Relationships between functional diversity and ecosystem functioning: A review

Functional diversity, which is the value, variation and distribution of traits in a community assembly, is an important component of biodiversity. Functional diversity is generally viewed as a key to understand ecosystem and community functioning. There are three components of functional diversity, i.e. functional richness, evenness and divergence. Functional diversity and species diversity can be either positively or negatively correlated, or uncorrelated, depending on the environmental conditions and disturbance intensity. Ecosystem functioning includes ecosystem processes, ecosystem properties and ecosystem stability. The diversity hypothesis and the mass ratio hypothesis are the two major hypotheses of explaining the effect of functional diversity on ecosystem functioning, diversity hypothesis reflects that organisms and their functional traits in a assemblage effect on ecosystem functioning by the complementarity of using resources, and mass ratio hypothesis emphasises the identify of the dominant species in a assemblage. These two hypotheses do not contradict each other and instead they reflect the two different sides of functional diversity and functional composition. The effect of functional diversity on ecosystem functioning also depends on abiotic factors, perturbation, management actions, etc. Function diversity potentially influences ecosystem service and management by effecting on ecosystem functioning. Ecosystem management groups should include functional diversity in their scheme and not just species richness.     

种、种的多样性及退化生态系统功能的恢复和维持研究

物种多样性是生态系统的重要特征并维持系统的功能支行,生物种和不同种类构成的群落为人类提供诸如营养物质循环、生物生产力、营养功能等形式的重要生态服务,特种多样性与生态系统抵御逆境和干扰的能力紧密相关,多样性的提高会增加系统的稳定性,与单个种和种类的数量相比,功能群和功能多样性对生态系统功能的影响效应要大得多,且易于被用来测度稳定性和预测群落变化,本文提出并探讨了种对生态系统功能作用的几种形式,理解物种多样性与生态系统的功能关系能指导退化生态系统恢复和维持其功能的实践活动,尤其为恢复的初始阶段进行群落的“种类组装”提供生态理论基础。     

生物多样性与生态系统功能:进展与争论

生物多样性与生态系统功能的关系已成为当前人类社会面临的一个重大科学问题,生物多样性的空前丧失,促使人们开展了大量研究工作来描述物种多样性-生态系统功能关系,并试图揭示多样性与系统功能关系的内在机制,本文将多样性对生态系统功能作用机制的有关假说分为统计学与生物学两大类：前者是从统计学角度来解释观察到的多样性-系统功能模式,包括抽样效应,统计均衡效应等;而后者是基于多样性的生物学效应给出的,包括生态位互补,种间正相互作用,保险效应等,本文较为详细地介绍了该领域内有代表性的实验工作,包括“生态箱”实验,Cedar Creek草地多样性实验,微宇宙实验,欧洲草地实验,以及在这些实验结果解释上的激烈争论。     

生物多样性与生态系统功能:最新的进展与动向

生物多样性与生态系统功能的关系及其内在机制是当前生态学领域的重大科学问题。 2 0 0 2年以来人们不再过多地纠缠于“抽样 -互补之争” ,对这一世纪课题的认识又有了新的进展。 (1)人们开始运用已有的知识揭示更大时间和空间尺度上的物种多样性 -生态系统功能关系。多样性作用机制可能存在着动态变化———“抽样向互补转型” :群落建立初期 ,抽样效应是主要的多样性作用机制 ;随时间推移 ,生态位互补成为主要机制。理论研究则预测 :局域尺度上生态系统功能与物种多样性呈现单峰曲线关系 ,在区域尺度上为单调上升关系 ;(2 )非生物因素与多样性 -生产力的交互关系吸引了许多实验研究。人们发现 :物种多样性 -生产力关系可能会受到资源供给率和环境扰动的修正 ,环境因素可能是多样性 -生产力关系的幕后操纵者 ;(3)人们开始重视营养级相互作用对于多样性 -生态系统功能关系的影响 ,生态位互补和抽样假说开始被扩展运用到消费者营养级上 ;(4 )人们开始认真思考物种共存机制在多样性 -生态系统功能关系的形成中所扮演的角色。理论模型研究表明 ,不同的物种共存机制会导致不同的多样性 -生产力关系     

