Environmental Change and the Sustainability of European Forests     

《Journal of Sustainable Forestry》2013,32(2-3):165-187

Summary

It is some years now since forest decline was a major public concern in Europe and was one of the principal environmental issues around which international research programs were focused. A number of internationally coordinated activities were initiated in the 1980s and 1990s and have continued until now; these contributed significantly to our current understanding of forestry and to the way in which forestry policies have developed. In short, the concept of sustainable development has had an increasing influence and is now of immeasurable value in forest policy, with sustainable forest management well established as its guiding principle. This sequence of events is examined here. The extent to which understanding has advanced is remarkable; much has changed. Arguably this period gave the first indication of the extent to which forests and ecosystems globally are threatened by environmental change. On the basis of the last 20 years, it is tempting to conclude that we now have an effective institutional framework and have made excellent progress. However, some of the recorded ecosystem responses seem anomalous; there are surprises in system responses, e.g., the linkage between sulphur and nitrogen depositions and forest growth. Even more importantly some specific pollutant problems remain and will intensify, and climate change has become an environmental issue of overwhelming importance.  相似文献   

我国几种温室环境控制系统的架构方案     

白春雨  时玲  张亚静  何根旺 《农机化研究》2006,(5):29-31

现代传感器技术、通信技术、自动化技术和计算机技术的发展为现代温室控制系统的架构提供了多种可选方案。为此,列举了几种典型的测控系统模式,并简要地分析了其优缺点,最后提出了未来温室控制系统的发展趋势。  相似文献   

抚育强度对云杉林土壤有机碳含量的影响     

郝凯婕 《山西林业科技》2014,(3):15-18

笔者分析了川西米亚罗林区典型低效林经不同强度的抚育间伐后,对5种处理的2个土层(0 cm~15 cm,15 cm~30 cm)的土壤总有机碳、微生物量碳含量的变化进行了动态监测,并分析了土壤总有机碳和微生物量碳含量的季节变化。结果表明,5种处理的土壤总有机碳和微生物量碳含量均是上层高于下层;在观测的4个季节内,上层、下层土壤总有机碳均是夏季春季冬季秋季,土壤总有机碳含量的上、下层均值是F3F2F1F4CK;土壤微生物量碳含量均是秋季冬季春季夏季;土壤微生物量碳含量的上、下层均值表现为F3F2F1CKF4,而且30%的间伐强度样地土壤总有机碳含量和微生物量碳含量均最高。  相似文献   

"效益-费用"法在林业公益事业建设项目经济评价中的应用   总被引：2，自引：0，他引：2  

董建昌 《林业调查规划》2002,27(4):10-15

政府对林业公益事业项目的投资 ,是以谋取公众福利最大化为目的的。企业投资项目的经济评价以财务评价为主 ,而政府对林业公益事业投资的经济评价则以国民经济评价为主。“效益—费用”分析评价法是一种动态经济评价方法 ,其评价结果能直观地反映政府公益性投资的经济效果 ,并且宜于在多方案比选中运用。举例说明其计算方法和评价效果  相似文献   

Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors     

Sebastian Klimek  Anne Richter gen. Kemmermann  Johannes Isselstein 《Biological conservation》2007,134(4):559-570

Decline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity.  相似文献   

Farmland birds and resource protection in the UK: Cross-cutting solutions for multi-functional farming?     

Richard B. Bradbury  Will B. Kirby 《Biological conservation》2006,129(4):530-542

Farmland bird declines in Europe are well documented. In the UK, agri-environment schemes are key mechanisms for reversing the declines of birds and other farmland biodiversity, but recent reviews suggest that wet habitats might be a gap in provision by these schemes. Important resources provided by wet habitats include: (i) damp soil, for probing species; (ii) permanent water to provide water-dependent invertebrates, as a source of food; (iii) bare or sparsely vegetated ground in the draw-down zone, to improve access to food; (iv) rank emergent vegetation for nesting. However, wet habitats have been lost from farmland as a result of loss of ponds and filling of ditches, as well as the effective removal of water from fields by surface run-off, itself affected by soil compaction, and extensive under-field drainage. The efficient removal of water from fields can cause problems downstream, both through flooding, and diffuse pollution. Regular farmland pollutants include pesticides, nitrogen, phosphorus and sediment, leading to environmental problems such as eutrophication and reduced quality of drinking water. Major new political instruments, such as the Water Framework Directive, will aim to reduce the impact of this diffuse pollution from agriculture. A variety of solutions to diffuse pollution, such as conservation tillage, buffer strips at field edges, and small constructed wetlands, could simultaneously provide some of the resources required by farmland birds. We suggest that future agri-environment schemes, to be truly multifunctional, could focus on bringing these diverse objectives together.  相似文献   

