上海城市污泥中有机磷酸酯阻燃剂/增塑剂分布的初步研究

采用超声提取、固相萃取和气相色谱质谱联用(GC-MS)分析技术,测定了12个上海市政污水处理厂外排污泥中的8种常见有机磷酸酯(OPs)的浓度水平与分布特征.所有污泥样品中检出多种OPs分布,OPs总含量范围为138—778 ng·g~(-1).主要污染物为三(1-氯-2-丙基)磷酸酯、三苯基磷酸酯、三-(2-氯乙基)磷酸酯(TCEP),浓度范围分别为LOD—206 ng·g~(-1)、8.82—52.9 ng·g~(-1)和7.12—65.7 ng·g~(-1).研究结果表明,生活污水和工业废水是OPs重要释放来源.因其显著毒性效应和持久性,TCEP被欧美等国禁用,但本研究污泥中广泛检出且含量水平较高(7.12—65.7 ng·g~(-1)),结果折射其高历史残留或持续使用.     

五氯酚和八氯代二苯并二嗯英复合暴露对斑马鱼胚胎发育的毒性效应

为了评价环境中五氯酚(PCP)和八氯代二苯并二嚼英(OCDD)对水环境以及鱼类的影响,以斑马鱼为模式生物,研究了PCP和OCDD对其胚胎发育的单一及复合毒性效应.结果表明,PCP单独暴露(浓度25μg·L-1～5mg·L-1)对斑马鱼胚胎发育具有较强的毒性效应,可导致胚胎孵化率显著下降,死亡率、畸形率显著上升,而OCDD单独暴露(200、500μg·L-1)对斑马鱼胚胎发育没有明显的毒性效应;OCDD与环境浓度的PCP复合暴露(OCDD PCP1:250μg·L-1 25μg·L-1;OCDD PCP2:250μg·L-1 50μg·L-1)对斑马鱼胚胎的存活与发育等没有显著影响,对斑马鱼胚胎内CYP1A基因表达以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的酶活力也没有显著影响,在实验浓度下二者共存没有明显的复合毒性效应.     

煤矿型城市城区居民人发中汞的空间分布特征及影响因素分析

为了解淮南市不同城区居民人发中Hg分布特征和影响当地居民人体Hg富集的因素。在淮南市市区选择68名正常状态下的居民头发,用氢化物发生-原子荧光法测定人发中总汞含量。结果显示:淮南市市区居民人发中Hg的平均浓度为(0.390±0.173)μg·g~(-1),Hg浓度主要分布于0~0.5μg·g~(-1)较低浓度区间内,占总样品数的77.94%;市区内人发中Hg平均浓度呈现出谢家集(0.468±0.144μg·g~(-1))>潘集(0.384±0.199μg·g~(-1))>田家庵(0.377±0.176μg·g~(-1))>大通(0.373±0.116μg·g~(-1));不同性别上,当地男性头发中Hg的平均含量为(0.436±0.188)μg·g~(-1),显著高于女性的(0.343±0.146)μg·g~(-1)(P=0.021<0.05);不同年龄段内,40~60岁年龄段居民头发中Hg平均含量最高,达0.445μg·g~(-1);不同工作、生活环境上,淮南市居民头发中Hg平均含量呈现出矿区>过渡区>对照城区,其Hg平均含量分别达(0.466±0.174)、(0.380±0.167)、(0.304±0.151)μg·g~(-1),矿区居民人发中Hg含量分别高出过渡区与对照城区居民人发Hg含量达22.6%和53.3%。相比较美国国家环境保护局提出的人发中Hg的参考剂量1μg·g~(-1),淮南市城区居民人发中Hg含量较低。但是对比非矿业活动区,矿区居民人发中Hg含量显著高于对照城区居民(P=0.0098<0.01),过渡区居民人发中Hg含量与矿区和对照城区差异性均不明显。     

