Species diversity reduces parasite infection through cross-generational effects on host abundance

With growing interest in the effects of biodiversity on disease, there is a critical need for studies that empirically identify the mechanisms underlying the diversity-disease relationship. Here, we combined wetland surveys of host community structure with mechanistic experiments involving a multi-host parasite to evaluate competing explanations for the dilution effect. Sampling of 320 wetlands in California indicated that snail host communities were strongly nested, with competent hosts for the trematode Ribeiroia ondatrae predominating in low-richness assemblages and unsuitable hosts increasingly present in more diverse communities. Moreover, competent host density was negatively associated with increases in snail species richness. These patterns in host community assembly support a key prerequisite underlying the dilution effect. Results of multigenerational mesocosm experiments designed to mimic field-observed community assemblages allowed us to evaluate the relative importance of host density and diversity in influencing parasite infection success. Increases in snail species richness (from one to four species) had sharply negative effects on the density of infected hosts (-90% reduction). However, this effect was indirect; competition associated with non-host species led to a 95% reduction in host density (susceptible host regulation), owing primarily to a reduction in host reproduction. Among susceptible hosts, there were no differences in infection prevalence as a function of community structure, indicating a lack of support for a direct effect of diversity on infection (encounter reduction). In monospecific conditions, higher initial host densities increased infection among adult hosts; however, compensatory reproduction in the low-density treatments equalized the final number of infected hosts by the next generation, underscoring the relevance of multigenerational studies in understanding the dilution effect. These findings highlight the role of interspecific competition in mediating the relationship between species richness and parasite infection and emphasize the importance of field-informed experimental research in understanding mechanisms underlying the diversity-disease relationship.     

Exploring the conservation status of an endangered coastal plant over the last nine years: a case study in Andalusia,Spain

Human pressure has been exponentially growing during recent decades in coastal areas, which have led to drastic losses of biodiversity in coastal ecosystems. The current conservation status of many coastal plant species is directly related to a lack of environmental criteria in the urban planning of coastal areas over recent decades. This study aimed to evaluate the evolution, over the last 9 years, of the conservation status of various populations of the endangered plant Glaucium flavum, exploring the extent to which human pressure and different management strategies practiced in the coastal areas where the populations are established have affected the conservation status of the species. The populations analysed have evolved in a different manner over the last 9 years, as have their threat factors, and a relationship was evident between their conservation status and the evolution of these different threat factors. Our results indicate that an appropriate planning of local management actions, such as the installation of walkways or the successful eradication of invasive species, may be determinant factors for successful conservation of the coastal vegetation. The presence of species that are sensitive to slight changes in the ecosystem, and the main factors that govern the plant performance of these species, must be given full consideration in decision-making processes of coastal planning and management.     

农药引起的两栖动物脑部的变化：亚致死浓度的毒死蜱如何直接影响神经发育

农药虽然可以控制病虫害,但其广泛使用造成自然环境的污染,致使非靶标生物暴露于农药污染环境中。即使低浓度农药暴露也会直接或间接影响水生生物群落。前期人工池塘(中宇宙)研究结果表明痕量毒死蜱(chlorpyrifos, CPF)可改变蝌蚪体态和神经发育。造成这个结果的原因可能为：1)CPF暴露的直接影响;2)农药造成了浮游动物数量下降扰乱食物网。为了明确原因,我们在CPF耐受浮游动物存在的情况下,考察了CPF对两栖动物发育的影响,这种浮游动物是不同营养级别水生生物群落的重要组成部分。豹蛙(Lithobates pipiens)蝌蚪饲养在中宇宙的环境,经过变态期,环境中含有0或1 μg/L CPF,或CPF敏感型浮游动物Daphnia pulex。CPF发育期暴露致使蝌蚪蜕变时视顶盖、延髓、间脑相对更宽,而这一结果与中宇宙中浮游动物种群无关。因此,CPF直接影响大脑发育,与不同营养级别的群落的无关。至于身体形态方面,CPF对无CPF敏感型浮游动物的中宇宙中饲养的蝌蚪蜕变形态没有影响,但在没有CPF污染时,蝌蚪身体形态对浮游动物种群数量很敏感。研究表明,生态水平的低剂量有机磷农药暴露可直接影响脊椎动物的神经发育。 精选自Sara J. McClelland, Randall J. Bendis, Rick A. Relyea, Sarah K. Woodley. Insecticide-induced changes in amphibian brains: How sublethal concentrations of chlorpyrifos directly affect neurodevelopment. Environmental Toxicology and Chemistry,2018,37:2692–2698.
详情请见 https://doi.org/10.1002/etc.4240
     

Chemically treated plastic aggregates for eco-friendly cement mortars

Journal of Material Cycles and Waste Management - The use of waste plastic as aggregate in cement composites can solve the problem of the disposal of waste plastics in a sustainable way, and it...     

