DETRITUS ABUNDANCE AND BENTHIC INVERTEBRATE CATCH IN ARTIFICIAL SUBSTRATE SAMPLES FROM MOUNTAIN STREAMS1

ABSTRACT: Artificial substrates were designed using rock filled polyethylene bags which were perforated with holes. The substrates trapped waterborne sediment and detritus which enhanced microhabitat complexity. Colonization was compared in side-by-side tests with multiple plate samplers in mountain streams ranging from second to seventh order. After 41 days the bag samples contained more sediment and detritus and more animals than did multiple plates. Plastic bags exceeded multiple plate samples by a factor of nearly 8 for individuals and 1.5 for taxa expressed as numbers/sampler. Although detritus amounts differed significantly between samplers, catch composition was similar in habitat preference and functional groups. Most taxa were “lotic erosional” or “lotic erosional-depositional” detritivores. The plastic bags better represented the streambed fauna judged by their greater similarity to dip net samples. Bag samplers had 4.5 × the colonization area of multiple plates, hence would be expected to support more species. Catch/m² of colonization area was not significantly different between samplers. Functionally the plastic bags act as detritus retention devices, offering a diverse, highly dynamic microhabitat for colonization. Results are interpretable in terms of research on microdistribution of stream benthos and the river continuum model. This study supports the conclusion that stream benthos abundance and diversity are related to the amount of detritus. Maximum diversity and numbers of individuals occurred in samples from third and fourth order streams. Grazers reached peak abundances in the same streams where the continuum model predicts P>R Shredders reached maximum abundances in third and fourth order streams where the riparian canopy was greatest. Predator abundance changed little with stream size. Although bag samples required more sorting time, the samplers are catch effective, inexpensive, and adaptable.     

New directions in Mexican environmental policy

Since taking office 1 December 1988, Mexico's incumbent president, Carlos Salinas de Gortari, has introduced important innovations in environmental policy that distinguish his administration from those of his predecessors. Greater administrative continuity, improved regulatory capacity achieved through statutory change, focused priorities centering on pollution abatement in Mexico City, and an aggressive search for external financing for pollution control are hallmarks of Salinas' approach. The success of these environmental reforms depends heavily on economic recovery, however, and environmental policy still suffers from underfunding, bureaucratic fragmentation, and heavy reliance on voluntarist enforcement mechanisms. Recently, U.S. congressional debate on a proposed free trade agreement with Mexico has been a factor in spurring the Salinas government to take new antipollution and conservation measures. Mexico's growing environmental movement is also an important force behind the government's new responsiveness in environmental matters. The Salinas administration recognizes the issue's political salience and has sought to defuse environmental criticism using a large arsenal of resources at its disposal. Salinas' environmental policy strategy may thus be characterized as both proactive and reactive in nature. While the reforms are evidence that Mexico is beginning to take environmental matters more seriously, economic recovery and sustained environmental activism remain vital to further progress.     

淀山湖浮游植物功能群演替特征及其与环境因子的关系

淀山湖属亚热带浅水湖泊,是上海市重要的水源地之一.为了解该湖浮游植物功能群的特征及其与环境因子的关系,于2015年1月至2016年12月逐月对浮游植物和环境因子进行调查分析.结果表明,淀山湖浮游植物可划分为26个功能群,其中15个功能群(B、C、D、F、G、H1、J、Lo、M、MP、P、W1、W2、X1和X2)为该湖的优势功能群.2015~2016年淀山湖优势浮游植物功能群呈现明显的周年演替特征,2015年为D/C→Lo/C/MP→MP/J/P/W1→P,2016年为P→W2/Lo→W2/G/M/H1→P.利用典范对应分析(CCA)探讨淀山湖浮游植物功能群与环境因子间的相互关系,结果表明水位波动(WLF)、溶解氧(DO)、水温(WT)、总磷(TP)、电导率(EC)、透明度(SD)和总氮(TN)是影响淀山湖浮游植物功能群的主要环境因子,其中氮磷营养盐和水位波动对淀山湖浮游植物功能群的影响应该引起关注.     

The influence of confounding factors on the relationship between muscle contraction level and MF and MPF values of EMG signal: a review

The purpose of this article is to gather results of studies on the relationship between median frequency (MF) and mean power frequency (MPF) and the level of muscle contraction, and to use those results to discuss the differences in the trends according to factors related to measurement technique and subject. Twenty-one studies with 63 cases for upper limb muscles and nine studies with 31 cases for lower limb muscles were analysed. Most results showed an increase in parameters with an increased level of muscle contraction, only some studies showed a decrease. The influence on parameters of the level of muscle contraction and factors such as subjects, type of contraction, muscle length and electrodes was analysed for each muscle. It was concluded that when analysing the influence of different factors on MF and MPF, because those factors interact they should be considered together, not separately.     

Adsorption and desorption of SO2, NO and chlorobenzene on activated carbon

Activated carbon (AC) is very effective for multi-pollutant removal; however, the complicated components in flue gas can influence each other''s adsorption. A series of adsorption experiments for multicomponents, including SO₂, NO, chlorobenzene and H₂O, on AC were performed in a fixed-bed reactor. For single-component adsorption, the adsorption amount for chlorobenzene was larger than for SO₂ and NO on the AC. In the multi-component atmosphere, the adsorption amount decreased by 27.6% for chlorobenzene and decreased by 95.6% for NO, whereas it increased by a factor of two for SO₂, demonstrating that a complex atmosphere is unfavorable for chlorobenzene adsorption and inhibits NO adsorption. In contrast, it is very beneficial for SO₂ adsorption. The temperature-programmed desorption (TPD) results indicated that the binding strength between the gas adsorbates and the AC follows the order of SO₂ > chlorobenzene > NO. The adsorption amount is independent of the binding strength. The presence of H₂O enhanced the component effects, while it weakened the binding force between the gas adsorbates and the AC. AC oxygen functional groups were analyzed using TPD and X-ray photoelectron spectroscopy (XPS) measurements. The results reveal the reason why the chlorobenzene adsorption is less affected by the presence of other components. Lactone groups partly transform into carbonyl and quinone groups after chlorobenzene desorption. The chlorobenzene adsorption increases the number of C = O groups, which explains the positive effect of chlorobenzene on SO₂ adsorption and the strong NO adsorption.     

