Impact of the 1998 Central American fires on PM2.5 mass and composition in the southeastern United States

The impact of the Central American fires on PM_2.5 mass concentration and composition in the Tennessee Valley region during portions of May, 1998, has been quantified. Elevated concentrations of smoke aerosol tracers—fine potassium, (and to a lesser extent, calcium and silicon) and, where available, organic and elemental carbon—were observed in the region during times in which satellite imagery (TOMS and GOES-8) showed regional transport of hazy, smoky airmasses from southern Mexico and adjacent areas of Central America. Back-trajectories from network sites in the Tennessee Valley network were consistent with this regional transport. The extent of transport of extra-regional fine particle mass during May, 1998, is discussed relative to the new US fine particle mass-based standards for fine particulate matter.     

Habitat-tree protection concepts over 200 years

The protection and sustainable management of habitat trees is an integral part of modern forest nature conservation concepts such as retention forestry. Bats, cavity-nesting birds, arboreal marsupials, and many different saproxylic species depend on habitat trees and their great variety of microhabitats and old-growth characteristics. With a focus on insights from temperate forests, we traced the development of habitat-tree protection over 200 years. The idea was first conceptualized by foresters and natural scientists in the early 19th century. At that time, utilitarian conservation aimed to protect cavity trees that provided roosts and nesting holes for insectivorous bats and birds. By the second half of the 19th century, habitat-tree protection was well known to foresters and was occasionally implemented. Knowledge of the protection of large old trees, a special kind of habitat tree, for sociocultural and aesthetic reasons developed similarly. But, many foresters of that time and in the following decades fundamentally rejected protection of habitat trees for economic reasons. Beginning in the 1970s, forest conservation and integrative forest management became increasingly important issues worldwide. Since then, the protection of habitat trees has been implemented on a large scale. Long-term views on the development of conservation concepts are important to inform the implementation of conservation today. In particular, historical analyses of conservation concepts allow the testing of long-term conservation outcomes and make it possible to study the resilience of conservation approaches to changing social or ecological conditions. We encourage all conservation ecologists to assess the practical and conceptual impact of the initial ideas that led to modern conservation concepts in terms of long-term biodiversity conservation.     

A Regional Perspective on the Diversity and Conservation of Tropical Andean Fishes

Abstract: The tropical Andes harbor an extraordinarily varied concentration of species in a landscape under increasing pressure from human activities. Conservation of the region's native plants and animals has received considerable international attention, but the focus has been on terrestrial biota. The conservation of freshwater fauna, particularly the conservation of fishes, has not been emphasized. Tropical Andean fishes are among the most understudied vertebrates in the world. We estimate that between 400 and 600 fish species inhabit the diverse aquatic environments in the region. Nearly 40% of these species are endemic. Tropical Andean fishes are vulnerable to ongoing environmental changes related to deforestation, water withdrawals, water pollution, species introductions, and hydropower development. Additionally, their distributions and population dynamics may be affected by hydrologic alterations and warmer water temperatures associated with projected climate change. Presently, at least three species are considered extinct, some populations are endangered, and some species are likely to decline or disappear. The long‐term persistence of tropical Andean fishes will depend on greater consideration of freshwater systems in regional conservation initiatives.     

What is in a name? Language,framing and environmental justice activism in California's Central Valley

According to the environmental justice (EJ) literature, one important factor in the movement's success is the development of a frame linking inequality to the disproportionate presence of environmental toxins in low-income communities of colour. This article highlights the resonance of this frame among grassroots activists and professional advocates in California's Central Valley. However, through interviews and focus groups with activists and advocates in six Central Valley communities, we found that only the latter identified their work as EJ. Grassroots activists instead identified their work as about health, community development and environmentalism. Moreover, some were unfamiliar with EJ as a concept while others denied its applicability to their work. Theoretically, our findings suggest that frame resonance needs to be delinked conceptually from movement identification; it is possible for a movement's analysis of social problems and solutions to resonate among those who do not identify with the movement itself. Pragmatically speaking, this can prevent some grassroots activists who are directly affected by environmental racism from accessing the resources and networks that the EJ movement has painstakingly built, and suggests that movement leaders may need to increase their outreach to community groups.     

