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1.
The issues of sustainability, efficiency, and profitability in private forestry dominated debate on Finnish and Swedish forest policy throughout the 20th century. The management and utilization of private forests have been significant for these countries since more than half of productive forest land has been owned by families. Forests have also played an important role in Finland’s and Sweden’s national economies. There was however no consensus among forest owners and forestry experts—forest scientists and forestry authorities—about the methods of achieving forestry sustainability and profitability, particularly in the early 1900s. This article focuses on the types of argument on which perceptions of good forest management were based, and the reasons for their use. The article also explores how disagreements and occasional open conflicts between private forest owners and forest authorities were solved, and what kind of regulative means were developed to avoid such differences. There are three main reasons for making a case study of Finland and Sweden: Firstly, the forest sector has played an important role in their national economies, secondly, the objectives and content of their forestry laws are quite similar, and thirdly, the tradition of family forest ownership has remained strong. The debate on good forest management in this period revolves around the two silvicultural paradigms: even-aged and uneven-aged systems. The former concerns formal, scientific knowledge of forest management, and the latter takes a traditional approach.  相似文献   

2.
Russian Journal of Ecology - The purpose of this study was to ascertain the stocks of coarse woody debris (CWD) in bilberry pine forests in the southern part of the Republic of Karelia (the middle...  相似文献   

3.
为更好地理解河流廊道对城市景观生态的意义,研究计算了四川省邛崃市景观类型多样性空间聚类特征和河流廊道景观格局特征。结果表明:(1)局部空间自相关指数Getis Ord Gi*显示研究区土地利用景观类型多样性存在高值聚类区,其形状与研究区河流廊道分布格局近似。(2)河流廊道主要与农田和林地景观毗邻,其两侧300 m缓冲区内主要景观类型为农田和林地,且林地破碎度小;而道路廊道主要与农田和建设用地毗邻,其两侧缓冲区内主要景观类型为农田和建设用地,其景观更为破碎化。(3)地形因素对研究区西部山区土地利用景观格局影响较大,景观类型多样性统计热点区域分布于西部河流台地。邛崃市河流廊道在提高该地区土地利用景观类型多样性中起到积极作用,需要保护邛崃市河流廊道景观多样性,加强河流与自然景观的连通性  相似文献   

4.
There is broad consensus that land use/cover has changed in central Europe over millennia. However, few studies have addressed the roles of the anthropogenic (socio-economic) and natural (biophysical) factors driving these changes over shorter periods (e.g., 100 years). In this study, we analyse the determinants of land cover composition at three discrete time periods (c. 1780, 1890, and 2000). We hypothesise that different anthropogenic and natural factors are the determinants of the main land cover types (arable fields, grasslands, and forests) and that the effects of natural and anthropogenic factors on the main land cover types differ among landscapes with highly dynamic and more stable forest-open land distributions. The study was carried out in the Uckermark region located in northeastern Germany. We compiled data on natural and anthropogenic factors (e.g. forest cover and number of inhabitants) of 65 municipalities in four landscape sections of equal size (10 × 10 km). Landscape sections were selected to reflect different dynamics (high/low) in conversion from forest to arable fields or grasslands and vice versa from 1780 to 2000. Averaged linear mixed-effect models explained between 7.5 and 81.2 % of the variance. The unique effect of anthropogenic factors varied from 2.1 to 18.7 % and that of natural factors varied from 0.2 to 43.4 %. In four of six models that included both types of factors, the natural factors were more influential than the anthropogenic factors. Except in three cases, anthropogenic and natural factors showed opposite effects on land cover types in more dynamic and more stable windows. Though the Uckermark region has been influenced by human activity for thousands of years, natural factors were a major determinant of land cover composition during all time periods, whereas anthropogenic factors became more important only during the latest time period under investigation.  相似文献   

5.
公路建设对区域的各种生态过程、灾害活动等影响引起广大学者的关注,目前对小尺度区域公路沿线景观格局的影响效应研究较少。利用3S技术对云南省昆明市东川区蒋家沟小流域内县乡级公路沿线三期影像的景观进行分类和制图,运用Fragstats3.3软件和景观指数计算方法,从斑块和景观两个层次上研究公路建设前后景观格局的变化。结果表明:(1)不同时期建设公路及全部公路沿线均出现坡耕地显著减少、梯田显著增加的趋势;在不同距离梯度上,针叶林、灌丛、坡耕地景观百分比不断降低,梯田、草地面积增加。(2)公路沿线景观格局动态变化则表现为:在斑块层次上,1973年前建设公路沿线景观形态更复杂,破碎化程度高,1973年后建设公路沿线阔叶林、针叶林斑块数量增加,破碎化趋势明显;在景观层次上,公路沿线景观多样性增加,景观内部连通性降低,整体景观格局破碎化加剧,但1973年前建设公路沿线空间连接性有所提升,1973年后建设公路沿线则表现出空间连接性下降的趋势,公路全线两侧150 m范围对景观水平指数的影响最大。  相似文献   

