高被引论文摘要

欧阳志云，王效科，苗鸿

高被引论文摘要

被引频次：2083

中国陆地生态系统服务功能及其生态经济价值的初步研究

欧阳志云，王效科，苗鸿

生态系统服务功能主要表现为提供保存生物进化所需要的丰富的物种与遗传资源，太阳能，二氧化碳的固定,有机质的合成，区域气候调节，维持水及营养物质的循环,土壤的形成与保护，污染物的吸收与降解及创造物种赖以生存与繁育的条件，维持整个大气化学组分的平衡与稳定，以及由于丰富的生物多样性所形成的自然景观及其具有的美学、文化、科学、教育的价值。生态系统的这些功能虽不表现为直接的生产与消费价值，但它们是生物资源直接价值产生与形成的环境。可以说，正是生态系统的服务功能，才使人类的生态环境条件得以维持和稳定。从生态系统的服务功能着手，首先研究中国陆地生态系统在有机物质的生产、CO2的固定、O2的释放、重要污染物质降解，以及在涵养水源、保护土壤中的生态功能作用，然后再运用影子价格，替代工程或损益分析等方法探讨了中国生态系统的间接经济价值。研究表明我国陆地生态系统具有巨大的生态经济效益，对维持我国社会经济的可持续发展具有不可替代的作用。

生态系统服务功能；生态经济价值

来源出版物：生态学报, 1999, 19(5): 607-613

被引频次：1252

长白山自然保护区森林生态系统间接经济价值评估

薛达元，包浩生，李文华

摘要：使用市场价值法、影子工程法、机会成本法和替代花费法等对长白山自然保护区森林牛态系统的功能价值进行了经济评估评价结果表明，保护区总的生态功能价值为176465.94万元，其中活立木生产量价值10777.43万元，涵养水源价值69741.2万元，保护土壤减少侵蚀的价值2307.02万元，固碳以减缓温室效应的价值87716.6万元，林分持留N、P、K分价值4338.88万元，降解SO2和防治病虫害价值158473万元。

关键词：自然保护区；森林生态系统；生物多样性；间接价值；长白山

来源出版物：中国环境科学, 1999, 19(3): 247-252

被引频次：529

陆地植物群落物种多样性的梯度变化特征

贺金生，陈伟烈

摘要：研究陆地植物群落物种多样性随环境因子及群落演替梯度的变化特征是揭示生物多样性与生态因子相互关系的重要方面。根据近期国内外的文献，综述了这方面的研究进展。随纬度的降低，通常物种多样性随之增加；随着水分梯度的变化，物种多样性的变化有6种趋势；随海拔高度的变化，物种多样性有5种模式；随土壤养分梯度的变化，表现出不同的规律；演替过程中物种多样性的变化趋势相似。关于植物群落物种多样性梯度格局的机制有多种假说，但仍需进一步研究。

关键词：物种多样性；纬度梯度；水分梯度；海拔梯度；养分梯度；演替梯度

来源出版物：生态学报, 1997, 17(1): 91-98

被引频次：469

景观生态学与生物多样性保护

李晓文，胡远满，肖笃宁

摘要：景观生态学的发展为生物多样性保护提供了新理论、方法和技术手段。从景观多样性与遗传多样性、物种多样性、生态系统多样性各层次生物多样性之间的相互关系及生物多样性保护的景观规划等方面评述近年来景观生态学应用于生物多样性保护的主要内容及研究进展，阐述了生物多样性动态及反馈、生物多样性保护的地理途径（GAP分析）、景观生态安全格局、区域和大陆尺度的生态网络等一些新的概念和方法。

