simpson index changed in adverse. Comparing with natural restoration, the community types of herb layer in Ⅱ and Ⅲ were at the more advanced stage of natural succession series though the species diversity index was lower, indicating that artificial planting would accelerate the succession process. In the same period of rehabilitation, the Margalef index, Shannon-Wiener index and Pielou index of natural restoration community were obviously higher on shady slope than on sunny slope, and the community type was at the more advanced stage of natural succession series, suggesting that the basic ecological rehabilitation condition on sunny slope was worse, and the succession rate was slower.

根据18块典型样地的植被调查数据，采用时空互代和对比分析法，从演替时间、生态修复模式和坡向3个方面研究了陕西省吴起县生态修复过程中植物群落物种多样性特征.结果表明：在25年自然演替序列中，退耕封育群落依次经历了猪毛菜、猪毛蒿、达乌里胡枝子、铁杆蒿和白羊草5种类型，建群种表现为1年生向多年生、低级向高级的演替趋势.其间，物种种类、Margalef指数、Simpson指数、Shannon-Wiener指数和Pielou指数均呈二次函数变化,说明黄土区退化生态系统在消除外界压力后，通过自然恢复可达到高级、稳定状态，但速度缓慢.地形条件和恢复年限一致时，4种主要修复模式形成的群落中，草本层的Margalef指数、Shannon-Wiener指数和Pielou指数表现为退耕封育＞退耕还草＞退耕还林＞荒山造林，Simpson指数则相反.与退耕封育模式相比，退耕还草和退耕还林模式在相同恢复期内形成的草本群落，虽然多样性指数较低，但更接近自然演替后期阶段，说明人工修复模式能加快演替进程.在相同恢复年限内，阴坡退耕封育群落的Margalef指数、Shannon-Wiener指数和Pielou指数明显大于阳坡，且群落类型更接近演替后期阶段，说明阳坡生态修复的本底条件更差，植被自然演替速率更缓慢.

For the purpose of determining the effects of slope gradient on its plant community diversity, some investigations were conducted with the Line Transect Method in 2010 along five roads surrounding Chengdu city. A total of 101 slope quadrats were investigated. These slopes have an altitude between 300-400 m and the same soil texture. The results showed that: (1)within the quadrats, there were 142 species of plants, belonging to 61 families and 121 genera. Sixteen genera and 19 species belonged to Compositae; Gramineae had 14 genera and 16 species; Leguminosae consisted of 9 genera and 11 species; Rosaceae had 4 genera and 7 species. These four families totally had 43 genera and 53 species, which account for 37% of the total species; (2)slope gradient had significant effect ( P P <0.05); to the richness of sunny slope community, its influence was significant. Analysis showed that the influence of gradient on the community diversity of roadside slopes surrounding the Chengdu Plain was significant; on the slopes where gradients were below 35°, vegetation community recovered well and the diversity of community was high; when the gradient was above 35°, diversity indexes declined rapidly, which made vegetation restoration harder.

以成都平原周边的5条道路的边坡植被群落作为研究对象，采用样线法，研究坡度对道路边坡的植物群落多样性的影响。选取101个海拔在300~400 m间并且土壤质地相同的边坡样方进行坡度分析。结果显示：（1）选取的样方中，共出现142种植物，属于61个科，121属。（2）边坡坡度对阳坡和阴坡的灌木层与草本层的植物群落物种多样性具有显著的影响( P P 35°的边坡来说，多样性指数呈下降趋势，不利于后期边坡恢复。

