应用物种敏感性分布评估微(纳米)塑料对水生生物的生态风险

水环境中的微(纳米)塑料对水生生物具有潜在的危害。为了评估微(纳米)塑料对水生生物的毒性效应及生态风险,本研究在广泛查阅并分析微(纳米)塑料相关毒理学研究数据的基础上,利用物种敏感性分布(Species Sensitivity Distributions,SSD)方法对其中5门10科11种水生生物的急性毒理数据进行曲线拟合;计算对应的5%危害浓度(the hazardous concentration for 5%of the species, HC_5)和潜在影响比例(potential affected fractions, PAF);计算了相应的急性生态效应阀值(predicted no effect concentration, PNEC_(acute)),并比较了各类水生生物对微(纳米)塑料的敏感性及其所受生态风险。结果表明,目前已有数据中微(纳米)塑料对费氏弧菌(Vibrio fischeri)的生态风险最大,对朱氏四爿藻(Tetraselmis chuii)的生态风险最小;基于Reweibull模型对水生生物数据所推导的PNEC_(acute)为0.185μg·L~(-1),约为当前微(纳米)塑料在水体环境中浓度的30%。利用SSD来预测微(纳米)塑料不同暴露浓度下对水生生物的PAF,发现当微(纳米)塑料暴露浓度小于10μg·L~(-1)时,水生生物所受的影响在可接受范围内;当暴露浓度达到1 000μg·L~(-1)时,将有26%的物种受到微(纳米)塑料的危害。此外,利用Rurrlioz软件估算了世界典型淡水与海水水域表层水体中微塑料对水生生物的PAF值,发现其PAF预测值都为0;将各水域微塑料浓度与急性生态效应阀值PNEC_(acute)比较后发现,除太湖外,其他水体环境中微塑料浓度都低于PNEC_(acute),说明如果只考虑微塑料本身的影响,目前世界典型水域表层水中微塑料对水生生物的危害程度大部分都在可接受的范围之内。     

应用物种敏感性分布评估DEHP对区域水生生态风险

应用物种敏感性分布（Species Sensitivity Distribution,SSD）方法构建了邻苯二甲酸二辛酯（Diethylhexyl phthalate,DEHP）对淡水生物的SSD曲线。在此基础上,计算了DEHP对不同生物的5%危害浓度（HC5）,分析比较DEHP对不同生物类别的毒性敏感性差异及其特征,并针对在不同污染物质量浓度下,评价了我国不同地区水体DEHP对不同生物类别的生态风险。结果表明,不同物种对DEHP污染物的耐受范围存在差异,从小到大依次为无脊椎动物〈脊椎动物〈藻类,这可能与各物种的组别多样性有关,耐受范围越大,表示随着质量浓度增加,风险增大的趋势较缓慢;DEHP对不同物种的HC5从小到大依次为藻类〈无脊椎动物〈脊椎动物。HC5越小,DEHP对该物种的生态风险越大,其中藻类对DEHP最敏感,其HC5为41.01μg·L-1,从总体上看,DEHP对淡水生物系统的HC5为4 521.46μg·L-1;不同质量浓度值得出的PAF值的大小,反映不同类别生物的损害程度。质量浓度在1 000μg·L-1以下,全部物种的PAF值几乎为0;当质量浓度达1 000μg·L-1时,藻类和无脊椎动物开始受到影响;当质量浓度达10 000μg·L-1时,61.85%和88.04%的藻类和无脊椎动物分别受到影响,全部物种有64.34%受到影响。我国不同地区河流湖库水体水生态风险评估表明其水生态风险极低,PAF接近于0。     

应用物种敏感性分布评估重金属对海洋生物的生态风险

应用生态风险评价中的物种敏感性分布(species sensitivity distributions,SSD)方法构建了8种常见重金属元素(As、Cd、Cr、Cu、Hg、Mn、Pb、Zn)对海洋生物的SSD曲线。在此基础上计算了8种重金属对海洋生物的5%危害浓度(HC5)及其不同暴露浓度对海洋生物的潜在影响比例(PAF),比较了海洋脊椎动物和无脊椎动物对8种重金属的敏感性以及不同重金属的急性生态风险。结果表明,重金属对甲壳类的生态风险均比鱼类大。8种重金属元素对所研究的海洋生物全部物种的HC5值的排序为Pb>Mn>Zn>Cr>Cu>Hg>Cd>As。暴露浓度小于10μg·L-1时,Cr和Hg的生态风险差异不大。在10μg·L-1的暴露浓度下,As、Cd、Cu和Hg均使全部物种中超过10%的生物受到影响。随着浓度升高,不同重金属的生态风险有不同幅度的增大,当浓度达到1000μg·L-1时,分别有82.49%、87.31%和85.90%的物种受到As、Cu和Hg的损害。不同生物的敏感性顺序会随重金属的浓度范围发生变化。     