基于傅里叶变换红外光谱技术分析壬基酚和双酚A对斑马鱼胚胎的影响

壬基酚(4-NP)和双酚A(BPA)是2种在环境中普遍检出的雌激素物质,已经在地表水中广泛检出,且浓度很高。壬基酚和双酚A在地表水中检测浓度最高分别达到了644μg·L^(-1)和12μg·L(-1)和12μg·L^(-1)。目前有大量研究表明壬基酚和双酚A具有环境内分泌干扰效应,但是较少研究利用傅里叶变换红外光谱技术分析这2种物质对斑马鱼胚胎生理生化的影响。傅里叶变换红外光谱作为一种基于官能团和极性键振动结构分析技术,已广泛用于大分子化合物结构分析以及蛋白质的二级结构解析,是获取分子结构信息的有力工具,经常用于毒理学领域。本研究基于傅里叶变换红外光谱技术,分析了壬基酚和双酚A对斑马鱼胚胎的毒性。结果表明,当壬基酚≥322μg·L(-1)。目前有大量研究表明壬基酚和双酚A具有环境内分泌干扰效应,但是较少研究利用傅里叶变换红外光谱技术分析这2种物质对斑马鱼胚胎生理生化的影响。傅里叶变换红外光谱作为一种基于官能团和极性键振动结构分析技术,已广泛用于大分子化合物结构分析以及蛋白质的二级结构解析,是获取分子结构信息的有力工具,经常用于毒理学领域。本研究基于傅里叶变换红外光谱技术,分析了壬基酚和双酚A对斑马鱼胚胎的毒性。结果表明,当壬基酚≥322μg·L^(-1)时,斑马鱼胚胎72 hpf孵化率分别只有33%、5%、0%、0%和0%;同时,暴露96 h时,可显著降低斑马鱼胚胎的存活率和增加致畸指数,且呈浓度依赖特征。特别是849.5μg·L(-1)时,斑马鱼胚胎72 hpf孵化率分别只有33%、5%、0%、0%和0%;同时,暴露96 h时,可显著降低斑马鱼胚胎的存活率和增加致畸指数,且呈浓度依赖特征。特别是849.5μg·L^(-1)和1 038.5μg·L(-1)和1 038.5μg·L^(-1)壬基酚暴露后,斑马鱼胚胎全部死亡。类似地,当双酚A≥5.55 mg·L(-1)壬基酚暴露后,斑马鱼胚胎全部死亡。类似地,当双酚A≥5.55 mg·L^(-1)时,斑马鱼胚胎72 hpf孵化率分别只有30%、0%、0%和0%;暴露96 h时,双酚A≥7.5 mg·L(-1)时,斑马鱼胚胎72 hpf孵化率分别只有30%、0%、0%和0%;暴露96 h时,双酚A≥7.5 mg·L^(-1)也导致斑马鱼胚胎的存活率显著下降和增加致畸指数,并随着浓度升高毒性增大。以胚胎死亡率和致畸形指数作为效应终点,壬基酚对斑马鱼胚胎的96 h-LC_(50)和EC_(50)分别为481.7μg·L(-1)也导致斑马鱼胚胎的存活率显著下降和增加致畸指数,并随着浓度升高毒性增大。以胚胎死亡率和致畸形指数作为效应终点,壬基酚对斑马鱼胚胎的96 h-LC_(50)和EC_(50)分别为481.7μg·L^(-1)和362.6μg·L(-1)和362.6μg·L^(-1);双酚A对斑马鱼胚胎的96 h-LC_(50)和EC_(50)为8.8 mg·L(-1);双酚A对斑马鱼胚胎的96 h-LC_(50)和EC_(50)为8.8 mg·L^(-1)和7.9 mg·L(-1)和7.9 mg·L^(-1)。红外光谱分析显示,当壬基酚≥158.5μg·L(-1)。红外光谱分析显示,当壬基酚≥158.5μg·L^(-1)时,对酰胺Ⅱ、脂质、蛋白磷酸化等波数有显著影响;当双酚A≥1.75 mg·L(-1)时,对酰胺Ⅱ、脂质、蛋白磷酸化等波数有显著影响;当双酚A≥1.75 mg·L^(-1)时,对酰胺Ⅰ、酰胺Ⅱ、脂质和碳水化合物等波数有显著影响。上述研究结果显示壬基酚和双酚A对斑马鱼存活率、畸形率以及生理生化均有显著的影响。     