Slope position and altitude are the integrative reflections of meteorological and site factors. Slope position affects the spatial distribution of environmental factors, and with the altitude together, builds species existent small habitats and shapes the community abundance patterns. In this paper, the species abundance patterns in tree layer, shrub layer, and herb layer of Quercus wutaishanica community at the upper, middle, and lower slopes along an altitude gradient in Dongling Mountain of Beijing were studied, based on five niche models, i.e ., broken stick model (BSM), niche preemption model (NPM), overlapping niche model (ONM), random assortment model (RAM), and dominance preemption model (DPM). Among the five models, the models that could well describe the species abundance pattern in the tree layer from low altitude to high altitude and from lower slope to upper slope were the RAM or NPM to DPM. The NPM could best simulate the species abundance pattern in shrub layer, followed by BSM, and RAM. The DPM could also well simulate the species abundance pattern in shrub layer at high altitude. The BSM could be the first choice to simulate the species abundance pattern in herb layer, whereas the NPM and ONM could be the second and third choice. Covariance analysis suggested that both slope position and altitude had no significant effects on the species abundance patterns of Quercus wutaishanica community in the study area.

海拔与坡位是气象因子和立地因子的综合表现。坡位影响环境因子在空间上的分布状况，与海拔共同营造物种生存的小生境，形成群落多度格局。本文选用5个描述种－多度关系的生态位模型（断棍模型BSM、生态位优先占领模型NPM、生态位重叠模型ONM、随机分配模型RAM、优势优先模型DPM），对北京东灵山辽东栎林的乔、灌、草3个层沿海拔梯度分别在上、中、下坡位进行群落多度格局调查。结果表明：在乔木层，从低海拔到高海拔、从下坡位到上坡位，能很好地反应群落多度格局变异的模型有由RAM、NPM向DPM过渡的趋势；能很好地拟合灌木层群落多度格局的生态位模型依次是NPM、BSM、RAM，DPM在高海拔地段拟合的效果也很好；BSM在草本层的拟合效果最好，其次是NPM和ONM。协方差分析表明，海拔和坡位都没有对辽东栎林的群落多度格局产生显著影响。

Successional patterns in species diversity indices each vegetation stratum on the Loess Plateau, Ziwu Mountain, northwest China, were studied using the method of substituting spatial difference for time change. Relationships between species diversity and environmental factors were also studied using Canonical Correspondence Analysis. The results indicated that: (1) Herb layer species richness, evenness and species diversity decreased gradually during community succession (P＜0.05); Shrub layer species diversity and richness showed a J\|shaped trend, while evenness did not change significantly except in the Ostryopsis davidiana community (P＞0.05); Tree layer species richness, evenness and species diversity did not change significantly (P＞0.05); There was a significant hump\|shaped pattern in species richness along the temporal gradient, which agrees with the intermediate species\|richness hypothesis. (2) Canopy cover, the main factor correlated with species composition of both herb and shrub layers (P＜0.01), with soil nutrients and slope position having smaller effects. In contrast, slope position had a significant effect on tree layer species composition (P＜0.01), which might reflect recruitment differences. (3) Community succession in this area occurs due to species dispersal and environmental filtering. Changes in species diversity in the different layers were likely due to species′ differential responses to changes in light availability during community succession.

采用空间代替时间的方法研究了黄土高原子午岭植物群落自然演替过程中不同层α物种多样性的变化规律，并通过CCA分析了物种多样性与环境间的关系。结果表明：（1）随演替的进展，草本层物种丰富度、均匀度及物种多样性均逐渐降低（P＜005）；灌木层物种的丰富度与物种多样性均呈现相似的“J”形变化趋势，而均匀度（虎榛子（Ostryopsis davidiana）群落除外）差异不显著（P＞0.05）；乔木层物种丰富度、均匀度以及物种多样性差异均不显著（P＞0.05）；群落总体物种丰富度随演替进展呈现明显的单峰模型，与中期物种丰富度假说一致。（2）林冠郁闭度是影响草本层和灌木层物种组成的主要环境因子（P＜001），其次为土壤养分和坡位；而坡位对乔木层物种组成的影响极显著（P＜0.01），这可能与乔木树种的更新差异有关。(3) 群落演替是物种扩散和环境筛综合作用的过程，物种对演替过程中变化光照资源的响应差异可能是该区不同层物种多样性变化的主要原因。

