微生物性状揭示物种分布格局、群落构建机制和生态系统功能

微生物性状是指与其存活、生长和繁殖紧密相关的一系列核心属性,这些属性能够反映微生物对环境变化的响应,进而影响微生物的物种分布格局、群落构建机制以及相应的生态系统功能。越来越多的研究表明,相比于微生物分类学信息,微生物性状可以在种群、群落和生态系统尺度等视角扩展我们对微生物生态过程的理解,并提供生态模式的机理性解释。本文回顾微生物性状研究的发展历程,总结近年来基于微生物性状研究的前沿科学问题,比如微生物性状的分类和测定方法、基于性状的功能多样性定义及应用、性状与物种分布格局和群落构建机制的关系、性状对生物多样性和生态系统功能的影响以及对环境变化的响应等。尽管微生物性状研究已经延伸到生态学领域的各个方面,有力推动着各个前沿科学问题的研究发展,但是仍然面临很多机遇与挑战。因此,本文也从研究方法和研究方向等方面对未来基于微生物性状的研究提出了展望。     

绿弯菌的研究现状及展望

绿弯菌是一个深度分支的门级别细菌类群,广泛分布于生物圈各种生境。现已生效发表的绿弯菌构成9个纲,但仅包含56个种;基于分子生态学的研究结果表明尚有大量绿弯菌类群仍是未培养状态。绿弯菌形态多样,营养方式和代谢途径十分丰富,参与了C、N、S等一系列重要生源元素的生物地球化学循环过程。研究该类群不仅有助于认识环境中微生物的多样性及其代谢特征,从而更好的理解微生物参与的生态学过程,还有助于揭示微生物对环境的适应及其进化。本文主要综述了绿弯菌的发现历史、营养、代谢及其在元素循环中的作用,并总结了其分离培养和潜在应用价值,最后展望了未来的研究方向,旨在为深入探究绿弯菌的进化、培养和驱动地球化学元素循环等研究提供参考。     

Scaling environmental change through the community-level: a trait-based response-and-effect framework for plants

Predicting ecosystem responses to global change is a major challenge in ecology. A critical step in that challenge is to understand how changing environmental conditions influence processes across levels of ecological organization. While direct scaling from individual to ecosystem dynamics can lead to robust and mechanistic predictions, new approaches are needed to appropriately translate questions through the community level. Species invasion, loss, and turnover all necessitate this scaling through community processes, but predicting how such changes may influence ecosystem function is notoriously difficult. We suggest that community‐level dynamics can be incorporated into scaling predictions using a trait‐based response–effect framework that differentiates the community response to environmental change (predicted by response traits) and the effect of that change on ecosystem processes (predicted by effect traits). We develop a response‐and‐effect functional framework, concentrating on how the relationships among species' response, effect, and abundance can lead to general predictions concerning the magnitude and direction of the influence of environmental change on function. We then detail several key research directions needed to better scale the effects of environmental change through the community level. These include (1) effect and response trait characterization, (2) linkages between response‐and‐effect traits, (3) the importance of species interactions on trait expression, and (4) incorporation of feedbacks across multiple temporal scales. Increasing rates of extinction and invasion that are modifying communities worldwide make such a research agenda imperative.     

Interdisciplinary knowledge exchange across scales in a globally changing marine environment

The effects of anthropogenic global environmental change on biotic and abiotic processes have been reported in aquatic systems across the world. Complex synergies between concurrent environmental stressors and the resilience of the system to regime shifts, which vary in space and time, determine the capacity for marine systems to maintain structure and function with global environmental change. Consequently, an interdisciplinary approach that facilitates the development of new methods for the exchange of knowledge between scientists across multiple scales is required to effectively understand, quantify and predict climate impacts on marine ecosystem services. We use a literature review to assess the limitations and assumptions of current pathways to exchange interdisciplinary knowledge and the transferability of research findings across spatial and temporal scales and levels of biological organization to advance scientific understanding of global environmental change in marine systems. We found that species‐specific regional scale climate change research is most commonly published, and “supporting” is the ecosystem service most commonly referred to in publications. In addition, our paper outlines a trajectory for the future development of integrated climate change science for sustaining marine ecosystem services such as investment in interdisciplinary education and connectivity between disciplines.     