Landlords,fear, and children's respiratory health: an untold story of environmental injustice in the central city

Recent research has explored the role of environmental inequalities in explaining health disparities, especially in urban environments. This paper investigates the role of the landlord in shaping indoor environmental injustices. Specifically, we rely on interview data from low-income parents in South Phoenix, AZ, with elementary-aged children with asthma. We found families living in poor quality rental housing that impacted children's breathing. Landlords were directly involved in keeping the homes in poor condition, even when asked by the tenant to fix the property, and immigrants were especially at risk. In general, relationships between landlords and tenants were unequal and coloured by the tenant's poverty and fears of eviction. Among the immigrant tenants, many had accompanying fears of authorities and deportation. The cycle of fear, poverty, and a lack of power compounded as tenants were hesitant to report problems, which reinforced the power of the landlord over the tenant and did nothing to improve living conditions. Recognising the role of landlords in creating substandard housing conditions is important as they represent a group that can be targeted for interventions.     

Towards sustainability management systems in three Swedish local authorities

This paper explores the development towards sustainability management systems (SMSs) in three Swedish local authorities. Many local authorities have extensive experience in using standardised Environmental Management Systems (EMSs). Recently EMSs have extended their reach by widening the scope of the systems including other dimensions of sustainable development. Case studies have been performed in three of the most EMS-experienced local authorities in Sweden. These authorities have extended their EMSs into a sustainability management approach in different ways. This paper discusses the development, possible contributions, and constraints with this development. Expanding EMSs into SMSs can be seen as a learning process in which a larger systems perspective leads to increased awareness that the management system becomes limited by only managing environmental issues. Expanding the EMSs into SMSs may lead to a more complete view of the organisation's total impact on nature and society, and issues that need to be managed.     

Identification of OHS-related factors and interactions among those and OHS performance in SMEs

An enterprise can modify several factors that impact on the Occupational Health and Safety (OHS) performance. Within the implementation of the E-merging project (financed by INAIL, the Italian National Institute for Insurance against Occupational Accidents) – to improve safety in Small- and Medium-sized Enterprises (SMEs) – development context, a thorough literature review, supported by later practitioners’ suggestions, has been performed in order to identify the factors which can be related to the OHS issue. Then, the mutual interactions among the identified OHS-related factors and the interactions among the OHS-related factors and the OHS performance have been identified for SMEs and tested on the basis of two existing data sources, i.e. the INAIL most recent dataset and a survey carried out among SMEs in the metalworking industry. This allows to understand the root causes of some evidences, which enables entrepreneurs and managers to plan interventions for the improvement of the OHS performance.     

Determination of resin acids during production of wood pellets--a comparison of HPLC/ESI-MS with the GC/FID MDHS 83/2 method

Resin acids are constituents of natural and technical products of widespread use. Exposure is known to cause health effects in the airways and on the skin. Liquid chromatography/positive ion electrospray-mass spectrometry (HPLC/pos ESI-MS) was investigated for determination of 7-oxodehydroabietic (7-OXO), dehydroabietic (DHAA) and abietic acid (AA) in wood dust-containing air samples as a derivatisation-free alternative to the GC/FID HSE method 83/2, developed by the Health and Safety Executive UK. The resin acid 7-OXO was measured as a marker for oxidised resin acids, which are known to be the main contact allergens in colophonium. The found detection limits were 0.42 ng m(-3) for 7-OXO, 5.2 ng m(-3) for DHAA and 9.4 ng m(-3) for AA, respectively, which are considerably lower than with the GC/FID method (24, 115 and 89 ng m(-3)). The two methods correlated well, although consistently and significantly lower concentrations of 7-OXO were detected with LC/MS. The higher concentration of this compound with MDHS 83/2 is suggested to be an artefact from the derivatisation step in the presence of soluble wood dust remains.     

Occurrence of pesticides in surface water bodies: a critical analysis of the Italian national pesticide survey programs

In recent years, several monitoring programs have been established as a consequence of EU Directives which include requirements for monitoring the quality of water resources (drinking water, groundwater and surface water). Plant protection products (PPPs) are an obvious target for monitoring activities, since they are directly released into the environment. In Italy, the National Environmental Protection Agency (ISPRA ex APAT) has recently published two reports containing the results of the National Plans for Control of Environmental Effects of PPP. These documents contain the collection of monitoring data related to the presence of PPP residues in surface water and groundwater. The first objective of this work was to critically analyze the results of monitoring campaigns on pesticide residues in surface waters in Italy. In particular, the paper focuses on whether and how the Italian approach satisfies the requirements of the Water Framework Directive, whether they are representative of the whole national territory, and how the utilized approach is appropriate for the characterization of risk to surface water. Starting from this analysis, some considerations about the limits of environmental monitoring as a tool for managing risk were highlighted.     

Impact of repeated irrigation of lettuce cultures with municipal wastewater on soil bacterial community diversity and composition

Environmental Science and Pollution Research - The effect of wastewater irrigation on the diversity and composition of bacterial communities of soil mesocosms planted with lettuces was studied over...