The Effects of Long-Term Grazing Exclosures on Range Plants in the Central Anatolian Region of Turkey

Over the last fifty years, almost half of the steppe rangeland in the Central Anatolian Region of Turkey (CAR) has been converted to cropland without an equivalent reduction in grazing animals. This shift has led to heavy grazing pressure on rangeland vegetation. A study was initiated in June 2003 using 6 multiscale Modified-Whittaker plots to determine differences in plant composition between areas that have not been grazed in 27 years with neighboring grazed plant communities. A total of 113 plant species were identified in the study area with the ungrazed plots containing 32 plants more than the grazed plots. The major species were Astragalus acicularis, Bromus tomentellus, Festuca valesiaca, Genista albida, Globularia orientalis, Poa bulbosa, and Thymus spyleus ssp rosulans. Grazing impacts on forbs were more pronounced than for grasses and shrubs. Based on Jaccard’s index, there was only a 37% similarity of plant species between the two treatments. Our study led to four generalizations about the current grazing regime and long-term exclosures in the steppe rangeland around the study area: (1) exclosures will increase species richness, (2) heavy grazing may have removed some plant species, (3) complete protection from grazing for a prolonged period of time after a long history of grazing disturbance may not lead to an increase in desirable plant species with a concomitant improvement in range condition, and (4) research needs to be conducted to determine how these rangelands can be improved.     

Cattle Grazing Mediates Climate Change Impacts on Ephemeral Wetlands

Abstract:  Climate change impacts depend in large part on land-management decisions; interactions between global changes and local resource management, however, rarely have been quantified. We used a combination of experimental manipulations and simulation modeling to investigate the effects of interactions between cattle grazing and regional climate change on vernal pool communities. Data from a grazing exclosure study indicated that 3 years after the removal of grazing, ungrazed vernal pools dried an average of 50 days per year earlier than grazed control pools. Modeling showed that regional climate change could also alter vernal pool hydrology. Increased temperatures and winter precipitation were predicted to increase periods of inundation. We evaluated the ecological implications of interactions between grazing and climate change for branchiopods and the California tiger salamander (  Ambystoma californiense ) at four sites spanning a latitudinal climate gradient. Grazing played an important role in maintaining the suitability of vernal pool hydrological conditions for fairy shrimp and salamander reproduction. The ecological importance of the interaction varied nonlinearly across the region. Our results show that grazing can confound hydrologic changes driven by climate change and play a critical role in maintaining the hydrologic suitability of vernal pools for endangered aquatic invertebrates and amphibians. These observations suggest an important limitation of impact assessments of climate change based on experiments in unmanaged ecosystems. The biophysical impacts of land management may be critical for understanding the vulnerability of ecological systems to climate change.     

Recognition of water masses according to geochemical signatures in the Central Mediterranean sea: Y/Ho ratio and rare earth element behaviour

This study reports the results of geochemical investigations carried out in the Strait of Sicily (Central Mediterranean Sea) during the oceanographic cruise BANSIC 2000, focusing on the area around the Pantelleria Island. We evaluate the interface processes between dissolved phase and suspended particulate matter in the water columns on the basis of Y/Ho ratio and rare earth elements and yttrium distributions that are suitable to trace the occurrence of different water layers in Central Mediterranean Area. The main source of trace elements to the sea water system was recognized in the atmospheric fallout, while different scavenging mechanisms among Y and rare earth elements occur. Cation exchange at the dissolved phase-suspended media interface is driven by their external electronic configurations as monitored through the Y/Ho ratios, shape, and amplitude of the tetrad effects calculated along the water columns. The shape and amplitude of the tetrad effects in bottom waters suggest that the preferential Y scavenging from deep water layers depends on the hydrothermal activity in the seafloor. Here, Y is surface-complexed through the formation of inner-sphere complexes; Ho and other heavy rare earth elements are sorbed onto suspended particulate matter surfaces as weak outer-sphere complexes; these materials have a montmorillonite like nature; and preferential incorporation medium rare earth elements in crystal structures of biogenic carbonates is suggested by the relationship between the Eu anomaly and the nutrient contents of water masses.     