A new graphical model for untangling complex relationships among environment, biodiversity, and ecosystem functioning

Recent advances in the research field of ‘biodiversity-ecosystem functioning’ have successfully begun to reconcile the apparent controversy on relationships between productivity and species richness. By unifying new advances into a single framework, I propose a 3D graphical model connecting the relationships among resource availability, species richness, and ‘community productivity.’ An emergent pattern from this model predicts that the effect of species richness on community productivity is maximized at intermediate levels of resource availability. This model will contribute to better understanding the relationships among environment, biodiversity, and ecosystem functioning.     

Biodiversity and ecosystem functioning in food webs: the vertical diversity hypothesis

One challenge in merging community and ecosystem ecology is to integrate the complexity of natural multitrophic communities into concepts of ecosystem functioning. Here, we combine food‐web and allometry theories to demonstrate that primary production, as measured by the total nutrient uptake of the multitrophic community, is determined by vertical diversity (i.e. food web's maximum trophic level) and structure (i.e. distributions of species and their abundances and metabolic rates across trophic levels). In natural ecosystems, the community size distribution determines all these vertical patterns and thus the total nutrient uptake. Our model suggests a vertical diversity hypothesis (VDH) for ecosystem functioning in complex food webs. It predicts that, under a given nutrient supply, the total nutrient uptake increases exponentially with the maximum trophic level in the food web and it increases with its maximum body size according to a power law. The VDH highlights the effect of top–down regulation on plant nutrient uptake, which complements traditional paradigms that emphasised the bottom–up effect of nutrient supply on vertical diversity. We conclude that the VDH contributes to a synthetic framework for understanding the relationship between vertical diversity and ecosystem functioning in food webs and predicting the impacts of global changes on multitrophic ecosystems.     

物种多样性与生态系统功能：影响机制及有关假说

本文主要介绍了有关物种多样性对生态系统功能的影响机制及有关假说,包括冗余种假说、铆钉假说、不确定假说、无效假说、补偿／关键种假说、非线性假说、单调／驼峰模型假说等。尽管这些假说的提出都有一定的理论或实验研究基础,但到目前为止,还没有一种假说被普遍认为反映了两者之间关系的实际情形（如果确实存在这样一种普适机制）。通过分析,我们发现在这些假说之间存在一定的内在联系,它们或者互相包含,或者互相补充,并且都可以归结到冗余种假说有关。     

Linking biodiversity to ecosystem function: implications for conservation ecology

We evaluate the empirical and theoretical support for the hypothesis that a large proportion of native species richness is required to maximize ecosystem stability and sustain function. This assessment is important for conservation strategies because sustenance of ecosystem functions has been used as an argument for the conservation of species. If ecosystem functions are sustained at relatively low species richness, then arguing for the conservation of ecosystem function, no matter how important in its own right, does not strongly argue for the conservation of species. Additionally, for this to be a strong conservation argument the link between species diversity and ecosystem functions of value to the human community must be clear. We review the empirical literature to quantify the support for two hypotheses: (1) species richness is positively correlated with ecosystem function, and (2) ecosystem functions do not saturate at low species richness relative to the observed or experimental diversity. Few empirical studies demonstrate improved function at high levels of species richness. Second, we analyze recent theoretical models in order to estimate the level of species richness required to maintain ecosystem function. Again we find that, within a single trophic level, most mathematical models predict saturation of ecosystem function at a low proportion of local species richness. We also analyze a theoretical model linking species number to ecosystem stability. This model predicts that species richness beyond the first few species does not typically increase ecosystem stability. One reason that high species richness may not contribute significantly to function or stability is that most communities are characterized by strong dominance such that a few species provide the vast majority of the community biomass. Rapid turnover of species may rescue the concept that diversity leads to maximum function and stability. The role of turnover in ecosystem function and stability has not been investigated. Despite the recent rush to embrace the linkage between biodiversity and ecosystem function, we find little support for the hypothesis that there is a strong dependence of ecosystem function on the full complement of diversity within sites. Given this observation, the conservation community should take a cautious view of endorsing this linkage as a model to promote conservation goals. Received: 2 September 1999 / Accepted: 26 October 1999     

