淡水湖泊生态系统退化驱动因子及修复技术研究进展

目前我国多数淡水湖泊污染、退化问题非常严重,诸多修复技术也已初见成效。影响淡水湖泊生态系统退化的驱动因子众多,既有生物因素也有非生物因素,它们之间相互联系,相互作用,且作用机理错综复杂。首先介绍了淡水湖泊生态系统退化的含义及形式;其次,分析、总结了淡水湖泊生态系统退化的驱动因子,从退化的生态学完整性意义和退化修复的技术手段上看,淡水湖泊生态系统主要受物理、化学和生物三大驱动因子影响,且基本遵循"环境变化-驱动力-压力(阈值)-状态-响应"原理;再次,在厘清湖泊生态系统退化驱动原理的基础上,从淡水湖泊生态系统功能模块和湖泊生态系统修复实践经验总结的角度出发,构建了淡水湖泊生态系统修复模块技术体系,并就湖泊富营养化和湖滨湿地生态系统退化修复的技术进行了讨论和对比;最后,对淡水湖泊生态系统修复的环境变化驱动因子的作用机制、作用途径和修复技术的长效机制等方面进行了展望。     

Assessing the ecological status in species-poor systems: A fish-based index for Mediterranean Rivers (Guadiana River,SW Spain)

The assessment of the ecological status of freshwater ecosystems is a key issue for many international laws such as the Water Framework Directive (WFD) in light of the actual impoverished status of these ecosystems. Different multimetric approaches have been successfully developed in different freshwater environments. However, multimetric indices are difficult to apply to Mediterranean rivers basins, characterized by freshwater fish communities very low in species richness and support a high number of endemics with generalist and opportunistic life strategies. Here we follow a site-specific approach to develop an adaptation of the multimetric procedure usually used in Indices of Biotic Integrity (IBI), resulting in the Index of Community Integrity (ICI). We modeled the presence–absence of 10 native freshwater fish species from the Guadiana River basin using the Assessment of Nearest Neighbor Analyses (ANNA) model, to assess the deviation of the observed and expected community composition at reference condition. ANNA, which is a multi-species model, allowed incorporating in the index some rare species, though not all of them present in the basin. Deviations were transformed into probabilities of belonging to a reference site and species by species measures were then integrated in a final score. The use of presence–absence only data reduces potential errors associated with estimations of species’ abundance and its seasonal changes, which is especially important in Mediterranean environments. The ICI was sensitive to both habitat degradation and the degree of dominance of non-native species within the freshwater fish community (or biotic perturbation), which have been traditionally overlooked in IBIs, but was unresponsive to natural sources of variation. Given the site-specific nature and the simplicity of the index that we propose here, we expect it to be applicable to other Mediterranean basins for which predictive models can be produced.     

Ecosystem Health Assessment in the Pearl River Estuary of China by Considering Ecosystem Coordination

Marine ecosystem is a complex nonlinear system. However, ecosystem health assessment conventionally builds on a linear superposition of changes in ecosystem components and probably fails to evaluate nonlinear interactions among various components. To better reflect the intrinsic interactions and their impacts on ecosystem health, an ecosystem coordination index, defined as the matching level of ecosystem structure/services, is proposed and incorporated into the ecosystem health index for a systematic diagnosis in the Pearl River Estuary, China. The analysis results show that the ecosystem health index over the last three decades decreased from 0.91 to 0.50, indicating deteriorating from healthy to unhealthy status. The health index is 3–16% lower than that calculated using the common method without considering ecosystem coordination. Ecosystem health degradation in the Pearl River Estuary manifested as significant decreases in structure/services and somewhat mismatching among them. Overall, the introduction of coordination in ecosystem health assessment could improve the understanding of the mechanism of marine ecosystem change and facilitate effective restoration of ecosystem health.     