滇中经济区生态环境现状及改善对策

以滇中经济区为研究对象,探讨和分析了滇中经济区目前的土地石漠化、水土流失、水资源短缺、水体污染、矿业污染以及重金属污染的生态环境现状,并从经济、社会以及生态环境协调发展的理念,从水土保持、石漠化的治理和开发、科技推广力度、生态环境建设的执法力度以及环保教育等方面提出了滇中经济区生态环境改善的对策。     

An optimized two-step derivatization method for analyzing diethylene glycol ozonation products using gas chromatography and mass spectrometry

The ozonation of hydroxyl compounds(e.g., sugars and alcohols) gives a broad range of products such as alcohols, aldehydes, ketones, and carboxylic acids. This study developed and optimized a two-step derivatization procedure for analyzing polar products of aldehydes and carboxylic acids from the ozonation of diethylene glycol(DEG) in a non-aqueous environment using gas chromatography–mass spectrometry. Experiments based on Central Composite Design with response surface methodology were carried out to evaluate the effects of derivatization variables and their interactions on the analysis. The most desirable derivatization conditions were reported, i.e., oximation was performed at room temperature overnight with the o-(2,3,4,5,6-pentafluorobenzyl) hydroxyl amine to analyte molar ratio of 6, silylation reaction temperature of 70°C, reaction duration of 70 min, and N,O-bis(trimethylsilyl)-trifluoroacetamide volume of 12.5 μL. The applicability of this optimized procedure was verified by analyzing DEG ozonation products in an ultrafine condensation particle counter simulation system.     

1980—2014年中亚地区植被净初级生产力对气候和CO2变化的响应

中亚干旱区分布着世界80%以上的温带荒漠,受气候变化影响显著。论文首先收集实验观测数据验证了干旱区生态系统模型（AEM）,然后运用AEM开展数值模拟实验量化研究了1980—2014年中亚净初级生产力（NPP）的时空格局,评估了不同环境因子（降水、温度、CO₂）的相对贡献率及其交互效应。结果表明：过去35 a中亚干旱区年均NPP总量为1 125±129 Tg C（1 T=10¹²）或218±25 g C/m²。哈萨克斯坦北部地区年NPP值较高（349±39 g C/m²）,而南疆地区年NPP值较低（123±45 g C/m²）。1980—2014年间,中亚NPP总体呈减少趋势 [-0.71 g C/(m²·a)],南疆极端干旱区的NPP降低最为显著 [-2.05 g C/(m²·a)]。相较于1980—1984年NPP均值,在1985—2014年中亚区域NPP总体降低了118 Tg（-10%）。其中CO₂施肥效应促进NPP增加了99.7 Tg （+8%）,气温升高的正效应促进NPP增加了35.4 Tg（+2%）,而降水减少导致NPP降低了221 Tg（-18%）。研究区内9%的地区的NPP主要控制因子为温度,主要分布在天山和哈萨克斯坦北部等高纬高寒地区。降水主控区面积占整个研究区的69%,主要分布在荒漠平原特别是南疆等植被受水分限制的区域。CO₂主控区占研究区面积的20%,主要分布在天山中山带森林区和低海拔地区等水热条件好的区域。研究表明新疆南部地区是中亚的关键生态脆弱区,其生态安全面临着气候变化的挑战,但21世纪的升温不大可能因刺激自养呼吸而对中亚区域NPP造成显著影响。