共查询到20条相似文献，搜索用时 31 毫秒
1.
Peter M. Chapman 《Marine pollution bulletin》1995,31(4-12):167-177
The following key issues in ecotoxicology, the integration of ecology and toxicology, are discussed: standardized tests and tests of specific hypotheses; future needs relative to ‘benchmarks’; exposure routes and reference comparisons; reproductive effects (e.g. for endocrine-disruptive chemicals) and non-standard data analyses; ‘acceptable’ variability; appropriate use of end-points (e.g. NOECs), biomarkers and bioindicators; external concentration effect vs internal dose response; setting testable hypotheses; integration and/or tiering with chemistry, physical and other variables; ‘validation’ vs proactivity. Ecotoxicology is proactive (e.g. directed testing, resulting in testable hypotheses) as opposed to reactive, the initial impetus for toxicology (determining the causes of observed effects). Ecotoxicology and policy must be integrated if the environment is to be protected. 相似文献
2.
《Limnologica》2017
We explored distributional patterns and habitat preferences of ostracods in the Burdur province (Turkey). At 121 sites we recorded 35 taxa (22 recent, 13 sub-recent), of which 23 represent new records for the province. According to the Index of Dispersion and d-statistics, the individual species exhibited clumped distributions. Cosmopolitan species dominated (63.64%). A direct effect of regional factors (e.g., elevation) was not observed, while local factors (e.g., water temperature) best explained species distribution among habitats. Based on alpha diversity values, natural habitats (springs, ponds, creeks) were more suitable than artificial habitats (e.g., troughs, dams), suggesting that natural habitats define regional species diversity. Twenty-two of the recorded species had wider ecological ranges than previously reported. Cosmopolitan species appeared to suppress non-cosmopolitan species due to their wider ecological range. 相似文献
3.
Natural and synthetic chemicals are essential to our daily lives, food supplies, health care, industries and safe sanitation. At the same time protecting marine ecosystems and seafood resources from the adverse effects of chemical contaminants remains an important issue. Since the 1970s, monitoring of persistent, bioaccumulative and toxic (PBT) chemicals using analytical chemistry has provided important spatial and temporal trend data in three important contexts; relating to human health protection from seafood contamination, addressing threats to marine top predators and finally providing essential evidence to better protect the biodiversity of commercial and non-commercial marine species. A number of regional conventions have led to controls on certain PBT chemicals over several years (termed ‘legacy contaminants’; e.g. cadmium, lindane, polycyclic aromatic hydrocarbons [PAHs] and polychlorinated biphenyls [PCBs]). Analytical chemistry plays a key role in evaluating to what extent such regulatory steps have been effective in leading to reduced emissions of these legacy contaminants into marine environments. In parallel, the application of biomarkers (e.g. DNA adducts, CYP1A-EROD, vitellogenin) and bioassays integrated with analytical chemistry has strengthened the evidence base to support an ecosystem approach to manage marine pollution problems. In recent years, however, the increased sensitivity of analytical chemistry, toxicity alerts and wider environmental awareness has led to a focus on emerging chemical contaminants (defined as chemicals that have been detected in the environment, but which are currently not included in regulatory monitoring programmes and whose fate and biological impacts are poorly understood). It is also known that natural chemicals (e.g. algal biotoxins) may also pose a threat to marine species and seafood quality. Hence complex mixtures of legacy contaminants, emerging chemicals and natural biotoxins in marine ecosystems represent important scientific, economic and health challenges. In order to meet these challenges and pursue cost-effective scientific approaches that can provide evidence necessary to support policy needs (e.g. the European Marine Strategy Framework Directive), it is widely recognised that there is a need to (i) provide marine exposure assessments for priority contaminants using a range of validated models, passive samplers and biomarkers; (ii) integrate chemical monitoring data with biological effects data across spatial and temporal scales (including quality controls); and (iii) strengthen the evidence base to understand the relationship between exposure to complex chemical mixtures, biological and ecological impacts through integrated approaches and molecular data (e.g. genomics, proteomics and metabolomics). Additionally, we support the widely held view that (iv) that rather than increasing the analytical chemistry monitoring of large number of emerging contaminants, it will be important to target analytical chemistry towards key groups of chemicals of concern using effects-directed analysis. It is also important to evaluate to what extent existing biomarkers and bioassays can address various classes of emerging chemicals using the adverse outcome pathway (AOP) approach now being developed by the Organization for Economic Cooperation and Development (OECD) with respect to human toxicology and ecotoxicology. 相似文献
4.
