Probing ecosystem health: a multi-disciplinary and multi-trophic assay strategy

The ecosystem health of stressed environments in the Great Lakes has been evaluated simultaneously by means of a battery of structural and functional tests based on current technology and involving various trophic levels. These tests attempt to assess ecosystem health at the organism level and simultaneously focus on water-borne and sediment-bound toxicities. The use of structural indicators has been successfully demonstrated. Similarly, functional tests were selectively chosen across various trophic levels and included size-fractionated primary productivity (filtered versus unfiltered assays), and Colpidium, Daphnia, Hyalella, and Pontoporeia assays. Some of the emerging techniques such as in situ plankton cages (I.P.C.), microcomputer-based chlorophyll fluorescence (Video Analysis System), and other assays are discussed. The multi-trophic and multi-disciplinary battery of tests followed in our laboratory adopts a field-to-laboratory approach. The availability of diverse bioassays have placed toxicologists and environmentalists in a position where they are now better equipped to probe the complexities of ecosystem health and its management.Dedicated to the memory of my mother who was a great teacher, guide and an incredible source of inspiration.     

生物完整性指数与水生态系统健康评价

生物完整性指数是目前水生态系统健康评价中应用最广泛的一个生态指标。本文扼要介绍了生物完整性指数的概念、水生态系统健康评价的原理以及大型底栖无脊椎动物完整性指数的构建方法,介绍了生物完整性指数在水生态系统健康评价中的应用及我国开展这方面工作的建议。     

From aquatic science to ecosystem health: a philosophical perspective

The development of an ecosystem (social, economic, environmental) approach to water management is traced from its origins in the Great Lakes of North America. The focus on health and integrity of ecosystems is an outgrowth of the Lamarckian concept of The Biosphere as a global system of matter, life, and mind. The driving forces behind the development of an ecosystem approach have been negative feedback from excessive demotechnic growth and faith that we can maintain a healthy relationship with Mother Earth.     

Initiating and promoting the aquatic ecosystem health concept: the Society and the Journal

Since the 1970's the management of aquatic habitats has changed from piecemeal monitoring to the ecosystem approach; this was initiated in the North American Great Lakes, comprising social, economic, and environmental aspects. The information included in this paper is based on the presentation made at the Seminar On Ecosystem Approach To Water Management held in Oslo, Norway during 1991. Recently, the multidisciplinary, holistic, and integrated concept of ecosystem health has emerged, and is being advanced for the implementation of an ecosystem approach to environmental management, which has resulted in the formation of an international society (Aquatic Ecosystem Health & Management Society) and the publication of a primary journal (Journal of Aquatic Ecosystem Health). The information has been updated to incorporate new developments and recent progress about the Society and the journal since the Oslo Seminar.     

Australian water quality guidelines: a new approach for protecting ecosystem health

The Australian and New Zealand Environment and Conservation Council (ANZECC) and the Australian Water Resources Council (AWRC) have developed a National Water Quality Management Strategy which seeks to ensure that the nation's water resources are managed on a sustainable basis. An important element of this strategy are the Australian Water Quality Guidelines which focus on the protection of Australian freshwater and marine ecosystems. Here the aim is to protect biodiversity and maintain the ecological integrity of each marine and freshwater resource. Specific guidelines have been formulated in terms of key indicators of quality, with a single reference value or ranges of reference values provided for guidance. For those indicators where ranges are provided, it is the expectation that State environmental and resource management agencies will undertake local, site-specific investigations of their own systems to define the specific levels to be adopted. For the first time, specific and quantitative biological indicators have been introduced; these are species richness, species composition, primary production, and ecosystem function.As Australia progresses towards broader, more holistic, ecologically-based management of the nation's water resources, the present water quality guidelines must be extended to ecosystem or environmental guidelines, where the maintenance of adequate water quality is seen as only one (albeit important) component. Other considerations must include habitat protection, sediment quality, and stream flow maintenance. This increased emphasis on more ecologically-focused management of Australia's inland and coastal waters will present a number of challenges for the three major groups involved: the community, the managers, and the researchers. These challenges are discussed.Based on a paper presented at a Workshop on Biological Assessment of Aquatic Ecosystem Health, Sydney, 1–2 October 1992.     