麻醉剂依托咪酯诱导斑马鱼幼鱼神经发育毒性

依托咪酯(etomidate, ET)在临床上常被用作麻醉剂。ET长期高剂量地使用会导致人类意识下降和认知障碍等负面效应。但ET对鱼类的神经毒性机制尚不清楚。在本文中,2 hpf (hours post-fertilization)的斑马鱼胚胎暴露于不同浓度ET (0.010、0.091、0.501、9.400、84.31和664.4μg·L^-1)至168 hpf。通过分析ET对斑马鱼胚胎生理发育、早期行为、细胞凋亡以及多巴胺(dopamine, DA)和γ氨基丁酸(gamma aminobutyric acid, GABA)通路相关基因转录表达水平的影响,评估其对斑马鱼幼鱼神经发育毒性。结果表明,664.4μg·L^-1 ET显著增大48 hpf和60 hpf斑马鱼胚胎孵化率。0.091μg·L^-1和0.501μg·L^-1 ET诱导168 hpf幼鱼体长减少。0.010、0.091、0.501、9.400、84.31和664.4μg·L^-1 ET增大48 hpf胚胎畸形评分。0...     

中国七大水系淡水沉积物中林丹(γ-HCH)的生态风险评估

林丹(γ-HCH)作为曾广泛应用的有机氯农药,自2000年在中国停止生产以来,全国范围内环境介质中仍广泛检出,对生物体及自然环境存在潜在危害。在收集γ-HCH的沉积物毒性数据基础上,通过物种敏感度分布(Species Sensitivity Distributions,SSD)曲线拟合的方法获得其沉积物质量基准。选取7种常用模型进行拟合,通过比较,最终采用S-Logistic模型拟合γ-HCH急性毒性曲线,得到急性基准值CMCsed=0.00530μg·g~(-1);采用S-Gompertz模型拟合γ-HCH慢性毒性曲线,得到慢性基准值CCCsed=0.00106μg·g~(-1)。我国七大水系68.2%的水体沉积物中γ-HCH的残留浓度均低于其CCCsed,说明其风险较低。但是,在海河和辽河流域某些点位的残留超标,需要引起足够的重视。所获得的沉积物基准值对评估沉积物中γ-HCH的生态风险和环境修复具有重要指导意义。     

山东某污水处理厂中环型和线型甲基硅氧烷的行为归趋

本文研究了山东某污水处理厂污水及污泥中3种环型甲基硅氧烷(D4—D6,CMS)和12种线型甲基硅氧烷(L5—L16,LMS)的行为归趋.进水中总甲基硅氧烷(∑MS)的浓度为15.7—65.7μg·L~(-1)(平均值:39.2μg·L~(-1)),其中∑LMS占比为98. 2%.进水中∑MS浓度夏季最高(65. 7μg·L~(-1)),其次分别是秋季(41.7μg·L~(-1))、冬季(33.7μg·L~(-1))和春季(15.7μg·L~(-1)).出水中∑MS浓度为6.24—14.3μg·L~(-1)(平均值:10.6μg·L~(-1)),平均去除率为73.0%.污泥中∑MS的浓度为14.1—48.4μg·g~(-1)(平均值:20.3μg·g~(-1)),D4—D6的泥水分配系数(lg Kd)为3.84—4.44,L6—L16的lg Kd为2.24—4.30.此外,通过计算甲基硅氧烷的危险商数(hazard quotients,HQ)评估了其对水生生物的危害,发现污水处理厂出水中目标化合物的潜在危害较低.     

