环境中的甲基汞对野生鸟类、哺乳动物和鱼类的影响

野生肉食鱼类、哺乳动物和鸟类可能因为食物中甲基汞摄入和毒性的增加而处于危险中。在对照饲喂研究中,食用包含环境现实浓度的汞(例如甲基汞)的食物在鱼类、鸟类和哺乳动物中导致一系列的中毒反应,包括行为方面的、神经化学方面的、激素方面的,以及生殖方面的变化。有限的田间研究,特别是几种野生食鱼鸟类,例如普通潜鸟的研究证实了实验室为基础的结果,表明甲基汞暴露与不同的甲基汞毒性指示物包括生殖的损害方面之间的显著关系。鱼类和野生动物由于食用甲基汞导致的潜在的群体效果因物种生命史,以及鱼类汞浓度的地区差异而异,因此,它们受汞沉积作用和环境甲基化速率的不同的影响。但是,群体模型表明汞排放的降低会对一些正经受甲基汞暴露增加影响的普通潜鸟群体带来真实的益处。可以预见的益处主要是通过随着捕食鱼体中汞浓度的减少而导致孵化和从小鸟到成鸟的发育的改善。其它的食鱼鸟类可能也会受益于汞暴露的降低但是还没有像对普通潜鸟那样进行过广泛的研究。

Bush, bugs, and birds;interdependency in a farming landscape

Changes in farming practices over the second half of the twentieth century greatly reduced the extent of natural areas remaining within agricultural landscapes. Field margins and hedgerows have recently been recognized as important habitat in maintaining wildlife diversity and proper ecosystem functioning. Ecotones, defined as the transitionary area of vegetation between woody plant species and the arable crop, are an especially important landscape element for birds and arthropods. In this manuscript, we aimed to evaluate which hedgerow attribute was best at predicting avian densities in a conventional and organic farming landscape. Furthermore, we wished to investigate if these same hedgerow attributes could explain arthropod family density, richness and diversity, and how these were correlated to avian densities. An information theory-based multimodel inference method was used to identify which factors influenced variability in avian densities. Although not always significant, avian densities increased with arthropod richness at our study sites. Ecotone width is the best predictor of avian densities and arthropod richness while percent gap is the most important factor if a manager wishes to increase avian diversity (H’) in hedgerow habitats. Increasing ecotone width benefits both avian densities and arthropod richness that in turn further increases bird numbers in our farming landscape.

A review of ecological impacts of global climate change on persistent organic pollutant and mercury pathways and exposures in arctic marine ecosystems

Bioaccumulative and biomagnifying contaminants, such as persistent organic pollutants （POPs） and mercury （Hg）, have for decades been recognized as a health concern in arctic marine biota. In recent years, global climate change （GCC） and related loss of arctic sea ice have been observed to be driving substantial change in arctic ecosystems. This review summarizes findings documenting empirical links between GCC-induced ecological changes and alterations in POP and Hg exposures and pathways in arctic marine ecosystems. Most of the studies have reported changes in POP or Hg concentrations in tissue in relation to GCC-induced changes in species trophic interactions. These studies have typically focused on the role of changes in abun- dance, habitat range or accessibility of prey species, particularly in relation to sea ice changes. Yet, the ecological change that re- suited in contaminant trend changes has often been unclear or assumed. Other studies have successfully used chemical tracers, such as stable nitrogen and carbon isotope ratios and fatty acid signatures to link such ecological changes to contaminant level variations or trends. Lower sea ice linked-diet changes/variation were associated with higher contaminant levels in some popula- tions of polar bears, ringed seals, and thick-billed murres, but the influence of changing trophic interactions on POP levels and trends varied widely in both magnitude and direction. We suggest that future research in this new area of GCC-linked ecotox- icology should focus on routine analysis of ancillary ecological metrics with POP and Hg studies, simultaneous consideration of the multiple mechanisms by which GCC and contaminant interactions can occur, and targeted research on changing exposures and toxicological effects in species known to be sensitive to both GCC and contaminants [Current Zoology 61 （4）： 617-628, 2015].