Assessing the impact of sewage effluent on the ecosystem health of the Toronto Waterfront (Ashbridges Bay), Lake Ontario

The ecosystem health of the Toronto Waterfront (Ashbridges Bay), Lake Ontario which receives treated sewage effluent was investigated during 1987 and 1988 by means of a functional and structural battery of tests. The functional tests included in situ size-fractionated primary productivity, Algal Fractionation Bioassays (AFBs), unfiltered and filtered bioassays, and sediment assays with Daphnia magna and Hyalella azteca. The structural evaluation involved the biomonitoring of the components of the microbial loop, such as bacteria, autotrophic picoplankton, heterotrophic nanoflagellates, and protozoa. The experimental results reveal a diversity of physiological responses to the complex nutrient and contaminant regimes by the indigenous phytoplankton. There was no evidence of the impact of chlorination on the primary productivity of the Bay. The overall productivity was higher during the post-chlorination period than the pre-chlorination phase. The high rates of microplankton + netplankton productivity near the outfall have been attributed to the bioavailability of nutrients which, quite possibly, exert ameliorating effects on metal toxicity. In contrast, the low ultraplankton rates have been interpreted to be due to their well-known sensitivity to contaminants. The Effluent Receiving Water Bioassays (ERWB) with filtered and unfiltered experiments provided interesting insight and appear to be a potentially useful assessment tool. Generally, the unfiltered water compared to the filtered was toxic to the offshore test phytoplankton. This demonstrates a unique ecological adaptation to the prevailing in situ conditions by the Bay community which might be important from the restoration point of view. However, the offshore population was found to be sensitive to the particulate-bound toxicity as indicated by the unfiltered bioassays. Consequently, it is essential to probe the complexity of nutrient-contaminant interactions which ultimately appear to determine the toxicity and the resulting health of the biota. Furthermore, our experiments have shown that the particulate-matter is an important carrier of both nutrients and contaminants in Ashbridges Bay. The sediment bioassays for Station 419 indicated that sediments were toxic during both the pre- and post-chlorination phases. Both solid and liquid phase testing indicated toxicity of sediment to the acute Daphnia test. The Hyalella chronic assay showed good survival during the 4-wk period of the experiment, in contrast to the toxicity observed for phytoplankton and Daphnia. This may be due to large mounts of organic matter available in the Bay. The invertebrate bioassays confirmed the lack of impact of chlorination. Finally, the microbial loop seems to be a sensitive, rapid, and an early warning bioindicator of anthropogenic stress. The multi-trophic battery of structural and functional strategy adopted in our laboratory appear to be holistic and effective. The strategy has a considerable potential for developing eco-technology for a badly needed assessment and restoration of ecosystem health of the Great Lakes as well as other perturbed environments in the world.     

Recovery in aquatic ecosystems: an overview of knowledge and needs

This article summarizes the views of scientists asked to address some of the critical unanswered questions concerning recovery in aquatic systems. Spatial and temporal variability were emphasized because of their implications for our abilities to distinguish between recovered and non-recovered ecosystems and the consequent effects such variability has on the statistical precision of developed recovery metrics. There was also consensus that pre-disturbance ecosystem states may not be re-established in the absence of a disturbance event and that better data sets will be required to separate the influences of natural variability from disturbance event induced fluctuations in many biological measures. Although discussions tended to focus at the population or community level, evidence from physiological-based measures of recovery indicates divergent rates of recovery at varying levels of biological organization, a fact which suggests a role for biomarkers in developing a complete understanding of recovery. Critical questions concerning the determination and understanding of recovery that remain to be answered are identified. This revised version was published online in July 2006 with corrections to the Cover Date.     

River bacteria time series analysis: a field and laboratory study which demonstrates aquatic ecosystem health

Time series analysis of heterotrophic baeterial viable counts on agar plates incubated at 20° and 4°C from weekly river water samples for 1 year has revealed a periodicity of 6 to 7 weeks in the total numbers. A cycle of increase and decrease in the counts which could not be attributed to season, river water temperature, pH, and flow rate has been observed in the heterotrophic bacteria which were isolated from river water samples. Spectral analysis has demonstrated a hidden periodicity in population increase and decrease which could not be detected by examination of the raw count data. Fluctuations with periodicity could imply that this is the expected behaviour in a well-balanced ecosystem. Pseudomonas fluorescens, the predominant species isolated from a river water sample which was at 0°C at the time of sampling, utilized two different pathways at 5° and 30°C. In addition, 2-ketogluconate, a product of the utilization of glucose, was utilized by the same organism. Fluctuations in enzymic responses could contribute to the overall periodicity in bacterial numbers. The flexibility in bacterial metabolism would serve to maintain P. fluorescens in the predominant flora. A feature which sustains health in this ecosystem, P. fluorescens, is one of the most successful of all biodegraders in the aquatic system.     