6.
We have measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDD/F), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDE) in 10 market baskets consisting of almost 4000 individual food samples representing 228 different food items, and also in the total diet basket. Lower bound concentrations of PCDD/Fs ranged between 0.0057 and 5.6 pg/g fresh weight in the market baskets and the corresponding values for PCBs from 39 to 25,000 pg/g. The fish basket contributed most to the concentrations of dioxins and PCBs, and also to concentrations of PBDEs in which the lower bound range was from 0.82 to 850 pg/g. We also assessed the average daily intakes of these substances by the Finnish adult population. The average daily intake of sum of PCDD/Fs and PCBs as WHO toxic equivalents was assessed to be 115 pg, which was 1.5 pg WHO-TEq/kg body weight using an average mean weight of 76 kg for the general population in Finland. The contribution of fish to the intake of PCDD/Fs was between 94% and 72%, depending on whether lower or upper bound concentrations were used. With respect to PCBs, the contribution of fish was 80%. The calculated intake of PBDEs of 44 ng/day was comparable to intake assessments from other countries. Fish also contributed most to the PBDE intake, but there was some other source of PBDEs that distinguishes the exposure to PBDEs from exposure to PCDD/Fs and PCBs. This additional source seemed to be found in the market basket that included beverages, spices, and sweets.  相似文献   

7.
The estimated net primary production (NPP) of Russian terrestrial ecosystems (annual average over the period from 1988 to 1992) is 9544 Tg of dry matter, or 4353 Tg of carbon. Of the total amount, forests account for approximately 39.2% (here and below, comparisons are made with respect to carbon content); natural grasslands and brushwoods, for 27.6%; farmlands (arable land and cultivated pastures), for 22.0%; and wetlands, for 11.2%. The average NPP density on lands covered with vegetation (1629.8 million hectares in Russia) is 267 g C/m2per year. The highest value (498 g C/m2per year) is characteristic of arable lands. Other land-use/land-cover (LULC) classes have the following NPP densities (in areas covered with vegetation): grasslands and brushwoods, 278 g C/m2; forests, 224 g C/m2; and wetlands, 219 g C/m2per year. In general, Russian terrestrial ecosystems accumulate 59.7% of the total NPP in the aboveground phytomass (47.8% in green parts and 11.9% in wood) and 40.3% in the underground phytomass. The latter parameter differs significantly in different LULC classes and bioclimatic zones. According to calculations, the uncertainty in estimating the total NPP is 11% (a priori confidential probability 0.9).  相似文献   

8.
The study presents three scenarios of land use and cover change (LUCC), the most important factor for environmental degradation in southern Mexico. We developed story lines and quantitative projections for regional scenarios based on historic LUCC processes, environmental policies, socioeconomic drivers, stakeholder consultations and official planning documents to gain a better understanding of drivers of LUCC, and quantitative scenarios were modeled with DINAMICA-EGO. Regionally specific interactions between social and natural systems are recognized, and detrimental policies and policy options for landscape conservation and management for sustainability are acknowledged in a base line, variant and alternative scenario. Incongruent policies and ineffective ground implementation of conservation actions were identified as the critical underlying drivers of deforestation and forest degradation that could lead to a severe reduction in natural forests, while the local socioeconomic situation stays precarious. The baseline scenario parts from an analysis of historic LUCC processes and shows the consequences of LUCC tendencies: 73% of temperate forests and 50% of tropical forests would get deforested until 2030. In the variant scenario, these tendencies are adjusted to planning goals extracted from official documents and recent changes in public policies. The alternative scenario further addresses policy options for fostering conservation and sustainable development, but because of the time lag of implementation, still 59% of temperate forests and 36% of tropical forest would get lost until 2030. Nevertheless, this represents a reduction of 13% of forest loss and 11% less pastureland due to the proposed measures of conservation, and sustainable management, including strategies for reforming agricultural systems, agricultural and forestry policies and trade, land tenure and livelihood risk management.  相似文献   