在藏北高原高寒草地样带上对４０个围栏内草地群落物种多样性和地上生物量进行测定，探讨了生长季降水对高寒草地生物量和物种多样性分布格局的影响以及地上生物量－物种多样性之间的关系模式。结果表明，降水格局显著地影响藏北高原内部高寒草地群落物种丰富度、多样性和均匀度，群落结构特征与初级生产力关系密切；藏北地区高寒草地地上生物量、物种丰富度、Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ指数和Ｐｉｅｌｏｕ均匀度指数随生长季累积降水呈指数增加趋势；在高寒草地群落物种丰富度－生产力关系研究中单峰模式的判别系数 R ２ （０．７５４）略高于线性回归模型（０．７４３）。沿藏北高原样带高寒草地物种丰富度随地上生物量单调递增，单峰模式的单调递减区间并未出现；然而单峰模型预示着在地上生物量高于１２１．１７ｇ／ｍ ２ 的高寒草地群落物种丰富度可能随生物量单调递减，从而使物种丰富度－地上生物量表现为较为标准的单峰模式；Ｓｈａｎｎｏｎ－Ｗｉｅｎｅｒ多样性指数和Ｐｉｅｌｏｕ均匀度指数与地上生物量也均呈单峰模式，但其单调递减区间窄于单调递增区间，峰值分别对应的草地群落地上生物量为７１．９０和６０．９０ｇ／ｍ ２ 。

Aims Better understanding the response of community structure and species diversity to nutrient and water enrichment is critical for desert grassland in arid areas. Nitrogen, phosphorus and potassium are the three elements necessary for plant production, and water promotes plant absorption of nutrients. Our objective was to analyze the effects of nutrient and water addition on community structure and species diversity in typical desert grassland in northwestern China. Methods Field experiments were conducted in Gubantunggut Desert grassland from 2009 to 2012. Nutrient and water additions were done on May 15, 2009–2011, and vegetation investigation was conducted on May 25, 2009–2012. The responses of community structure and species diversity of plants to nutrient, rainfall and snow additions were studied. Important findings After the nutrient and water additions, the number of species decreased by 35.3%, the number of species in Poaceae family increased and species in Cruciferae family decreased. In 2009 and 2010, none of the three treatments (nutrient addition, water addition and the coupling effect of nutrient and water) significantly influenced species richness, Simpson index, Shannon-Wiener index or Pielou evenness index. In 2012, nutrient addition had a significant effect on species richness ( p

为进一步了解养分添加和水分添加对干旱区草地植物多样性的影响, 2009–2011年5月15日, 对准噶尔盆地荒漠草地进行养分和水分添加, 2009–2012年5月25日进行植被调查, 研究群落结构与植物多样性对养分N、P、K与水分(雨、雪)添加的响应, 得出以下结果: (1)添加肥、水后, 荒漠草地植物群落结构发生了变化, 物种数由肥、水添加前的17种减少到添加后的11种, 减少了35.3%, 禾草类植物数目增加, 十字花科植物数量下降; (2)通过裂区试验方差分析, 2009年和2010年, 养分主效应对物种丰富度、Simpson指数、Shannon-Wiener指数、Pielou均匀度指数的影响不显著, 水分主效应和肥水交互作用对以上4个植物多样性指数的影响也不显著; (3) 2012年, 养分主效应对物种丰富度影响显著( p p