珠江口淇澳岛红树林湿地生态系统健康评价

基于湿地生态系统健康理论和压力-状态-响应模型,以珠江口淇澳岛红树林湿地生态系统为研究对象,构建了红树林湿地生态系统健康评价指标体系,并确定了具体的评价指标、评价标准、指标权重、评价等级和评价方法,对珠江口淇澳岛红树林湿地生态系统健康状况进行了评价.结果表明:2008年,淇澳岛红树林湿地生态系统总健康指数为0.6580,评价等级为Ⅱ级(健康);压力、状态和响应指标的健康指数分别为0.3469、0.8718和0.7554,说明该评价系统存在一定的压力,而状态和响应方面较好.作为省级自然保护区,珠江口淇澳岛红树林湿地生态系统健康水平有待进一步提升.红树林湿地生态系统健康评价研究目前尚不成熟,进一步研究需重点关注针对红树林特征的评价因子筛选、相关数据的长期定位监测、生态系统健康与生态系统功能的定量关系研究等.     

Regional fish community indicators of landscape disturbance to catchments of the conterminous United States

Biological assessments of river conditions are increasingly conducted at regional and continental scales that match the extent of large-scale river management efforts. Multimetric indices composed of biological community indicators are commonly used to assess ecological condition and indices have recently been applied in large regions. Methods for large-scale multimetric index creation emphasize repeatability, comparability across regions, and objective selection of candidate metrics. Here we used an extensive fish dataset to create a large pool of fish community metrics which were screened to create multimetric indices (MMIs) in eight ecoregions covering the conterminous U.S. Candidate metrics were tested for metric range, corrected for natural gradients using boosted regression trees, and then tested for repeatability and sensitivity to landscape disturbance. Temporally stable and repeatable metrics were then evaluated for redundancy and used to compose MMIs for each region. Our MMIs were significantly correlated to independently developed MMIs, accurately reproducing prior index values with moderate to high precision and little bias. Our study demonstrates the utility of boosted regression tree models for correcting metric values for natural abiotic gradients and shows that the order of screening tests has a potentially important influence on metric selection. The resultant regional indices and component metrics provide a basis for assessing condition and testing hypotheses about landscape influences on aquatic ecosystems at a national scale in the US.     

A tiered framework for assessing groundwater ecosystem health

The notion of ecosystem health has been widely adopted in environmental policy, particularly in the management of river systems. Despite this, even a notional understanding of ecosystem health and its assessment in connected aquifer ecosystems remains elusive. In this article, we propose a definition and provide a tiered framework for the assessment of ecosystem health in groundwater. From the literature we identify general attributes of a healthy groundwater ecosystem and from these develop primary (Tier 1) indicators of health. Where Tier 1 benchmarks are exceeded or more detailed assessment is required, we discuss a range of indicators (Tier 2) that may together generate a multimetric index of groundwater health. Our case study using samples from an alluvial aquifer in north-western New South Wales, Australia, demonstrates the utility of both tiers of the framework, and the ability of the approach to separate disturbed and undisturbed sites. The process of multimetric development is simple and our Tier 2 benchmarks determined from limited data. Nevertheless, our framework will be applicable and readily adaptable to site-specific contexts.     

Biodiversity acts as insurance of productivity of bacterial communities under abiotic perturbations

Anthropogenic disturbances are detrimental to the functioning and stability of natural ecosystems. Critical ecosystem processes driven by microbial communities are subjected to these disturbances. Here, we examine the stabilizing role of bacterial diversity on community biomass in the presence of abiotic perturbations such as addition of heavy metals, NaCl and warming. Bacterial communities with a diversity gradient of 1–12 species were subjected to the different treatments, and community biomass (OD₆₀₀) was measured after 24 h. We found that initial species richness and phylogenetic structure impact the biomass of communities. Under abiotic perturbations, the presence of tolerant species in community largely contributed in community biomass production. Bacterial diversity stabilized the biomass across the treatments, and differential response of bacterial species to different perturbations was the key reason behind these effects. The results suggest that biodiversity is crucial for maintaining the stability of ecosystem functioning and acts as ecological insurance under abiotic perturbations. Biodiversity in natural ecosystems may also uphold the ecosystem functioning under anthropogenic disturbance.     

