俄罗斯出口关税调整对中国木材市场的影响

俄罗斯是中国最大的原木进口来源国,俄罗斯政府宣布从2010年1月起将原木出口关税从当前的6.5%增加到80%.本文通过建立中国区域木材市场模型,模拟了俄罗斯原木出口关税提高将对我国各地区的木材市场产生的数量影响.由模型得到的结论是:东北地区将受到的影响最大,森林资源的采伐压力会因为进口关税的大幅度提高而增加;中部地区的采伐量将增加约2%左右;而西部和南部地区的采伐数量几乎不变.从全国范围来看,我国采伐总量将增加3.23%.从地区间的贸易影响来看,中部地区的木材进口会流向东北地区,来弥补东北进口木材数量减少带来的影晌.据此,文章最后提出了相应的政策建议:进口渠道的多元化,保证国内的木材安全;相关政府部门应进一步为中国林业加工企业到俄罗斯投资提供便利和引导,从而进一步明晰产业分工格局;从俄罗斯进来的原木减少,应将大部分板材落地加工,促使地区木材产品结构调整和产业升级,逐渐改变单以加工锯材为主的产品结构.     

Social learning from public engagement: dreaming the impossible?

Learning that transcends participation processes is critical if public engagement is to translate into a legacy of enhanced environmental citizenship. However, a lack of empirical evidence has limited discussion to date to largely ‘aspirational’ claims. This paper offers the first rigorous examination of whether public participation does generate beyond-process social learning. Initially we review the literature on public participation and environmental citizenship to identify the key dimensions of social learning. We then re-visit a well-worked case study of an innovative public engagement process on the Hampshire waste strategy from the 1990s. Approximately one third of the original participants have been interviewed to identify whether and how the experience had a lasting effect on them. Key methodological difficulties are discussed, not least the analytical difficulties of attributing learning to a process that happened ten years previously. However, we argue that there is evidence that both instrumental and communicative learning have taken place, and conclude by identifying key areas that require further research.     

Promoting the use of BaP as a marker for PAH exposure in UK soils

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants that frequently accumulate in soils. There is therefore a requirement to determine their levels in contaminated environments for the purposes of determining impacts on human health. PAHs are a suite of individual chemicals, and there is an ongoing debate as to the most appropriate method for assessing the risk to humans from them. Two methods predominate: the surrogate marker approach and the toxic equivalency factor. The former assumes that all chemicals in a mixture have an equivalent toxicity. The toxic equivalency approach estimates the potency of individual chemicals relative to the usually most toxic Benzo(a)pyrene. The surrogate marker approach is believed to overestimate risk and the toxic equivalency factor to underestimate risk. When analysing the risks from soils, the surrogate marker approach is preferred due to its simplicity, but there are concerns because of the potential diversity of the PAH profile across the range of impacted soils. Using two independent data sets containing soils from 274 sites across a diverse range of locations, statistical analysis was undertaken to determine the differences in the composition of carcinogenic PAH between site locations, for example, rural versus industrial. Following principal components analysis, distinct population differences were not seen between site locations in spite of large differences in the total PAH burden between individual sites. Using all data, highly significant correlations were seen between BaP and other carcinogenic PAH with the majority of r ² values > 0.8. Correlations with the European Food Standards Agency (EFSA) summed groups, that is, EFSA2, EFSA4 and EFSA8 had even higher correlations (r ² > 0.95). We therefore conclude that BaP is a suitable surrogate marker to represent mixtures of PAH in soil during risk assessments.     

The institutional design of forest certification standards initiatives and its influence on the role of science: the case of forest genetic resources

In the 1990s a wide array of non-governmental certification initiatives emerged as a way to promote the sustainable management of resources in sectors such as fisheries and forestry. In this paper, we examine two related questions about these initiatives: how does the institutional design of certification initiatives affect the way science is used in the development of certification standards and in whose interest is science employed? Using the empirical case of forest certification and the specific standards various initiatives have created to address the management of forest genetic resources, we show how structural aspects of decision-making processes affects the standards adopted and the rationalization for their appropriateness. Two basic models of decision-making-stakeholder participation and technical expertise-are discussed in relation to three certification initiatives active in North America-the Canadian Standards Association, the Sustainable Forestry Initiative and the Forest Stewardship Council. By examining the standards these initiatives set for the management of forest genetic resources, we illustrate how two dimensions of science-uncertainty and the logic of cause and effect-are used to rationalize cautious and rigid versus flexible and discretionary standards for the management of forest genetic resources. Our findings indicate that the design or structure of certification decision-making processes, and their embedded balance of authority, mediate the form of standards initiatives will justify on the basis of science.     