9.
基于景观指数的细碎化对耕地生产效率影响研究   总被引:5,自引:0,他引:5  
研究细碎化对耕地生产规模效益和技术效率影响,以对农地政策制定提供一定依据。综合考虑地块面积、形状和分布因素,用景观指数量化耕地细碎化水平,把细碎化变量代入C D生产函数,研究细碎化对耕地生产规模效益影响,用SFA方法测度耕地生产技术效率,用多元线性回归研究细碎化对耕地生产技术效率影响。结果表明:表征细碎化的第一主成分和地块平均面积、地块密度、面积加权形状指数和面积加权分维数载荷值大于88%,第二主成分和边界密度指数载荷值大于91%;在C D生产函数中代入细碎化变量后所有单元规模弹性下降;表征细碎化的第一主成分和第二主成分对耕地生产技术效率影响系数分别是-0077、-0.011,且通过显著性检验。研究结论认为基于景观指数的细碎化对耕地生产规模效益和技术效率有显著负影响;应从农地市场培育和农地整理两方面减轻细碎化程度,提高耕地生产规模效益和技术效率  相似文献   

10.
The forest–grassland mosaics of southern Brazil have been subject to many land use and policy changes over the decades. Like many grasslands around the world, the Campos grasslands are declining with few conservation efforts underway. In contrast, forests receive much attention and many incentives. It is hypothesized that perception of land cover has the potential to shape ecosystems. Here we conduct a questionnaire to further our understanding of decision-making practices that alter landscapes (Campos grassland, Araucaria forest, agriculture and plantation) and direct land policies in the region. Our analysis reveals that plantations are significantly less desirable than the other landscape types. However, plantation land use has increased by 87 % over the past few decades, as a result of industry and government incentives. The proportions of other landscape types have remained consistent over the past two decades. Restoration of native vegetation is not a priority of landowners and restoration would require a financial incentive.  相似文献   

11.
城市地表形态对热环境的影响——以上海市为例   总被引:1,自引:0,他引:1  
基于遥感与GIS技术,利用Landsat7-ETM+影像反演地表温度,用社会经济统计数据、土地利用现状数据和道路交通网络数据计算城市景观形态参数以表征地表特征,从行政区(县)、5km间距同心环带和局部区块3个水平上划分空间单元建立数据样本,分析城市地表形态对热环境空间分布格局的影响。结果表明:(1)景观混合度和景观分裂度对地表温度有恒定的负向影响,区块连通性与地表温度负相关;(2)景观分裂度对热环境的影响取决于地类属性:分裂度大的增温地类,地表增温效应弱;分裂度大的降温地类,地表降温效应强;(3)人口密度和经济密度可对地表温度产生恒定正向影响;(4)人口密度、建设用地比例和房屋建筑比例是分布在区(县)尺度、同心圆环尺度和典型区块尺度上影响地表热环境最显著的地表形态要素。  相似文献   

12.
The regional bioeconomy has a high importance for generating socio-economic impacts, especially in sparsely populated resource peripheries. The benefits include increased employment and income and improved security of supply. In this study, the modified regional input?Coutput model is applied for analysing the socio-economic impacts of Suutela wooden village construction in North Karelia, Finland. The main objective of this article is to provide an illustrative example on the regional input?Coutput modelling, applied to the investigation of the socio-economic impacts of a conventional, decentralised bioeconomy. Based on this Finnish case of a wooden village with bioenergy district heating, we demonstrate both the employment and income potentials of a decentralised bioeconomy. The results indicate good socio-economic potential of local wood construction, resulting in about 250 personnel working years and a total economic impact of 43.7 million euros on the regional economy. To maintain the sensitivity of the input?Coutput modelling, it is considered more suitable for overall regional impact estimations, rather than pointing out differences between the subsystems. When modified for research purposes, the regional input?Coutput model is well capable to efficiently describe the socio-economic impacts and providing information for local decision-makers to support new projects of a bioeconomy.  相似文献   

13.
使用GIS(地理信息系统,Geographic Information System)的缓冲区法、空间叠置分析法以及景观格局分析法,分析不同等级的行政中心驻地对土地利用景观格局的影响。研究结果表明:(1)耕地是丰县的景观基质,聚落(城乡建设用地)景观是丰县主要的景观类型。与行政中心的距离越近,人为景观的面积比重就越高,大于各景观类型的现状比重,表现出较强烈的空间吸引特性;相反,自然景观所占比重远远低于现状比重,反映出较明显的空间排斥效应。(2)与镇政府的距离变大,土地利用景观的破碎程度、聚集程度、斑块形状的规则程度均先减弱后增强;与县政府驻地的距离变大,景观的破碎程度呈现“减弱-增强-稳定”模式,景观形状的复杂程度变大,聚集程度先减弱后稳定,景观的多样性与异质性受两等级行政中心驻地距离的影响程度均较小。(3)镇级、县级行政中心分别在1 500 m、3 000 m范围内对土地利用景观格局的影响程度大  相似文献   