To prevent harm to human health from degrading ecosystems, epidemiologists need useful indicators that are sensitive to those
shifts in health status that might parallel these declines. Traditional measures of health (e.g., life expectancy, infant
mortality) are intuitively linkable to effects from environmental degradation but, in fact, they do not appear to provide
early warning indications of negative ecological impacts on health. Alternative health measures, such as social well-being,
may be needed for epidemiological research. New measures must combine those factors having policy relevance, including sensitive
measures of well-being and of health, with models of those human behaviours that contribute to ecological declines. Exposure
factors (e.g., pollution) made worse by ecosystem changes (e.g., global warming) also are relevant. In addition, epidemiologists
must be able to relate health outcomes not only to the traditional base of geo-political boundaries (e.g., census tracts or
countries), but more appropriately to eco-regions (e.g., climate regions). Only then could direct comparisons of effect be
made between areas that have eco-region as the common base for defining both denominators and numerator events for rate calculations
and comparisons. In conclusion, administrative infrastructure is needed so that meaningful eco-epidemiology can be conducted.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
6.
Biological invasions represent a relevant ecological and economic problem of our globalized world. While a few species have been classified as invasive due to their ecological and economic impacts on the invaded ecosystems (e.g., zebra mussel), others show contrasting invasive potential, depending on the invaded ecosystem and/or the traits of the exotic species. This paper reviews the worldwide distribution, ecological impacts and the reasons that explain the invasive success of the aquatic mud snail Potamopyrgus antipodarum Gray (Hydrobiidae, Mollusca), which is native to New Zealand. This review shows that most studies on P. antipodarum distribution have been conducted in Europe, North America and Australia, and few studies in Asia. The distribution of this snail is still unknown in other parts of the world (e.g., Africa, South and Central America). The range of invaded aquatic ecosystems varies from fresh to salt water and from lentic to lotic ecosystems. The ecological impact of this species is due to the fast population growth rate and to the extremely high densities that it can reach, leading to altered C and N cycles in invaded ecosystems. However, at low densities mud snails have been shown to enhance secondary production. Additionally, P. antipodarum has been found to overcome the negative effects of predators and parasites (e.g., it survives the pass through the digestive tracts of fish). This review contributes to assess the magnitude and ecological risk of P. antipodarum invasion throughout the world. 相似文献
7.
In this study, we assessed importance of sediment-associated trace metals in structuring benthic macroinfaunal assemblages along multiple environmental gradients in chronically polluted salt marshes of the Arthur Kill - AK (New York, USA). More than 90% of benthic macroinfaunal communities at the northern AK sites consisted of a considerably large number of only a few polychaete and oligochaete species. Approximately 70% of among-site variances in abundance and biomass of benthic macroinfaunal communities was strongly associated with a few environmental variables; only sediment-associated mercury consistently contributed to a significant proportion of the explained variances in species composition along natural environmental gradients (e.g., salinity). Although sediment-associated copper, lead, and zinc were substantially elevated at some of the AK sites, their ecological impacts on benthic macroinfaunal communities appeared to be negligible. These findings suggest that cumulative metal-specific impacts may have played an important role in structuring benthic macroinfaunal communities in chronically polluted AK ecosystems. 相似文献
8.
