缺氧胁迫及对贝类免疫系统的影响

人为压力源的强度和多样性日益增加已引发全球海洋生态系统中栖息地和生物多样性丧失。与全球变暖、海洋酸化类似,海域缺氧现象的频发使得缺氧现象成为重要的全球压力源。本文以贝类为研究对象,综述了缺氧的定义和等级、缺氧的原因,并集中探讨了缺氧胁迫对贝类免疫系统的影响,以期为贝类养殖和病害防治提供理论依据,并为我国贝类产业能够及时应对未来环境变化提供参考资料。     

Food-web interactions govern the resistance of communities after non-random extinctions

Growing concern about how loss of biodiversity will affect ecosystems has stimulated numerous studies. Although most studies have assumed that species go extinct randomly, species often go extinct in order of their sensitivity to a stress that intensifies through time (such as climate change). Here we show that the consequences of random and ordered extinctions differ. Both depend on food-web interactions that create compensation; that is, the increase of some species when their competitors and/or predators decrease in density due to environmental stress. Compensation makes communities as a whole more resistant to stress by reducing changes in combined species densities. As extinctions progress, the potential for compensation is depleted, and communities become progressively less resistant. For ordered extinctions, however, this depletion is offset and communities retain their resistance, because the surviving species have greater average resistance to the stress. Despite extinctions being ordered, changes in the food web with successive extinctions make it difficult to predict which species will show compensation in the future. This unpredictability argues for 'whole-ecosystem' approaches to biodiversity conservation, as seemingly insignificant species may become important after other species go extinct.     

Neutral metacommunity models predict fish diversity patterns in Mississippi-Missouri basin

River networks, seen as ecological corridors featuring connected and hierarchical dendritic landscapes for animals and plants, present unique challenges and opportunities for testing biogeographical theories and macroecological laws. Although local and basin-scale differences in riverine fish diversity have been analysed as functions of energy availability and habitat heterogeneity, scale-dependent environmental conditions and river discharge, a model that predicts a comprehensive set of system-wide diversity patterns has been hard to find. Here we show that fish diversity patterns throughout the Mississippi-Missouri River System are well described by a neutral metacommunity model coupled with an appropriate habitat capacity distribution and dispersal kernel. River network structure acts as an effective template for characterizing spatial attributes of fish biodiversity. We show that estimates of average dispersal behaviour and habitat capacities, objectively calculated from average runoff production, yield reliable predictions of large-scale spatial biodiversity patterns in riverine systems. The success of the neutral theory in two-dimensional forest ecosystems and here in dendritic riverine ecosystems suggests the possible application of neutral metacommunity models in a diverse suite of ecosystems. This framework offers direct linkage from large-scale forcing, such as global climate change, to biodiversity patterns.     

A global synthesis reveals biodiversity loss as a major driver of ecosystem change

Evidence is mounting that extinctions are altering key processes important to the productivity and sustainability of Earth's ecosystems. Further species loss will accelerate change in ecosystem processes, but it is unclear how these effects compare to the direct effects of other forms of environmental change that are both driving diversity loss and altering ecosystem function. Here we use a suite of meta-analyses of published data to show that the effects of species loss on productivity and decomposition--two processes important in all ecosystems--are of comparable magnitude to the effects of many other global environmental changes. In experiments, intermediate levels of species loss (21-40%) reduced plant production by 5-10%, comparable to previously documented effects of ultraviolet radiation and climate warming. Higher levels of extinction (41-60%) had effects rivalling those of ozone, acidification, elevated CO(2) and nutrient pollution. At intermediate levels, species loss generally had equal or greater effects on decomposition than did elevated CO(2) and nitrogen addition. The identity of species lost also had a large effect on changes in productivity and decomposition, generating a wide range of plausible outcomes for extinction. Despite the need for more studies on interactive effects of diversity loss and environmental changes, our analyses clearly show that the ecosystem consequences of local species loss are as quantitatively significant as the direct effects of several global change stressors that have mobilized major international concern and remediation efforts.     

陇东黄土高原地区生态系统格局变化及驱动力分析

利用地理信息与生态遥感解译技术,对2013至2018年陇东黄土高原生物多样性保护优先区域生态系统格局变化特征进行定量分析.结果表明:研究区生态系统结构较为简单,主要以森林-灌丛、草地、农田3种Ⅰ级生态系统和落叶阔叶林、落叶阔叶灌丛、温性草原、草丛、旱地5种Ⅱ级生态系统为主;研究期内各类生态系统面积变化率、综合动态度和景...     