环境DNA技术在地下生态学中的应用

地下生态过程是生态系统结构、功能和过程研究中最不确定的因素。由于技术和方法的限制,作为"黑箱"的地下生态系统已经成为限制生态学发展的瓶颈,也是未来生态学发展的主要方向。环境DNA技术,是指从土壤等环境样品中直接提取DNA片段,然后通过DNA测序技术来定性或定量化目标生物,以确定目标生物在生态系统中的分布及功能特征。环境DNA技术已成功用于地下生态过程的研究。目前,环境DNA技术在土壤微生物多样性及其功能方面的研究相对成熟,克服了土壤微生物研究中不能培养的问题,可以有效地分析土壤微生物的群落组成、多样性及空间分布,尤其是宏基因组学技术的发展,使得微生物生态功能方面的研究成为可能;而且,环境DNA技术已经在土壤动物生态学的研究中得到了初步应用,可快速分析土壤动物的多样性及其分布特征,更有效地鉴定出未知的或稀少的物种,鉴定土壤动物类群的幅度较宽;部分研究者通过提取分析土壤中DNA片段信息对生态系统植物多样性及植物分类进行了研究,其结果比传统的植物分类及物种多样性测定更精确,改变了以往对植物群落物种多样性模式的理解。同时,环境DNA技术克服传统根系研究方法中需要洗根、分根、只能测定单物种根系的局限,降低根系研究中细根区分的误差,并探索性地用于细根生物量的研究。主要综述了基于环境DNA技术的分子生物学方法在土壤微生物多样性及功能、土壤动物多样性、地下植物多样性及根系生态等地下生态过程研究中的应用进展。环境DNA技术对于以土壤微生物、土壤动物及地下植物根系为主体的地下生态学过程的研究具有革命性意义,并展现出良好的应用前景。可以预期,分子生物学技术与传统的生态学研究相结合将成为未来地下生态学研究的一个发展趋势。     

The Bryosphere: An Integral and Influential Component of the Earth’s Biosphere

A significant fraction of the Earth’s land surface is dominated by bryophytes. Research on carbon and nitrogen budgets of tundra, boreal, and peatland ecosystems has demonstrated the important role of mosses in understanding global change. Bryophytes are also habitat to a highly diverse microbiota that plays a key role in the function of these ecosystems. Here we define the term bryosphere to emphasize the combined role of mosses and their associated organisms in the functioning of ecosystems from local to global scales. In this minireview, we emphasize the value of the bryosphere as a spatially bounded, whole ecosystem that integrates aboveground and belowground processes, and we highlight the potential of the bryosphere as a natural model system (NMS) to assist in the study of environmental change on biodiversity and ecosystem functioning. We propose a formal definition of the bryosphere, attempt to summarize the current state of knowledge of the bryosphere, and discuss how the bryosphere can be a complex yet tractable system under an NMS framework. Recent use of the bryosphere as an NMS has shown how alterations in food web structure can affect ecosystem function in a manner that, although predicted by theory, has remained largely untested by experiment. An understanding of the biodiversity, ecosystem functioning, and adaptation of the bryosphere can be advanced by manipulative experiments coupled with a blend of techniques in molecular, physiological, community, and ecosystem ecology. Although studies described herein have demonstrated the utility of the bryosphere NMS for addressing ecological theory, the bryosphere is an underutilized system with exceptional promise.     