Biodiversity and ecosystem functioning relations in European forests depend on environmental context

The importance of biodiversity in supporting ecosystem functioning is generally well accepted. However, most evidence comes from small‐scale studies, and scaling‐up patterns of biodiversity–ecosystem functioning (B‐EF) remains challenging, in part because the importance of environmental factors in shaping B‐EF relations is poorly understood. Using a forest research platform in which 26 ecosystem functions were measured along gradients of tree species richness in six regions across Europe, we investigated the extent and the potential drivers of context dependency of B‐EF relations. Despite considerable variation in species richness effects across the continent, we found a tendency for stronger B‐EF relations in drier climates as well as in areas with longer growing seasons and more functionally diverse tree species. The importance of water availability in driving context dependency suggests that as water limitation increases under climate change, biodiversity may become even more important to support high levels of functioning in European forests.     

Field observed relationships between biodiversity and ecosystem functioning during secondary succession in a tropical lowland rainforest

The relationship between biodiversity and ecosystem functioning (BEF) is one of the most concerned topics in ecology. However, most of the studies have been conducted in controlled experiments in grasslands, few observational field studies have been carried out in forests. In this paper, we report variations of species diversity, functional diversity and aboveground biomass (AGB) for woody plants (trees and shrubs) along a chronosequence of four successional stages (18-year-old fallow, 30-year-old fallow, 60-year-old fallow, and old-growth forest) in a tropical lowland rainforest recovered after shifting cultivation on Hainan Island, China. Fifty randomly selected sample plots of 20 m × 20 m were investigated in each of the four successional stages. Four functional traits (specific leaf area, wood density, maximum species height and leaf dry matter content) were measured for each woody plants species and the relationships between species/functional diversity and AGB during secondary succession were explored. The results showed that both plant diversity and AGB recovered gradually with the secondary succession. AGB was positively correlated with both species and functional diversity in each stage of succession. Consistent with many controlled experimental results in grasslands, our observational field study confirms that ecosystem functioning is closely related to biodiversity during secondary succession in species rich tropical forests.     

Integrating internal and external dispersal in metacommunity assembly: preliminary theoretical analyses

Internal dispersal, which occurs among local communities within a metacommunity, and external dispersal, which supplies immigrants from outside the metacommunity, can both have a major impact on species diversity. However, few studies have considered the two simultaneously. Here I report preliminary computer-simulation results to suggest that internal and external dispersal can interact to influence species richness. Specifically, the results show that internal dispersal did not affect species richness under frequent external dispersal, whereas it enhanced richness in local communities while decreasing richness in metacommunities under infrequent external dispersal. Conversely, external dispersal influenced species richness in local communities more greatly in the absence of internal dispersal than in its presence, while external dispersal did not affect richness in metacommunities regardless of internal dispersal. Furthermore, internal and external dispersal interactively determined the importance of community assembly history in generating and maintaining variation in local community structure. Overall, these results suggest that the two dispersal types can reciprocally provide the context in which each affects species diversity and therefore that their effects cannot be understood in isolation of the other.Electronic Supplementary Material Supplementary material is available for this article at Tadashi Fukami is the recipient of the ninth Denzaburo Miyadi Award.     