关键词：景观生态学；景观多样性；生物多样性保护；景观规划

来源出版物：生态学报, 1999, 19(3): 399-407

被引频次：428

干扰的类型、特征及其生态学意义

陈利顶，傅伯杰

摘要：干扰是自然界中无时无处不在的一种现象，是在不同时空尺度上偶然发生的不可预知的事件，直接影响着生态系统的结构和功能演替。根据不同分类原则，干扰可以分为自然干扰和人为干扰；内部干扰和外部干扰；物理干扰、化学干扰和生物干扰；局部干扰和跨边界干扰。常见的干扰类型包括火干扰、放牧、土壤物理干扰、土壤化学干扰、践踏、外来种入侵、洪水泛滥、森林采伐、矿山开发、道路建设和旅游等。干扰主要具有以下一些特点：1）多重性；2）生态影响的相对性；3）明显的尺度性；4）是对生态演替过程的再调节；5）是自然生态系统中不协调的现象；6）时空尺度的广泛性。干扰的一个突出作用是导致生态系统中各类资源的改变和生态系统结构的重组。干扰的生态环境影响有利有弊，不仅取决于干扰本身性质，还取决于干扰作用的客体。适度的干扰可以促进生物多样性和生物资源的保护。因此研究干扰的性质、生态效应、有利的适度规模以及与人类活动的关系具有重要意义。

关键词：干扰；类型；景观异质性；生物多样性；生态学意义

来源出版物：生态学报, 2000, 20(4): 581-586

被引频次：380

区域生态安全格局：概念与理论基础

马克明，傅伯杰，黎晓亚，等

摘要：提出区域生态安全格局概念的提出，适应了生态系统恢复和生物多样性保护的发展需求。针对区域生态环境问题，通过干扰排除以及空间格局规划和管理，能够保护和恢复生物多样性，维持生态系统结构、功能和过程的完整性，实现对区域生态环境问题的有效控制和持续改善。区域生态安全格局的研究对象具有针对性、研究尺度具有区域性、研究问题具有系统性、研究手段具有主动性。它强调区域尺度的生物多样性保护、退化生态系统恢复及其空间合理配置、生态系统健康的维持、景观生态格局的优化、以及对社会经济发展需求的满足。它更加强调格局与过程安全及其整体集成，将生态系统管理对策落实到具体的空间地域上，实现管理效果的直观可视。相关理论，景观生态学、干扰生态学、保护生物学、恢复生态学、生态经济学、生态伦理学、和复合生态系统理论等为其提供了坚实的理论基础。区域生态安全格局不存在一个固定标准，人类对生态系统服务功能需求的不断变化是生态系统管理的根本原因。实现区域生态安全不但要以社会、经济、文化、道德、法律、和法规为手段，更要以其不断发展对生态系统服务功能的新需求为目标逐步进行。区域生态安全格局研究对于解决区域生态环境问题具有不可替代的作用，具有广阔应用前景。

关键词：区域生态安全格局；理论基础；生态恢复；生物保护；社会经济发展

来源出版物：生态学报, 2004, 24(4): 761-768

被引频次：330

多样性指数在海洋浮游植物研究中的应用

孙军，刘东艳

摘要：对海洋浮游植物群落分析中常用的多样性指数进行了比较研究。对物种丰富度依赖型、丰度依赖型和实测浮游植物群落中物种丰富度、Shannon指数（以2或e为底）、Pielou均匀度指数、Simpson指数（1-D或1/D形式）、Margalef指数、Berger-Parker指数、McIntosh指数、McIntosh均匀度指数、Brillouin指数、Brillouin均匀度指数、Fisherα指数和Q统计指数等不同多样性指数计算结果进行了比较，发现不同多样性指数对浮游植物群落多样性的分析存在明显差异。对于一般情况下浮游植物群落多样性的研究，物种丰富度、Margalef指数、Fisherα指数、Shannon指数、Simpson相遇指数和Pielou指数的综合使用是较合适的，但对Margalef指数和Fisherα指数的结果要谨慎解释。并在综合应用各指数的基础上提出了浮游植物群落多样性分析的一般步骤。

关键词：浮游植物；多样性指数；等级丰度作图；生物多样性

来源出版物：海洋学报, 2004, 26(1): 62-75

被引频次：276

土壤微生物多样性影响因素及研究方法的现状与展望

周桔，雷霆

摘要：土壤微生物是土壤生态系统的重要组成部分，在土壤有机物质分解和养分释放、能量转移等生物地化循环中起着重要作用。随着人们对生物多样性重要性认识的不断深入及研究方法的不断改进，土壤微生物多样性，尤其是功能多样性的研究工作逐渐受到生态学家的重视。本文从土壤微生物多样性的影响因素以及研究方法等方面阐述了目前国内外土壤微生物多样性的研究现状，并对其未来研究方向进行了展望。