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.     

国际海洋生态系统研究态势及对我国的启示

利用文献计量学方法分析了国际海洋生态系统研究的主要国家和机构状况,分析了近年来相关研究计划的主要内容,给出国际海洋生态系统研究的9个研究热点：全球气候变化对生态系统的影响研究;海洋生态系统服务功能;人类社会与海洋生态系统的关系研究;海洋生物多样性;基于生态系统的海洋管理;海洋生态系统保护;深海生态系统研究;海洋生态系统研究相关技术、模型;极地生态系统考察。最后给出对我国海洋生态系统研究的7条建议。     

内蒙古中部地区土地利用变化区域差异分析

采用地理信息系统(GIS)空间叠加的分析方法以及数理统计方法,选择土地利用变化类型面积比和土地利用变化类型重要值2个指标,分析了内蒙古中部地区不同自然生态区土地利用变化空间分布特征.其结果表明:土地利用类型之间的相互转化在很大程度上受自然条件的限制,土地利用转化类型的面积比沿着干旱半干旱半湿润的梯度逐渐变化;土地利用变化的方向总体上是耕地和草地之间的相互转化,同时大量的草地转化为其他用地也是一个值得关注的问题.     

Bioturbators enhance ecosystem function through complex biogeochemical interactions

Predicting the consequences of species loss is critically important, given present threats to biological diversity such as habitat destruction, overharvesting and climate change. Several empirical studies have reported decreased ecosystem performance (for example, primary productivity) coincident with decreased biodiversity, although the relative influence of biotic effects and confounding abiotic factors has been vigorously debated. Whereas several investigations focused on single trophic levels (for example, grassland plants), studies of whole systems have revealed multiple layers of feedbacks, hidden drivers and emergent properties, making the consequences of species loss more difficult to predict. Here we report functionally important organisms and considerable biocomplexity in a sedimentary seafloor habitat, one of Earth's most widespread ecosystems. Experimental field measurements demonstrate how the abundance of spatangoid urchins--infaunal (in seafloor sediment) grazers/deposit feeders--is positively related to primary production, as their activities change nutrient fluxes and improve conditions for production by microphytobenthos (sedimentatry microbes and unicellular algae). Declines of spatangoid urchins after trawling are well documented, and our research linking these bioturbators to important benthic-pelagic fluxes highlights potential ramifications for productivity in coastal oceans.     

"植物-土壤"相互反馈的关键生态学问题:格局、过程与机制

植物与土壤之间相互反馈的格局、过程与机制,不但是决定生态系统结构、功能及过程的关键科学问题,而且是陆地生态系统响应全球变化的重要组成部分。基于目前国内外研究现状,从养分循环角度剖析“植物-土壤”间的反馈效应,探明相互反馈在空间尺度(根面、根际、种类、生态系统以及区域等)与时间尺度(秒至千年)上的级联效应及其变化格局;阐明根际、植物种类、生态系统及区域地理等水平上“植物-土壤”的相互反馈机制,重点揭示根系分泌、共生、生长及代谢的根际界面过程对植物水分/养分吸收与土壤物理学修饰的调控机制,剖析“植物种类-凋落物化学-土壤生物-土壤有机质”相互作用对地上-地下养分循环过程的驱动机制,运用“上行-下行控制理论及腐屑食物网模型”揭示地上-地下生物群落交互作用的过程与机制,以及土壤地质演变(岩石风化模式、土壤形成模式及土壤养分格局的变化)与区域植被演替(优势种更替及植被分布模式、地上-地下凋落物输入格局等的变化)相互反馈的过程与机制;从“植物-土壤”相互反馈的理论视角,分析生态退化与恢复、外来物种生态入侵、大气氮沉降、二氧化碳浓度升高以及植物多样性减少等全球生态问题的特征、形成机制以及可能的应对策略,揭示生态系统“地上-地下”相互反馈的生态学过程,以及陆地生态系统对全球生态环境变化的响应特征与机理。     

Future projections for Mexican faunas under global climate change scenarios

Global climates are changing rapidly, with unexpected consequences. Because elements of biodiversity respond intimately to climate as an important driving force of distributional limitation, distributional shifts and biodiversity losses are expected. Nevertheless, in spite of modelling efforts focused on single species or entire ecosystems, a few preliminary surveys of fauna-wide effects, and evidence of climate change-mediated shifts in several species, the likely effects of climate change on species' distributions remain little known, and fauna-wide or community-level effects are almost completely unexplored. Here, using a genetic algorithm and museum specimen occurrence data, we develop ecological niche models for 1,870 species occurring in Mexico and project them onto two climate surfaces modelled for 2055. Although extinctions and drastic range reductions are predicted to be relatively few, species turnover in some local communities is predicted to be high (>40% of species), suggesting that severe ecological perturbations may result.     

