An understanding of the diversity spatial organization in plant communities provides essential information for management and conservation planning. In this study we investigated, using a multi-species approach, how plant–plant interactions determine the local structure and composition of diversity in a set of Mediterranean plant communities, ranging from semi-arid to subalpine habitats. Specifically, we evaluated the spatial pattern of diversity (i.e., diversity aggregation or segregation) in the local neighborhood of perennial plant species using the ISAR (individual species–area relationship) method. We also assessed the local pattern of beta-diversity (i.e., the spatial heterogeneity in species composition among local assemblages), including the contribution of species turnover (i.e., species replacement) and nestedness (i.e., differences in species richness) to the overall local beta-diversity. Our results showed that local diversity segregation decreased in the less productive plant communities. Also, we found that graminoids largely acted as diversity segregators, while forbs showed more diverse neighborhoods than expected in less productive study sites. Interestingly, not all shrub and dwarf shrub species aggregated diversity in their surroundings. Finally, an increase in nestedness was associated with less segregated diversity patterns in the local neighborhood of shrub species, underlining their role in creating diversity islands in less productive environmental conditions. Our results provide further insights into the effect of plant–plant interactions in shaping the structure and composition of diversity in Mediterranean plant communities, and highlight the species and groups of species that management and conservation strategies should focus on in order to prevent a loss of biodiversity.

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。

Shallow slope damage is one of the important factors leading to ecological damage.This paper discusses the slope stabilization mechanism of herbaceous plants in terms of their effects on habitat and root parameters,and summarizes the practical experience of herbaceous plants in ecological slope engineering in terms of species configuration and management measures.Finally,the directions of herbaceous plant slope stabilization research are proposed:to improve the concept of herbaceous plant slope stability enhancement,to clarify the specific slope stabilization mechanism of herbaceous plants,to establish ecological processes and quantitative models,and to improve the species allocation patterns,spatial layout strategies,and sustainable management measures in specific habitats.

边坡浅层破坏是导致生态环境破坏的重要因素之一。本文针对草本植物的边坡稳定性提升效果与潜力,从对生境的影响和根系参数方面讨论了草本植物的固坡机理;总结了生态边坡工程中草本植物在物种配置与管理措施方面的实践经验。最后,提出了草本植物固坡研究的方向:完善草本植物的边坡稳定性提升概念,探清草本植物的具体固坡机理,建立生态过程和定量化模型,提升特定生境下的物种配置模式、空间布局策略与可持续管理措施。

本研究以赛罕乌拉保护区2种不同土壤母质(黄土和沙母质)与3种利用方式(围栏打草、季节性放牧和自由放牧)草地为对象,基于群落组成调查数据,计算人为干扰指数与物种多样性指数,研究草地植物群落物种多样性与草地退化程度间的关系。结果表明: 土壤母质与人为利用方式的差异使草地处于不同的退化状态,黄土与沙母质类型草地退化程度均随人为利用强度的增加而上升,且当人为利用方式相同时,黄土母质草地人为干扰指数(均值1.21)比沙母质草地(均值1.48)低。各样地物种多样性指数总体随土壤母质的砂质化和人为利用强度的增加而下降,其中Margalef丰富度指数为1.57～4.27,Shannon多样性指数为1.16～2.39,Simpson优势度指数为0.76～0.87,Pielou均匀度指数为0.71～0.80。随着人为干扰指数增加,丰富度指数、多样性指数和优势度指数均下降,而均匀度指数有上升趋势。过度放牧对2种土壤母质草地均会造成严重威胁,黄土与沙母质草地最适宜的利用方式分别为围封打草和季节性放牧。在今后生物多样性保护的实施过程中,需兼顾草地不同土壤母质与人为利用方式的影响,针对不同土壤母质条件规划不同的草地利用方式,实现因地制宜的草地恢复与管理。

为探究多年生人工草地在青海湖流域的适应性和稳定性，本研究以青海草地早熟禾(Poa pratensis.Qinghai)和青海中华羊茅(Festuca sinensis.Qinghai)单播及混播人工草地为研究对象，分析不同种植方式下人工草地植被和土壤养分特征的变化。结果表明：青海草地早熟禾+青海中华羊茅混播草地和青海草地早熟禾单播草地的生物量和盖度高于青海中华羊茅单播草地，且在生长旺期(8月)，青海草地早熟禾+青海中华羊茅混播草地生物量最高，为586.2 g·m^-2；青海草地早熟禾单播、青海中华羊茅单播和青海草地早熟禾+青海中华羊茅混播草地间土壤有机质、全氮、全磷、硝态氮、铵态氮和土壤含水量在相同土壤深度下差异不显著，但土壤氮、磷及有机质间存在显著的相关性。综上所述，在青海湖流域建植青海草地早熟禾+青海中华羊茅混播型人工草地可以获得较高的产量，但需在种植和管理过程中协调好土壤氮、磷间的关系。