《Limnologica》2020
Headwater streams are interesting ecological systems for studies of metacommunities given their high degrees of isolation, unidirectionality of water flow and hierarchical organization in the drainage network. In addition, for passively dispersing aquatic organisms (e.g. planktonic diatoms), connectivity between sites is unidirectional, which implies a higher isolation of headwaters, leading to a greater dispersal limitation between streams. The aim of this study was to evaluate the relative importance of local environmental (i.e., physicochemical variables) and spatial (i.e., distance between sites) components to the planktonic diatom community in 28 headwater streams of the Cerrado, central region of Brazil. Due the fact that each sampling point was located in a different headwater stream, we expected that spatial components (a proxy for diatom dispersal) were more important than local environmental conditions to the structure of the diatom metacommunity. We found 51 morphospecies of diatoms (Bacillariophyceae). The community composition of diatoms showed strong spatial variation, which was also indicated by high beta diversity (mainly contributed by the turnover component). The variation in diatom community composition, species richness, total density, and Local Contribution to Beta Diversity (LCBD) of headwaters streams was explained solely by spatial factors. Based on these results, we inferred that due to dispersal limitation, the diatom communities of these headwaters tend to show distinct species composition, with high species turnover among the local communities. We highlight the importance of headwater streams as reservoirs of biodiversity for a riverine diatom metacommunity. 相似文献
9.
Causes and consequences of the Cambrian explosion 总被引：1，自引：0，他引：1
The Cambrian explosion has long been a basic research frontier that concerns many scientific fields.Here we discuss the cause-effect links of the Cambrian explosion on the basis of first appearances of animal phyla in the fossil record,divergence time,environmental changes,Gene Regulatory Networks,and ecological feedbacks.The first appearances of phyla in the fossil record are obviously diachronous but relatively abrupt,concentrated in the first three stages of the Cambrian period(541–514 Ma).The actual divergence time may be deep or shallow.Since the gene regulatory networks(GRNs)that control the development of metazoans were in place before the divergence,the establishment of GRNs is necessary but insufficient for the Cambrian explosion.Thus the Cambrian explosion required environmental triggers.Nutrient availability,oxygenation,and change of seawater composition were potential environmental triggers.The nutrient input,e.g.,the phosphorus enrichment in the environment,would cause excess primary production,but it is not directly linked with diversity or disparity.Further increase of oxygen level and change of seawater composition during the Ediacaran-Cambrian transition were probably crucial environmental factors that caused the Cambrian explosion,but more detailed geochemical data are required.Many researchers prefer that the Cambrian explosion is an ecological phenomenon,that is,the unprecedented ecological success of metazoans during the Early Cambrian,but ecological effects need diverse and abundant animals.Therefore,the establishment of the ecological complexity among animals,and between animals and environments,is a consequence rather than a cause of the Cambrian explosion.It is no doubt that positive ecological feedbacks could facilitate the increase of biodiversity.In a word,the Cambrian explosion happened when environmental changes crossed critical thresholds,led to the initial formation of the metazoan-dominated ecosystem through a series of knock-on ecological processes,i.e.,"ecological snowball"effects. 相似文献
10.
AbstractHydrologic metrics have been used widely to quantify flow-ecology relationships; however, there are several challenges associated with their use, including the selection from a large number of available metrics and the limitation that metrics are a synthetic measure of a multi-dimensional flow regime. Using two case studies of fish species density and community composition, we illustrate the use of functional linear models to provide new insights into flow–ecology relationships and predict the expected impact of environmental flow scenarios, without relying on hydrologic metrics. The models identified statistically significant relationships to river flow over the 12 months prior to sampling (r2 range 36–67%) and an environmental flow scenario that may enhance native species’ densities while controlling a non-native species. Hydrologic metrics continue to play an important role in ecohydrology and environmental flow management; however, functional linear models provide an approach that overcomes some of the limitations associated with their use.
Editor Z.W. Kundzewicz; Guest editor M. AcremanCitation Stewart-Koster, B., Olden, J.D., and Gido, K.B., 2014. Quantifying flow–ecology relationships with functional linear models. Hydrological Sciences Journal, 59 (3–4), 629–644. 相似文献
11.