Primary forests are irreplaceable for sustaining tropical biodiversity

Human-driven land-use changes increasingly threaten biodiversity, particularly in tropical forests where both species diversity and human pressures on natural environments are high. The rapid conversion of tropical forests for agriculture, timber production and other uses has generated vast, human-dominated landscapes with potentially dire consequences for tropical biodiversity. Today, few truly undisturbed tropical forests exist, whereas those degraded by repeated logging and fires, as well as secondary and plantation forests, are rapidly expanding. Here we provide a global assessment of the impact of disturbance and land conversion on biodiversity in tropical forests using a meta-analysis of 138 studies. We analysed 2,220 pairwise comparisons of biodiversity values in primary forests (with little or no human disturbance) and disturbed forests. We found that biodiversity values were substantially lower in degraded forests, but that this varied considerably by geographic region, taxonomic group, ecological metric and disturbance type. Even after partly accounting for confounding colonization and succession effects due to the composition of surrounding habitats, isolation and time since disturbance, we find that most forms of forest degradation have an overwhelmingly detrimental effect on tropical biodiversity. Our results clearly indicate that when it comes to maintaining tropical biodiversity, there is no substitute for primary forests.     

气候变化对森林生态系统的主要影响述评

森林生态系统是陆地生态系统的主体,其对减少大气中的CO₂浓度从而减缓全球变暖有着决定性的作用。为了探究气候变化对森林生态系统的影响以及森林生态系统的反馈机制,发展合理的森林经营策略以应对气候变化,笔者综述了国内外有关气候变化对森林生态系统影响的相关研究方法与成果,重点讨论了气候变化对森林结构、组成和分布、森林生产力、森林碳库、森林生态系统生物多样性、生态系统生态服务功能等方面的影响,论述了森林生态系统对气候变化的反馈机制,并指出了现有研究的不足之处,提出了适应或者减缓气候变化对森林生态系统影响的森林经营策略,主要包括:①坚决贯彻实施退耕还林政策; ②加强保护天然林; ③制定科学的森林经营对策; ④加速我国碳汇林业的发展。     

气候变化对森林的影响与多尺度适应性管理研究进展

森林作为陆地生态系统的主体和全球气候系统的重要组成部分,对调节全球碳平衡和减缓气候变化具有不可替代的作用。目前的研究表明,气候变化已经对全球各类森林产生了不同程度的影响,而且全球气候变暖的加剧将对森林产生毁灭性的影响。森林管理是一项缓解气候变化影响的关键因子,为应对全球气候变化,森林经营管理必须做出相应的调整以适应和减轻气候变化的消极影响。本文系统总结了全球气候变化对森林及树木分布、生理生态和物候、森林生产力、碳循环、生物多样性、森林水文、森林灾害等产生的现实和潜在的影响,并针对气候变化下的可能影响,从基因、物种、森林生态系统、流域和生物圈多个尺度阐述了适应性管理的对策,以提高各生命系统适应气候变化的能力,实现森林的可持续经营和生物圈的可持续发展。     

