Anthropogenic changes of the environment influence the distribution and abundance of pollinators such as bumblebees and have been proposed as one of the main causes in their worldwide decline. In order to evaluate the impact of expanding anthropogenic landscapes on supporting pollinator potential, reliable tools are needed. Bombus terrestris is one of the most abundant bumblebee species in Europe, and these bumblebees are known as generalist pollinators of not only wild flowers in nature but also of crops in agriculture. For more than two decades, these bumblebees have been commercially mass reared for biological pollination in greenhouses. In this project, we placed commercial hives of the bumblebee B. terrestris containing one queen and 40 workers, in three different locations in the region of Ghent (Belgium), and the performance of these hives was followed during a 4-week period in spring 2012. In parallel, we determined the floral richness and diversity index in the chosen study sites. The sites consisted of a rich urban environment with patchy green areas opposed to an urban environment with poor landscape metrics; a third rural study site showed average positive landscape metrics. The results demonstrated that the hive biomass and numbers of workers increased significantly in the rich compared to the poor environment, providing a mechanism to discriminate between study sites. In addition, the bumblebee-collected pollen showed that the flowering plants Salix spp. and Rosaceae/Prunus spp. are dominant food sources in all anthropogenic environments during early spring. Finally, the results are discussed in relation to the optimization of the experimental setup and to the use of commercial bumblebee hives in assessing local pollinator support within any given environment. 相似文献
Well-known mathematical models related to blending problem are extended and adjusted to the specific blending problem in copper production. Certain constraints are deduced from the process of making copper as well as from the ecological aspects of the production process. The models are applied to the production experience at the copper-smelting plant RTB Bor. The implementation of introduced models was made in the programming package MATHEMATICA. Numerical results corresponding to the introduced mathematical model were compared with results obtained by implementing the classical mathematical models. 相似文献
The environmental Kuznets curve (EKC) hypothesis assumes the nonlinear relationship between production and its environmental effects, suggesting that the negative effect of production on the natural environment is reversed at higher levels of development. In contrast to the majority of the studies, this paper considers the possibility of non-linear effects of per capita output on agricultural land use (cropland), as one of the natural resource stocks, and additionally examines the influence of demographic and productivity variables on the agricultural land use. The study draws on panel data from 143 economies over the 1990–2019 period and employs a series of panel econometrics techniques (including panel unit root and cointegration tests, panel ordinary least squares, generalized method of moments, and panel quantile models). The results unequivocally indicate the inverted U-shaped relationship between the GDP per capita and cropland use, as per EKC hypothesis. The results are robust with respect to employing different techniques, the identified turning points correspond to low and low-middle-income levels, and the effects of agricultural productivity and population density on land use are respectively negative and positive. 相似文献
Ambio - The peregrine falcon (Falco peregrinus) and the gyrfalcon (Falco rusticolus) are top avian predators of Arctic ecosystems. Although existing monitoring efforts are well established for both... 相似文献
In this article, several findings on socio-economic conditions derived from national reports and a web-based questionnaire are discussed and related to the changing role of forestry and the future forest policy development. A number of Central and South-eastern European countries taking part in a SEE-ERA-NET project ReForMan project (www.reforman.de) participated in data acquisition: Austria, Bosnia and Herzegovina, Croatia, Germany, Serbia and Slovenia. The aim of the research was to illustrate the present structure of forestry sector, as well as investigate newly emerging topics in forestry of Central and South-eastern Europe. The results indicated certain patterns in attitudes and perceptions among stakeholders that can be related to socio-economic conditions defined for each country. Clear differences between member and non-member countries exist only in level of implementation of EU legislation. Results showed consensus on main threats to the forests among all countries, but also some country specifics in perceptions of factors influencing forestry, their importance and professional competencies. These results could be additionally explained by influence of historical conditions which shaped development of forest sector in SEE region especially in its organizational dimension as well as in perceived role of forestry expressed through recognition of main forest functions. The influence of European forest policy processes in the region is evident through adaptation of EU legislation and perceived implications of international processes on national levels. Based on this observation, two possible options for future development of the forestry sector can be foreseen: (i) focusing on the productive function of forests and fostering its' sustainable use; or (ii) putting an emphasis on environmental and social issues. In both cases supporting public participation in decision-making processes is recommendable. Another conclusion based on perceived medium to low professional competencies to cope with new topics, that there is lack of confidence and need for professional support in decisionmaking processes. 相似文献
The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets. 相似文献
In this work, continuous and size-segregated aerosol measurements at Mt. Krvavec, Slovenia, during the Eyjafjallajökull volcanic eruption were performed. Based on chemical and morphological characteristics of size-segregated particles, the presence of the volcanic aerosols after long-range transport to Slovenia was to be confirmed.