Stable social aggregations in an Australian lizard,Egernia stokesii

Social groups in many animal species contain family members, and are maintained by parental care, and then tolerance of related individuals in the group. Lizards rarely show prolonged parental care, and rarely form stable social aggregations, although cohesive groups have been reported in the Australian skink genus, Egernia. A population of Egernia stokesii was surveyed for six seasons on Camel Hill, South Australia. At this site individuals occupied rock crevices for refuges on an isolated rocky outcrop of about 1.5 ha. The population was divided into 17 stable social groups, each containing 2-17 individual lizards. Surveyed juveniles took more than 5 years to reach mature size, and most juveniles and subadults remained in the social group of their parents for that period and longer. There were 2-8 permanent adult members of each group. Group members shared common crevice refuges, basked close together (and sometimes on top of each other) and defecated in common scat piles. There was low mortality after the first 2 years of life, and low dispersal either into or out of the population. Some individuals were "floaters" that did not belong to a social group. Over the study a number of these became established in groups. The social structure of these lizards resembles the family groups reported in many species of birds and mammals where group members help to raise the offspring of relatives. The low level of parental care in lizards suggests that the evolution of this form of social organisation in lizards has resulted from different processes than in other vertebrate taxa.     

Identifying landscape scale patterns from individual scale processes

Extrapolating across scales is a critical problem in ecology. Explicit mechanistic models of ecological systems provide a bridge from measurements of processes at small and short scales to larger scales; spatial patterns at large scales can be used to test the outcomes of these models. However, it is necessary to identify patterns that are not dependent on initial conditions, because small scale initial conditions will not normally be measured at large scales. We examined one possible pattern that could meet these conditions, the relationship between mean and variance in abundance of a parasitic tick in an individual based model of a lizard tick interaction. We scaled discrepancies between the observed and simulated patterns with a transformation of the variance–covariance matrix of the observed pattern to objectively identify patterns that are “close”.     

Home range overlap of mothers and their offspring in the sleepy lizard, Tiliqua rugosa

This paper reports a field investigation of interactions between juveniles and their mothers in the Australian sleepy lizard, Tiliqua rugosa. In their first spring season, juvenile lizards maintain home ranges largely within the home range of their mother. Juvenile home ranges are significantly smaller than those of adult males and females, and juveniles move significantly less often and significantly shorter distances than adults. While siblings were never found together in the spring, they showed a significant tendency to be closer to each other than if they were randomly located in their home ranges. Juveniles and mothers were never found together, nor was there any evidence for any positive (or negative) spatial association. Nevertheless, the extended tolerance of home range overlap represents a greater degree of mother-offspring association than has been previously reported for other lizards. Despite this, the level of parental care can only be described as minimal. Received: 20 June 1997 / Accepted after revision: 29 December 1997     

The critical loads/levels approach to gaseous pollutant emission control

There is increasing pressure to control gaseous acidifying emissions to prevent harmful environmental effects; many governments are looking for a more effective and scientific means of assessing effects and planning emission controls compared with arbitrarily uniform percentage reductions. The critical loads/levels concept may offer the basis for a solution which is acceptable internationally. There is already agreement to map the critical loads and levels for countries in Europe and North America as a first step towards assessment. Recent developments in defining and quantifying critical loads and levels show the approach could be sufficiently adaptable to apply to the effects of different pollutants on a range of environmental receptors. Whilst it is difficult to arrive at an agreed single definition, various international groups have arrived at definitions which suit their own particular purposes. Despite a variety of different approaches to arriving at estimates of critical loads, there is broad agreement at the figures calculated by the different methods. An extension of the concept, the target load/level, provides a practical solution for implementing control strategies to prevent or minimize environmental effects.     

An empirical map of critical loads of acidity for soils in Great Britain

The method used to produce a critical load map of acidity for soils in Great Britain is described. Critical loads were assigned to the dominant soil in each 1 km grid square of the UK national grid. Mineral soils were assigned a critical load based on mineralogy and chemistry, using approaches appropriate to UK conditions. Critical loads for peat soils are based primarily on a maximum acceptable reduction of peat pH, and results from laboratory equilibration studies. The map shows that soils with small critical loads (<0.5 kmol_c ha⁻¹ year⁻¹) i.e. highly sensitive to acidic deposition, dominate in the north and west of Britain; the south and east are dominated by soils with large critical loads, with small areas of more sensitive soils associated with sandy soil-forming materials. A modified critical load map illustrates the potential impact of agricultural liming on soil critical loads.     

Egg mass and shell thickness in dippers Cinclus cinclus in relation to stream acidity in Wales and Scotland

The shell thickness and mass of eggs of the dipper (Cinclus cinclus) collected on streams of different pH in Wales and Scotland were measured. The aluminium, phosphorus and calcium content of their invertebrate prey were also measured. In a regression analysis, significant at p<0.05, stream pH accounted for up to 7% of the variance in shell thickness, with shells decreasing by 2.5% of the overall mean with each unit of pH decline. In the Welsh sample, differences in shell thickness due to pH were small compared with differences between years across all sites. In data pooled between Scotland and Wales, pH accounted for 17% of the variance in egg mass, but a greater proportion (25%) in Scottish eggs alone. Aluminium concentrations in invertebrates showed no relationship with stream pH, but calcium levels in two insect orders increased significantly with pH. Calcium rich prey, such as Gammarus, were found only in circumneutral streams. The importance of calcium in the diet of dippers before and during egg formation is discussed. No evidence that aluminium in prey adversely affected dipper eggs was found.