Comprehensive analysis of the carbon impacts of vehicle intelligent speed control

In recent years sophisticated technologies have been developed to control vehicle speed based on the type of road the vehicle is driven on using Global Positioning Systems and in-car technology that can alter the speed of the vehicle. While reducing the speed of road vehicles is primarily of interest from a safety perspective, vehicle speed is also an important determinant of vehicle emissions and thus these technologies can be expected to have impacts on a range of exhaust emissions. This work analyses the results from a very large, comprehensive field trial that used 20 instrumented vehicles with and without speed control driven almost 500,000 km measuring vehicle speed at 10 Hz. We develop individual vehicle modal emissions models for CO₂ for 30 Euro III and Euro IV cars at a 1-Hz time resolution. Generalized Additive Models were used to describe how emissions from individual vehicles vary depending on their driving conditions, taking account of variable interactions and time-lag effects. We quantify the impact that vehicle speed control has on-vehicle emissions of CO₂ by road type, fuel type and driver behaviour. Savings in CO₂ of ≈6% were found on average for motorway-type roads when mandatory speed control was used compared with base case conditions. For most other types of road, speed control has very little effect on emissions of CO₂ and in some cases can result in increased emissions for low-speed limit urban roads. We also find that there is on average a 20% difference in CO₂ emission between the lowest and highest emitting driver, which highlights the importance of driver behaviour in general as a means of reducing emissions of CO₂.     

Impact of genetic diversity and inbreeding on the life-history of Chironomus midges over consecutive generations

We report results of a multigenerational experiment with Chironomus riparius. Two strains with a high and a low level of genetic variability were exposed to a low, environmentally relevant TBT concentration of 80 μg Sn kg⁻¹ sediment dw nominally (time weighted mean, based on measured concentrations: 4.5 μg Sn kg⁻¹ sediment dw), and various life history traits as well as genetic diversity were monitored for eleven consecutive generations. While TBT effects are hardly visible in the outbred and genetically diverse strain, the inbred and genetically impoverished strain shows a clearly reduced population growth rate compared to the control. Moreover, the impoverished strain shows an increase in fitness over time. Analyses of variation at five microsatellite loci revealed that the level of genetic variation is strongly reduced in the inbred compared to the outbred strain. Moreover, genetic diversity increases over time in the inbred strain. This finding explains the observed increase in fitness in both inbred lineages (control and TBT exposed). The results document that inbreeding and the level of genetic diversity might be of crucial importance in populations under pollution stress. Furthermore, ecotoxicological bioassays have to consider genetic diversity if results between laboratories should be comparable. Our data provides evidence that genetic diversity strongly contributes to the survival of a population exposed to chemical pollution.     

Spatial and temporal small-scale variability of nitrogen mobilization in a forest ecosystem with high N deposition in NW-Germany

For conifer stands in NW-Germany with high DIN load (23-35 kg N ha⁻¹ a⁻¹) and a long history of nitrogen export the risk of N mobilization were investigated. Ammonium is the most mobilized N species, pointing towards either conditions not favoring nitrification or, more likely - under the dominant aerobic conditions - a very high amount of ammonium in the forest floor. Independence of net nitrification and net ammonification from each other indicates the existence of two separate systems. The nitrifying system depends very much on biotic conditions - as a function of energy and moisture - and seems not to be directly related to N deposition. In contrast, for the ammonification system (Oe horizon) a correlation with the sum of ammonium deposition three months prior to sampling was found. However, the role of disturbance, i.e. nitrogen export, during the last centuries and the role of recovery of the N balance during the last 150 years is still not clear.     

Rapid genetic erosion in pollutant-exposed experimental chironomid populations

Few studies have evaluated how effectively environmental contamination may reduce genetic diversity of a population. Here, we chose a laboratory approach in order to test if tributyltin (TBT) exposure at environmentally relevant concentrations leads to reduced genetic variation in the midge Chironomus riparius. Two TBT-exposed and two unexposed experimental populations were reared simultaneously in the laboratory for 12 generations. We recorded several life-history traits in each generation and monitored genetic variation over time using five variable microsatellite markers. TBT-exposed strains showed increased larval mortality (treatments: 43.8%; controls: 27.8%), slightly reduced reproductive output, and delayed larval development. Reduction of genetic variation was strongest and only significant in the TBT-exposed strains (treatments: −45.9%, controls: −24.4% of initial heterozygosity) after 12 generations. Our findings document that chemical pollution may lead to a rapid decrease in genetic diversity, which has important implications for conservation strategies and ecological management in polluted environments.     