14.
We investigate the relationship between land-use changes (1987–2007) and the spatial distribution of the average declared income of resident population in a southern European metropolitan region (Athens, Greece) as a contribution to the analysis of suburbanization processes in the Mediterranean region. To demonstrate that urban expansion is accompanied with multiple modifications in the use of the surrounding non-urban land, we developed a computational approach based on spatial indexes of landscape configuration and proximity as a result of changes in the local socio-spatial structure. Diversity in the use of land surrounding built-up parcels in the Athens’ metropolitan region increased significantly between 1987 and 2007, reflecting a progressive fragmentation of the exurban landscape. The percentage of forests and (high-quality) natural land surrounding built-up parcels increased from 8.1 to 9.4 % between 1987 and 2007. The reverse pattern was observed for (low-quality) sparsely vegetated areas, declining from 65 to 47 %. Large built-up parcels were surrounded by a higher percentage of natural land than small parcels. The largest increase over time in forest and natural land surrounding built-up parcels was observed in municipalities with high per capita declared income, and the reverse pattern was observed for sparse vegetation. Our results demonstrate that scattered urban expansion determines a polarization in suburban areas with high-quality and low-quality natural amenities. Sprawl increases economic inequality and socio-spatial disparities contributing to a spatially unbalanced distribution of natural amenities with higher consumption of high-quality land.  相似文献   

15.
基于景观格局的盐城海岸带土地利用时空变化分析   总被引:2,自引:0,他引:2  
在GIS和RS技术支持下,以行政区划为评价单元,通过土地利用转移矩阵、景观格局指数对盐城海岸带土地利用变化的主要方式、景观格局特征及时空分异规律进行定量分析。结果表明:2000~2010年,盐城海岸带土地利用类型以耕地、建设用地和水域为主,其中耕地是盐城海岸带的优势类型,虽然近年来呈逐渐下降的趋势,但仍是区域景观基质类型,均占总面积的78%以上;海岸带景观水平趋于破碎化,区域景观格局更加复杂化、分散化和多样化;研究区北部景观水平特征指数较中部、南部为高。自然地理条件、经济发展水平及不同土地利用方式所带来的利益差异是导致盐城海岸带景观格局变化的关键驱动因素。  相似文献   

16.
The transformations in Slovak agriculture from the 1950s to the present day, considering both the generic (National and EU) and site-specific (local) drivers of landscape change, were analysed in five mountain study areas in the country. An interdisciplinary approach included analysis of population trends, evaluation of land use and landscape change combined with exploration of the perceptions of local stakeholders and results of previous biodiversity studies. The generic processes active from the 1950s to 1970s were critical for all study areas with impacts lasting right up until the present day. Agricultural collectivisation, agricultural intensification and land abandonment had negative effects in all study areas. However, the precise impacts on the landscape were different in the different study areas due to site-specific attributes (e.g. population trends, geographic localisation and local attitudes and opportunities), and these played a decisive role in determining the trajectory of change. Regional contrasts in rural development between these territories have increased in the last two decades, also due to the imperfect preconditions of governmental support. The recent Common Agricultural Policy developments are focused on maintenance of intensive large-scale farming rather than direct enhancement of agro-biodiversity and rural development at the local scale. In this context, local, site-specific attributes can and must form an essential part of rural development plans, to meet the demands for management of the diversity of agricultural mountain landscapes and facilitate the multifunctional role of agriculture.  相似文献   

17.
Roles of intensive reindeer grazing and several additional land use factors in the reduction in ground lichens (Cladonia spp.) in pastures grazed by the semi-domesticated reindeer have been argued in Finland. Our analysis showed that several factors and processes explain the standing biomass of lichens (during 2005–2008) and the recent changes in this biomass (after 1995–1996) on lichen pastures located in the 20 northernmost herding districts in Finland. The higher the long-term reindeer densities on the lichen pastures the lower was the lichen biomass. The lichen biomass was also strongly affected by the grazing system; the lowest biomass values of lichens were measured in all grazing areas that were used in the snow-free seasons. The lichen biomass in pine forests less than 80 years old and in all mountain type lichen pastures was lower than that in mature and old pine forests. The lichen biomass also decreased as the proportion of arboreal lichen pastures within a district decreased and the proportion of human infrastructure increased. The aerial drift of heavy metals from the Kola Peninsula appeared to reduce lichens in a small north-eastern part of the study area. Increases in summer precipitation and winter temperatures increased the amount of lichens, but increases in summer temperatures and winter precipitation had the opposite effect. Reindeer densities, grazing system, pasture type and the previous abiotic factors were also associated with the reduction in lichen biomass between the inventories. We conclude that several local, regional and even global factors and processes affect the state of reindeer pastures in large and complex grazing ecosystems. Therefore, more comprehensive research and management strategies for the entire reindeer herding environment are needed.  相似文献   