生态系统途径——生态系统管理的一种新理念

介绍了生态系统途径的概念和内涵．生态系统途径最早由西方生态学家提出。随后得到一系列国际学术组织和国家的认同和支持,其中《生物多样性公约》、世界自然保护联盟和世界野生动物基金发挥了重要作用,．生态系统途径的实质是对土地、水和生物资源进行综合管理,旨在生态系统保护、生物资源可持续利用和共享生物资源三者之间达到平衡．作为生态系统管理的一种方法论,它以生物为核心。将人类及文化的多样性视为生态系统的一个组成部分,2000年《生物多样性公约》缔约国会议上制定的生态系统管理的12条基本原则和5项行动指南,丰富了生态系统途径的内涵,明确了实施的办法,我国在生态系统管理方面有着丰富的学术储备和经验总结。但也存在一定问题。

     

Grasshoppers affect grassland ecosystem functioning: Spatial and temporal variation

Using experiments and monitoring, we find that grasshoppers in a grassland ecosystem impact ecosystem functioning (nutrient cycling and primary production) in different ways among sites in the ecosystem. Experiments conducted over many years at two sites (21 and 15 years, respectively) with the same grasshopper and plant species demonstrated that grasshoppers increased nitrogen availability (N) and consequently annual plant production (ANPP) at one site, and decreased N and consequently ANPP at the other site. Comparing the two sites, N increased on average by 8% and up to 21.6%, and resulting ANPP increased on average by 18.6% and up to 33.3%. Grasshoppers increase N and ANPP by preferentially feeding on slower decomposing plants, and the opposite occurs by preferentially feeding on faster decomposing plants. Monitoring 20 random sites in the ecosystem, grasshoppers consistently increased N and ANPP over 3 years at 40% of sites, consistently decreased N and ANPP at 35% of sites, and sometimes increased and decreased N and ANPP at 25% of sites. Therefore, grassland grasshoppers, and insects in many ecosystems, may strongly affect ecosystem functioning.     

植物遗传多样性与生态系统功能关系的研究进展

全球变化和人类活动导致物种生境的萎缩, 造成很多植物种群数量缩减, 遗传多样性快速丧失。对于物种多样性低的生态系统, 优势种的遗传多样性可能比物种多样性对生态系统功能产生更大的影响。因此, 了解遗传多样性和生态系统功能的关系(GD-EF)及其机制对生物多样性保护、应对环境变化和生态修复具有指导意义。该文综述了植物遗传多样性对生态系统结构(高营养级生物群落结构)和生态系统功能(初级生产力、养分循环和稳定性)的影响及机制、功能多样性对GD-EF的影响、遗传多样性效应和物种多样性效应的比较, 以及GD-EF在生态修复等实际应用的研究进展。最后指出当前研究的不足之处, 以期为后续研究提供参考: 1)还需深入研究GD-EF机制; 2)未评估遗传多样性对生态系统多功能性的影响; 3)不同遗传多样性测度对生态系统功能的影响不明确; 4)缺少长期的和多空间尺度结合的GD-EF实验; 5)遗传多样性效应相对于其他因子的作用不清楚。     

Extinction order and altered community structure rapidly disrupt ecosystem functioning

By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences.     

Linking biodiversity indicators,ecosystem functioning,provision of services and human well-being in estuarine systems: Application of a conceptual framework

Assuming that human well-being strongly relies on the services provided by well-functioning ecosystems, changes in the ecological functioning of any system can have direct and indirect effects on human welfare. Intensive land use and tourism have expanded in recent decades along coastal ecosystems, together with increasing demands for water, food and energy; all of these factors intensify the exploitation of natural resources. Many of the interrelations between ecosystem functioning and the provision of ecosystem services (ES) still require quantification in estuarine systems. A conceptual framework to assess such links in a spatially and temporally explicit manner is proposed and applied to the Mondego estuary (Portugal). This framework relies on three consecutive steps and discriminates among biodiversity structural components, ecosystem functioning and stability and the services provided by the ecosystem.Disturbances in abiotic factors were found to have a direct effect on biodiversity, ecosystem functioning and the provision of ES. The observed changes in the species composition of communities had a positive effect on the ecosystem's productivity and stability. Moreover, the observed changes in the estuarine ES provision are likely to arise from changing structural and abiotic factors and in the present case from the loss or decline of locally abundant species. This study also indicates that linear relationships between biodiversity, ecosystem functioning and services provision are unlikely to occur in estuarine systems. Instead, cumulative and complex relations are observed between factors on both temporal and spatial scales. In this context, the results suggest several additional conclusions: (1) biodiversity and ecosystem functioning interaction with human well-being need to be incorporated into decision-making processes aimed at the conservative management of systems; (2) the institutional use of research results must be part of the design and implementation of sustainable management activities; and (3) more integrative tools/studies are required to account for the interactions of estuarine ecosystems with surrounding socio-economic activities. Therefore, when performing integrated assessments of ecosystem dynamics, it becomes essential to consider not only the effects of biodiversity and ecosystem functioning on services provision but also the effects that human well-being and ES provision may have on estuarine biodiversity and ecosystem functioning.The proposed framework implies taking into account both the functional and the commodities points of view upon natural ecosystems and by this representing a line of thought which will deserve further research to explore more in detail the conceptual links between biodiversity–ecosystem functioning–services provided.     