In arid and semi-arid areas, the interactions and relationships between grassland ecosystem and soil water are important for revealing the role of grasslands in regulating water balance and for predicting future grasslands in line with climate change and other important scientific issues. We reviewed the effects of grasslands on soil moisture, as well as the responses and adaptation mechanisms of grasslands to soil moisture, from different interfaces and on different scales. Further, we analyzed the modeling methods used to simulate the relationships between grasslands and soil moisture. The effects of climate change on the relationships between grasslands and soil moisture were also summarized, since this is currently a topic of high interest. The grasslands affect soil moisture by influencing both hydrological and ecological processes. Various vegetation factors influenced soil moisture on different spatial scales and different interfaces. Soil moisture directly affects individual plant morphology characteristics, especially the leaf, stomata, and roots, leading to changes in plant physiological and ecological processes such as photosynthesis, transpiration, and soil water absorption. Furthermore, soil moisture also changes the interspecific relationships between grass species, as well as the grassland community composition and structure, which ultimately affects the functions of the grassland ecosystem. The complexity of plant water transport in the soil-plant-atmosphere continuum (SPAC) system increases the difficulty of modeling research. A full understanding of the mechanisms involved in the interaction between vegetation and soil water is key to solving the problem. Revealing the responses of relationships between plants and soil water to climate change is conducive for the accurate prediction of the impact of climate change on grassland ecosystems in arid and semiarid regions. Based on the analysis of the present research, studies on the interactions between grasslands and soil water have mainly focused on the analysis of a one-way effect, and there are deficiencies in the coupling effects and feedback between grasslands and soil water. Finally, the following further studies are proposed: 1) investigating the relationship between soil water and the dominant species and plant functional types of the grasslands, especially the mechanisms of the interactions, the threshold response, and adaptation mechanisms of different species, and the plant traits indicators that can reflect the plant responses to soil moisture; 2) investigating the conversion and comparison of different temporal and spatial scales, and the study of grassland-soil water relationships on community, landscape, ecosystem, regional, and global scales; 3) investigating plant models on individual, community, and ecosystem scales, and their coupling with water transfer models among soil-vegetation-atmosphere systems for good prediction of future changes and plant distributions of grassland, and better modeling of soil moisture; and 4) investigating the effects of climate change on the relationships and feedback between grassland and soil water, especially the plant physiological and ecology characteristics related to soil moisture.

研究干旱半干旱草地生态系统与土壤水分关系和相互作用机理对于揭示草地生态系统稳定性及其水土关键要素的变化过程具有重要意义。从不同界面、不同尺度综述了草地生态系统对土壤水分的影响及草地生态系统的响应与适应机制,总结了草地生态系统与土壤水分关系模型研究的相关进展,并分析了气候变化对草地生态系统和土壤水分关系的影响。草地生态系统通过影响水文过程和生态过程来影响土壤水分,土壤水分在植物生长发育、形态、生理生态过程、种间关系、群落组成和结构以及草地生态系统功能等方面对草地生态系统产生影响;充分揭示草地生态系统-土壤水分相互作用机理是模型研究的关键;气候变化对草地生态系统植物与土壤水分关系具有重要影响。今后应加强以下研究:1)开展草地不同优势种和植物功能型与土壤水分关系的研究,找出能反映植物对土壤水分响应的性状指标,阈值响应点及适应机制;2)注重对不同时间和空间尺度上的转换和比较;3)加强个体、群体和生态系统尺度草地植物生长模型的研究及其与土壤-植被-大气水分传输模型的耦合;4)加强草地生态系统与土壤水分关系对气候变化响应的研究。

The relationships among community structures, plant diversity and environmental factors during the recovery process of a natural community of the loess hilly region were analyzed based on community survey, soil moisture and nutrient contents of four typical communities. Results showed that Gramineae, Compositae,Leguminosae and Rosaceae had strong ecological adaptability and their community composition was relatively simple. Artemisia sacrorum was widespread and dominated the area with importance. Perennial herbs dominated in this area, followed by semi-shrubs, annual or biennial herbs and shrubs. There are similar communities in the same orientation of slopes. Diversity indices of communities with different standing conditions were closely related with the moisture conditions of each site. The effects of vegetation cover, slope, altitude and aspect on diversity were related to soil moisture. Soil moisture, playing an important role in affecting community structure and diversity, is a key factor for the recovery and reconstruction of vegetation.