基于PSR的黄河河口区生态系统健康评价

根据压力-状态-响应(PSR)框架模型,从广义上定义河口区生态系统,将河口及毗邻的陆域、海域生态系统作为一个整体,从压力指标、状态指标、响应指标3个方面构建了黄河河口区生态系统健康评价的指标体系,以研究区1991年数据和相关国家标准为基准,2013年代表现况,利用综合指数法(CEI)评价了黄河河口区的生态系统健康状况。结果显示:黄河河口区生态系统健康评价的响应指数最高(0.9055),压力指数居中(0.8288),状态指数最低(0.6458),综合指数为0.7427。总体来看,与1991年相比,目前黄河河口区生态系统仍处于"健康"状态,但健康状况明显下降,其中状态指数下降最为严重。从区域轻度开发到人类活动强烈干扰阶段,黄河河口区存在过度捕捞、湿地不合理开发、浅海养殖过度及污染物排放等一系列影响生态系统健康的问题,应进行区域的生态恢复和科学管理。     

北京市白河和潮河流域生态健康评价

选取北京市重要的饮用水源密云水库上游白河和潮河流域,结合北京山区流域生态现状,构建了涵盖水域生境结构、水生生物、生态压力和陆域生态格局与功能、生态压力5大类13项指标的评价指标体系,开展了流域生态健康评价。结果表明白河和潮河流域的健康状态整体处于良好等级,但水生生物和陆域生态格局状况相对较差。14个子流域的健康状况差异并不显著,琉璃河、白河下段、汤河上游的健康状况相对较好,潮河中下段和小汤河的健康状况相对较差。流域内不合理的畜禽养殖、岸边带种植及民俗旅游是导致流域生态健康退化的主要原因,建议加强污染负荷排放的控制和监管涉水活动对水生生境的干扰以改善流域健康状况,并重点关注可指示水生态系统早期退化的生物指数,以实现可持续性和适应性的流域管理,保障密云水库的水生态安全。     

The Health of Ecology and the Ecology of Health

The health of ecology refers to ecosystem health—an extension of the concept of health to the ecosystem level. Health is reflected in the absence of distress syndrome, and by productivity, organization and resilience that characterize sustainability in the Earth's ecosystems. Transformation of ecosystems under stress from healthy to pathological conditions is often irreversible, even when the initial stress factors are removed. The ecology of health refers to the fact that human health is influenced by ecological conditions. The breakdown of ecosystems under stress are often conducive to an increase in human pathogens, recycling toxic substances, reduced yields and compromised food supplies, scarcity of potable water, and air pollution, all of which increases human health vulnerability. Addressing human health issues from an ecological perspective takes account of the social, ecological, and biophysical determinants. This opens the door to potential interventions “upstream”, in order to prevent illness, in addition to treating the disease once the malady has occurred.     

Insights in the ecology and evolutionary history of the Miscellaneous Crenarchaeotic Group lineage

Members of the archaeal Miscellaneous Crenarchaeotic Group (MCG) are among the most successful microorganisms on the planet. During its evolutionary diversification, this very diverse group has managed to cross the saline–freshwater boundary, one of the most important evolutionary barriers structuring microbial communities. However, the current understanding on the ecological significance of MCG in freshwater habitats is scarce and the evolutionary relationships between freshwater and saline MCG remains poorly known. Here, we carried out molecular phylogenies using publicly available 16S rRNA gene sequences from various geographic locations to investigate the distribution of MCG in freshwater and saline sediments and to evaluate the implications of saline–freshwater transitions during the diversification events. Our approach provided a robust ecological framework in which MCG archaea appeared as a core generalist group in the sediment realm. However, the analysis of the complex intragroup phylogeny of the 21 subgroups currently forming the MCG lineage revealed that distinct evolutionary MCG subgroups have arisen in marine and freshwater sediments suggesting the occurrence of adaptive evolution specific to each habitat. The ancestral state reconstruction analysis indicated that this segregation was mainly due to the occurrence of a few saline–freshwater transition events during the MCG diversification. In addition, a network analysis showed that both saline and freshwater MCG recurrently co-occur with archaea of the class Thermoplasmata in sediment ecosystems, suggesting a potentially relevant trophic connection between the two clades.     