Wild dogma： An examination of recent ＂evidence＂ for dingo regulation of invasive mesopredator release in Australia

There is growing interest in the role that apex predators play in shaping terrestrial ecosystems and maintaining tro- phic cascades. In line with the mesopredator release hypothesis, Australian dingoes （Canis lupus dingo and hybrids） are assumed by many to regulate the abundance of invasive mesopredators, such as red foxes Vulpes vulpes and feral cats Fells catus, thereby providing indirect benefits to various threatened vertebrates. Several recent papers have claimed to provide evidence for the bio- diversity benefits of dingoes in this way. Nevertheless, in this paper we highlight several critical weaknesses in the methodologi- cal approaches used in many of these reports, including lack of consideration for seasonal and habitat differences in activity, the complication of simple track-based indices by incorporating difficult-to-meet assumptions, and a reduction in sensitivity for as-sessing populations by using binary measures rather than potentially continuous measures. Of the 20 studies reviewed, 15 of them （75%） contained serious methodological flaws, which may partly explain the inconclusive nature of the literature investigating interactions between invasive Australian predators. We therefore assert that most of the ＂growing body of evidence＂ for meso- predator release is merely an inconclusive growing body of literature only. We encourage those interested in studying the eco- logical roles of dingoes relative to invasive mesopredators and native prey species to account for the factors we identify, and cau- tion the value of studies that have not done so [Current Zoology 57 （5）： 568-583, 2011].

Do concentrations in eggs and liver tissue tell the same story of temporal trends of mercury in high Arctic seabirds?

Mercury（Hg） remains a key contaminant of concern in Arctic biota, and monitoring of Hg concentrations in seabird tissues will be an effective approach to track the effects of implementing the Minamata Convention. We examined trends in total Hg（THg） in liver and egg tissues of two Arctic seabirds, thick-billed murres（Uria lomvia） and northern fulmars（Fulmarus glacialis）, between 1976 and 2013 to assess whether both tissues showed similar patterns of Hg change. Hepatic THg was consistently higher than egg THg, and both species had similar egg THg concentrations, but fulmars had higher hepatic THg than murres.Murre THg concentrations showed more relative variation through time than fulmars.We suggest that egg THg better reflects exposure of birds to THg in local, Arctic prey,whereas liver THg may incorporate longer term, year-round THg exposure. Additional analysis of THg distribution in Arctic seabirds post-laying would help inform interpretation of long-term trends.

Levels and trends of poly-and perfluoroalkyl substances in the Arctic environment-An update

Poly-and perfluoroalkyl substances(PFASs)are important environmental contaminants globally and in the early 2000s they were shown to be ubiquitous contaminants in Arctic wildlife.Previous reviews by Butt et al.and Letcher et al.have covered studies on levels and trends of PFASs in the Arctic that were available to 2009.The purpose of this review is to focus on more recent work,generally published between 2009 and 2018,with emphasis on PFASs of emerging concern such as perfluoroalkyl carboxylates(PFCAs)and short-chain perfluoroalkyl sulfonates(PFSAs)and their precursors.Atmospheric measurements over the period 2006e2014 have shown that fluorotelomer alcohols(FTOHs)as well as perfluorobutanoic acid(PFBA)and perfluoroctanoic acid(PFOA)are the most prominent PFASs in the arctic atmosphere,all with increasing concentrations at Alert although PFOA concentrations declined at the Zeppelin Station(Svalbard).Results from ice cores show generally increasing deposition of PFCAs on the Devon Ice cap in the Canadian arctic while declining fluxes were found in a glacier on Svalbard.An extensive dataset exists for long-term trends of long-chain PFCAs that have been reported in Arctic biota with some datasets including archived samples from the 1970s and 1980s.Trends in PFCAs over time vary among the same species across the North American Arctic,East and West Greenland,and Svalbard.Most long term time series show a decline from higher concentrations in the early 2000s.However there have been recent(post 2010)increasing trends of PFCAs in ringed seals in the Canadian Arctic,East Greenland polar bears and in arctic foxes in Svalbard.Annual biological sampling is helping to determine these relatively short term changes.Rising levels of some PFCAs have been explained by continued emissions of long-chain PFCAs and/or their precursors and inflows to the Arctic Ocean,especially from the North Atlantic.While the effectiveness of biological sampling for temporal trends in long-chain PFCAs and PFSAs has been demonstrated,this does not apply to the C4eC8ePFCAs,perfluorobutane sulfonamide(FBSA),or perfluorobutane sulfonate(PFBS)which are generally present at low concentrations in biota.In addition to air sampling,sampling abiotic media such as glacial cores,and annual sampling of lake waters and seawater would appear to be the best approaches for investigating trends in the less bioaccumulative PFASs.