关键词：生物多样性；微生物；土壤

来源出版物：生物多样性, 2007, 15(3): 306-311

被引频次：255

植物物种多样性的垂直分布格局

唐志尧，方精云

摘要：生物多样性沿环境梯度的变化趋势是生物多样性研究的一个重要议题，而海拔梯度包含了多种环境因子的梯度效应，因此研究生物多样性的海拔梯度格局对于揭示生物多样性的环境梯度变化规律具有重要意义。在不同的研究尺度，植物多样性沿海拔梯度具有不同的分布格局，而形成这种格局的因素有很大差异。本文从α多样性，β多样性和γ多样性三个尺度总结了植物物种多样性沿海拔梯度分布格局及其环境解释。α多样性沿海拔梯度的分布格局在不同生活型的物种之间差异很大，但对于木本植物来说，虽然也存在其他格局，但α多样性随海拔升高而降低是被广泛接受的一种格局。在一般情况下，β多样性随着海拔的升高而降低，并且对于不同生活型的物种，β多样性沿海拔梯度具有相似的分布格局。γ多样性沿海拔梯度具有两种分布格局：偏峰分布格局和显著的负相关格局；特有物种数往往随着海拔的升高而减少，而特有度则随着海拔的升高而增加。

关键词：物种多样性；海拔梯度；α多样性；β多样性；γ多样性

来源出版物：生物多样性, 2008, 19(3): 702-715

被引频次：247

生物多样性科学前沿

陈灵芝，钱迎倩

摘要：由国际生物科学联盟（IUBS）在1991年首先提出，至今已由其它5个重要国际组织或项目（SCOPE，UNESCO，ICSU，IGPB-GCTE及IUMS）共同主持的DIVERSITAS是迄今生物多样性科学研究唯一的国际性项目。1996年7月，科学指导委员会草拟了本阶段新的操作计划，并于同年8月在IUBS执行委员会上讨论。操作计划详述了10个组成方面的内容，其中5个为核心组成部分，其它5个为特别目标研究领域（STARS）。“生物多样性对生态系统功能的作用”是最核心的组成方面，也是1991年提出的唯一的研究内容。生物多样性的保护，恢复和持续利用既是重要的研究内容又是研究所要达到的最后目的。特别目标研究领域包括了土壤和沉积物、海洋、淡水和微生物生物多样性等重要而过去未引起足够重视的领域。DIVERSITAS的研究内容与《生物多样性公约》中的有关条款十分吻合，说明科学研究就是为履行《公约》服务的。明确研究的指导思想，按中国国情选择好有代表性的优先地区以及开展国际合作，逐步与国际接轨是下一步开展生物多样性研究应考虑到的几个方面。

关键词：DIVERSITAS；生物多样性；生态系统功能；《生物多样性公约》；优先地区

来源出版物：生态学报, 2007, 15(3): 306-311

被引频次：8766

来源出版物：Ecology Letters, 2001, 4 (4): 379-391

被引频次：2727

Effects of biodiversity on ecosystem functioning: A consensus of current knowledge

Hooper DU; Chapin FS; Ewel JJ; et al.

