排序方式: 共有9条查询结果,搜索用时 15 毫秒
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Stevens CJ Duprè C Dorland E Gaudnik C Gowing DJ Bleeker A Diekmann M Alard D Bobbink R Fowler D Corcket E Mountford JO Vandvik V Aarrestad PA Muller S Dise NB 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2243-2250
A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha−1 yr−1) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. 相似文献
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Skarpe C Aarrestad PA Andreassen HP Dhillion SS Dimakatso T du Toit JT Duncan Halley J Hytteborn H Makhabu S Mari M Marokane W Masunga G Ditshoswane M Moe SR Mojaphoko R Mosugelo D Motsumi S Neo-Mahupeleng G Ramotadima M Rutina L Sechele L Sejoe TB Stokke S Swenson JE Taolo C Vandewalle M Wegge P 《Ambio》2004,33(6):276-282
Northern Botswana and adjacent areas, have the world's largest population of African elephant (Loxodonta africana). However, a 100 years ago elephants were rare following excessive hunting. Simultaneously, ungulate populations were severely reduced by decease. The ecological effects of the reduction in large herbivores must have been substantial, but are little known. Today, however, ecosystem changes following the increase in elephant numbers cause considerable concern in Botswana. This was the background for the "BONIC" project, investigating the interactions between the increasing elephant population and other ecosystem components and processes. Results confirm that the ecosystem is changing following the increase in elephant and ungulate populations, and, presumably, developing towards a situation resembling that before the reduction of large herbivores. We see no ecological reasons to artificially change elephant numbers. There are, however, economic and social reasons to control elephants, and their range in northern Botswana may have to be artificially restricted. 相似文献
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印染行业清洁生产技术 总被引:3,自引:0,他引:3
论述了目前印染行业水污染的现状及原因,指出调整产业结构、应用新工艺、大力提倡节约用水、清沽生产将是印染行业实现可持续发展的必由之路。 相似文献
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Stevens CJ Gowing DJ Wotherspoon KA Alard D Aarrestad PA Bleeker A Bobbink R Diekmann M Dise NB Duprè C Dorland E Gaudnik C Rotthier S Soons MB Corcket E 《Environmental management》2011,48(5):885-894
There is a growing evidence base demonstrating that atmospheric nitrogen deposition presents a threat to biodiversity and ecosystem function in acid grasslands in Western Europe. Here, we report the findings of a workshop held for European policy makers to assess the perceived importance of reactive nitrogen deposition for grassland conservation, identify areas for policy development in Europe and assess the potential for managing and mitigating the impacts of nitrogen deposition. The importance of nitrogen as a pollutant is already recognized in European legislation, but there is little emphasis in policy on the evaluation of changes in biodiversity due to nitrogen. We assess the potential value of using typical species, as defined in the European Union Habitats Directive, for determining the impact of nitrogen deposition on acid grasslands. Although some species could potentially be used as indicators of nitrogen deposition, many of the typical species do not respond strongly to nitrogen deposition and are unlikely to be useful for identifying impact on an individual site. We also discuss potential mitigation measures and novel ways in which emissions from agriculture could be reduced. 相似文献
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Christina Skarpe Per Arild Aarrestad Harry P. Andreassen Shivcharn S. Dhillion Thatayaone Dimakatso Johan T. du Toit Duncan J. Halley Hkan Hytteborn Shimane Makhabu Moses Mari Wilson Marokane Gaseitsiwe Masunga Ditshoswane Modise Stein R. Moe Rapelang Mojaphoko David Mosugelo Sekgowa Motsumi Gosiame Neo-Mahupeleng Mpho Ramotadima Lucas Rutina Lettie Sechele Thato B. Sejoe Sigbjrn Stokke Jon E. Swenson Cyril Taolo Mark Van 《Ambio-人类环境杂志》2004,33(6):254-260
博茨瓦纳北部及其毗邻地区分布着世界上最大的非洲象种群(Loxodonta africana),而在100年前,由于过度捕猎,大象的种群数量极为稀少. 相似文献
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Carly J. Stevens Cecilia Duprè Cassandre Gaudnik Albert Bleeker Didier Alard David Fowler J. Owen Mountford Per Arild Aarrestad Nancy B. Dise 《Environmental pollution (Barking, Essex : 1987)》2010,158(9):2940-2945
Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha−1 yr−1) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. 相似文献
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The area along the Norwegian-Russian border is threatened by air pollution from emission sources on the Kola Peninsula. A permanent network of 78 systematically chosen monitoring sites has been established in eastern Finnmark, Norway. Species abundance data from the ground vegetation have been recorded from 1320 systematically chosen permanent plots inside 66 of these sites, using frequency in subplots and visual estimates of percentage cover. Environmental variables were obtained for the whole site. Multivariate data analysis has been used to describe the variation in the species composition and to study its relation to environmental variables and pollution impact. The analyses show that much of the variation in the species composition, based on average species abundance at the sites, is well explained by different soil and climatic conditions. However, estimated SO2 deposition, Ni, and Cu in the soil, and Ni in Cladina tissue have also been found to be statistically significantly correlated with the variation in the species data, but they explain only a minor part of the variation. The pollution impact over several years may have lead to a reduced lichen cover in the bottom-layer vegetation. Further development in an either negative or positive direction can be detected by re-investigations of the monitoring sites. 相似文献
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将时间-活动模式与微环境空气污染物监测相结合估计儿童个体NOx暴露水平. 分别在北京和青岛两市各选择3所学校监测校园环境污染物,并在每个学校选择10名儿童监测其家庭居室空气中ρ(NOx)及个体24 h NOx暴露水平,同时收集其时间-活动信息,采用时间-活动模式估计儿童的个体暴露水平. 交通工具中的NOx暴露水平可通过校门口空气中ρ(NOx)和交通工具的污染水平系数(λ)估计.结果表明:利用时间-活动模式模拟的儿童个体24 h NOx暴露水平为0.041 mg/m3,与调整后的个体暴露实测水平相关性较好(R0.785,P<0.01),差值为(-0.002 6±0.013 0) mg/m3,二者的差异无统计学意义 (t0.139,P>0.05).表明采用时间-活动模式与微环境空气质量监测结果相结合方法估计的儿童NOx暴露水平与个体实际暴露水平一致. 相似文献
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