Cleaner-client interactions on a Caribbean reef: influence of correlates of parasitism

We investigated the influence of known correlates of parasitism, namely fish density, body size and social behaviour, on three highly variable aspects of the interactions between cleaning gobies (Elacatinus spp.) and their clients, on a Barbadian coral reef. We specifically considered (1) variability in client visit rate to cleaning stations, (2) cleaning goby preference for specific clients and (3) variation in the time spent cleaning by cleaners. Using phylogenetically independent contrasts, we found that client species that were abundant on the reef visited cleaning stations more often than rarer client species. This could be due to the positive relationship between ectoparasite load and client density, or alternatively may simply reflect the frequency of contact between cleaners and clients. Cleaning gobies spent more time cleaning large-bodied clients, which usually have higher ectoparasite loads, although cleaning goby preference for clients was influenced by none of the correlates of client parasitism. Overall, factors assumed to correlate with ectoparasite load had a limited influence on the variability observed in the interactions between cleaning gobies and their clients. Received: 27 October 1999 / Received in revised form: 11 January 2000 / Accepted: 24 January 2000     

Ecological economics: themes, approaches, and differences with environmental economics

This article provides a short overview of the main themes of ecological economics (EE). It is argued that EE provides a platform that fosters multidisciplinary environmental research by bringing together the core contributing disciplines – economics and ecology. In addition, EE is regarded as a pluralistic approach to environmental research that can be set opposite to, and has indeed developed as a response to, traditional environmental and resource economics. A comparison of the two fields is presented to clarify the essential differences between them. In addition, specific themes are examined in more detail. These include: sustainable development; the growth debate; international trade; dynamic processes; and behaviour and policy. Electronic Publication     

Role of organic and black carbon in the chemical composition of atmospheric aerosol at European background sites

The mass concentrations of inorganic ions, water-soluble organic carbon, water-insoluble organic carbon and black carbon were determined in atmospheric aerosol collected at three European background sites: (i) the Jungfraujoch, Switzerland (high-alpine, PM_2.5 aerosol); (ii) K-puszta, Hungary (rural, PM_1.0 aerosol); (iii) Mace Head, Ireland (marine, total particulate matter). At the Jungfraujoch and K-puszta the contribution of carbonaceous compounds to the aerosol mass was higher than that of inorganic ions by 33% and 94%, respectively. At these continental sites about 60% of the organic carbon was water soluble, 55–75% of the total carbon proved to be refractory and a considerable portion of the water soluble, refractory organic matter was composed of humic-like substances. At Mace Head the mass concentration of organic matter was found to be about twice than that of nonsea-salt ions, 40% of the organic carbon was water soluble and the amount of highly refractory carbon was low. Humic-like substances were not detected but instead low molecular weight carboxylic acids were responsible for about one-fifth of the water-soluble organic mass. These results imply that the influence of carbonaceous compounds on aerosol properties (e.g. hygroscopic, optical) might be significant.     

Making work safer: Testing a model of social exchange and safety management

Introduction

This study tests a conceptual model that focuses on social exchange in the context of safety management. The model hypothesizes that supportive safety policies and programs should impact both safety climate and organizational commitment. Further, perceived organizational support is predicted to partially mediate both of these relationships.

Methods

Study outcomes included traditional outcomes for both organizational commitment (e.g., withdrawal behaviors) as well as safety climate (e.g., self-reported work accidents). Questionnaire responses were obtained from 1,723 employees of a large national retailer.

Results

Using structural equation modeling (SEM) techniques, all of the model's hypothesized relationships were statistically significant and in the expected directions. The results are discussed in terms of social exchange in organizations and research on safety climate.

Impact on Industry

Maximizing safety is a social-technical enterprise. Expectations related to social exchange and reciprocity figure prominently in creating a positive climate for safety within the organization.     

能见度降低条件下楼梯上行疏散实验研究

为探究地下公共建筑能见度降低场景中,个体及小群体楼梯上行疏散特征,在某公共建筑楼梯间进行个体疏散和小群体疏散实验,分析不同能见度条件下个体在梯段及平台上的疏散速度、疏散行为、小群体特征等关键参数。研究结果表明：梯段速度受能见度影响程度大于平台速度,在正常能见度条件下,小群体行为会对疏散移动速度产生负面影响,在低能见度条件下,小群体行为有助于提升疏散效率,表现在小群体平均速度高于群体中最慢个体速度且小群体和个体之间的速度差异较小。     

Recycling behaviour and attitude: the case of the Hong Kong people and commercial and household wastes

The increasing environmental awareness caused by the green movement has led to changes in attitude towards our traditionally wasteful society. Recent surveys in Hong Kong have shown that waste recycling has gained increasing verbal support among its citizens. This paper reports on recent findings which reveals that some discrepancies exist between people's attitude and behaviour towards waste recycling. The implication of this phenomenon on how and when a waste recycling policy should be carried out is considerable. Two major types of barriers to waste recycling and reduction were evident. Technical barriers to recycling included lack of appropriate information, lack of conveniently located bins and of temporary storage space, whilst the most critical barrier to paper waste recycling was the presence of non-recyclable materials in some paper items. Psychological barriers included the attitude of being troubled, and that too little waste was involved to be worth the effort. Technical barriers were found to dominate in commercial paper waste recycling, and can usually be overcome while psychological barriers were more significant in household waste recycling and are more difficult to solve. Thus, it might be concluded that, if a large scale household waste recycling programme were in place in Hong Kong, more effort should be devoted towards educating the public, to eliminate as many psychological barriers as possible. Findings from attitude surveys on recycling can provide valuable information for policy makers. However, a review of the literature indicates that findings from attitudinal and self-reported behavioural surveys may exaggerate the proportion of those who have a favourable attitude towards the surveyed subject matter. Thus, it is prudent for policy makers to consider the response rate of the surveys also.     