Environmental and biotic drivers of soil microbial β‐diversity across spatial and phylogenetic scales

Soil microbial communities play a key role in ecosystem functioning but still little is known about the processes that determine their turnover (β‐diversity) along ecological gradients. Here, we characterize soil microbial β‐diversity at two spatial scales and at multiple phylogenetic grains to ask how archaeal, bacterial and fungal communities are shaped by abiotic processes and biotic interactions with plants. We characterized microbial and plant communities using DNA metabarcoding of soil samples distributed across and within eighteen plots along an elevation gradient in the French Alps. The recovered taxa were placed onto phylogenies to estimate microbial and plant β‐diversity at different phylogenetic grains (i.e. resolution). We then modeled microbial β‐diversities with respect to plant β‐diversities and environmental dissimilarities across plots (landscape scale) and with respect to plant β‐diversities and spatial distances within plots (plot scale). At the landscape scale, fungal and archaeal β‐diversities were mostly related to plant β‐diversity, while bacterial β‐diversities were mostly related to environmental dissimilarities. At the plot scale, we detected a modest covariation of bacterial and fungal β‐diversities with plant β‐diversity; as well as a distance–decay relationship that suggested the influence of ecological drift on microbial communities. In addition, the covariation between fungal and plant β‐diversity at the plot scale was highest at fine or intermediate phylogenetic grains hinting that biotic interactions between those clades depends on early‐evolved traits. Altogether, we show how multiple ecological processes determine soil microbial community assembly at different spatial scales and how the strength of these processes change among microbial clades. In addition, we emphasized the imprint of microbial and plant evolutionary history on today's microbial community structure.     

Empirical and theoretical challenges in aboveground–belowground ecology

A growing body of evidence shows that aboveground and belowground communities and processes are intrinsically linked, and that feedbacks between these subsystems have important implications for community structure and ecosystem functioning. Almost all studies on this topic have been carried out from an empirical perspective and in specific ecological settings or contexts. Belowground interactions operate at different spatial and temporal scales. Due to the relatively low mobility and high survival of organisms in the soil, plants have longer lasting legacy effects belowground than aboveground. Our current challenge is to understand how aboveground–belowground biotic interactions operate across spatial and temporal scales, and how they depend on, as well as influence, the abiotic environment. Because empirical capacities are too limited to explore all possible combinations of interactions and environmental settings, we explore where and how they can be supported by theoretical approaches to develop testable predictions and to generalise empirical results. We review four key areas where a combined aboveground–belowground approach offers perspectives for enhancing ecological understanding, namely succession, agro-ecosystems, biological invasions and global change impacts on ecosystems. In plant succession, differences in scales between aboveground and belowground biota, as well as between species interactions and ecosystem processes, have important implications for the rate and direction of community change. Aboveground as well as belowground interactions either enhance or reduce rates of plant species replacement. Moreover, the outcomes of the interactions depend on abiotic conditions and plant life history characteristics, which may vary with successional position. We exemplify where translation of the current conceptual succession models into more predictive models can help targeting empirical studies and generalising their results. Then, we discuss how understanding succession may help to enhance managing arable crops, grasslands and invasive plants, as well as provide insights into the effects of global change on community re-organisation and ecosystem processes.     

Moving forward in global‐change ecology: capitalizing on natural variability

Natural resources managers are being asked to follow practices that accommodate for the impact of climate change on the ecosystems they manage, while global‐ecosystems modelers aim to forecast future responses under different climate scenarios. However, the lack of scientific knowledge about short‐term ecosystem responses to climate change has made it difficult to define set conservation practices or to realistically inform ecosystem models. Until recently, the main goal for ecologists was to study the composition and structure of communities and their implications for ecosystem function, but due to the probable magnitude and irreversibility of climate‐change effects (species extinctions and loss of ecosystem function), a shorter term focus on responses of ecosystems to climate change is needed. We highlight several underutilized approaches for studying the ecological consequences of climate change that capitalize on the natural variability of the climate system at different temporal and spatial scales. For example, studying organismal responses to extreme climatic events can inform about the resilience of populations to global warming and contribute to the assessment of local extinctions. Translocation experiments and gene expression are particular useful to quantitate a species' acclimation potential to global warming. And studies along environmental gradients can guide habitat restoration and protection programs by identifying vulnerable species and sites. These approaches identify the processes and mechanisms underlying species acclimation to changing conditions, combine different analytical approaches, and can be used to improve forecasts of the short‐term impacts of climate change and thus inform conservation practices and ecosystem models in a meaningful way.     

