Documenting lemming population change in the Arctic: Can we detect trends?

Lemmings are a key component of tundra food webs and changes in their dynamics can affect the whole ecosystem. We present a comprehensive overview of lemming monitoring and research activities, and assess recent trends in lemming abundance across the circumpolar Arctic. Since 2000, lemmings have been monitored at 49 sites of which 38 are still active. The sites were not evenly distributed with notably Russia and high Arctic Canada underrepresented. Abundance was monitored at all sites, but methods and levels of precision varied greatly. Other important attributes such as health, genetic diversity and potential drivers of population change, were often not monitored. There was no evidence that lemming populations were decreasing in general, although a negative trend was detected for low arctic populations sympatric with voles. To keep the pace of arctic change, we recommend maintaining long-term programmes while harmonizing methods, improving spatial coverage and integrating an ecosystem perspective.     

EcoEffect for outdoor environments; the process of tool development

Numerous evaluation tools for the built environment have been developed in recent decades only some however integrate the outdoor environment. In EcoEffect, a Swedish assessment system, the outdoor environment is one of five areas covered. The purpose of this article is to describe and discuss various issues that evolved during the testing and developing phase of the EcoEffect Outdoor tool. The tool is designed to cover all important health risks to people in an outdoor environment, to show the relationship between circumstances in the outdoor environment and the levels specified in Swedish legislation and to enable a speedy and accurate assessment of the outdoor environment on a property. The work has been carried out in cooperation with experts, residents and representatives of the construction and property sectors. The tool has been tested on existing properties, discussed in focus groups, and has been subject to theoretical development. The results have provided a basis for changing both the EcoEffect Outdoors tool and the framework of the EcoEffect system. Important conclusions here include the notion that a clear account should be given of the fundamental values of the tool, that environmental impact should be reported in the same way throughout the whole assessment process and that the tool has to adhere to both scientific and practical validity to be useful for the building sector.     

The causes and consequences of partial prey consumption by wolves preying on moose

For a wide range of taxa, partial prey consumption (PPC) is a frequent occurrence. PPC may arise from physiological constraints to gut capacity or digestive rate. Alternatively, PPC may represent an optimal foraging strategy. Assessments that clearly distinguish between these causes are rare and have been conducted only for invertebrate species that are ambush predators with extra-intestinal digestion (e.g., wolf spiders). We present the first strong test for the cause of PPC in a cursorial vertebrate predator with intestinal digestion: wolves (Canis lupus) feeding on moose (Alces alces). Previous theoretical assessments indicate that if PPC represents an optimal foraging strategy and is not caused by physiological limitations, then mean carcass utilization is negatively correlated with mean kill rate and the utilization of individual carcasses is uncorrelated with time between kills. Wolves exhibit exactly this pattern. We explore how the typical portrayal of PPC by wolves has been not only misleading but also detrimental to conservation by promoting negative attitudes toward wolves.     

Identification of soil contamination hotspots with veterinary antibiotics using heavy metal concentrations and leaching data—a field study in China

In regions with high livestock densities, the usage of antibiotics and metals for veterinary purposes or as growth promoters poses a risk in manured soils. We investigated to which degree the concentrations and depth distributions of Cu, Zn, Cr and As could be used as a tracer to discover contaminations with sulfonamides, tetracyclines and fluoroquinolones. Besides, we estimated the potential vertical translocation of antibiotics and compared the results to measured data. In the peri-urban region of Beijing, China, soil was sampled from agricultural fields and a dry riverbed contaminated by organic waste disposal. The antibiotic concentrations reached 110 μg kg^?1 sulfamethazine, 111 μg kg^?1 chlortetracycline and 62 μg kg^?1 enrofloxacin in the topsoil of agricultural fields. Intriguingly, total concentrations of Cu, Zn, Cr and As were smaller than 65, 130, 36 and 10 mg kg^?1 in surface soil, respectively, therewith fulfilling Chinese quality standards. Correlations between sulfamethazine concentrations and Cu or Zn suggest that in regions with high manure applications, one might use the frequently existing monitoring data for metals to identify potential pollution hotspots for antibiotics in topsoils. In the subsoils, we found sulfamethazine down to ≥2 m depth on agricultural sites and down to ≥4 m depth in the riverbed. As no translocation of metals was observed, subsoil antibiotic contamination could not be predicted from metal data. Nevertheless, sulfonamide stocks in the subsoil could be estimated with an accuracy of 35–200 % from fertilisation data and potential leaching rates. While this may not be sufficient for precise prediction of antibiotic exposure, it may very well be useful for the pre-identification of risk hotspots for subsequent in-depth assessment studies.     