弱粘煤低温氧化活性基团与热效应的研究*

为研究煤氧化过程中活性基团的演变规律及热效应的变化特征,利用原位红外实验装置,实时测量煤升温过程中官能团的动态变化,数据处理得到弱粘煤红外波谱图,利用差减法对特征温度点下的红外光谱图进行处理,得到煤样的差示光谱,计算特征温度点下的红外结构参数;采用差示扫描量热仪,测量煤氧化过程中热流的变化,得到弱粘煤的热流曲线图,并对热流曲线进行阶段划分和氧化动力学计算。结果表明:弱粘煤中芳环数量比较少,环周围侧链较长,内部结构疏松,内部毛细管比较发达,内表面积较大,更容易发生自燃;整个氧化过程中羟基最为活跃,含氧官能团次之,其次是脂肪烃;红外参数计算结果HAL,I2整体呈减小趋势,I1,I3整体呈增大趋势;弱粘煤放热阶段的活化能值为25.12～61.26 kJ/mol,并随着升温速率的增大而减小,与此阶段放热量随升温速率的增大而增大相对应。     

Simulating dynamics of managed monsoon evergreen broad-leaved forest in south China

The forest succession model FORDYN is developed based on TREEDEV model. TREEDEV is a process-based tree growth model, that calculates tree growth based on carbon and nitrogen balance, and is calculated using on the photo-production of leaves, respiration, nitrogen content of all organisms and that in soil, and other losses due to respiration, litter and renewal of stems, branches, leaves and roots. In the FORDYN model succession is divided into three phases called early, middle and late succession, and the transition between these three succession phases is distinguished by a difference in leaf area index. As a verification of the model we used the characteristics and available data of a monsoon evergreen broad-leaved forest in Dinghushan Biosphere Reserve (DHS-BR). The model was validated with natural forest data. In addition, a sensitivity analysis was performed in which 30 independent variables were varied and analyzed in connection with their influence on 16 dependent variables describing forest conditions. The simulation results describe the changes in total biomass, carbon and nitrogen change in plant–litter–soil system of an undisturbed monsoon evergreen broad-leaved forest during succession. We compared these findings with simulation in which different logging management strategies were used. The results show that having a longer logging cycle, delaying the first logging time and a smaller logging fraction the scenario can contribute to a sustainable forest development, while still having a positive economic yield.     

土壤动物在污染评价中的作用、现行指标及胁迫环境下的耐受性

土壤污染的动物评价方法需要改进与创新.论文从土壤动物功能群的生物学特性、生活习性及其在土壤养分循环中的作用等方面,综述了土壤动物在土壤污染评价中的应用;介绍了目前国际上通用的土壤动物评价指标和使用方法,包括种群特征、群落结构和生态区域模型;联系土壤污染状况和趋势,阐述了土壤动物对污染胁迫的耐受性及其对现行土壤污染评价方法的影响,并在可塑型适应和组成型适应上探讨了土壤动物耐受性产生的遗传学机理与生物学指标.     

Choice of stakeholder groups and members in multicriteria decision models

Simplistic economic objectives such as maximisation of producer profits are of little relevance in generating information to assist in the management of natural resources beyond the individual firm level. To provide data and information to support decision-making in natural resource management, it is necessary to take into account the views of various stakeholder groups and the multiple objectives of each group, through the use of some form of multicriteria analysis (MCA). Important decisions arise in the choice of stakeholder, since this will influence the management advice generated. Many groups and individuals can be affected by resource management decisions, but it would be impractical to attempt to identify the objectives and estimate their importance for each group. Also, questions arise concerning whether or not to include government agencies (which represent the broader community) and researchers as stakeholders. A further issue concerns choosing representative samples of stakeholder groups, from which to obtain preference data. Discussions with modellers and a reading of the literature would suggest that the choice of stakeholder groups and representatives is conducted haphazardly and is perhaps biased, and that a more systematic approach is needed. This article explores the above issues with reference to a number of multicriteria analyses, including local studies.     

Building capacity through action research: reflections on working with low-carbon communities in the UK

This paper describes a four-year programme of “action research” (AR) undertaken with six communities in the UK, referred to as the Evaluating Low-Carbon Communities (EVALOC) project. The research combined a programme of research events with phased household-level monitoring of energy and carbon-reduction interventions. The carbon-reduction interventions were funded by the UK’s Department of Energy and Climate Change prior to the onset of the research. AR has recently been adopted within the context of environmental behaviour change programmes in the UK, with a number of methodological challenges. The EVALOC project’s challenges included developing a collaborative research design; building reciprocity between the researchers and research participants; dealing with biases and burdens in the research process; ensuring analytical rigour in the interpretation of the primarily qualitative evidence and dealing with the long-term and process-driven outcomes that arise from such interactions. This paper explores and discusses the challenges of AR in relation to selected research outcomes from EVALOC. We conclude by suggesting that the AR approach has helped to build capacity in the participating low-carbon communities (LCCs), through supporting the design, delivery and evaluation of their energy and carbon-reduction activities.