A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning

As the earth system changes in response to human activities, a critical objective is to predict how biogeochemical process rates (e.g. nitrification, decomposition) and ecosystem function (e.g. net ecosystem productivity) will change under future conditions. A particular challenge is that the microbial communities that drive many of these processes are capable of adapting to environmental change in ways that alter ecosystem functioning. Despite evidence that microbes can adapt to temperature, precipitation regimes, and redox fluctuations, microbial communities are typically not optimally adapted to their local environment. For example, temperature optima for growth and enzyme activity are often greater than in situ temperatures in their environment. Here we discuss fundamental constraints on microbial adaptation and suggest specific environments where microbial adaptation to climate change (or lack thereof) is most likely to alter ecosystem functioning. Our framework is based on two principal assumptions. First, there are fundamental ecological trade-offs in microbial community traits that occur across environmental gradients (in time and space). These trade-offs result in shifting of microbial function (e.g. ability to take up resources at low temperature) in response to adaptation of another trait (e.g. limiting maintenance respiration at high temperature). Second, the mechanism and level of microbial community adaptation to changing environmental parameters is a function of the potential rate of change in community composition relative to the rate of environmental change. Together, this framework provides a basis for developing testable predictions about how the rate and degree of microbial adaptation to climate change will alter biogeochemical processes in aquatic and terrestrial ecosystems across the planet.     

宏观生态系统科学整合研究的多学科知识融合及其技术途径

综合认识大尺度的宏观生态系统结构功能、空间变异和动态演变的过程机理和模式机制,实现对生态系统变化及其对人类福祉影响的定量模拟、科学评估和预测预警,服务生态系统的利用保护及调控管理,是当代宏观生态系统科学的重要发展方向,正在孕育并形成大尺度的宏观生态系统科学整合生态学(IEMES)研究新领域。本研究通过对宏观生态系统科学整合生态学研究的基础理论、多学科知识融合途径及其关键技术问题的系统分析,形成以下几个基本认识: 1)宏观生态系统科学整合生态学研究是以区域、大陆和全球尺度的宏观生态系统为研究对象,采用多学科知识融合方法和技术,致力于解决人类社会发展的食物安全、资源安全、生态安全、环境安全等重大资源环境问题。2)宏观生态系统科学整合生态学研究的基本科技任务是: 理解宏观生态系统的结构功能基本属性,监测生态系统状态变化,解释生态系统时空演变规律,认知生态系统运维过程机理,定量评估生态系统功能状态及服务能力,预测生态系统动态演变及地理格局,预警生态系统变化及生态环境灾害。3)宏观生态系统科学整合生态学研究需要重新构造“多源数据分析-多模型模拟-多学科知识融合”的理论和方法学体系,发展“多尺度观测、多方法印证、多过程融合、跨尺度模拟”的多学科知识融合关键技术。4)大陆尺度的地基-空基-天基多时空尺度生态系统观测试验网络是承载多学科知识深度融合研究的基础科技设施,需要围绕区域、大陆和全球尺度的宏观生态系统科学问题,发展多要素-多过程-多界面-多介质-多尺度-多方法的多学科维度生态学知识融合关键技术。     

Integrating microbial ecology into ecosystem models: challenges and priorities

Microbial communities can potentially mediate feedbacks between global change and ecosystem function, owing to their sensitivity to environmental change and their control over critical biogeochemical processes. Numerous ecosystem models have been developed to predict global change effects, but most do not consider microbial mechanisms in detail. In this idea paper, we examine the extent to which incorporation of microbial ecology into ecosystem models improves predictions of carbon (C) dynamics under warming, changes in precipitation regime, and anthropogenic nitrogen (N) enrichment. We focus on three cases in which this approach might be especially valuable: temporal dynamics in microbial responses to environmental change, variation in ecological function within microbial communities, and N effects on microbial activity. Four microbially-based models have addressed these scenarios. In each case, predictions of the microbial-based models differ—sometimes substantially—from comparable conventional models. However, validation and parameterization of model performance is challenging. We recommend that the development of microbial-based models must occur in conjunction with the development of theoretical frameworks that predict the temporal responses of microbial communities, the phylogenetic distribution of microbial functions, and the response of microbes to N enrichment.     

