Biodiversity Differences between Managed and Unmanaged Forests: Meta-Analysis of Species Richness in Europe

Abstract: Past and present pressures on forest resources have led to a drastic decrease in the surface area of unmanaged forests in Europe. Changes in forest structure, composition, and dynamics inevitably lead to changes in the biodiversity of forest‐dwelling species. The possible biodiversity gains and losses due to forest management (i.e., anthropogenic pressures related to direct forest resource use), however, have never been assessed at a pan‐European scale. We used meta‐analysis to review 49 published papers containing 120 individual comparisons of species richness between unmanaged and managed forests throughout Europe. We explored the response of different taxonomic groups and the variability of their response with respect to time since abandonment and intensity of forest management. Species richness was slightly higher in unmanaged than in managed forests. Species dependent on forest cover continuity, deadwood, and large trees (bryophytes, lichens, fungi, saproxylic beetles) and carabids were negatively affected by forest management. In contrast, vascular plant species were favored. The response for birds was heterogeneous and probably depended more on factors such as landscape patterns. The global difference in species richness between unmanaged and managed forests increased with time since abandonment and indicated a gradual recovery of biodiversity. Clearcut forests in which the composition of tree species changed had the strongest effect on species richness, but the effects of different types of management on taxa could not be assessed in a robust way because of low numbers of replications in the management‐intensity classes. Our results show that some taxa are more affected by forestry than others, but there is a need for research into poorly studied species groups in Europe and in particular locations. Our meta‐analysis supports the need for a coordinated European research network to study and monitor the biodiversity of different taxa in managed and unmanaged forests.     

A safety analysis of roundabouts and turbo roundabouts based on Petri nets

Objective: In this work, a roundabout and a turbo roundabout model are compared and previous modeling with continuous Petri nets and safety are analyzed through indicators of complexity. Petri nets are a graphic and mathematical representation that allow a faithful modeling of urban systems.

Method: The methodology has been designed for the transformation of a real system to small subgraphs that represent the maneuvers in roundabouts, approximated as roads and lanes of incorporation. Places within the roundabout have been located and defined as continuous places from their influence and visibility toward adjacent conditions. The transitions have been modeled by time and inhibitory arcs, which represent priorities and areas where drivers must pay attention. The created networks represent a faithful model of vehicle flow trajectories in the roundabouts.

Results: The methodology is applied to the same real road intersection. The case study is a recent transformation from roundabout to turbo roundabout. The roundabout network complexity is corroborated by a greater number of entries and exits that lead to each roundabout place (reflected in the maneuvers that can be performed) and a greater number of inhibiting arcs. In most of the turbo roundabout places, the driver’s only option is reduced to occupying next place. The possibility of choosing between several places supposes a greater trajectory intersection and an increased time for decision making. The only situation where the complexity is the same between both systems is when a vehicle accesses the inner lane of the roundabout from the left lane on a single-lane road. The main maneuvers causing accidents have been modeled and their solution in a turbo roundabout is presented.

Conclusions: The reduced complexity of the turbo roundabout is due to the strict limitations in lane changes, turning turbo roundabouts into a safer model: A lower number of possible movements that can be performed by drivers and a smaller number of trajectories with collision risk. Petri nets have proven to be perfectly applicable to the representation of traffic circular systems (such as roundabouts and turbo roundabouts) and to measure the complexity and security of the system.     

Rain and throughfall chemistry in a Norway spruce forest in the Western Prealps

From January 1987 to December 1989 precipitation was collected in an open field in a forested area of the Western Prealps. The site faces the intensely industrialized area of the Po Valley. In a Norway spruce plantation, next to the open field sampler, throughfall was collected from January 1987 to August 1989 for a period of 32 months. In the common sampling period median pH values of the open field precipitation and throughfall were 4.28 and 4.19 respectively. Open field precipitation has yearly deposition rates of acidity, Ca, S, and N of 0.81, 9.82, 24.83 and 32.81 kg/ha(-1) respectively. The throughfall showed significant increases in the deposition rates for Ca, Mg, K, N and S, due to abundant dry deposition and, probably, to nutrient leaching contributed by the canopies of the spruce. On the basis of available data, an initial approach to atmosphere-canopy interaction was made.     