In order to explore the root architecture of herbaceous plants in the Benggang area, eight Gramineae species were studied (<em>Imperata cylindrica</em>, <em>Eulalia speciosa</em>, <em>Miscanthus floridulus</em>, <em>Eriachne pallescens</em>, <em>Cynodon dactylon</em>, <em>Paspalum wettsteinii</em>, <em>Pennisetum</em> sp. and <em>Vetiveria zizanioides</em>). Six root architecture parameters were analyzed and comprehensively evaluated using principal component analysis. The results showed that the average diameter of the tested herbaceous roots was between 0.36 and 0.63 mm. There were no significant differences in the total root length of <em>E. speciosa</em>, <em>M. floridulus</em>, <em>E. pallescens</em>, <em>P. wettsteinii</em> and <em>V. zizanioides</em>. The total root surface area, total root volume, root tip numbers and crossing numbers varied by plant species. The total root surface area of <em>Pennisetum</em> sp. was the largest and that of <em>I. cylindrica</em> the smallest. The root tips and crossing numbers of <em>Pennisetum</em> sp. were also the largest. Average diameter, total root surface area and total root volume were the main factors influencing root architecture. The composite score order of the eight species&#x02019; roots was <em>Pennisetum</em> sp.&#x0003E;<em>P. wettsteinii</em>&#x0003E;<em>E. speciosa</em>&#x0003E;<em>M. floridulus</em>&#x0003E;<em>V. zizanioides</em>&#x0003E;<em>E. pallescens</em>&#x0003E;<em>C. dactylon</em>&#x0003E;<em>I. cylindrica</em>. These results help to provide a scientific basis for the screening, allocating and popularizing of herbaceous plants for the control of erosion.

为探究崩岗区草本植物根系构型特征,以8种禾本科植物:白茅、金茅、五节芒、鹧鸪草、狗牙根、宽叶雀稗、巨菌草和香根草为研究对象,运用主成分分析法对其6个根系构型参数进行分析和综合评分。结果表明:试验草本根系平均直径为0.36~0.63 mm;金茅、五节芒、鹧鸪草、宽叶雀稗和香根草总根长无显著差异;总根表面积、总根体积、根尖数和交叉数均不同,巨菌草的总根表面积最大,白茅的最小,巨菌草的根尖数和交叉数均最大。根系构型的主要影响因子是平均直径、总根表面积和总根体积。8种植物根系综合得分依次为:巨菌草&#x0003E;宽叶雀稗&#x0003E;金茅&#x0003E;五节芒&#x0003E;香根草&#x0003E;鹧鸪草&#x0003E;狗牙根&#x0003E;白茅。研究成果可为崩岗治理中草本植物的筛选、配置和推广提供科学依据。

In the dry and warm valleys of the middle reaches of the Dadu River, landslides and debris flows occur frequently. Studying vegetation on these slopes is valuable in understanding vegetation succession in regards to ecological restoration of highly disturbed landscapes. In this study, plots were selected along the Dadu River every 5 km to investigate species composition, distribution, topography, soil characteristics, and vegetation change in the middle reaches of the Dadu River valley. Plant communities were classified, compared and sorted using multiple regression tree (MRT), alpha diversity index and canonical correspondence analysis (CCA). The results showed that the landscape were divided into four communities based on three factors: soil carbon, pH and C : N, i.e. Lespedeza floribunda-Arthraxon hispidus-Elsholtzia ciliate, Ficus tikoua-Dodonaea viscosa-Carex schneideri, Pinus yunnanensis-Quercus variabilis and Arthraxon hispidus-Heteropogon contortus. Shrub and grass dominate this area, with occasional areas of bare ground which is liable to debris flow disasters. The species richness, dominance and diversity of shrub-grass (Lespedeza floribunda) community are consistently higher than arbor and grass communities, although species diversity values are not significant. The shrub and grass community is widely distributed, although fragile and unstable as alien species reached 8.33% within these communities. MRT and CCA analysis showed that pH, C : N, slope direction and soil bulk density are the main factors influencing vegetation distribution pattern as soil influences are more important than topography.