地上枯落物的累积、分解及其在陆地生态系统中的作用

了解陆地生态系统地上枯落物的累积和分解过程对认识它的生态作用、通过管理地上枯落物调控陆地生态系统功能和服务有重要意义。综述了陆地生态系统地上枯落物的积累和分解过程及其影响因素,然后概括了通过这些过程地上枯落物所发挥的生态作用,最后,在全球变化背景下,基于当前研究进展提出陆地生态系统地上枯落物研究的前景。地上枯落物累积在时间尺度上一般遵循植物的生命周期,同时也受环境因子的调控。大的空间尺度上,枯落物累积主要受水热因子控制,伴随植被类型的变化,表现随纬度升高而减少的趋势。然而,在局域尺度内,枯落物累积除受水、热因子限制,还被群落结构、土壤条件、植食动物等因素影响,表现较大变异性。当前,人类干扰作为一个不可忽视的因素,正在强烈甚至不可逆转的改变地表植被覆盖和枯落物累积。地上枯落物的分解过程包括淋溶、光降解、土壤动物和微生物分解,这些过程同时进行并相互影响。尽管目前还不清楚,但区分这些分解过程和分解产物的去向对了解陆地生态系统物质循环有重要意义。枯落物分解首先被自身类型、化学组成、物种多样性决定,同时也受分解者群体、非生物环境影响。其中,枯落物分解与其化学特性、物种多样性及土壤养分状况的关系是研究的热点,也是广泛争议的焦点。通过累积和分解,地上枯落物对陆地生态系统有物理、化学、生物作用。目前,枯落物的物理和化学作用研究较为透彻,而由于受枯落物数量、环境条件、响应植物特征或一些有待挖掘的未知因素的共同限制,地上枯落物的生物作用,尤其对植物的作用在不同研究中仍没有达成普遍的共识。全球变化可能影响地上枯落物累积、分解和生态作用。在全球变化的背景,研究地上枯落物产量和性状变化、阐明枯落物分解的分室模型、继续分析枯落物性状和分解关系、深入揭示枯落物的生态作用及其制约因素,理解和预测地上枯落物数量和质量变化对陆地生态系统功能和服务的影响是必要的。     

Stoichiometric flexibility as a regulator of carbon and nutrient cycling in terrestrial ecosystems under change

Ecosystems across the biosphere are subject to rapid changes in elemental balance and climatic regimes. A major force structuring ecological responses to these perturbations lies in the stoichiometric flexibility of systems - the ability to adjust their elemental balance whilst maintaining function. The potential for stoichiometric flexibility underscores the utility of the application of a framework highlighting the constraints and consequences of elemental mass balance and energy cycling in biological systems to address global change phenomena. Improvement in the modeling of ecological responses to disturbance requires the consideration of the stoichiometric flexibility of systems within and across relevant scales. Although a multitude of global change studies over various spatial and temporal scales exist, the explicit consideration of the role played by stoichiometric flexibility in linking micro-scale to macro-scale biogeochemical processes in terrestrial ecosystems remains relatively unexplored. Focusing on terrestrial systems under change, we discuss the mechanisms by which stoichiometric flexibility might be expressed and connected from organisms to ecosystems. We suggest that the transition from the expression of stoichiometric flexibility within individuals to the community and ecosystem scales is a key mechanism regulating the extent to which environmental perturbation may alter ecosystem carbon and nutrient cycling dynamics.     