In this study, a stochastic rough-approximation water management model (SRAWM) associated with optimistic and pessimistic options is proposed for supporting regional sustainability in an irrigation system (IS) of an arid region with uncertain information. SRAWM can not only handle conventional stochastic variations in objective functions or constraints, but also tackle objective and subjective (i.e., risk performance of the decision maker) fuzziness through rough-approximation model based on measure Me. The developed model would be applied to a real case study of an irrigation district (ID) in Kaidu-kongque River Basin, China, which is encountering challenges in economic development and a serious environmental crisis (e.g., drought, water deficit, land deterioration, stalinization, soil erosion and water pollution) synchronously. Simulation technical (i.e., support vector regression) is put into SRAWM framework to reflect dynamic prediction of water demand in the future. Results of optimized irrigation area, water allocation, water deficit, pollution reduction, water and soil erosion and system benefit under various water-environmental policies (corresponding to various ecological effects) are obtained. Tradeoffs between ecological and irrigative water usages can facilitate the local decision makers rectifying the current irrigation patterns and ecological protection polices. Moreover, compromises between systemic benefit and failure risk can help policymakers to generate a robust risk-control plan under uncertainties. These detections are beneficial to achieve conjunctive goals of socio-economic development and eco-environmental sustainability in such an arid IS. 相似文献
12.
Induction, adaptation and recovery of biological responses: implications for environmental monitoring 总被引：3，自引：0，他引：3
A wide range of biological responses have been used to identify exposure to contaminants, monitor spatial and temporal changes in contamination levels, provide early warning of environmental deterioration and indicate occurrences of adverse ecological consequences. To be useful in environmental monitoring, a biological response must reflect the environmental stress over time in a quantitative way. We here argue that the time required for initial induction, maximum induction, adaptation and recovery of these stress responses must first be fully understood and considered before they can be used in environmental monitoring, or else erroneous conclusions (both false-negative and false-positive) may be drawn when interpreting results. In this study, data on initial induction, maximum induction, adaptation and recovery of stress responses at various biological hierarchies (i.e., molecular, biochemical, physiological, behavioral, cytological, population and community responses) upon exposure to environmentally relevant levels of contaminants (i.e., metals, oil, polycyclic aromatic hydrocarbons (PAHs), organochlorines, organophosphates, endocrine disruptors) were extracted from 922 papers in the biomarker literature and analyzed. Statistical analyses showed that: (a) many stress responses may decline with time after induction (i.e., adaptation), even if the level of stress remains constant; (b) times for maximum induction and recovery of biochemical responses are positively related; (c) there is no evidence to support the general belief that time for induction of responses at a lower biological hierarchy (i.e., molecular responses and biochemical responses) is shorter than that at higher hierarchy (i.e., physiological, cytological and behavioral responses), although longer recovery time is found for population and community responses; (d) there are significant differences in times required for induction and adaptation of biological responses caused by different types of contaminants; (e) times required for initial and maximum induction of physiological responses in fish are significantly longer than those in crustaceans; and (f) there is a paucity of data on adaptation and recovery of responses, especially those at population and community levels. The above analyses highlight: (1) the limitations and possible erroneous conclusions in the present use of biomarkers in biomonitoring programs, (2) the importance of understanding the details of temporal changes of biological responses before employing them in environmental management, and (3) the suitability of using specific animal groups as bioindicator species. 相似文献
13.
Response of aquatic plants to abiotic factors: a review 总被引：7，自引：0，他引：7
This review aims to determine how environmental characteristics of aquatic habitats rule species occurrence, life-history
traits and community dynamics among aquatic plants, and if these particular adaptations and responses fit in with general
predictions relating to abiotic factors and plant communities. The way key abiotic factors in aquatic habitats affect (1)
plant life (recruitment, growth, and reproduction) and dispersal, and (2) the dynamics of plant communities is discussed.