大渡河中游干暖河谷区滑坡和泥石流灾害频发, 对该区域坡面植物群落的研究有助于揭示植被演替的方向, 为坡面植被生态恢复提供基本依据。本研究沿大渡河中游河谷区每隔约5 km设置典型样地, 调查了植被的物种组成和分布以及样地的地形、土壤等10个生境因子, 探讨河谷区植被的连续性变化, 并通过多元回归树(multivariate regression trees, MRT)、多样性指数和典范对应分析(canonical correspondence analysis, CCA)等方法对植物群落进行分类、比较和排序。结果表明: 大渡河中游干暖河谷植被以土壤碳含量、pH值和C : N等3个因子为节点, 可划分为多花胡枝子(Lespedeza floribunda)-荩草(Arthraxon hispidus)-香薷(Elsholtzia ciliate)(群落A)、地果(Ficus tikoua)-车桑子(Dodonaea viscosa)-川滇薹草(Carex schneideri)(群落B)、云南松(Pinus yunnanensis)-栓皮栎(Quercus variabilis)(群落C)和荩草-扭黄茅(Heteropogon contortus)(群落D)等4种群落。该区域以灌木和草本为主要植被类型(群落A、B、C), 间或有裸地分布, 易成为泥石流灾害产生的物源区; 以多花胡枝子为主的灌草群落A的物种丰富度、优势度与多样性表现一致, 均高于以乔木和草本为主的群落C和D, 但物种多样性优势并不显著, 灌草群落分布广而结构单一, 外来物种占比为8.33%, 是生态系统脆弱和不稳定的表现。多元回归树和典范对应分析结果表明, pH值、C : N、坡向和土壤容重等4个因子对植物群落组成和分布影响最大, 且土壤因子的影响大于地形因子。

黄土高原植被恢复使沟头立璧土壤侵蚀过程发生显著变化。为明确黄土高塬沟壑区草地沟头立壁土壤抗冲性特征及其影响因素,以裸地为对照,利用室内原状土槽冲刷试验研究了草地沟头立壁0～1 m不同土层(0～10、10～20、20～40、40～60、60～80、80～100 cm)土壤理化性质和抗冲性特征。结果表明: 草地和裸地沟头土壤水稳性团聚体含量和粘聚力随土层加深均呈减小趋势。裸地沟头土壤有机质含量、土壤抗冲系数随土层深度的增加呈减小趋势,而草地沟头土壤有机质含量、土壤抗冲系数随土层加深先增加后减小,且均在10～20 cm土层达到最大值(24.30 g·kg^-1和58.86 L·g^-1),草地各土层土壤抗冲系数是裸地的1.7～9.3倍。沟头土壤抗冲性与土壤有机质含量、水稳性团聚体含量、黏聚力和植物根长密度呈极显著相关,其中与土壤有机质含量(r=0.98)的关系最密切。该研究可为黄土高塬沟壑区沟头溯源侵蚀机理的研究提供基础数据,并为有效防治该区域水土流失提供科学依据。

Vegetation has been proven to be an effective measure to mitigate soil erosion in most regions and climates. However, it is not clear how some herbaceous plants affect the ability of soil to resist slope flow erosion in the Mollisol region of Northeast China. In this study, four herbaceous plant plots of 50 m × 4.5 m, including Zea mays L., Sorghum bicolor × Sudanense, Avena sativa L. and Lolium multiflorum Lam., were established in a sloping land with an abandoned land as the control to detect the effect of herbaceous plants on soil anti-scourability (ANS). A hydraulic flume experiment was carried out to determine the soil ANS, and the root traits and soil properties were also measured at different slope positions. The results showed that the mean soil ANS ranged from 17.55 to 94.77 L g−1 among different herbaceous plants, of which the Lolium multiflorum Lam. showed the strongest controlling effect on soil ANS (259.87%), followed by Sorghum bicolor × Sudanense (66.87%) and Avena sativa L. (18.12%), while the soil ANS of Zea mays L. decreased by 33.37% compared with the control. Soil ANS varied with slope position, and the mean soil ANS at the upslope was 116.50–134.21% higher than that of the middle slope and downslope. Additionally, soil ANS was positively related to root mass density (RMD), root length density (RLD), root surface area density (RSAD), soil total porosity and field capacity but was negatively related to soil bulk density (p &lt; 0.05). Furthermore, the Lolium multiflorum Lam. exhibited better root distribution (i.e., high RSAD, RLD, RMD, and low root diameter) and soil physical structure (i.e., high soil porosity structure, water-holding capacity and low bulk density) than other plant species. Thus, the Lolium multiflorum Lam. is beneficial for enhancing soil erosion resistance to overland flow, especially at the up and middle slopes, and it could be preferred to control sloped soil erosion in Northeast China.