Abstract:Humans are altering the composition of biological communities through a variety of activities that increase rates of species invasions and species extinctions, at all scales, from local to global. These changes in components of the Earth’s biodiversity cause concern for ethical and aesthetic reasons, but they also have a strong potential to alter ecosystem properties and the goods and services they provide to humanity. Ecological experiments, observations, and theoretical developments show that ecosystem properties depend greatly on biodiversity in terms of the functional characteristics of organisms present in the ecosystem and the distribution and abundance of those organisms over space and time. Species effects act in concert with the effects of climate, resource availability, and disturbance regimes in influencing ecosystem properties. Human activities can modify all of the above factors; here we focus on modification of these biotic controls. The scientific community has come to a broad consensus on many aspects of the relationship between biodiversity and ecosystem functioning, including many points relevant to management of ecosystems. Further progress will require integration of knowledge about biotic and abiotic controls on ecosystem properties, how ecological communities are structured, and the forces driving species extinctions and invasions. To strengthen links to policy and management, we also need to integrate our ecological knowledge with understanding of the social and economic constraints of potential management practices. Understanding this complexity, while taking strong steps to minimize current losses of species, is necessary for responsible management of Earth’s ecosystems and the diverse biota they contain. Based on our review of the scientific literature, we are certain of the following conclusions: 1) Species’ functional characteristics strongly influence ecosystem properties. Functional characteristics operate in a variety of contexts, including effects of dominant species, keystone species’, ecological engineers, and interactions among species (e.g., competition, facilitation, mutualism, disease, and predation). Relative abundance alone is not always a good predictor of the ecosystem-level importance of a species, aseven relatively rare species (e.g., a keystone predator) can strongly influence pathways of energy and material flows. 2) Alteration of biota in ecosystems via species invasions and extinctions caused by human activities has altered ecosystem goods and services in many well-documented cases. Many of these changes are difficult, expensive, or impossible to reverse or fix with technological solutions. 3) The effects of species loss or changes in composition, and the mechanisms by which the effects manifest themselves, can differ among ecosystem properties, ecosystem types, and pathways of potential community change. 4) Some ecosystem properties are initially insensitive to species loss because (a) ecosystems may have multiple species that carry out similar functional roles, (b) some species may contribute relatively little to ecosystem properties, or (c) properties may be primarily controlled by abiotic environmental conditions. 5) More species are needed to insure a stable supply of ecosystem goods and services as spatial and temporal variability increases, which typically occurs as longer time periods and larger areas are considered. We have high confidence in the following conclusions: 1) Certain combinations of species are complementary in their patterns of resource use and can increase average rates of productivity and nutrient retention. At the same time, environmental conditions can influence the importance of complementarity in structuring communities. Identification of which and how many species act in a complementary way in complex communities is just beginning. 2) Susceptibility to invasion by exotic species is strongly influenced by species composition and, under similar environmental conditions, generally decreases with increasing species richness. However, several other factors, such as propagule pressure, disturbance regime, and resource availability also strongly influence invasion success and often override effects of species richness in comparisons across different sites or ecosystems. 3) Having a range of species that respond differently to different environmental perturbations can stabilize ecosystem process rates in response to disturbances and variation in abiotic conditions. Using practices that maintain a diversity of organisms of different functional effect and functional response types will help preserve a range of management options. Uncertainties remain and further research is necessary in the following areas: 1) Further resolution of the relationships among taxonomic diversity, functional diversity, and community structure is important for identifying mechanisms of biodiversity effects. 2) Multiple trophic levels are common to ecosystems but have been understudied in biodiversity/ ecosystem functioning research. The response of ecosystem properties to varying composition and diversity of consumer organisms is much more complex than responses seen in experiments that vary only the diversity of primary producers. 3) Theoretical work on stability has outpaced experimental, work, especially field research. We need long-term experiments to be able to assess temporal stability, as well as experimental perturbations to assess response to and recovery from a variety of disturbances. Design and analysis of such experiments must account for several factors that covary with species diversity. 4) Because biodiversity both responds to and influences ecosystem properties, understanding the feedbacks involved is necessary to integrate results from experimental communities with patterns seen at broader scales. Likely patterns of extinction and invasion need to be linked to different drivers of global change, the forces that structure communities, and controls on ecosystem properties for the development of effective management and conservation strategies. 5) This paper focuses primarily on terrestrial systems, with some coverage of freshwater systems, because that is where most empirical and theoretical study has focused. While the fundamental principles described here should apply to marine systems, further study of that realm is necessary. Despite some uncertainties about the mechanisms and circumstances under which diversity influences ecosystem properties, incorporating diversity effects into policy and management is essential, especially in making decisions involving large temporal and spatial scales. Sacrificing those aspects of ecosystems that are difficult or impossible to reconstruct, such as diversity, simply because we are not yet certain about the extent and mechanisms by which they affect ecosystem properties, will restrict future management options even further. It is incumbent upon ecologists to communicate this need, and the values that can derive from such a perspective, to those charged with economic and policy decision-making.