Evaluating ecosystem health

In the past decade, metaphors drawn from human health are finding increasing application in environmental assessment at ecosystem levels. If ecosystem medicine is to come of age, it must cope with three fundamental dilemmas. The first stems from the recognition that there are no strictly objective criteria for judging health. Assessments of health, as in humans, inevitably are based on some combination of established norms and desirable attributes. The second stems from the irregular pulse of nature which either precludes the early recognition of substantive changes or gives rise to false alarms. The third is posed by the quest for indicators that have the attributes of being holistic, early warning, and diagnostic. Indicators that excel in one of these aspects, often fail in another.Advances in ecosystem medicine are likely to come from closer collaboration with medical colleagues in both clinical and epidemiological areas. In particular the time appears ripe for a more systematic effort to characterize ecosystem maladies, to validate treatments and to develop more sophisticated diagnostic protocols. These aspects are illustrated with comparisons drawn from studies of environmental transformation in the Laurentian Great Lakes, the Baltic Sea and Canadian terrestrial ecosystems.Dedicated to Prof. J. Stan Rowe whose pioneering work in formulating a holistic perspective on ecosystem health has substantially contributed to the development of these ideas.     

河流生态系统健康及其评价

概括了河流生态系统健康概念的涵义,详细介绍了以着重藻类、无脊椎动物、鱼类为主要指示生物的河流生态系统健康的评价方法,并就其评价管理将这些方法分为预测模型法（predictive models）和多指标法（multimetrics两大类,提出了河流健康评价方法的发展方向,以及我国应尽快开展的研究工作。     

森林生态系统健康及其评估监测

介绍了森林生态系统健康的概念及其内涵 ,并主要从管理目标途径、生态系统途径和综合途径等方面对森林生态系统健康进行了探讨 ,分析了已有的森林生态系统健康评估的思想和方法 .生态指示者的广泛应用是目前森林生态系统健康评估监测的主要手段 .此外 ,文中还综合介绍了森林生态系统健康评估方法 ,特别是详细介绍了EMAP和FHM等研究计划 ,以期对我国目前的森林生态系统健康研究有所借鉴     

The ecosystem approach to environmental assessment: moving from theory to practice

The ecosystem approach to environmental management is viewed by many as being fundamental to the development of appropriate management strategies. While this approach represents a major advance in the way researchers view environmental assessment, the approach in itself does not provide practical information as to what questions to ask and what tools to use in assessing and managing ecosystems. Similarly, the concept of ecosystem health, as it is usually defined, has little practical value for ecosystem managers. We suggest the next stage in environmental assessment will be the development of specific frameworks designed to assess individual ecosystems. Of primary importance is the need to consider the basic structure and function of the ecosystem itself. Such consideration, together with explicit identification of anthropogenic stresses particular to the system, serves to identify those components most at risk and those issues most deserving of attention. Researchers should explore critical linkages between environmental stressors and their observable, measurable and predictable effects on ecological parameters and use this understanding to develop a management strategy that incorporates appropriate ecological indicators. The importance of these considerations will be illustrated using examples from the Northern River Basins Study.     

Fisheries in the Southern Ocean: an ecosystem approach

The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is bound by its Article II, 3 to follow an ecosystem approach to management. This approach has been extended to the application of a precautionary approach in the late 1980s. In our review, we deal primarily with the science-related aspects of CCAMLR and its development towards an ecosystem approach to the management of the living resources of the Southern Ocean. To assist the Commission in meeting its objectives, as set out in Article II, 3, the Scientific Committee established the CCAMLR Ecosystem Monitoring Programme to detect possible effects of krill fishing on the performance of top-level predators, such as albatrosses, penguins, petrels and fur seals. Fisheries in the Southern Ocean followed the fate of other fisheries worldwide in which target species were depleted to low level one after the other. Currently, two types of fisheries are open: the longline fisheries on Patagonian toothfish (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni) and the trawl fisheries on mackerel icefish (Champsocephalus gunnari). Both fisheries are managed in a single-species context, however, with conservation measures in place to protect by-catch species, such as rattails (Macrouridae) and skates and rays (Rajidae). Two major problems still exist in fisheries in the Southern Ocean: the by-catch of birds in longline fisheries primarily in the Indian Ocean and the high level of IUU fishing again in the Indian Ocean. Both, the by-catch of birds and high IUU catches undermine the credibility of CCAMLR to safeguard the marine living resources in the Southern Ocean.     