为祁连山康乐草原生产力恢复与提高提出有效措施、生物多样性保护和资源可持续利用提供理论依据,采用样方法对祁连山高寒草地不同退化程度植物群落结构和土壤特性进行调查、测定和分析,并运用5个多样性指标(Margalef丰富度指数、Dominance优势度指数、Simpson多样性指数、Evenness均匀度指数和Shannon多样性指数)研究了其物种多样性变化。结果表明:1)轻度退化草地(LDG)-中度退化草地(MDG)-重度退化草地(SDG),不同退化草地植物群落特征(密度、高度、频度、总盖度和地上生物量)整体呈现降低趋势且差异显著(P&#x0003C;0.05),表现为LDG&#x0003E;MDG&#x0003E;SDG;2)研究区植物共15科35属39种,其中豆科、蔷薇科、禾本科、菊科和莎草科中的植物均具备较强生态适应性,各退化程度草地植被型分别为草地早熟禾+珠芽蓼、赖草+矮生嵩草、矮生嵩草+赖草,其中禾草是群落的优势种;3)高寒草地功能群植物呈现杂类草最多,禾草类次之,毒草类占有比例最少,其中在不同退化草地杂类草、毒草类重要值分别为75.14%(SDG)&#x0003E;48.67%(LDG)&#x0003E;30.05%(MDG)、20.81%(LDG)&#x0003E;18.01%(SDG)&#x0003E;17.11%(MDG);4)不同退化草地群落物种优势度指数在重度退化草地最高为0.23,而轻度退化草地物种Margalef丰富度指数最高为2.64、Shannon多样性指数最高为2.09;5)随退化程度加重,土壤全磷、全氮、有机质和含水量呈现下降的趋势,pH呈升高的趋势,且不同退化草地土壤环境因子含量对植被生长贡献率不同。综上所述,随着康乐草地退化程度增加群落结构向单一趋势演替且环境限制因子也发生相应变化。

We examined the impacts of shrub community roots on soil antiscourability in alpine gorge area in Jiajin Mountains of Sichuan Province. The Ward cluster analysis method was employed to divide communities into different types. Field sampling and undisturbed soil erosion experiment were conducted to analyze the root distribution characteristics of different community types and their effects on soil erosion resistance. The results showed that shrub communities in Jiajin Mountains could be divided into four types, with root length density and root surface area density following the order of<em>Quercus semicarpifolia</em>+<em>Salix wallichiana</em><em>Fragaria vesca</em> community (type Ⅳ) &gt; <em>Rhododendron vernicosum</em><em>Ligularia fischeri</em> community (type Ⅰ) &gt;<em>R. tatsienense</em>+<em>Cotoneaster subadpressus</em><em>Pteridium aquilinum</em>var. latiusculumcommunity (type Ⅱ) &gt;<em>Q. semicarpifolia</em>+<em>C. subadpressus</em><em>P. aquilinum</em>var. <em>latiusculum</em> community (type Ⅲ); (2) Each community was dominated by roots of &lt;1 mm diameter, while community type Ⅳ had the highest root biomass; (3) Results of the undisturbed soil erosion test showed that soil sand content in each community type decreased over time and then tended to be gentle, while the soil antiscourability coefficient was fluctuatingly increased with erosion time. The soil of type Ⅳ had stronger antiscourability; (4) Results of correlation analysis showed that roots of 0.5-1 mm diameter, total root weight density and total root volume were the main factors influencing soil anti-scourability of shrubs in Jiajin Mountains. Our results provide a basis for studies of soil erosion pattern of shrub community in the alpine gorge area.