Community structure – Ecosystem function relationships in the Congo Basin methane cycle depend on the physiological scale of function

Belowground ecosystem processes can be highly variable and difficult to predict using microbial community data. Here, we argue that this stems from at least three issues: (a) complex covariance structure of samples (with environmental conditions or spatial proximity) can make distinguishing biotic drivers a challenge; (b) communities can control ecosystem processes through multiple mechanisms, making the identification of these controls a challenge; and (c) ecosystem function assessments can be broad in physiological scale, encapsulating multiple processes with unique microbially mediated controls. We test these assertions using methane (CH₄)‐cycling processes in soil samples collected along a wetland‐to‐upland habitat gradient in the Congo Basin. We perform our measurements of function under controlled laboratory conditions and statistically control for environmental covariates to aid in identifying biotic drivers. We divide measurements of microbial communities into four attributes (abundance, activity, composition, and diversity) that represent different forms of community control. Lastly, our process measurements differ in physiological scale, including broader processes (gross methanogenesis and methanotrophy) that involve more mediating groups, to finer processes (hydrogenotrophic methanogenesis and high‐affinity CH₄ oxidation) with fewer mediating groups. We observed that finer scale processes can be more readily predicted from microbial community structure than broader scale processes. In addition, the nature of those relationships differed, with broad processes limited by abundance while fine‐scale processes were associated with diversity and composition. These findings demonstrate the importance of carefully defining the physiological scale of ecosystem function and performing community measurements that represent the range of possible controls on ecosystem processes.     

基于BIOLOG技术分析氮沉降和降水对土壤微生物功能多样性的影响

土壤微生物是有机物分解和养分循环的主要介质,因此在维持土壤的功能多样性和持续性方面发挥着关键作用。气候变化驱动因素会影响土壤微生物的生理活动,引起其群落结构和功能多样性的改变,并对生物地球化学循环和气候―生态系统反馈产生连锁效应,其中氮沉降和降水是全球气候变化的研究热点。土壤氮(N)的有效性有可能通过改变微生物的群落组成以调节微生物对降水变化的响应,但目前关于N沉降和降水及其交互作用对土壤微生物群落功能多样性的影响机制仍不清楚。为了准确预测未来气候条件下生态系统的功能状况,需要更好地了解土壤微生物对环境变化的响应。基于BIOLOG技术综述了氮沉降和降水变化及其交互作用对土壤微生物功能多样性影响的相关研究进展,可以为进一步研究全球气候变化背景下地下生态学的发展提供参考。另外,分析阐述了当前工作中存在的一些主要瓶颈,并对未来的研究热点进行了探讨和展望。     

Investigating the eco-evolutionary response of microbiomes to environmental change

Microorganisms are the primary engines of biogeochemical processes and foundational to the provisioning of ecosystem services to human society. Free-living microbial communities (microbiomes) and their functioning are now known to be highly sensitive to environmental change. Given microorganisms' capacity for rapid evolution, evolutionary processes could play a role in this response. Currently, however, few models of biogeochemical processes explicitly consider how microbial evolution will affect biogeochemical responses to environmental change. Here, we propose a conceptual framework for explicitly integrating evolution into microbiome–functioning relationships. We consider how microbiomes respond simultaneously to environmental change via four interrelated processes that affect overall microbiome functioning (physiological acclimation, demography, dispersal and evolution). Recent evidence in both the laboratory and the field suggests that ecological and evolutionary dynamics occur simultaneously within microbiomes; however, the implications for biogeochemistry under environmental change will depend on the timescales over which these processes contribute to a microbiome's response. Over the long term, evolution may play an increasingly important role for microbially driven biogeochemical responses to environmental change, particularly to conditions without recent historical precedent.     