Evaluating the performance of multiple remote sensing indices to predict the spatial variability of ecosystem structure and functioning in Patagonian steppes

Assessing the spatial variability of ecosystem structure and functioning is an important step towards developing monitoring systems to detect changes in ecosystem attributes that could be linked to desertification processes in drylands. Methods based on ground-collected soil and plant indicators are being increasingly used for this aim, but they have limitations regarding the extent of the area that can be measured using them. Approaches based on remote sensing data can successfully assess large areas, but it is largely unknown how the different indices that can be derived from such data relate to ground-based indicators of ecosystem health. We tested whether we can predict ecosystem structure and functioning, as measured with a field methodology based on indicators of ecosystem functioning (the landscape function analysis, LFA), over a large area using spectral vegetation indices (VIs), and evaluated which VIs are the best predictors of these ecosystem attributes. For doing this, we assessed the relationship between vegetation attributes (cover and species richness), LFA indices (stability, infiltration and nutrient cycling) and nine VIs obtained from satellite images of the MODIS sensor in 194 sites located across the Patagonian steppe. We found that NDVI was the VI best predictor of ecosystem attributes. This VI showed a significant positive linear relationship with both vegetation basal cover (R² = 0.39) and plant species richness (R² = 0.31). NDVI was also significantly and linearly related to the infiltration and nutrient cycling indices (R² = 0.36 and 0.49, respectively), but the relationship with the stability index was weak (R² = 0.13). Our results indicate that VIs obtained from MODIS, and NDVI in particular, are a suitable tool for estimate the spatial variability of functional and structural ecosystem attributes in the Patagonian steppe at the regional scale.     

Biodiversity, ecosystem functioning and food webs in fresh waters: assembling the jigsaw puzzle

1. Dramatic advances have been made recently in the study of biodiversity–ecosystem functioning (B-EF) relations and food web ecology. These fields are now starting to converge, and this fusion has the potential to improve our understanding of how environmental stressors modulate ecosystem processes and the supply of 'goods and services'.
2. Food web structure and dynamics can exert particularly strong influences on B-EF relations in fresh waters, as consumer–resource interactions (e.g. trophic cascades) are often more important than horizontal interactions within trophic levels. For instance, many freshwater food webs are size structured, with large organisms tending to occupy the higher trophic levels and often exerting powerful effects on ecosystem processes. However, because they are also vulnerable to perturbations, non-random losses of these large taxa can alter both food web structure and ecosystem functioning profoundly.
3. Recently, the focus of food web research has shifted away from exploring patterns, towards developing an understanding of processes (e.g. quantifying fluxes of individuals, biomass, energy, nutrients) and how the two interact. Many of the best-characterized food webs are from fresh waters, and these ecosystems are now being used to address some of the shortcomings of earlier B-EF studies. I have identified several key gaps in our current knowledge and highlighted potentially fruitful avenues of future B-EF and food web research.
4. A major challenge for this newly emerging research is to place it within a unified theoretical framework. The application of metabolic theory and ecological stoichiometry may help to achieve this goal by considering biological systems within the constraints imposed upon them by physical and chemical laws.