某湿地生态保护区水体中铜的生态风险评价及管理限值研究

铜是生物必需的微量元素,但过量暴露会对生物产生毒害效应。针对我国南方城市某湿地生态保护区水体重金属污染问题,参照《澳大利亚和新西兰淡水和海水水质指南》,应用物种敏感度分布(speeies sensitivity distribution,SSD)方法和联合概率曲线(joint probability curve,JPC)方法评价水体中铜的生态风险评价,在此基础上提出水体中铜浓度的管理限值。根据该湿地生态保护区生物调查历史数据以及其他文献数据,整理了415个本地物种的清单,通过美国环境保护署ECOTOX数据库以及其他文献共获取了13个物种的毒性数据,构建了Weibull分布、对数正态分布、正态分布、对数Logistic分布、Logistic分布、BurrⅢ型分布和Gumbel分布等7个SSD模型。结果表明,利用13个本地物种铜毒性数据构建的SSD模型具有合理性,不同模型计算得到的湿地生态保护区水体中铜的总体风险期望值为0.054~0.121。其中,BurrⅢ型分布模型的拟合效果最好,据此推导得到以保护水生生态系统为目标的铜的高可靠性与中等可靠性触发值分别为2.55μg·L~(-1)和1.41μg·L~(-1)。考虑到管理目标的可达性和现状的生态风险水平,提出该湿地生态保护区水体中铜浓度的管理限值为3μg·L~(-1)。     

基于物种敏感性分布法的毒死蜱对稻田生态系统生态风险评价

生物敏感性分布法(Species Sensitivity Distributions,SSD)是一种基于单物种测试和概率统计学的、较高级的外推风险评估方法。该方法在国内外均被广泛应用于各种污染物风险评价中。本文选取了采用logistic和normal这2种SSD分布模型,分析了国内外毒死蜱对3组水生生物组合的毒性数据;并且获得各自SSD的HCx值。3组毒性数据分别为:浙江稻田水生生物组,长三角地区水生生物组和美国水生生物组。浙江稻田水生物SSD分布的HC5为:0.32μg·L~(-1)(logistic模型)和0.35μg·L~(-1)(normal模型);HC10为1.50μg·L~(-1)(logistic模型)和1.26μg·L~(-1)(normal模型);HC20为8.13μg·L~(-1)(logistic模型)和5.96μg·L~(-1)(normal模型);HC50为145.44μg·L~(-1)(logistic模型)和115.74μg·L~(-1)(normal模型)。据此判断水稻种植季节,稻田水域毒死蜱对食蚊鱼、鳑鲏、泽蛙蝌蚪、轮虫、常见腹足类和双壳类软体动物以及绝大多数藻类等的风险较小。利用冗余分析研究了生物物种数量、物种组成结构和拟合模型对HCx影响。结果表明:物种组成结构对HCx有较为明显的影响。具体表现为对毒死蜱较为敏感物种数量与HCx存在明显的负相关性;对毒死蜱不敏感的物种则与HCx呈现正相关性。     

水环境中藻毒素生态风险的物种敏感性分布评价

藻毒素对人体的健康风险已受普遍关注,然而其对水生态物种敏感性分布的影响尚不明朗。本研究采集已有实验数据,利用种间相关性分析(ICE)模型和物种敏感性分布评估(SSDs)方法,筛选了64个水生生物物种的71组急性毒性数据(EC50),构建水生生物对肝毒素(节球藻毒素、柱孢藻毒素)和神经毒素(类毒素、贝毒素)的SSD方程。在此基础上,计算不同暴露浓度下的潜在影响比例(PAF)以及保护95%物种基础上藻毒素对水生生物的生态风险阈值(HC5),比较不同类别生物对藻毒素的敏感性以及藻毒素对水生生物的生态风险。结果表明:(1)在95%物种保护保证率下,节球藻毒素、柱孢藻毒素、类毒素和贝毒素对全部物种的HC5值分别为74.96、205.39、194.39、0.3μg·L~(-1),贝毒素水生态风险最高,柱孢藻毒素最低。(2)柱孢藻毒素、类毒素对无脊椎动物的HC5值分别为122.93、95.19μg·L~(-1),低于全部物种的HC5值,无脊椎动物受柱孢藻毒素、类毒素影响较其他物种大。(3)物种潜在影响比例可明确表征敏感性,柱孢藻毒素、类毒素在各浓度暴露情景下对无脊椎动物的PAF值均高于脊椎动物,显示无脊椎动物的敏感性较高。     