A method for lake ecosystem health assessment: an Ecological Modeling Method (EMM) and its application

Ecosystem health is a newly proposed concept that sets new goals for environmental management. Its definition, indexing and assessment methods are still being perfected. An Ecological Modeling Method (EMM) for lake ecosystem health assessment is proposed in this paper. The EMM's procedures are: (1) to analyze the ecosystem structure of a lake in order to determine the structure and complexity of the lake's ecological model; (2) to develop a model having ecological health indicators, by designing a conceptual diagram, establishing model equations, estimating model parameters and being integrated with ecological indicators; (3) to compare the simulated and observed values of important state variables and process rates (i.e. model calibration) in order to evaluate the applicability of the model to lake ecosystem health assessment; (4) to calculate ecosystem health indicators based on the developed model; and (5) to assess lake ecosystem health according to the values of the ecosystem health indicators. The EMM was applied, as a case study, to the ecosystem health assessment of a eutrophic Chinese lake (Lake Chao) between April 1987 and March 1988. A relative order of health states from poor to good was determined as follows: August–October 1987 > April–May 1987 > June–July 1987 > November–December 1987 > January–March 1988. These results compared quite favourably with the actual current conditions at Lake Chao. The EMM method, therefore, was suitable in assessing lake ecosystem health at Lake Chao.     

生态系统健康研究的一些基本问题探讨

目前有关生态系统健康研究的一些基本问题尚未达成共识。本文分析了健康、系统与生态系统3个与生态系统健康关联的概念,在此基础上,对生态系统健康的概念及其内涵、研究价值、研究的内容框架、研究的合理尺度以及生态系统质量诊断与质量等级评价进行了探讨。指出生态学上的生态系统是系统科学意义上系统的一类,整体性、稳定性和可持续性是生态系统的重要特征,生态系统健康可通过它的充分必要条件给出,即具备良好的整体性,能够维持较高的稳定性,并能实现良好的可持续性。生态系统质量标准分为质量诊断标准和质量等级评价标准,质量诊断是一种是与非的事实判断,而质量等级评价是一种价值判断。生态系统质量等级评价指标可分为限制可比型和非限制可比型两类。生态系统的复杂性决定了生态系统健康研究须借助于系统科学和非线性科学的理论与方法,生态系统病变的滞后性决定了生态系统健康研究必须加强生态系统质量预测与预警,而生态系统健康的跨学科性决定了生态系统健康研究需要生态学、环境学、医学、社会学以及经济学等领域研究人员的广泛合作。     

Use of models for integrated assessment of ecosystem health

An argument is presented for a greater use of numerical models in integrated assessment of ecosystem health. Ecosystem health has many facets which are interconnected and interact, and which can only be measured in integrated assessments. Modelling is an essential feature of integrated assessment being one of the few ways human groups can form a consensus understanding of the complex dynamics which occur. Functional assumptions are made explicit. The argument is expanded in response to a series of key questions: What is ecosystem health? How do we do integrated assessments? What is modelling? What are some successful examples? What should one conclude? The answers are illustrated with references to the International Joint Commission's program to develop and implement Remedial Action Plans for the Great Lakes' Areas of Concern, particularly in the Bay of Quinte, Lake Ontario. Three recommendations are offered: (i) Increase the use of models, (ii) Build models with existing data and hypotheses before initiating new programs, and (iii) Allow for iterative model development but be prepared to build a new model when a new problem arises.     

Balanced nitrogen economy as a flexible strategy on yield stabilizing and quality of aquatic food crops in wetland ecosystem

In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying 'Tal' situation of New Alluvial Zone of Indian subtropics. The study was designed in factorial randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Euryale ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.571 ha-1), matured nut yield of makhana (3.06 t ha-1) and flower stalks of water-lily as vegetables (6.38 t ha-1) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha-1) and inorganic sources (NPK @ 30:20:20 kg ha-1 along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops. Besides production of food crops, INM also greatly influenced the soil and water characterization and it was favourably reflected in this study. The physico-chemical characteristics of soil (textural class, pH, organic carbon, organic matter, ammoniacal nitrogen, nitrate nitrogen, available nitrogen, phosphorus and potassium) are most important and contributed a significant improvement due to cultivation of these aquatic crops. Analysis of such wet bodies represented the water characteristics (pH, BOD, COD, CO3 =, HCO3-, NO3- N, SO4-S and Cl-) were most responsive, adaptable and quite favourable for the cultivation of these crops in this vast waste unused wetlands for the mankind without any environmental degradation.     