Biodiversity improves water quality through niche partitioning

Excessive nutrient loading of water bodies is a leading cause of water pollution worldwide, and controlling nutrient levels in watersheds is a primary objective of most environmental policy. Over the past two decades, much research has shown that ecosystems with more species are more efficient at removing nutrients from soil and water than are ecosystems with fewer species. This has led some to suggest that conservation of biodiversity might be a useful tool for managing nutrient uptake and storage, but this suggestion has been controversial, in part because the specific biological mechanisms by which species diversity influences nutrient uptake have not been identified. Here I use a model system of stream biofilms to show that niche partitioning among species of algae can increase the uptake and storage of nitrate, a nutrient pollutant of global concern. I manipulated the number of species of algae growing in the biofilms of 150 stream mesocosms that had been set up to mimic the variety of flow habitats and disturbance regimes that are typical of natural streams. Nitrogen uptake rates, as measured by using (15)N-labelled nitrate, increased linearly with species richness and were driven by niche differences among species. As different forms of algae came to dominate each unique habitat in a stream, the more diverse communities achieved a higher biomass and greater (15)N uptake. When these niche opportunities were experimentally removed by making all of the habitats in a stream uniform, diversity did not influence nitrogen uptake, and biofilms collapsed to a single dominant species. These results provide direct evidence that communities with more species take greater advantage of the niche opportunities in an environment, and this allows diverse systems to capture a greater proportion of biologically available resources such as nitrogen. One implication is that biodiversity may help to buffer natural ecosystems against the ecological impacts of nutrient pollution.     

Elevated CO2 increases productivity and invasive species success in an arid ecosystem

Arid ecosystems, which occupy about 20% of the earth's terrestrial surface area, have been predicted to be one of the most responsive ecosystem types to elevated atmospheric CO2 and associated global climate change. Here we show, using free-air CO2 enrichment (FACE) technology in an intact Mojave Desert ecosystem, that new shoot production of a dominant perennial shrub is doubled by a 50% increase in atmospheric CO2 concentration in a high rainfall year. However, elevated CO2 does not enhance production in a drought year. We also found that above-ground production and seed rain of an invasive annual grass increases more at elevated CO2 than in several species of native annuals. Consequently, elevated CO2 might enhance the long-term success and dominance of exotic annual grasses in the region. This shift in species composition in favour of exotic annual grasses, driven by global change, has the potential to accelerate the fire cycle, reduce biodiversity and alter ecosystem function in the deserts of western North America.     

试论气候变化对中国生态、经济发展的影响

随着社会经济的发展和科学技术的进步,气候变暖的现实已对人类社会和自然生态系统构成了严重的威胁。世界经济的迅速发展和社会的进步,向大气排放的有害物质及化石能源消耗与日俱增,带来了日益严重的环境问题,导致全球平均气温逐年升高。中国是一个发展中国家,从能源方面入手采取减缓全球气候变化的措施,促进我国的能源利用水平,推进我国能源优质化的进程,加快我国实现经济增长方式从粗放型向集约型的根本性转变。     

土壤生态学研究前沿

土壤生态学以土壤生态系统为研究对象,主要探讨土壤生物多样性及其生态功能,以及土壤生物与环境之间的相互作用.综述了土壤生态学的主要研究方向与研究内容,介绍了当下大尺度土壤微生物地理分布格局研究、土壤生物互作与土壤食物网、土壤生物组与土壤健康和新型土壤污染等研究领域的前沿热点,并对未来研究方向进行了展望.土壤生态学研究有助...     

全球变化研究的新内容与方向

随着对全球变化研究的深入，全球变化已不仅仅局限在全球气候变化上，内容已扩展到全球人口增长、大气成分变化、养分生物地球化学循环变化，土地利用和覆盖的改变及生物多样性的丧失等方面，未来全球变化研究将重点放在全球变化对生物多样性的影响，生态系统中CO2浓度升高，营养、温度、水分变化对生态过程的影响，景观水平上的研究以及人类决定的反馈生态学等方面。     

Issues and prospects of belowground ecology with special reference to global climate change

The theory of ecology is based on over 100 a of research and investigation, all centered on aboveground patterns and processes. However, as contemporary ecologists are increasingly acknowledging, belowground structures, functions, and processes are some of the most poorly understood areas in ecology. This lack of understanding of belowground ecological processes seriously restricts the advance of global change research. The interdisciplinary field of belowground ecology began to flourish in the 1990s, along with the expansion of global change research, and quickly gained momentum. Belowground ecology aims to investigate belowground structures, functions, and processes, as well as their relationships with corresponding aboveground features, emphasizing the responses of belowground systems under global change conditions. Key research areas include root ecology, belowground animals, and soil microorganisms. This review summarizes and analyzes the relationships between aboveand belowground ecosystems, root ecology, root biogeography, belowground biodiversity, as well as research areas with particular challenges and progress. This commentary emphasizes certain theoretical issues concerning the responses of belowground processes to global change, and concludes that belowground ecology is a critical research priority in the 21st century.