To explore root architecture and its effects on soil reinforcement of main tree species in typical black soil region, we measured root spatial distribution characteristics, root fractal characte-ristics, and geometric morphological characteristics of <i>Amygdalus triloba</i>, <i>Caragana microphylla</i>, <i>Betula platyphylla</i>, <i>Acer negundo</i>, <i>Picea koraiensis</i>, <i>Pinus sylvestris </i>var<i>. mongolica</i>, using whole root excavation method and WinRHIZO Pro LA2004 root analysis system. All the examined species are distributed widely in typical black soil region. The vertical uprooting force was determined by <i>in-situ </i>uprooting tests. The results showed that inclined roots were dominant in <i>A. triloba</i>, horizontal roots were dominant in <i>C. microphylla</i>, <i>B. platyphylla</i>, <i>A. negundo</i> and <i>P. koraiensis</i>, and the horizontal and vertical distribution of roots were commensurable in <i>P. sylvestris </i>var<i>. mongolica</i>. Except for the total root surface area of <i>B. platyphylla</i> and the total root length of <i>P. koraiensis</i>, the total root length and root surface area of shrub species were significantly greater than those of arbor species, while deciduous broad-leaved trees were significantly larger than coniferous evergreen trees. The total root volume of <i>B. platyphylla</i> was significantly larger than that of <i>C. microphylla</i>,<i> A. negundo</i>, <i>P. koraiensis </i>and <i>P. sylvestris </i>var<i>. mongolica</i>. The root fractal dimension and abundance of <i>A. triloba</i>, <i>C. microphylla</i>, <i>B. platyphylla </i>were significantly higher than those of <i>P. koraiensis</i> and <i>P. sylvestris </i>var<i>. mongolica</i>. The average maximum uprooting force of <i>A. triloba</i>, <i>C. microphylla</i>, and <i>A. negundo</i> was significantly higher than that of <i>B. platyphylla</i>, <i>P. koraiensis</i>,<i> </i>and <i>P. sylvestris </i>var<i>. mongolica</i>. Due to the role of total root length, total root surface area and the number of inclined roots, root system of <i>A. triloba</i>, <i>C. microphylla</i> and <i>A. negundo </i>showed strong soil reinforcement capacity. <i>A. triloba</i>, <i>C. microphylla</i> and <i>A. negundo</i> could be used as the option-preferred tree species when constructing soil and water conservation vegetation in typical black soil region.

为量化典型黑土区主要树种根系构型特征,探究其对固土能力的影响,以该区分布较广的榆叶梅、小叶锦鸡儿、白桦、糖槭、红皮云杉、樟子松单株个体为研究对象,采用全根挖掘和WinRHIZO Pro LA2004分析系统相结合对其根系空间分布、几何形态、分形等特征进行测定,同时采用原位整株根系拉拔的方法量化根系垂直拉拔力。结果表明: 榆叶梅以倾斜根为主,小叶锦鸡儿、白桦、糖槭和红皮云杉以水平根为主,樟子松根系在水平和垂直分布上较为均衡;除白桦总根表面积和红皮云杉总根长外,灌木树种总根长、总根表面积显著大于乔木,落叶阔叶乔木总根长、总根表面积显著大于针叶常绿乔木,白桦总根体积显著大于小叶锦鸡儿、糖槭、红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和白桦根系分形维数和分形丰度显著大于红皮云杉和樟子松;榆叶梅、小叶锦鸡儿和糖槭整株根系平均最大垂直拉拔力显著大于白桦、樟子松和红皮云杉。主要受根系总根长、总根表面积和倾斜根数量的影响,榆叶梅、小叶锦鸡儿和糖槭根系表现出较强的固土能力,可作为典型黑土区水土保持植被构建中优先选择的树种。

为了了解平茬对灌丛群落草本植物的影响，本文以内蒙古典型草原小叶锦鸡儿（Caragana microphylla Lam）群落为研究对象，设置了不平茬、一年平茬1次和一年平茬2次共3种处理，分析了平茬前后群落特征与植被化学计量特征的变化。结果表明：与未平茬相比，两种平茬处理下群落内禾本科植物密度均显著增加，平茬第二年禾本科生物量显著高于未平茬处理；平茬后两年内草地群落物种多样性指数随平茬次数增加均有增加趋势，且一年平茬2次处理时，Margalef丰富度指数显著高于未平茬处理；草本群落总生物量随平茬次数增加呈现先下降后增加的变化趋势；平茬后植被C、N含量、C/N比无显著变化，但植被N/P比显著增加。可见，平茬处理改变了小叶锦鸡儿群落的结构特征，提高了群落物种多样性及禾本科植物的密度，有助于典型草原的植被恢复。