Keywords:biodiversity; complementary resource use; ecosystem goods and services; ecosystem processes; ecosystem properties; functional characteristics; functional diversity; net primary production; sampling effect; species extinction; species invasions; species richness; stability

来源出版物：Ecological Monographs, 2005, 75 (1): 3-35

被引频次：2409

Effects of habitat fragmentation on biodiversity

Fahrig, L

Abstract:The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in different ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscapescale process involving both habitat loss and the breaking apart of habitat. Results of empirical studies of habitat fragmentation are often difficult to interpret because (a) many researchers measure fragmentation at the patch scale, not the landscape scale and (b) most researchers measure fragmentation in ways that do not distinguish between habitat loss and habitat fragmentation per se, i.e., the breaking apart of habitat after controlling for habitat loss. Empirical studies to date suggest that habitat loss has large, consistently negative effects on biodiversity. Habitat fragmentation per se has much weaker effects on biodiversity that are at least as likely to be positive as negative. Therefore, to correctly interpret the influence of habitat fragmentation on biodiversity, the effects of these two components of fragmentation must be measured independently. More studies of the independent effects of habitat loss and fragmentation per se are needed to determine the factors that lead to positive versus negative effects of fragmentation per se. I suggest that the term“fragmentation” should be reserved for the breaking apart of habitat, independent of habitat loss.

来源出版物：Annual Review of Ecology Evolution and Systematics, 2003, 34: 487-515

被引频次：2154

Routing security in wireless ad hoc networks

Colwell, RK; Coddington, JA

Abstract:Both the magnitude and the urgency of the task of assessing global biodiversity require that we make the most of what we know through the use of estimation and extrapolation. Likewise, future biodiversity inventories need to be designed around the use of effective sampling and estimation procedures, especially for ‘hyperdiverse’groups of terrestrial organisms, such as arthropods, nematodes, fungi, and microorganisms. The challenge of estimating patterns of species richness from samples can be separated into (i) the problem of estimating local species richness, and (ii) the problem of estimating the distinctness, or complementarity, of species assemblages. These concepts apply on a wide range of spatial, temporal, and functional scales. Local richness can be estimated by extrapolating species accumulation curves, fitting parametric distributions of relative abundance, or using non-parametric techniques based on the distribution of individuals among species or of species among samples. We present several of these methods and examine their effectiveness for an example data set. We present a simple measure of complementarity, with some biogeographic examples, and outline the difficult problem of estimating complementarity from samples. Finally, we discuss the importance of using 'reference' sites (or sub-sites) to assess the true richness and composition of species assemblages, to measure ecologically significant ratios between unrelated taxa, to measure taxon/sub-taxon (hierarchical) ratios, and to ‘calibrate’ standardized sampling methods. This information can then be applied to the rapid, approximate assessment of species richness and faunal or floral composition at ‘comparative’ sites.

来源出版物：Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 1994, 345 (1311): 101-118

被引频次：1902

Mechanisms of maintenance of species diversity

Chesson, P

Abstract:The focus of most ideas on diversity maintenance is species coexistence, which may be stable or unstable, Stable coexistence can be quantified by the long-term rates at which community members recover from low density. Quantification shows that coexistence mechanisms function in two major ways: They may be (a) equalizing because they tend to minimize average fitness differences between species, or (b) stabilizing because they tend to increase negative intraspecific interactions relative to negative interspecific interactions. Stabilizing mechanisms are essential for species coexistence and include traditional mechanisms such as resource partitioning and frequencydependent predation, as well as mechanisms that depend on fluctuations in population densities and environmental factors in space and time. Equalizing mechanisms contribute to stable coexistence because they reduce large average fitness inequalities which might negate the effects of stabilizing mechanisms. Models of unstable coexitence, in which species diversity slowly decays over time, have focused almost exclusively on equalizing mechanisms. These models would be more robust if they also includedstabilizing mechanisms, which arise in many and varied ways but need not be adequate for full stability of a system. Models of unstable coexistence invite a broader view of diversity maintenance incorporating species turnover.

Keywords:coexistence; competition; predation; niche; spatial and temporal variation

来源出版物：Annual Review of Ecology and Systematics, 2000, 31: 343-366

被引频次：1743

Ecology-biodiversity and ecosystem functioning: Current knowledge and future challenges

Loreau, M; Naeem S; Inchausti P; et al.

Abstract:The ecological consequences of biodiversity loss have aroused considerable interest and controversy during the past decade. Major advances have been made in describing the relationship between species diversity and ecosystem processes, in identifying functionally important species, and in revealing underlying mechanisms. There is, however, uncertainty as to how results obtained in recent experiments scale up to landscape and regional levels and generalize across ecosystem types and processes. Larger numbers of species are probably needed to reduce temporal variability in ecosystem processes in changing environments. A major future challenge is to determine how biodiversity dynamics, ecosystem processes, and abiotic factors interact.