Evaluation of the effect of long-range transport of air pollutants on coastal atmospheric monitoring sites in and around Taiwan

Long-range transport of pollution outflow from Asian mainland has been noticed and expected to play a significant role in Pacific background. Since 1993 the Taiwanese Environmental Protection Administration (TEPA) is conducting ground-based observations of various particulate and gaseous pollutants at 74 monitoring stations in Taiwan. One of these stations, Heng-Chun at the south coast of Taiwan can be considered as a background station with only negligible amounts of local pollution, and another one, Wan-Li at the north coast, predominantly receives air that has not passed over Taiwan, so that background air can be analysed by means of sectorisation. In this work, the sectorised 13-year time series of measurements of CO, SO₂, O₃, NO_x and PM₁₀, from the Wan-Li station are presen and compared to data from the Heng-Chun station and another TEPA background station off the coast of mainland China, Ma-Zu. The CO and O₃ measurements are also compared to data from the Yonaguni station, a Pacific island site, part of the Global Atmospheric Watch (GAW) network.The similarity of the sectorised data from the Wan-Li station with the data of the other station indicates that atmospheric measurements from the Wan-Li site can be used to make inferences about trends in western Pacific background air pollution and the effect of long-range transport of pollutants. The measurement time series from 1993 to 2006 do not indicate a significant trend in the monthly mean O₃ concentrations in accordance with other research about ozone in tropical latitudes. An increasing trend in CO concentrations of 2.8% per annum is observed between 1999 and 2006 for long-range transport to northern Taiwan, and a doubling of the SO₂ and NO_x concentrations observed at the Wan-Li and Heng-Chun sites within the period 2001–2006. SO₂ concentrations are found to quadruple at Ma-Zu within the same period. The data suggest that pollution from the Asian mainland enhances significantly the background air pollution over the Pacific.     

Spillover of functionally important organisms between managed and natural habitats

Land-use intensification has led to a landscape mosaic that juxtaposes human-managed and natural areas. In such human-dominated and heterogeneous landscapes, spillover across habitat types, especially in systems that differ in resource availability, may be an important ecological process structuring communities. While there is much evidence for spillover from natural habitats to managed areas, little attention has been given to flow in the opposite direction. This paper synthesizes studies published to date from five functionally important trophic groups, herbivores, pathogens, pollinators, predators, and seed dispersers, and discusses evidence for spillover from managed to natural systems in all five groups. For each of the five focal groups, studies in the natural to managed direction are common, often with multiple review articles on each subject which document dozens of examples. In contrast, the number of studies which examine movement in the managed to natural direction is generally less than five studies per trophic group. These findings suggest that spillover in the managed to natural direction has been largely underestimated. As habitat modification continues, resulting in increasingly fragmented landscapes, the likelihood and size of any spillover effect will only increase.     

喜马拉雅中部药用植物的商业评估

本研究对尼泊尔全国药用植物的年产量及商业价值进行了评估.我们对尼泊尔15个地区的当地药用植物交易者(n=149)和印度的地区批发商(n=53)进行了无限制问卷调查,借以收集数据.据估计,年交易额的范围为7000～27 000t,案例年份1997～1998年的产量为14 500t.按印度主要市场的地区批发商购买价格计算,相应的年出口额估计为700～3000万美元,1997～1998年为1600万美元.约有10%的农户参与了商品化采集.低海拔生态区在产量和价值两方面均占优势;就价值而言,药草是最重要的生活型.约有36%的产量和51%的价值来自破坏性采集.有人认为,年产量和价值数据仍有可能属于保守估计.本文还简短讨论了本研究结果对喜马拉雅药用植物保护及贸易的意义.