Many factors related to plant nutrition are rather similar in both aquatic and terrestrial habitats (e.g. light, temperature,
substrate nutrient content, CO2 availability) or differ markedly in intensity (e.g. light), variations (e.g. temperature) or in their effective importance
for plant growth (e.g. nutrient content in substrate and water). Water movements (water-table fluctuations or flow velocity)
have particularly drastic consequences on plants because of the density of water leading to strong mechanical strains on plant
tissues, and because dewatering leads to catastrophic habitat modifications for aquatic plants devoid of cuticle and support
tissues. Several abiotic factors that affect aquatic plants, such as substrate anoxia, inorganic carbon availability or temperature,
may be modified by global change. This in turn may amplify competitive processes, and lead ultimately to the dominance of
phytoplankton and floating species. Conserving the diversity of aquatic plants will rely on their ability to adapt to new
ecological conditions or escape through migration. 相似文献
14.
藻类是湖泊生态系统中重要的初级生产者,物种多样性高且对水环境变化敏感,其生产力水平与群落构建模式是反映湖泊环境梯度和生态系统特征的可靠指标。其中硅藻优势属种的演替模式及其环境条件识别,是开展湖泊生态健康和环境质量评价的重要内容。本文选择亚热带地区浅水湖泊异龙湖开展季节调查,对20个采样点的叶绿素a和硅藻群落组成等指标开展分布特征及其驱动因子的定量评价,系统分析藻类变化的时空模式、驱动因子及其指标异同。2020年12月一2021年9月,异龙湖水环境特征的季节波动明显,综合营养指数TSI平均为74.76,总体处于富营养水平。在80个水体样品中共发现硅藻21属68种,群落结构以浮游类型(平均占比79.33%±20.69%)的耐中富营养种为主;在4个季节的调查中,膜糊直链藻Aulacoseira ambigua(61.62%±20.26%)为优势种。主成分分析显示,硅藻群落组成存在明显的空间差异和季节变化。冗余分析和方差分解等结果表明,水体营养因子(TN、TP和N:P)是影响叶绿素a浓度空间变化的重要因子(解释方差为19.08%±11.4%),水温和水深梯度的影响较小(9.63%±11.31%... 相似文献
15.
The ability of seven hyperaccumulator macrophytes which grow naturally in the heavy metal contaminated channels of three different industries (Hindustan Aeronautical Ltd., Eveready Ltd., and Scooter India Ltd.) to accumulate heavy metals was recorded. All these industries use electroplating processes in their manufacturing and are located in the inner area of Lucknow City, U.P., India. Of the three industries monitored, effluent released from Eveready Ltd. contained the highest concentration of heavy metals. In general, accumulations of heavy metals depend upon the plant species and the metal concentration in the media. All plant samples showed heterogeneous metal accumulations, except for Fe or Cd. It was observed that some plant species accumulated high level of metals, e. g., Eichhornnia crassipes for Fe (4052.44 μg/g), Mn (788.42 μg/g), and Cu (315.50 μg/g), and Spirodela polyrhiza for Cd (12.75 μg/g), Pb (20.25 μg/g), and Cr (128.27 μg/g), even when the metal concentrations were not high in the effluent. In summary, these two plants were found to be the best accumulators at each contaminated site. The results will be helpful in the selection of plant species which can be used as bioaccumulators or bioindicators. 相似文献
16.
太湖湖滨带的生态建设 总被引：23，自引：6，他引：17
太湖湖滨带是太湖流域重点污染控制区之一。本文根据流域生态学与流域管理学的原理,提出了太湖湖滨带生态建设的途径。（1）发展生态农业,减少农田污染。（2）入湖河道沿岸两侧建设河岸林带,成为农田与河流间的缓冲带。（3）加强沿岸丘陵的水土保持。（4）充分利用湖泊湿地的净化功能,作为治理太湖富营养化的有效措施。（5）选择入湖河道河口,在试验基础上建立人工湿地。推动太湖湖滨带生态建设工程顺利开展的措施：（1）提高全社会的环境保护意识。（2）从组织和制度上加强湖滨带污染控制管理。（3）建立环境监测和信息管理系统。（4）开展湖滨带污染控制工程的试验研究。 相似文献
17.