5种有机磷农药的淡水水生生物基准

采用毒性百分数排序法推导了马拉硫磷、乐果、甲基对硫磷、敌敌畏和对硫磷等5种有机磷农药的淡水水生生物基准,得出5种有机磷农药的基准最大浓度(CMC)分别为0.477、1.392、0.247、0.085、0.155μg·L-1;基准连续浓度(CCC)分别为0.030、0.688、0.092、0.056、0.030μg·L-1.将推导出的双值基准与我国地表水环境质量标准比较,结果表明,二者差别较大,我国目前这5种有机磷农药的水质标准可能在一定程度上存在着对水生生物"欠保护"的情况.5种有机磷农药的淡水水生生物基准可为我国淡水水生生物基准的制订提供一定的数据参考.     

基于不同毒性终点的双酚A(BPA)预测无效应浓度(PNEC)研究

双酚A(BPA)已被证实是一种类雌激素类物质。本研究根据BPA对水生生物毒性效应的特点,按照不同的毒性终点将BPA的毒性数据进行归类,采用物种敏感度分布法(species sensitivity distribution,SSD)推导了BPA对水生生物的预测无效应浓度(predicted no effect concentration,PNEC)。结果表明:以雌激素效应为暴露终点的急、慢性PNEC分别为25.11μg·L-1、1.075μg·L-1;而以所有数据的急、慢性毒性效应为暴露终点推导的PNEC值分别为355.7μg·L-1、7.549μg·L-1。BPA对水生生物的雌激素效应更为敏感,建议在推导BPA这类内分泌干扰物的PNEC值时,应依据其毒性终点分别推导,从而得到更加合理的基准值。研究成果以期为我国地表水环境质量标准的制修订提供数据支持。     

北京市污水处理厂出水中雌二醇的概率生态风险评价

随着北京市再生水补给河湖规模扩大,污水处理厂出水中雌激素活性物质引起的受纳水体生态风险日益受到关注。以雌二醇为例,利用物种敏感度分布(species sensitivity distribution,SSD)模型和联合概率曲线(joint probability curve,JPC)方法开展北京市污水处理厂出水的概率生态风险评价研究。通过文献调研整理了北京市约430个物种,利用美国环境保护署ECOTOX数据库获取了其中7个物种的雌二醇毒性数据,构建了正态分布、对数正态分布、Logistic分布、对数Logistic分布、Weibull分布、Burr III型分布和Gumbel分布等7个SSD模型,评价了北京市污水处理厂二沉池出水以及"混凝-沉淀-过滤-臭氧"、"超滤-臭氧"和"超滤-活性炭-臭氧"3种深度处理工艺组合出水的生态风险。结果表明,利用北京市7个物种雌二醇毒性数据构建的SSD模型具有合理性,SSD模型选择对生态风险评价结果的影响较大,对数正态分布、对数Logistic分布、Weibull分布和Burr III型均是可接受的SSD模型,其中拟合效果最佳的Burr III型分布模型给出了最保守的风险估计。Burr III型分布模型的模拟结果显示,北京市污水处理厂二沉池出水以及3种深度处理工艺组合出水的总体风险期望值分别为0.070、0.040、0.036和0.026,该结果可以为北京市未来水生态保护目标的设定以及污水处理工艺的升级改造提供决策参考。     

中国典型河湖水体铅的水生生物安全基准与生态风险评价

采用物种敏感度排序法(SSR)对我国铅的淡水水生生物安全基准进行推导,并以太湖为例进行了流域水生生物安全基准推导。对于难以获得的本土生物毒性数据,开展了相应的毒性试验。获得了我国国家与太湖流域铅的水生生物安全基准值,基准最大浓度(CMC)分别为63.92、104.26μg·L-1,基准连续浓度(CCC)分别为1.21、4.06μg·L-1。同时,对我国主要河流以及太湖流域进行了铅的生态风险评价,联合概率曲线法显示影响5%水生生物种类的概率分别为66.22%和43.19%,熵值法则显示中国主要河流存在较大的铅暴露风险,因此,我国铅的潜在生态风险较大,主要河流与太湖流域存在铅污染问题。     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).