Prey and predator density‐dependent interactions under different water volumes

Predation is a critical ecological process that directly and indirectly mediates population stabilities, as well as ecosystem structure and function. The strength of interactions between predators and prey may be mediated by multiple density dependences concerning numbers of predators and prey. In temporary wetland ecosystems in particular, fluctuating water volumes may alter predation rates through differing search space and prey encounter rates. Using a functional response approach, we examined the influence of predator and prey densities on interaction strengths of the temporary pond specialist copepod Lovenula raynerae preying on cladoceran prey, Daphnia pulex, under contrasting water volumes. Further, using a population dynamic modeling approach, we quantified multiple predator effects across differences in prey density and water volume. Predators exhibited type II functional responses under both water volumes, with significant antagonistic multiple predator effects (i.e., antagonisms) exhibited overall. The strengths of antagonistic interactions were, however, enhanced under reduced water volumes and at intermediate prey densities. These findings indicate important biotic and abiotic contexts that mediate predator–prey dynamics, whereby multiple predator effects are contingent on both prey density and search area characteristics. In particular, reduced search areas (i.e., water volumes) under intermediate prey densities could enhance antagonisms by heightening predator–predator interference effects.     

Non-native fish species are related to the loss of ecological integrity in Neotropical streams: a multimetric approach

Hydrobiologia - The use of multimetric indices (MMIs) became a common practice for evaluating ecological integrity of aquatic ecosystems. However, most developed MMIs ignore non-native species as...     

The ecological importance of crocodylians: towards evidence‐based justification for their conservation

Large‐bodied predators are well represented among the world's threatened and endangered species. A significant body of literature shows that in terrestrial and marine ecosystems large predators can play important roles in ecosystem structure and functioning. By contrast, the ecological roles and importance of large predators within freshwater ecosystems are poorly understood, constraining the design and implementation of optimal conservation strategies for freshwater ecosystems. Conservationists and environmentalists frequently promulgate ecological roles that crocodylians are assumed to fulfil, but often with limited evidence supporting those claims. Here, we review the available information on the ecological importance of crocodylians, a widely distributed group of predominantly freshwater‐dwelling, large‐bodied predators. We synthesise information regarding the role of crocodylians under five criteria within the context of modern ecological concepts: as indicators of ecological health, as ecosystem engineers, apex predators, keystone species, and as contributors to nutrient and energy translocation across ecosystems. Some crocodylians play a role as indicators of ecosystem health, but this is largely untested across the order Crocodylia. By contrast, the role of crocodylian activities in ecosystem engineering is largely anecdotal, and information supporting their assumed role as apex predators is currently limited to only a few species. Whether crocodylians contribute significantly to nutrient and energy translocation through cross‐ecosystem movements is unknown. We conclude that most claims regarding the importance of crocodylians as apex predators, keystone species, ecosystem engineers, and as contributors to nutrient and energy translocation across ecosystems are mostly unsubstantiated speculation, drawn from anecdotal observations made during research carried out primarily for other purposes. There is a paucity of biological research targeted directly at: understanding population dynamics; trophic interactions within their ecological communities; and quantifying the short‐ and long‐term ecological impacts of crocodylian population declines, extirpations, and recoveries. Conservation practices ideally need evidence‐based planning, decision making and justification. Addressing the knowledge gaps identified here will be important for achieving effective conservation of crocodylians.     

生态系统退化程度诊断：生态恢复的基础与前提

 生态系统退化程度诊断是进行生态恢复与重建的基础和前提。然而目前的生态系统化程度诊断大多停留在定性的水平,如何对退化生态系统的退化程度进行定量的诊断就成为恢复生态学与生态恢复实践所面临的一个迫切且十分关键的问题。在综述前人研究的基础上,比较系统地论述了生态系统退化程度诊断的一系列问题：绘制了描述生态系统退化程度的概念模型;认为在实践中退化程度诊断的参照系统可以选择相应的受人类或自然干扰程度比较轻的“自然生态系统”;归纳了生态系统退化程度诊断的生物途径、生境途径、生态过程途径、生态系统功能/服务途径、景观途径;把诊断方法分为单途径单因子诊断法、单途径多因子诊断法、多途径综合诊断法;分析了生态系统退化程度诊断的可能指标（体系）;给出了生态系统退化程度诊断的策略与流程,并对生态系统退化程度诊断及生态恢复过程中应注意的事项进行了讨论。建议我国加强典型生态系统退化程度的综合诊断研究。     

Uncertainties in biotic indicators and a corrigendum to : Implications for biomonitoring