选择陕北黄土丘陵区不同立地条件下的4个典型群落,进行群落调查与土壤水分和养分的测定,探索天然群落自然恢复过程中群落的结构组成、植物多样性与环境因子的关系,为该地区的植被恢复提供指导。结果表明:植物群落组成主要集中在菊科、禾本科、豆科和蔷薇科,这4大科植物在该区具有较强的生态适应性;研究区天然群落组成较为简单;铁杆蒿( Artemisia sacrorum )在各立地均有分布,且重要值相对较大,为各个群落的优势种或者亚优势种;植物的生活型中多年生草本植物占优势,其次是半灌木,再其次是一、二年生草本植物,灌木植物所占的比例最少;相同坡向不同坡位的群落较为相似;不同立地条件下群落多样性指数的大小与各立地的水分条件关系密切。植被盖度、坡度、海拔高度和坡向对多样性产生影响,主要是通过直接影响土壤含水量实现的。土壤含水量是影响植物群落组成和多样性最为关键的生态因子,是黄土高原植被恢复和重建的关键性因子。

A plant community is an assemblage of plant populations that live in certain area, and interact with and adapt to one another in the context of long-term environmental changes. Plant communities maintain global ecosystem functions, and provide food and habitats for animals and other organisms. Plant communities also provide primary resources for human survival and development, and are therefore indispensable to human societies. China is among the countries with the most diverse plant communities in the world. However, no systematic national inventory has been conducted for Chinese plant communities. This fact obstructs exploitation and protection of China’s plant resources, and also hampers the development of the fields of Chinese ecology and geography. There is an urgent need to survey Chinese plant communities using consis-tent methods and protocols. In this paper, we review major concepts in plant community ecology, and pro-pose a framework for developing plant community inventories based on recent progress in community ecol-ogy and our own experience with long-term field surveys. Our framework provides protocols for site selec-tion and plot design, items to be measured in a plot, and measurements of functional traits of dominant spe-cies. We also review protocols for field surveys of large, long-term plots. The protocols proposed in this pa-per are expected to be a base for standardizing methodology for inventory of Chinese plant communities.

植物群落是不同植物在长期环境变化中相互作用、相互适应而形成的组合。它提供着人类赖以生存的主要物质资源, 维系着地球生态系统的健康和功能, 也为各种动物和其他生物提供食物来源和栖息地, 是人类生存和发展不可或缺的物质基础, 具有不可替代的作用。我国植物群落类型多样, 在世界上首屈一指, 但我国至今尚没有一次全面和系统的植物群落清查, 不仅影响了人们对我国植物资源的了解、利用和保护, 也不利于我国生态学、环境科学和地理学等相关学科的发展。采用统一的方法体系和技术规范开展我国植物群落的清查工作势在必行, 并具有紧迫性。本文基于作者长期的野外工作实践和国内外的群落调查方法, 首先简要定义了与植物群落清查有关的重要概念, 在此基础上, 论述了调查样地的设置原则和体系、群落清查的技术指标和方法、主要优势种生态属性的测定方法和规范, 并介绍了大样地调查的主要步骤。通过本文的介绍、归纳和总结, 试图为制定我国植物群落清查的技术规范提供基础材料和技术储备。

Spatiotemporal variation of soil moisture represents the differentiation and diversity of soil moisture properties at different scales of time and space, which is related to the joint effects of several environmental factors, including vegetation, land use, meteorological factors ( e . g . , rainfall), topography and soil at multiple scales. However, the key scale and dominant factors are differed with different time, space and scale. This paper reviewed the studies on the spatiotemporal variation of soil moisture and its relation to the environmental factors, with the focus on the studies of the Loess Plateau in China. The issues worthy to be further studied were also put forward, including the spatiotemporal variation of soil moisture and its relation to environmental factors at multiple-scales, scaling-up or scaling-down of soil moisture spatiotemporal differentiation, and determination of key scales and corresponding affecting factors.