Results and conclusions
Continuous measurements with the aethalometer and SMPS indicated the suspected volcanic ash plume passing over the sampling site. The aerosols collected by discrete sampling showed a chemical signature similar to the known elemental signature of the Icelandic volcanic ash. Coarse particles showed a composition typical for silicates rich in metals; in many cases also S was present. Morphological analysis showed particles with features indicative of an explosive volcanic eruption, e.g., pumice and pumice shards, glass shards, minerals, evidence of steam condensation, etc. The high sulfate concentration associated with the fine particles resulted in sulfate crystallization within the cascade impactor leading to the formation of large structures resembling a “fern”. Mass size distributions for Fe, Ti, Mn, Ca, Na, and Mg showed one primary peak (for Fe, Mn, and Ti at 2.8 μm; for Ca, Na, and Mg at ca. 4 μm), which supports the fact that most of the particles in the coarse sizes were silicates rich in metals. The size distribution of the water-soluble SO42? showed a maximum peak at 0.75 μm, which also confirms the high sulfate concentration in the fine particles. Chemical and morphological characterization of aerosols collected at Mt. Krvavec indeed confirmed that volcanic ash plume passed over Slovenia. 相似文献
Atmospheric deposition of nitrogen (N) and sulfur (S) containing compounds affects soil chemistry in forested ecosystems through (1) acidification and the depletion of base cations, (2) metal mobilization, particularly aluminum (Al), and iron (Fe), (3) phosphorus (P) mobilization, and (4) N accumulation. The Bear Brook Watershed in Maine (BBWM) is a long-term paired whole-watershed experimental acidification study demonstrating evidence of each of these acidification characteristics in a northeastern U.S. forested ecosystem. In 2003, BBWM soils were studied using the Hedley fractionation procedure to better understand mechanisms of response in soil Al, Fe, and P chemistry. Soil P fractionation showed that recalcitrant P was the dominant fraction in these watersheds (49%), followed by Al and Fe associated P (24%), indicating that a majority of the soil P was biologically unavailable. Acidification induced mobilization of Al and Fe in these soils holds the potential for significant P mobilization. Forest type appears to exert important influences on metal and P dynamics. Soils supporting softwoods showed evidence of lower Al and Fe in the treated watershed, accompanied by lower soil P. Hardwood soils had higher P concentrations in surface soils as a result of increased biocycling in response to N additions in treatments. Accelerated P uptake and return in litterfall overshadowed acidification induced P mobilization and depletion mechanisms in hardwoods. 相似文献
Environmental Economics and Policy Studies - This paper provides an empirical examination on the interactions among macroeconomic policies, the energy market and environmental quality. The analysis... 相似文献
Environmental objects (surface and groundwater, soil, bottom sediments, wastewater) are reservoirs in which large-scale multidirectional exchange of determinants of antibiotic resistance between clinical strains and natural bacteria takes place. The review discusses the results of studies on antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG) isolated from environmental objects (water, soil, sewage, permafrost) of the Russian Federation. Despite the relevance of the topic, the number of available publications examining the resistomes of Russian water bodies and soils is small. The most studied environmental objects are surface waters (rivers, lakes), permafrost deposits. Soil resistomes are less studied. Data on ARG and ARB in wastewater are the least covered in publications. In most of the studies, antibiotic resistance of isolated pure bacterial cultures was determined phenotypically. A significant number of publications are devoted to the resistance of natural isolates of Vibrio cholerae, since the lower reaches of the Volga and Don rivers are endemic to cholera. Molecular genetic methods were used in a small number of studies. Geographically, the south of the European part of Russia is the most studied. There are also publications on the distribution of ARG in water bodies of Siberia and the Russian Far East. There are practically no publications on such developed regions of Russia as the center and northwest of the European part of Russia. The territory of the country is very large, anthropogenic and natural factors in its various regions vary significantly; therefore, it seems interesting to combine all available data in one work.