Many bioindicators based on species composition have been proposed during the past 30 years in both terrestrial and freshwater ecosystems. Kelly (2011) raised the need to better communicate the usefulness and meaning of the indices and their uncertainties. A survey of European bioindicators of freshwater ecosystems has recently highlighted that most indices have not even considered uncertainties. While recording errors have sometimes been taken into account into the calculation of index uncertainties, the reliability of biotic indices in terms of causality and predictability between a given environmental pressure and bioindicator response have seldom been considered. This has led to serious misunderstanding of what bioindicators may be able to achieve. Here a correction to Ponader et al. (2007) is presented showing that the tolerance (ecological niche) of individual species of diatoms along nutrient enrichment gradients is much wider than formerly presented. The correction, together with the comments by Kelly (2011) and recent whole ecosystem experiments seriously question the reliability of diatoms as nutrient indicators, similarly to recent findings with aquatic macrophytes. A more mechanistic basis for biomonitoring is needed based on current ecological science, rather than early 20th century community ecology.     

区县尺度下的河流生态系统健康评价——以北京房山区为例

伴随郊区城市化的快速发展,高强度人工管控对河流生态系统产生持续胁迫作用,河流生态系统健康受到严重威胁甚至损害。以北京房山区河流水系为例,于2016—2017年在区域内的31处样点进行野外调查。选取河流的水环境功能、防洪效益功能、生态效益功能和支持利用功能4方面16个具体评价指标,并通过层次分析法计算权重,构建区县尺度下的河流生态系统健康评价指标体系,并进行健康状况评价。结果表明:房山区河流的防洪效益功能与生态效益功能中"健康与亚健康"状态比例分别为58.0%与41.9%,而水环境功能与和支持利用功能中"较差与差"状态比例为71.0%与41.9%;河流生态系统健康整体水平较差,勉强满足河流生态系统一般需求。同时,房山区境内的拒马河与小清河的河流生态系统健康状态远优于大石河与永定河。河流生态基流是影响河流生态系统健康的关键因素,适当释放库区截留水量与调配区外清洁水体,已成为恢复房山区河流生态系统健康的前提与基础。     

Linking Water Quality and Quantity in Environmental Flow Assessment in Deteriorated Ecosystems: A Food Web View

Most rivers worldwide are highly regulated by anthropogenic activities through flow regulation and water pollution. Environmental flow regulation is used to reduce the effects of anthropogenic activities on aquatic ecosystems. Formulating flow alteration–ecological response relationships is a key factor in environmental flow assessment. Traditional environmental flow models are characterized by natural relationships between flow regimes and ecosystem factors. However, food webs are often altered from natural states, which disturb environmental flow assessment in such ecosystems. In ecosystems deteriorated by heavy anthropogenic activities, the effects of environmental flow regulation on species are difficult to assess with current modeling approaches. Environmental flow management compels the development of tools that link flow regimes and food webs in an ecosystem. Food web approaches are more suitable for the task because they are more adaptive for disordered multiple species in a food web deteriorated by anthropogenic activities. This paper presents a global method of environmental flow assessment in deteriorated aquatic ecosystems. Linkages between flow regimes and food web dynamics are modeled by incorporating multiple species into an ecosystem to explore ecosystem-based environmental flow management. The approach allows scientists and water resources managers to analyze environmental flows in deteriorated ecosystems in an ecosystem-based way.     

A stressor specific multimetric approach for monitoring running waters in Austria using benthic macro-invertebrates

We investigated four stream types in four different bioregions, classified by catchment area and altitude, and stressed by different degrees of organic pollution and habitat alteration. We examined a macro-invertebrate based multimetric approach for Austrian rivers as a potential assessment method within the European Water Framework Directive. Benthic macro-invertebrate data (100 samples including reference sites) were used to develop a multimetric index for each stream type and targeted stressors. Sites were pre-classified based on physical, chemical, and land use criteria into five ecological quality classes. More than 200 biological metrics were tested for their sensitivity to the targeted stressors, their spatial and temporal variability and their ability to discriminate between different types and degrees of stress. Metrics for index development were selected to reflect different levels of information including ecosystem, community, and individual levels (Karr, 1991; Barbour et al., 1995; Gerritsen, 1995). Combinations of metrics were selected to distinguish best between non or slightly impaired and stressed sites (evaluated by calculating discrimination efficiency values and power analysis). The resulting four indices comprised seven to nine metrics from five to seven metric categories, and distinguished reference/slightly disturbed sites from stressed sites with close to 100% efficiency. The indices can form the basis for stressor-specific assessment of stream condition.