Environmental paleomicrobiology: using DNA preserved in aquatic sediments to its full potential

In-depth knowledge about spatial and temporal variation in microbial diversity and function is needed for a better understanding of ecological and evolutionary responses to global change. In particular, the study of microbial ancient DNA preserved in sediment archives from lakes and oceans can help us to evaluate the responses of aquatic microbes in the past and make predictions about future biodiversity change in those ecosystems. Recent advances in molecular genetic methods applied to the analysis of historically deposited DNA in sediments have not only allowed the taxonomic identification of past aquatic microbial communities but also enabled tracing their evolution and adaptation to episodic disturbances and gradual environmental change. Nevertheless, some challenges remain for scientists to take full advantage of the rapidly developing field of paleo-genetics, including the limited ability to detect rare taxa and reconstruct complete genomes for evolutionary studies. Here, we provide a brief review of some of the recent advances in the field of environmental paleomicrobiology and discuss remaining challenges related to the application of molecular genetic methods to study microbial diversity, ecology, and evolution in sediment archives. We anticipate that, in the near future, environmental paleomicrobiology will shed new light on the processes of microbial genome evolution and microbial ecosystem responses to quaternary environmental changes at an unprecedented level of detail. This information can, for example, aid geological reconstructions of biogeochemical cycles and predict ecosystem responses to environmental perturbations, including in the context of human-induced global changes.     

Latitudinal patterns of forest ecosystem stability across spatial scales as affected by biodiversity and environmental heterogeneity

Our planet is facing a variety of serious threats from climate change that are unfolding unevenly across the globe. Uncovering the spatial patterns of ecosystem stability is important for predicting the responses of ecological processes and biodiversity patterns to climate change. However, the understanding of the latitudinal pattern of ecosystem stability across scales and of the underlying ecological drivers is still very limited. Accordingly, this study examines the latitudinal patterns of ecosystem stability at the local and regional spatial scale using a natural assembly of forest metacommunities that are distributed over a large temperate forest region, considering a range of potential environmental drivers. We found that the stability of regional communities (regional stability) and asynchronous dynamics among local communities (spatial asynchrony) both decreased with increasing latitude, whereas the stability of local communities (local stability) did not. We tested a series of hypotheses that potentially drive the spatial patterns of ecosystem stability, and found that although the ecological drivers of biodiversity, climatic history, resource conditions, climatic stability, and environmental heterogeneity varied with latitude, latitudinal patterns of ecosystem stability at multiple scales were affected by biodiversity and environmental heterogeneity. In particular, α diversity is positively associated with local stability, while β diversity is positively associated with spatial asynchrony, although both relationships are weak. Our study provides the first evidence that latitudinal patterns of the temporal stability of naturally assembled forest metacommunities across scales are driven by biodiversity and environmental heterogeneity. Our findings suggest that the preservation of plant biodiversity within and between forest communities and the maintenance of heterogeneous landscapes can be crucial to buffer forest ecosystems at higher latitudes from the faster and more intense negative impacts of climate change in the future.     

水分条件变化对土壤微生物的影响及其响应机制研究进展

土壤微生物在维持陆地生态系统服务中扮演着重要的角色.土壤水分条件是影响微生物活性与生态系统功能的重要因素之一,全球气候变化所引起的极端干旱与降雨必将加速土壤水分的剧烈变化.由于不同土壤微生物对干旱胁迫的耐受性不同及其对水分变化的响应差异,使得土壤水分条件变化直接改变了土壤微生物活性与群落结构,进而对微生物介导的关键过程与土壤生态系统功能造成深刻的影响.因此,全面深入地理解水分条件变化下土壤微生物群落的结构变化特征与响应机制具有重要意义.本文在总结土壤水分条件变化对土壤微生物活性(土壤呼吸与酶活性)和微生物群落结构的影响的基础上,进一步阐述了土壤微生物对干旱胁迫与水分条件变化的响应机制和生态学策略,包括: 1)积累胞内溶质、产生胞外聚合物、进入休眠状态等应对干旱胁迫的细胞生理策略;2)微生物之间、微生物与植物之间相关抗逆性基因的转移及土壤微生物群落的功能冗余等应对水分变化的微生物机制.研究水分条件变化下土壤微生物群落结构及生态系统功能之间的内在联系,不仅有助于进一步剖析微生物介导的土壤生态过程,而且能够为今后陆地生态系统对气候变化的响应研究和模型预测提供理论依据.