来源出版物：Science, 2001 294 (5543): 804-808

被引频次：1563

Emerging infectious diseases of wildlife: Threats to biodiversity and human health

Daszak, P; Cunningham, AA

Abstract:Emerging infectious diseases (EIDs) of free-living wild animals can be classified into three major groups on the basis of key epizootiological criteria: (i) EIDs associated with “spill-over” from domestic animals to wildlife populations living in proximity; (ii) EIDs related directly to human intervention, via host or parasite translocations; and (iii) EIDs with no overt human or domestic animal involvement. These phenomena have two major biological implications: first, many wildlife species are reservoirs of pathogens that threaten domestic animal and human health; second, wildlife EIDs pose a substantial threat to the conservation of global biodiversity.

Keywords:Attestation; public key infrastructure (PKI); Supervisory Control And Data Acquisition (SCADA); security; smart grid; trusted computing

来源出版物：Science, 2000, 287(5452): 443-449

被引频次：1535

Impacts of biodiversity loss on ocean ecosystem services

Worm, Boris; Barbier, Edward B.; Beaumont, Nicola; et al.

Abstract:Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean’s capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.

来源出版物：Science, 2006, 314(5800): 787-790

Biodiversity loss and its impact on humanity

Cardinale, Bradley J.; Duffy, J. Emmett; Gonzalez,Andrew; et al.

The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world’s nations declared that human actions were dismantling the Earth’s ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.来源出版物：Nature, 2012 486 (7401): 59-67被引频次：3195Biodiversity：Global biodiversity scenarios for the year 2100Sala, OE; Chapin FS; Armesto JJ; et al.Abstract:Scenarios of changes in biodiversity for the year 2100 can now be developed based on scenarios of changes in atmospheric carbon dioxide, climate, vegetation, and Land use and the known sensitivity of biodiversity to these changes. This study identified a ranking of the importance of drivers of change, a ranking of the biomes with respect to expected changes, and the major sources of uncertainties. For terrestrial ecosystems, land-use change probably will have the largest effect, followed by climate change, nitrogen deposition, biotic exchange, and elevated carbon dioxide concentration. For freshwater ecosystems, biotic exchange is much more important. Mediterranean climate and grassland ecosystems likely will experience the greatest proportional change in biodiversity because of thesubstantial influence of all drivers of biodiversity change. Northern temperate ecosystems are estimated to experience the least biodiversity change because major land-use change has already occurred. Plausible changes in biodiversity in other biomes depend on interactions among the causes of biodiversity change. These interactions represent one of the largest uncertainties in projections of future biodiversity change.来源出版物：Science, 2000, 287 (5459): 1770-1774被引频次：2805Quantifying biodiversity: Procedures and pitfalls in the measurement and comparison of species richnessGotelli, NJ; Colwell RKAbstract:Species richness is a fundamental measurement of community and regional diversity, and it underlies many ecological models and conservation strategies. In spite of its importance, ecologists have not always appreciated the effects of abundance and sampling effort on richness measures and comparisons. We survey a series of common pitfalls in quantifying and comparing taxon richness. These pitfalls can be largely avoided by using accumulation and rarefaction curves, which may be based on either individuals or samples. These taxon sampling curves contain the basic information for valid richness comparisons, including category-subcategory ratios (species-to-genus and species-to-individual ratios). Rarefaction methods-both sample-based and individualbased-allow for meaningful standardization and comparison of datasets. Standardizing data sets by area or sampling effort may produce very different results compared to standardizing by number of individuals collected, and it is not always clear which measure of diversity is more appropriate. Asymptotic richness estimators provide lower-bound estimates for taxon-rich groups such as tropical arthropods, in which observed richness rarely reaches an asymptote, despite intensive sampling. Recent examples of diversity studies of tropical trees, stream invertebrates, and herbaceous plants emphasize the importance of carefully quantifying species richness using taxon sampling curves.

species richness; species density; taxon sampling; taxonomic ratios; biodiversity; rarefaction; accumulation curves; asymptotic richness; richness estimation; category-subcategory ratios