毒死蜱和吡虫啉对意大利工蜂(Apis mellifera L.)的慢性经口毒性

文章以毒死蜱和吡虫啉为受试农药,以4日龄内的意大利工蜂(Apis melifera L.)为受试生物,研究2种农药对意大利工蜂的10 d经口慢性毒性。结果显示:参比物质乐果对意大利工蜂的10 d半致死浓度(10 d-LC50)为0.550μg a.i.·g~(-1)食物,平均每天半致死剂量(LDD50)为0.019μg a.i.·蜂~(-1)·天~(-1);在有效试验条件下,毒死蜱对意大利工蜂的10 d LC50为0.582μg a.i.·g~(-1)食物,LDD50为0.021μg a.i.·蜂~(-1)·天~(-1);吡虫啉对意大利工蜂的10 d LC50为0.055μg a.i.·g~(-1)食物,LDD50为1.542 ng a.i.·蜂~(-1)·天~(-1)。试验结果可为毒死蜱和吡虫啉的安全使用提供科学参考,同时可促进我国农药对蜜蜂的安全性评价体系的完善。     

4-壬基酚对斑马鱼(Danio rerio)胚胎/仔鱼的毒性效应

4-壬基酚(4-NP)作为一种稳定的环境内分泌干扰物,会对生物体的生长发育造成影响。以斑马鱼(Danio rerio)胚胎为供试体,研究4-壬基酚对斑马鱼胚胎生长发育的毒性效应。斑马鱼胚胎被暴露在一系列浓度的4-壬基酚溶液中(2.0、5.0、10.0、25.0、50.0和125.0μg·L-1),暴露120 h后空白组初孵仔鱼因饥饿出现死亡即停止实验。记录暴露120 h内斑马鱼胚胎的死亡数、孵化数,畸形数、仔鱼体长及30 s心跳数。结果表明,4-壬基酚对斑马鱼胚胎48、72和96 h的半致死浓度(LC50)分别为131.4、47.2和26.8μg·L-1;125.0μg·L-1的4-壬基酚对斑马鱼胚胎的高致死效应使其孵化率显著降低;与空白对照组相比,4-壬基酚的暴露可显著提高斑马鱼胚胎尾部畸形率和仔鱼的心包囊肿率,其中斑马鱼胚胎尾部畸形率随处理浓度的增加而增加,呈正剂量-效应关系;经4-壬基酚暴露处理的斑马鱼仔鱼的体长及30 s心跳数较空白对照组均显著下降。2.0μg·L-14-壬基酚对斑马鱼胚胎及仔鱼即具有致畸和致死效应,对其胚胎的发育有不利影响。     

基于PBPK模型的大鼠体内镉分布的比较:联合暴露及单独暴露

环境中同时存在着多种重金属元素,联合暴露与单独暴露时,重金属在体内的蓄积分布情况也可能有所差异。为探究重金属元素(汞、铬、砷、铅)对镉(Cd)在体内分布的影响,建立了大鼠在Cd暴露下的药代动力学(PBPK)模型,并进行了包括Cd在内5种重金属的联合毒性实验,比较了Cd单独给药与重金属混合物给药2种方式下大鼠肝脏、肾脏中的Cd浓度水平。结果表明,联合暴露高(Hg Cl23.67 mg·kg~(-1),NaAsO_2 3.67 mg·kg~(-1),CdCl_2 10.55 mg·kg~(-1),K_2Cr_2O_7 6.40 mg·kg~(-1),Pb(OOCCH_3)_2·3H_2O 133.33 mg·kg~(-1))、中(HgCl_20.367 mg·kg~(-1),NaAsO_2 0.367 mg·kg~(-1),CdCl_2 1.055 mg·kg~(-1),K2Cr2O70.640 mg·kg~(-1),Pb(OOCCH_3)_2·3H_2O 13.333 mg·kg~(-1))、低(HgCl_2 0.0367 mg·kg~(-1),Na As O20.0367 mg·kg~(-1),Cd Cl20.1055 mg·kg~(-1),K_2Cr_2O_7 0.0640 mg·kg~(-1),Pb(OOCCH3)2·3H2O 1.3333 mg·kg~(-1))剂量组大鼠肝脏中Cd浓度分别为13.37、0.78和0.06μg·g~(-1);肾脏中Cd浓度分别为14.41、1.64和0.15μg·g~(-1)。与对照组相比,暴露组中Cd浓度有显著升高,且不同剂量组之间均有显著性差异。同剂量Cd单独暴露的PBPK模拟结果显示,肝脏及肾脏中的Cd浓度水平落在联合毒性实验结果的浓度范围内,初步推断其他4种重金属的联合暴露并没有影响Cd在大鼠肾脏和肝脏中的浓度分布。     

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).