The ability to achieve ecological sustainability and the sustainable development of marine and estuarine ecosystems constitutes a complex major challenge and depends on many driving forces, often conflicting with each other. In particular, there are three major drivers: (a) the search for human well-being, health and safety, (b) the maintenance of ecological sustainability and environmental equilibrium, and (c) the tolerance of an increasing human population pressure and demand for wealth creation.We propose here the use of a conceptual guidance tool – the ecological sustainability trigon (EST) – as a means of building and testing environmental management scenarios. Although it requires further testing, the EST allows us to (a) address those three major drivers using human society view as a common currency, and (b) describe our behaviour, energetics (economy) and dynamics through ecological theory. Moreover, the EST appears promising for gap analysis and the means to address new research questions. 相似文献
18.
Jérémy Piffady Éric Parent Yves Souchon 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(7):1719-1734
Global change calls for an understanding of how temperature and flow regimes influence aquatic ecosystems. Fish assemblages are a major component of river ecosystems and are thought to exhibit more integrative informative responses than single species to environmental variations, whether rare and sudden or gradual and continuous. The use of long-term datasets is thus of primary importance, allied to statistical modeling. For each of three previously identified species clusters, we performed Bayesian variable selection and inference within a hierarchical log Poisson Generalized Linear Model using a spike and slab normal prior to pinpoint which subset of environmental variables is of importance for each fish assemblage. Fish counts from electrofishing experiments are known to provide overdispersed data and, not surprisingly, the contribution of recorded environmental effects is found to be weak compared with those of other intra-assemblage sources of variation. The posterior distribution of the regression parameters is in coherence with what was expected from biological knowledge of the three species clusters. In particular, thermophilic species tend to benefit from warmer waters, whereas the recruitment of cold water species decreases due to global warming effects. Our study provides an example of the advantages of hierarchical modeling for quantifying interspecies ecological effects and selecting common environmental variables of importance. 相似文献
19.
Linking landscape patterns to specific ecological processes has been and will continue to be the key topic in landscape ecology.However,this goal is difficult to achieve by using the traditional landscape metric based on the Patch-Mosaic Model(PMM),as they don't integrate ecological processes with landscape patterns.In this paper,we proposed a conceptual model,i.e.,the Source-Pathway-Sink Model(SPSM),which designates the role of a landscape unit into "source", "sink",or "pathway" based on specific ecological processes during the landscape pattern analysis.While the traditional landscape metrics derived from the PMM model is visual-or geometrical-oriented and lack of linkage to ecological significance,the SPSM model is process-oriented,dynamic,and scale dependent.A comparison between the PMM and the SPSM models shows that the SPSM model is complementary to the PMM model,and can provide a simple and dynamic perspective on landscape pattern analysis.The SPSM model may represent a conceptual innovation in landscape ecology. 相似文献
20.
C. Trigal C. Fernandez-Alaez M. Fernandez-Alaez 《Aquatic Sciences - Research Across Boundaries》2014,76(1):61-72
Using data from 31 ponds, we investigated the importance of environmental (e.g. habitat complexity, nutrient content, pH) and biotic factors (i.e. fish predation) on the spatial patterns of planktonic (phytoplankton and zooplankton) and benthic (macroinvertebrates) assemblages. We also evaluated the degree of concordance among assemblages and between the functional and taxonomic composition of assemblages, and test the hypothesis that surrogates of biodiversity (e.g. taxonomic or functional groups) can be used in pond conservation and biomonitoring studies. We found that the spatial patterns of benthic and pelagic assemblages were determined by macrophyte coverage, water quality and, to a lesser extent, fish. However, shifts in the taxonomic and functional composition were not congruent. Moreover, local environmental variation was slightly more important for the taxonomic than the functional composition of assemblages, except for phytoplankton. The degree of concordance among assemblages was also weak, which may be partly due to the fact that species respond individualistically to environmental variation. These findings also suggest that the coupling between benthic and pelagic habitats in flatland ponds is weak, and that the use of surrogate measures or indicator groups in pond conservation studies may not be appropriate. 相似文献