土壤水分的时空变异是指在一定的景观内，不同时间、地点和土层的土壤水分特征存在明显的差异性和多样性。土壤水分时空变异是由多重尺度上的土地利用（植被）、气象（降雨）、地形、土壤、人为活动等诸因子综合作用的结果，但就其某一具体地区而言存在着重点尺度和主控因子，土壤水分时空变异的重点尺度与主控因子的时空关系因时间、空间和尺度而异。本文综述了土壤水分（尤其是黄土高原地区）的时空变异与其环境因子时空关系的研究进展，并提出了广泛开展多重时空尺度上土壤水分的时空变异与其诸因素的时空关系，研究土壤水分时空变异性的尺度转换规律，确定重点尺度及其相应的主控因子。

The investigation on the species and composition characteristics of Carex lasi ocarpa and Calamagrostis angustifolia communities distributed mostly i n Sanjiang Pla in showed that C.lasiocarpa and C.pseudocuraica were the dominant specie s,wi th the total important value 56.4%. C.angustifolia was the dominant species o f C.angustifolia community,with the important value 50.8%.Species diversity anal ysis suggested that there were some fluctuations in Simpson (D),ShannonWien er (H) indices,and Pielou evenness (J) of the two co mmunities.In these two communities,significant positive correlation was observ ed between H and J,significant negative correlation existed between H and D,bu t no significant correlation was found between H and D.The H,D,J and S of C .lasiocarpa community were higher than those of C.angustifolia community,b ut the difference was no significant.The similarity index of the two communities was 46.5%,indicating that there was a definite relation between them.

以三江平原分布最广的毛果苔草( Carex lasiocarpa )群落和小叶章( Calamagrostis a ngustifolia )群落为研究对象, 研究2个群落的植物物种及其组成特征。结果 表明，毛果苔草群落以毛果苔草为优势种，以漂筏苔草( C.pseudocuraica )为亚优势种 ，二者的重要值之和为56.4%；小叶章群落以小叶章为优势种，其重要值为50.8% 。物种多样性分析表明，毛果苔草群落和小叶章群落的Simpson指数（D）、Shannon-Wiene r指数(H)和Pielou 均匀度指数(J)均有较大波动，且H与J呈显著正相关，与D呈显著负相关 ，与S无显著相关关系；毛果苔草群落的H、D、J和S均高于小叶章群落，但差异不显著；2 群落的相似性指数为46.5%，表明二者间存在一定的联系。

Climate change has resulted in altered hydrothermal conditions and variation in soil moisture content which affects plant community structure and function on the Loess Plateau. The effect of soil water on the plant community in the semiarid natural grassland of the Loess Plateau was investigated using a large scale randomized design trial. Key results were: 1) Above-ground biomass and litter biomass were significantly positively correlated with soil water content. 2) Plant diversity and species richness were significantly positively correlated with soil moisture. 3) Plant functional groups were also affected by soil water content; both grass and legume species increased significantly with increase in soil water content, whereas forbs decreased significantly. It was concluded that soil moisture is one of the most important factors limiting community productivity and plant species diversity. Additionally, grass species may be able to indicate or reflect soil moisture status. Soil moisture changes may be driving plant community succession in semi-arid grassland.

气候变化导致水热条件发生变化,从而引起土壤含水量改变,必然影响区域植物群落结构和功能。本研究以黄土高原半干旱区天然草地群落为研究对象,在较大空间尺度上根据随机设置样地法调查区域内典型地带性草地群落,研究黄土高原半干旱区土壤含水量的变化对草地群落的影响。结果表明,1)地上生物量、凋落物质量与土壤含水量呈显著正相关;地下生物量和总生物量与土壤含水量虽正相关但不显著;2)物种多样性和物种丰富度均随着土壤含水量的增加而增加;3)植物功能群受土壤水分的影响,表现为禾本科和豆科随着土壤含水量的增加而增加,而杂类草相反。总之,在半干旱区土壤水分是限制群落生产力和物种多样性的重要因子,而禾本科和豆科作为指示物种可以反映土壤的水分状况。土壤水分的变化可能是导致半干旱区天然草地群落演替的驱动力,草地退化可能与土壤含水量的改变有关。