Current-use halogenated and organophosphorous flame retardants:A review of their presence in Arctic ecosystems

Since the ban of polybrominated diphenyl ethers(PBDEs)and hexabromocyclododecane(HBCDD),other flame retardants may be increasingly used.Thirty-one current-use halogenated(HFRs)and 24 organophosphorous flame retardants(PFRs)have been sought in Arctic ecosystems so far.Air measurements provide evidence of long-range atmospheric transport for the majority of these compounds,with much higher concentrations for PFRs than for HFRs.Some HFRs,i.e.bis(2-ethylhexyl)-tetrabromophthalate(BEH-TEBP),2-ethylhexyl-2,3,4,5-tetrabromobenzoate(EH-TBB)and hexabromobenzene(HBBz),had air concentrations comparable to those of PBDEs in some studies.Complementary data for seawater and ice indicate dry deposition of HFRs,while net volatilization from seawater was observed for some PFRs.Studies in the marine environment indicate a wide presence of HFRs in marine biota,but generally at low levels,i.e.typically lower than those of PBDEs.Exceptions exist,namely 2,4,6-tribromophenyl 2,3-dibromopropyl ether(TBP-DBPE)and decabromodiphenyl ethane(DBDPE),which were found in concentrations comparable to PBDEs in some species.The same was the case for 2,4,6-tribromophenyl allyl ether(TBP-AE)in a study from the terrestrial environment.PFRs generally had low concentrations in biota,probably due to metabolic transformation of PFR triesters,as suggested by in vitro studies.Elevated PFR concentrations occurred in some individuals,generally indicating a larger variability of PFRs in biota than found for HFRs.The commercially important tetrabromobisphenol A(TBBPA)was only detected sporadically,and only in abiotic matrices.

Hexachlorobutadiene(HCBD)contamination in the Arctic environment:A review

Hexachlorobutadiene(HCBD)is a halogenated hydrocarbon that is primarily produced as an unintentional byproduct in the manufacture of chlorinated solvents.Similarities between HCBD and other persistent organic pollutants(POPs)led to its listing in 2015 for global regulation under the Stockholm Convention on POPs.HCBD's toxicity and propensity for long-range transport means there is special concern for its potential impacts on Arctic ecosystems.The present review comprehensively summarizes all available information of the occurrence of HCBD in the Arctic environment,including its atmospheric,terrestrial,freshwater and marine ecosystems and biota.Overall,reports of HCBD in Arctic environmental media are scarce.HCBD has been measured in Arctic air collected from monitoring stations in Finland and Canada,yet there is a dearth of data for other abiotic matrices(i.e.soils,sediments,glacier ice,freshwaters and seawater).Low HCBD concentrations have been measured in Arctic terrestrial and marine biota,which is consistent with laboratory studies that indicate that HCBD has the potential to bioaccumulate,but not to biomagnify.Available data for Arctic biota suggest that terrestrial birds and mammals and seabirds,have comparatively higher HCBD concentrations than fish and marine mammals,warranting additional research.Although spatial and temporal trends in HCBD concentrations in the Arctic are currently limited,future monitoring of HCBD in the Arctic will be important for assessing the impact of global regulations newly-imposed by the Stockholm Convention on POPs.

Co-contaminants of microplastics in two seabird species from the Canadian Arctic

Through ingestion and subsequent egestion,Arctic seabirds can bioaccumulate microplastics at and around their colony breeding sites.While microplastics in Arctic seabirds have been well documented,it is not yet understood to what extent these particles can act as transport vehicles for plastic-associated contaminants,including legacy persistent organic pollutants(POPs),trace metals,and organic additives.We investigated the occurrence and pattern of organic and inorganic co-contaminants of microplastics in two seabird species from the Canadian Arctic-northern fulmar(Fulmarus glacialis)and black-legged kittiwake(Rissa tridactyla).We found that fulmars had higher levels of plastic contamination and emerging organic compounds(known to be plastic additives)than kittiwakes,whereas higher concentrations of legacy POPs were found in kittiwakes than the fulmars.Furthermore,fulmars,the species with the much larger foraging range(~200 km),had higher plastic pollution and overall contaminant burdens,indicating that birds may be acting as long-range transport vectors for plasticassociated pollution.Our results suggest a potential connection between plastic additive contamination and plastic pollution burdens in the bird stomachs,highlighting the importance of treating plastic particles and plastic-associated organic additives as co-contaminants rather than separate pollution issues.