气候变化对景观和区域过程的影响及其对气候系统的反馈

北极生态系统的生物和物理过程会在不同的时间、空间尺度上对地球生态系统产生反馈作用,并与之相互影响.气候变化对北极地区的影响及其对全球气候系统的反馈主要存在着四种潜在机制反照率改变、生态系统对温室气体的排放或吸收、甲烷类温室气体的排放、影响海洋暖流淡水量的增长.这些反馈机制在某种程度上是由生态系统的分布和特征,尤其是大规模植被区域变化来控制的.通过少量全年的CO2通量测量表明,目前在地理分布上碳源区要比碳汇区要多.根据目前现有的关于CH4排放源地信息表明,景观规模上的CH4排放量对北极地区的温室效应平衡至关重要.北极地区的能量和水量平衡在变化的气候下,也是一个很重要的反馈机制.植被密度以及分布范围的增加会导致反射率的下降,因而会使地表吸收更多的能量.其效果可能会抵消由于极地沙漠地带向极地苔原带的的转化,或极地苔原带向极地森林带的转化,而造成的植被总净初级生产力碳沉降能力的提高而引起的负反馈.永久冻土带的退化对示踪气体动力学有着很复杂的影响.在不连续的永久冻土带地区,升温将会导致其完全消失.依赖于当地水文条件,温室气体排放可能由于气候环境变的干燥或湿润而使得其通量有所变化.总的来说,影响反馈的各种过程复杂的相互作用,以及这些过程随着时间地点的变化,加之数据的缺乏,又会在陆地生态系统气候变化对气候系统产生反馈作用的净效应估计上,产生许多的不确定性,这种不确定性将会影响到一些反馈的大小和方向.     

均衡的植物养分有助于增强茶树抵御真菌的能力从而减少杀虫剂的使用

人们正加大努力以求最大限度地降低杀虫剂的使用,这些杀虫剂是控制茶树和其它作物的病虫害的基本手段 .在中国,由于土壤常常缺少碳酸钾,所以适量使用这种养料有助于减少对杀虫剂的需要 .已经证实,在土壤中加入钾后,茶树感染真菌病的比率下降 .     

大气酸化和实验酸化的北方湖泊中石生藻类群落的复原能力

藻类群落对恢复中酸化湖泊的环境变化具有高度响应性.本文比较了北方湖泊的石生藻类群落从大气酸化(安大略省基拉尼公园)和实验酸化(南302湖,安大略省实验湖泊区)的化学恢复,以评价严重酸化的时空尺度对分类学复原能力(即恢复速率)的影响.复原能力以经过典型对应分析(CCA)湖泊在pH恢复过程中的排序空间上的位移来表示.基拉尼湖泊的复原能力相对而言几乎可以忽略,说明南303号湖8年时间酸化实验对生物恢复的影响要弱于几十年来的大气酸化作用.溶解性有机碳、溶解性无机碳以及钙的增长很好地解释了恢复过程中的酸化湖泊的石生物种丰度的时间变化.南302湖中观察到了相反的分类学复原能力和抗性的轨迹(抗性指扰动后自原来状态的偏离),显示在恢复和酸化过程中影响石生物种的生态因子随相应的pH值不同而不同.本文的发现揭示了在对严重酸化湖泊的生态系统恢复建立模型时,一定要考虑扰动的时空尺度以及引起恢复和酸化轨迹差异的生物滞后响应.