The re-expansion and improving status of the silver-spotted skipper butterfly (Hesperia comma) in Britain: a metapopulation success story     

Zoe G. Davies  Robert J. Wilson  Tom M. Brereton 《Biological conservation》2005,124(2):189-198

Many specialist species are declining as a result of habitat loss and fragmentation, such that conservation actions typically aim to stem rates of decline rather than bring about genuine recovery. Here, we document the recovery of a species from former population refuges. An extensive survey of the entire British range of Hesperia comma, conducted in 2000, recorded over three times the number of tetrads (2 km × 2 km grid squares) occupied in 1982. This was accompanied by a fourfold increase in the number of populations and a 10-fold increase in the habitat area occupied. The improving status of H. comma is the product of good habitat management, recovering rabbit populations and climate warming, which have improved the quality, and increased the availability, of suitable habitat. This has enabled remnant metapopulations to expand, via distance-dependent colonisation, through large networks of habitat. Metapopulation recovery in H. comma demonstrates that landscape-scale conservation can be successful.  相似文献   

Aesthetic preferences of non-farmers and farmers for different land-use types and proportions of ecological compensation areas in the Swiss lowlands   总被引：1，自引：0，他引：1  

Xenia Junge  Petra Lindemann-Matthies  Marcel Hunziker  Beatrice Schüpbach 《Biological conservation》2011,(5):1430-1440

Beyond its traditional function of food production, agricultural land offers public amenities such as the protection of natural resources and landscape scenery. This study investigates the preferences of non-farmers and farmers for nine landscape scenarios in the Swiss lowlands. The nine landscapes were the result of a photo editing process combining three land-use types (arable crops, grassland and a mixture of both) and three proportions of ecological compensation areas (0%, 10% and 30%). The landscape photographs were randomly arranged on one page of a paper-based questionnaire which was sent to a random sample of 4000 Swiss households (non-farmers) and 500 farmers. The respondents (1376 non-farmers and 276 farmers) rated each landscape by attractiveness. Both non-farmers and farmers preferred a mixed land-use type or one dominated by arable crops over one dominated by grassland. Non-farmers’ preference ratings were highly influenced by the proportion of ecological compensation areas (ECAs) in the rated landscape: Non-farmers rated a landscape with a mixed land-use type and 30% ECAs highest, whereas farmers rated a landscape dominated by arable crops and 10% ECAs highest. The results indicate that heterogeneous landscapes (mixed land use, high proportion of ECAs) influence scenic beauty positively. Thus, farming practices and agro-environment schemes such as ECAs can have an impact on the visual attractiveness of a landscape.  相似文献   

Grassland nature reserves for breeding wading birds in England and the implications for the ESA agri-environment scheme     

M Ausden  G.J.M Hirons 《Biological conservation》2002,106(2):279-291

The two principal mechanisms available to conserve breeding wading birds on lowland wet grassland in England are nature reserves and agri-environment schemes, particularly the Environmentally Sensitive Area (ESA) scheme. ESAs offer payments to landowners in return for maintaining (‘low tiers’) or enhancing (‘high tiers’) the landscape, biodiversity and historic value of the land. Lowland wet grassland nature reserves managed by the Royal Society for the Protection of Birds (RSPB) have been successful at conserving breeding lapwings and redshank but habitat management usually only results in short-term increases in numbers of breeding snipe. Within ESAs, populations of breeding wading birds fare better on land managed under high tiers than on land managed under low tiers. Land managed under high tiers also supports more pairs of breeding wading birds per £ of ESA grant received than land managed under low tiers. Means of increasing the cost-effectiveness of the ESA scheme in conserving breeding wading birds are discussed in the light of these results.  相似文献   

A conceptual framework for damage compensation schemes     

Kathleen Schwerdtner  Bernd Gruber 《Biological conservation》2007,134(3):354-360

Damage compensation schemes are widely used to mitigate human-wildlife conflicts. Despite the growing relevance of such conflicts, a theoretical framework to analyze the cost-effectiveness of damage compensation schemes is still missing. The article aims to fill this gap by proposing a conceptual framework by categorizing cost categories, which can be used to compare different types of compensation schemes. To demonstrate the value of the framework, we present an example that compares ex-post compensation and compensation in advance in the European otter (Lutra lutra) in the Upper Lusatia, Germany. We find that the two types of schemes differ widely in their transaction costs. Transaction costs themselves are closely related to the temporal and spatial distribution of damages. Therefore, the choice between the two types of compensation schemes depends on the distribution of damages, which itself depends on the species under concern. Based on this, we recommend a compensation-in-advance type of damage compensation scheme for the otter in the Upper Lusatia, Germany.  相似文献