A review of chlorinated paraffin contamination in Arctic ecosystems

Chlorinated paraffins(CPs)present a complex mixture of congeners which are often analysed and assessed as short-,medium-and long-chain CPs,i.e.SSCCP(C10eC13),SMCCP(C14eC17)and SLCCP(
C18).Their complexity makes the chemical analysis challenging,in particular in terms of accurate quantification,but promising developments involving ultra-high resolution mass spectrometry have been presented lately.Most Arctic data exist for SCCPs,while LCCPs have not yet been studied in the Arctic.SSCCP concentrations in Arctic air often exceeded those of SMCCP,usually with a predominance of the most volatile C10 congeners,and of banned persistent organic pollutants(POPs),such as polychlorinated biphenyls(PCBs).The presence of SCCPs and MCCPs in Arctic air,as well as in the Antarctic and in the remote regions of the Tibetan plateau,provides evidence of their long-range transport including sufficient environmental persistence to reach the Arctic.Arctic vegetation accumulated SCCPs partly from air and partly through root uptake from soil,with consequences for the SCCP profile found in Arctic plants.No results have yet been reported for CPs in terrestrial Arctic animals.Results for freshwater sediment and fish confirmed the long-range transport of SCCPs and MCCPs and documented their bioaccumulation.Where additional PCB data were available,SPCB was usually higher than SSCCP in freshwater fish.Both SCCPs and MCCPs were widely present in marine Arctic biota(e.g.mussels,fish,seabirds,seals,whales,polar bears).In mussels and Atlantic cod,SMCCP concentrations exceeded those of SSCCP,while this was less clear for other marine species.Marine mammals and the long-lived Greenland shark roughly had SSCCP concentrations of 100e500 ng/g lipid weight,often dominated by C11 congeners.Biomagnification appeared to be more pronounced for SSCCP than for SMCCP,but more studies will be needed.Increasing SSCCP concentrations were observed in Arctic air and sediment over time,but not in beluga monitored since the 1980s.For both SCCPs and MCCPs,increasing concentrations over time have been shown in blue mussels and Atlantic cod at some,but not all stations.Indications exist of local sources of SCCPs in the Arctic,including Arctic settlements and research stations.In studies involving multiple locations,a general decrease of SCCP concentrations with increasing latitude or distance from point sources was observed as well as relatively more MCCPs at locations closer to potential CP sources.Monitoring of SCCPs and MCCPs has been initiated in some Arctic regions and will be important to assess the effect of recent regulations of SCCPs and the use of potential replacement chemicals.

A review of halogenated natural products in Arctic,Subarctic and Nordic ecosystems

Halogenated natural products(HNPs)are organic compounds containing bromine,chlorine,iodine,and rarely fluorine.HNPs comprise many classes of compounds,ranging in complexity from halocarbons to higher molecular weight compounds,which often contain oxygen and/or nitrogen atoms in addition to halogens.Many HNPs are biosynthesized by marine bacteria,macroalgae,phytoplankton,tunicates,corals,worms,sponges and other invertebrates.This paper reviews HNPs in Arctic,Subarctic and Nordic ecosystems and is based on sections of Chapter 2.16 in the Arctic Monitoring and Assessment Program(AMAP)assessment Chemicals of Emerging Arctic Concern(AMAP,2017)which deal with the higher molecular weight HNPs.Material is updated and expanded to include more Nordic examples.Much of the chapter is devoted to“bromophenolic”HNPs,viz bromophenols(BPs)and transformation products bromoanisoles(BAs),hydroxylated and methoxylated bromodiphenyl ethers(OH-BDEs,MeO-BDEs)and polybrominated dibenzo-p-dioxins(PBDDs),since these HNPs are most frequently reported.Others discussed are 2,20-dimethoxy-3,30,5,50-tetrabromobiphenyl(2,20-dimethoxy-BB80),polyhalogenated 10-methyl-1,20-bipyrroles(PMBPs),polyhalogenated 1,10-dimethyl-2,20-bipyrroles(PDBPs),polyhalogenated N-methylpyrroles(PMPs),polyhalogenated N-methylindoles(PMIs),bromoheptyl-and bromooctyl pyrroles,(1R,2S,4R,5R,10E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(20-chloroethenyl)-5-methylcyclohexane(mixed halogenated compound MHC-1),polybrominated hexahydroxanthene derivatives(PBHDs)and polyhalogenated carbazoles(PHCs).Aspects of HNPs covered are physicochemical properties,sources and production,transformation processes,concentrations and trends in the physical environment and biota(marine and freshwater).Toxic properties of some HNPs and a discussion of how climate change might affect HNPs production and distribution are also included.The review concludes with a summary of research needs to better understand the role of HNPs as“chemicals of emerging Arctic concern”.

Wild dogma II： The role and implications of wild dogma for wild dog management in Australia

The studies of Allen （2011） and Allen et al. （2011） recently examined the methodology underpinning claims that dingoes provide net benefits to biodiversity by suppressing foxes and cats. They found most studies to have design flaws and/or observational methods that preclude valid interpretations from the data, describing most of the current literature as ＇wild dogma＇. In this short supplement, we briefly highlight the roles and implications of wild dogma for wild dog management in Australia. We discuss nomenclature, and the influence that unreliable science can have on policy and practice changes related to apex predator management