18.
Geographic information system (GIS), remote sensing (RS), gradient analysis, and landscape pattern metrics were coupled to quantitatively characterize the spatiotemporal change of land use and landscape pattern over the period 1988–2007 in a coastal gulf region, southeast China. The results obtained show an increase in cropland, buildup land, and aquiculture area and decrease in orchard, woodland, and beach area during 1988–2007. Landscape fragmented processes were strengthened and landscape pattern structure became more complicated in the last two decades in Luoyuan gulf region. The dynamics intensity of landscape pattern is stronger during 2002–2007 than that during 1988–2002. Spatial difference of urban–rural landscape pattern can be detected distinctively in two transects in terms of landscape metrics. Urbanization processes and the policy developed to transfer seawater into buildup land are two driving forces leading to the spatiotemporal change of landscape pattern in Luoyuan gulf region in the last two decades.  相似文献   

19.
Analysis of geographic variation of chloroplast DNA in the eastern European and western Siberian (Tobol) groups of Calluna vulgaris populations isolated from each other for a long period of time has revealed distinct differentiation between them. It has been shown that three populations growing in the Russian Plain and Karelia share two haplotypes characteristic of central Europe, while three Tobol populations contain one haplotype F occurring in Sweden. These results confirm the hypothesis of genetic divergence between the Tobol and eastern European groups of C. vulgaris populations.  相似文献   

20.

Landslide poses severe threats to the natural landscape of the Lesser Himalayas and the lives and economy of the communities residing in that mountainous topography. This study aims to investigate whether the landscape change has any impact on landslide occurrences in the Kalsi-Chakrata road corridor by detailed investigation through correlation of the landslide susceptibility zones and the landscape change, and finally to demarcate the hotspot villages where influence of landscape on landslide occurrence may be more in future. The rational of this work is to delineate the areas with higher landslide susceptibility using the ensemble model of GIS-based multi-criteria decision making through fuzzy landslide numerical risk factor model along the Kalsi-Chakrata road corridor of Uttarakhand where no previous detailed investigation was carried out applying any contemporary statistical techniques. The approach includes the correlation of the landslide conditioning factors in the study area with the changes in land use and land cover (LULC) over the past decade to understand whether frequent landslides have any link with the physical and hydro-meteorological or, infrastructure, and socioeconomic activities. It was performed through LULC change detection and landslide susceptibility mapping (LSM), and spatial overlay analysis to establish statistical correlation between the said parameters. The LULC change detection was performed using the object-oriented classification of satellite images acquired in 2010 and 2019. The inventory of the past landslides was formed by visual interpretation of high-resolution satellite images supported by an intensive field survey of each landslide area. To assess the landslide susceptibility zones for 2010 and 2019 scenarios, the geo-environmental or conditioning factors such as slope, rainfall, lithology, normalized differential vegetation index (NDVI), proximity to road and land use and land cover (LULC) were considered, and the fuzzy LNRF technique was applied. The results indicated that the LULC in the study area was primarily transformed from forest cover and sparse vegetation to open areas and arable land, which is increased by 6.7% in a decade. The increase in built-up areas and agricultural land by 2.3% indicates increasing human interference that is continuously transforming the natural landscape. The landslide susceptibility map of 2019 shows that about 25% of the total area falls under high and very high susceptibility classes. The result shows that 80% of the high landslide susceptible class is contained by LULC classes of open areas, scrubland, and sparse vegetation, which point out the profound impact of landscape change that aggravate landslide occurrence in that area. The result acclaims that specific LULC classes, such as open areas, barren-rocky lands, are more prone to landslides in this Lesser Himalayan road corridor, and the LULC-LSM correlation can be instrumental for landslide probability assessment concerning the changing landscape. The fuzzy LNRF model applied has 89.6% prediction accuracy at 95% confidence level which is highly satisfactory. The present study of the connection of LULC change with the landslide probability and identification of the most fragile landscape at the village level has been instrumental in delineation of landslide susceptible areas, and such studies may help the decision-makers adopt appropriate mitigation measures in those villages where the landscape changes have mainly resulted in increased landslide occurrences and formulate strategic plans to promote ecologically sustainable development of the mountainous communities in India's Lesser Himalayas.

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