Paleolimnology: an important tool for effective ecosystem management

Effective management of aquatic resources requires long-term environmental data. However, because long-term observations are rarely available, indirect proxy methods must be used to substitute for these missing historical data sets. Major advances have been made in paleolimnology over the last decade, and many of these advances can be applied directly to integrated and cost-effective assessments of aquatic ecosystem health. This commentary uses the analogy of human health to argue that paleolimnological data provide information crucial to the decision-making processes of ecosystem managers.Keynote lecture, presented at the International Sumposium on Aquatic Ecosystem Health, Waterloo, Ontario, July 23, 1990.     

Essential role of seaweed cultivation in integrated multi-trophic aquaculture farms for global expansion of mariculture: an analysis

Ecologically friendly aquaculture crops, such as seaweeds, herbivores, omnivores, and detritivores can be cultured using relatively less of our limited natural resources and produce relatively less pollution. They also top FAO’s estimates of aquaculture crops for the 21st century. These crops already comprise nearly 90% of global aquaculture tonnage, >90% of all aquaculture production in China and >60% of production even in North America. Consumers prefer them, most likely due to their low prices. Production costs of organisms low on the food chain are low due to the ability of these organisms to efficiently utilize low-cost, mostly plant-based diets and to recycle their own waste. Thus, ecologically friendly aquaculture is not a dream but a dominant global reality. The less ecologically-friendly aquaculture of salmon, sea bream, fed shrimp, among others, has attracted public opposition to aquaculture, but these crops totaled approximately only 10% of global production in 2004. The profitability of industrialized monocultures of these crops is threatened further by rising costs of energy and feed, environmental regulation compliance, disease, and public opposition. Current monoculture practices and perceptions intrinsic to the aquaculture industry can be turned around into a vision of sustained profitable expansion of carnivores production with trophically lower organisms in ecologically-balanced aquaculture farms. This category of aquaculture, which is the modern intensive form of polyculture practiced in Asia, feeds the waste of carnivore culture to lower trophic level organisms, primarily algae and mollusks. Species are selected based on their ecological functions in addition to their economic potential. Ecologically-balanced farms turn the costly treatment of carnivore waste outside the farm to a revenue-generating process of biofiltration, conversion, and resource recovery into plant and mollusk crops inside the farm. In doing so, they solve several of the major problems faced by modern aquaculture. The aquaculture industry can protect its own interests – and reap major benefits – by understanding the importance of ecological balance, the potential of seaweeds as components in feeds, and the importance of the culture and R&D of low trophic level organisms. The industry should also accept the relevance of environmental, social, and image aspects of aquaculture to its success. Governments have the tools to reward multi-trophic farms with seaweeds by means of tax credits and nutrient credits and to penalize unbalanced monoculture approaches by means of ‘polluter pays’ fines, thereby providing the multi-trophic farms with a significant economic advantage. Such measures have been discussed, but their implementation has been slow.     

Mercury Pollution from a Chloralkali Source in a Tropical Lake and Its Biomagnification in Aquatic Biota: Link between Chemical Pollution,Biomarkers, and Human Health Concern

Mercury is a highly toxic heavy metal that can cause adverse ecological and toxicological impacts through the mechanism of biomagnification. Hg accumulation in aquatic biota may thus also pose a serious threat to humans and other fish-eating animals. The present work observed the transfer of Hg from abiotic (water and sediments) to biotic (algae, aquatic macrophytes, and fish) components, belonging to different trophic levels in a tropical lake in India. Hg was analyzed in water, sediments, plants, and fish collected from different sampling points, receiving the discharge of chloralkali effluent. Hg concentrations increased significantly from lake water and sediments to algae and aquatic macrophytes. Statistical analysis (Pearson correlation) revealed a significant positive correlation between Hg in water and plants (r = 0.88–0.93; p < .01 and p < .05) as well as for Hg in sediment and plants (r = 0.50–0.83; p < .01 and p < .05). However, the increase in Hg concentration in fish was not significantly correlated with lake ambient water (r = 0.31–0.36), sediments (r = 0.29–0.33), and aquatic plants (r = 0.31–0.36). Results obtained encourage the use of naturally occurring wetland plants in designed systems like constructed wetlands to ameliorate Hg pollution in lakes, rivers, and ponds resulting from the discharge of industrial effluents, especially chloralkali effluent, hence reducing the human health risks associated with Hg.