Remote sensing of aquatic vegetation: theory and applications

Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.     

Multibiomarker approach in fish to assess the impact of pollution in a large Brazilian river, Paraiba do Sul

This article examines the advantages of the use of biomarkers as environmental indicators by applying it to Paraiba do Sul watershed, one of the most important Brazilian water bodies, which is in a critical environmental situation. We use a multibiomarker approach in fish as an integrated strategy to assess the impact of pollution. It comprehends a general biomarker of fish health, the condition factor (CF), and specific biomarkers of contaminant exposure such as metallothionein (MT), acetylcholinesterase (AChE) activity and biliary polycyclic aromatic hydrocarbons (PAH) metabolites. Our results revealed different effects in the fish from diverse locations with varying degrees of pollution. Furthermore, fish located just upstream of the water-treatment plant of the metropolitan area of Rio de Janeiro has shown to be affected by metals. This study indicates the usefulness of integrating a set of biomarkers to define the effects of anthropogenic inputs in aquatic bodies under complex polluted situations.     

The Evolution and Role of Non-OPEC Production in the International Oil Market

In 1982, for the first time since OPEC was founded in 1961, its production was surpassed by the non-OPEC countries in the world excluding the centrally planned economies. In that year, for the world as a whole, OPEC provided 35% of the oil consumed. The decline was brought about by a decrease in consumption and by a marked increase in production from non-OPEC sources. It is expected that non-OPEC producers will have the capacity to meet more than half of the world's oil requirements until the early 1990s, at which time OPEC producers will again assume the role of providing over 50% of the world's oil.     

Protective effect of gamma-oryzanol against manganese-induced toxicity in Drosophila melanogaster

Environmental Science and Pollution Research - Manganese (Mn) is an essential element that, in excess, seems to be involved in the development of different neurodegenerative conditions....     

渤海湾两条河流及其近岸海域水体中DOM的光谱特征及影响因素

应用三维荧光光谱结合吸收光谱分析,研究了2019年夏季天津市大清河-独流减河水系和河北省黄骅市捷地减河及其河口区水体中溶解有机物（DOM）的空间分布特征、来源及其影响因素。紫外-可见光谱结果表明,研究区水体的SUVA₂₅₄与盐度有显著正相关关系;两条河流的下游水体中S_275-295均值均大于上游和中游。平行因子分析结果表明,两条河流均检测到两种类腐殖质组分C1（240,300/390 nm）和C3（260,335/477 nm）以及一种类蛋白质组分C2（225,275/339 nm）。在大清河-独流减河水系及其近岸海域水体中,这三种组分与盐度呈显著负相关关系,其中由于人为输入（TN和TP含量高,工业排污）影响导致C2与盐度的相关性弱于C1和C3。该水系水体在低盐度时C2的占比高于捷地减河,主要受到工农业废水输入与其支流子牙河汇入的共同影响,而捷地减河主要受农业废污水输入的影响。此外,自然因素（盐度、海水混合）和人为因素（人为输入、筑坝拦截）的不同导致渤海湾两条入海河流中有色溶解有机质（CDOM）的光学特性和混合行为出现显著差异。其中筑坝拦截导致独流减河坝前水体的CDOM平均分子量低于下游水体,并且增强了河口区陆源类腐殖质的去除作用。综上,三维荧光光谱结合平行因子分析能判别河流局部条件的差异对整体CDOM空间分布特征的影响,研究结果可为渤海湾地区河流及河口水体CDOM生物地球化学过程研究提供基础数据。     

基于游客视角的红色旅游资源开发价值共创机制

以井冈山风景名胜区作为案例地,基于价值共创理论,运用大数据分析与内容分析方法,收集并分析马蜂窝网站上井冈山景区的游记文本,构建红色旅游资源开发的价值共创机制：以历史文化遗产、自然景观资源和标志性景观符号为资源基础,游客通过红色文化体验、学习培训活动、解说服务体验和自然景观体验等实践活动,获得对红色历史文化的认知、情感的联结和价值观的塑造。另外,红色旅游景区现有的价值共创实践仍旧有限,红色旅游资源开发价值共创机制整合了游客需求、景区支持以及可能存在的价值共创实践,对创新红色旅游资源开发利用手段与产业转型升级具有实践意义。