Public perception of drought and climate change in southeast England

Droughts occur as a natural feature of many climates. Several southern areas of the UK experienced water stress during 2004–2006 because of low water availability and high water demand. Climate change scenarios suggest that drought frequency could increase here in the future. This will increase the competition for water across all sectors. Understanding people's perceptions of drought and climate change is likely to be an important factor for sustainable water management by pointing to barriers to behavioural change. A mixed methodology study using questionnaires and focus groups was conducted in the Anglian and southern regions of the UK to explore public perceptions of drought and climate change. Respondents attributed the 2004–2006 regional drought to lower than average rainfall. Water-intensive lifestyles, a growth in population, increasing housing developments, leaking pipes and the privatization of water companies were also implicated. The majority of respondents claimed to change their behaviour to conserve water during 2006. Regarding the future, and under a number of different scenarios, people were more inclined to accept restrictions than agree to pay more to ensure the supply of water. They were concerned about climate change and recognized that more frequent water shortages may be one of the impacts, but this concern did not necessarily translate into action. Barriers to engagement with climate change and water-efficient behaviour included a lack of accessible information, a lack of knowledge regarding the integration of environmental spheres, a lack of resources, and a perceived lack of institutional engagement. The barriers identified appear to pose a major challenge to successful adaptation to climate change.     

Modelling pheromone anemotaxis for biosecurity surveillance: Moth movement patterns reveal a downwind component of anemotaxis

Insect pheromone traps are becoming an increasingly important tool in biosecurity and pest surveillance, alerting managers to the presence of unwanted organisms. To expand the role of these traps beyond their present sentinel role, it is necessary to develop reliable operational models of local insect dispersal. Following the detection of an insect incursion using a pheromone trap, such models could simulate the dispersal of the insect from its emergence site to the point of detection, enabling biosecurity managers to estimate the most likely proximal source of the incursion. An individual-based moth movement model was developed to simulate observed patterns of moth movement in response to the presence or absence of a pheromone. Using parameters derived from a genetic algorithm, it was possible to fit a model based on the three behavioural components (upwind, upwind with zigzags and casting) described in insect anemotaxis theory to a subset of observed movement patterns (0-135° to the wind), but not to the whole spectrum of movement patterns. It appears that current insect anemotaxis theory is missing a downwind flight component. Whilst the frequency of downwind movements is small; their ground speed could lead to significant downwind displacement, having a disproportionately strong influence on a moth movement model, and hence projections of the likely source or target locations.     

Comparison of batch leaching tests and influence of pH on the release of metals from construction and demolition wastes

Construction and demolition wastes are suitable for use in road construction. However, leaching characterization of recycled materials is required to determine their pollutant potential and the consequence of their application in different scenarios. The motivation of this paper is derived from the increasing use of different leaching test methods. In Europe, the confusion resulting from the wide variety of tests used to evaluate environmental properties of construction materials implies that an evaluation of the current practices and the attempt to consolidate the approaches are required.Two equilibrium-based leaching tests (the Dutch test and the European standard) were conducted to assess the environmental impact of four recycled aggregates. Three natural limestone aggregates were used as controls. Both tests measure the potential release of hazardous elements under extreme conditions using different leaching parameters (L/S ratio, pH value and contact time). The results proved that pH is the most relevant factor on the assessment of the differences between leaching methods due to its strong control on the pollutant release.To classify the materials according to their environmental effects, the concentration limit values of the metals imposed by Council Decision 2003/33/EC were used as a reference. The comparison allowed the classification of the recycled aggregates as inert wastes, with the exception of the MR-2 aggregate, which was classified as non-hazardous material.     

Mercury, cadmium and lead concentrations in different ecophysiological groups of earthworms in forest soils

Bioaccumulation of Hg, Cd and Pb by eight ecophysiologically distinct earthworm species was studied in 27 polluted and uncontaminated forest soils. Lowest tissue concentrations of Hg and Cd occurred in epigeic Lumbricus rubellus and highest in endogeic Octolasion cyaneum. Soils dominated by Dendrodrilus rubidus possess a high potential of risk of Pb biomagnification for secondary predators. Bioconcentration factors (soil-earthworm) followed the sequence ranked Cd > Hg > Pb. Ordination plots of redundancy analysis were used to compare HM concentrations in earthworm tissues with soil, leaf litter and root concentrations and with soil pH and CEC. Different ecological categories of earthworms are exposed to Hg, Cd and Pb in the topsoil by atmospheric deposition and accumulate them in their bodies. Species differences in HM concentrations largely reflect differences in food selectivity and niche separation.