首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
森林生态系统恢复力评价——以江西省莲花县为例   总被引:2,自引:1,他引:1  
生态系统恢复力是森林资源可持续发展的中心目标之一。在明确生态系统恢复力定义和尺度的基础上,分析了森林生态系统恢复力的影响因素,从生境条件和生态存储两方面遴选出26个指标,建立了森林生态系统恢复力评价指标体系,并以江西省莲花县为案例区,采用组合赋权法确定了指标权重,通过空间叠加计算了莲花县森林生态系统恢复力。结果表明:森林生态系统恢复力主要受内部存储的影响,其权重达到0.554。莲花县森林生态系统恢复力在0.103到0.464之间,平均值为0.268,恢复力达到或超过平均水平的森林面积为37 907 hm2,占森林总面积的49.2%,整体处于较低水平;分级结果表明仅48.16%的森林达到高或较高恢复力水平;在空间分布上,莲花县森林生态系统恢复力为南高北低,南部和中部的森林大多处于高或较高恢复力水平,北部地区大部分森林处于中等、较低或低恢复力水平。此外,恢复力高的森林沿乡镇边界线分布的特点非常明显。该研究结果可为森林资源管理提供重要科学依据。  相似文献   

2.
Planting urban trees and expanding urban forest canopy cover are often considered key strategies for reducing climate change impacts in urban areas. However, urban trees and forests can also be vulnerable to climate change through shifts in tree habitat suitability, changes in pests and diseases, and changes in extreme weather events. We developed a three-step framework for urban forest vulnerability assessment and adaptation that scales from regional assessment to local on-the-ground action. We piloted this framework in the Chicago region in 10 locations representing an urban-exurban gradient across a range of socioeconomic capacities. The majority of trees across a seven-county region had low to moderate vulnerability, but many of the least vulnerable species were nonnative invasive species. Urban forests in the 10 pilot locations ranged in vulnerability largely due to differences in economic and organizational adaptive capacity. Adaptation actions selected in these locations tended to focus on increased biodiversity and restoration of natural disturbance regimes. However, adaptation actions in more developed sites also included incorporating new species or cultivars. Lessons learned from the pilot area can be used to inform future efforts in other urban areas.  相似文献   

3.
Due to large scale afforestation programs and forest conservation legislations, India’s total forest area seems to have stabilized or even increased. In spite of such efforts, forest fragmentation and degradation continues, with forests being subject to increased pressure due to anthropogenic factors. Such fragmentation and degradation is leading to the forest cover to change from very dense to moderately dense and open forest and 253 km2 of very dense forest has been converted to moderately dense forest, open forest, scrub and non-forest (during 2005–2007). Similarly, there has been a degradation of 4,120 km2 of moderately dense forest to open forest, scrub and non-forest resulting in a net loss of 936 km2 of moderately dense forest. Additionally, 4,335 km2 of open forest have degraded to scrub and non-forest. Coupled with pressure due to anthropogenic factors, climate change is likely to be an added stress on forests. Forest sector programs and policies are major factors that determine the status of forests and potentially resilience to projected impacts of climate change. An attempt is made to review the forest policies and programs and their implications for the status of forests and for vulnerability of forests to projected climate change. The study concludes that forest conservation and development policies and programs need to be oriented to incorporate climate change impacts, vulnerability and adaptation.  相似文献   

4.
We make an assessment of the impact of projected climate change on forest ecosystems in India. This assessment is based on climate projections of the Regional Climate Model of the Hadley Centre (HadRM3) and the dynamic global vegetation model IBIS for A2 and B2 scenarios. According to the model projections, 39% of forest grids are likely to undergo vegetation type change under the A2 scenario and 34% under the B2 scenario by the end of this century. However, in many forest dominant states such as Chattisgarh, Karnataka and Andhra Pradesh up to 73%, 67% and 62% of forested grids are projected to undergo change. Net Primary Productivity (NPP) is projected to increase by 68.8% and 51.2% under the A2 and B2 scenarios, respectively, and soil organic carbon (SOC) by 37.5% for A2 and 30.2% for B2 scenario. Based on the dynamic global vegetation modeling, we present a forest vulnerability index for India which is based on the observed datasets of forest density, forest biodiversity as well as model predicted vegetation type shift estimates for forested grids. The vulnerability index suggests that upper Himalayas, northern and central parts of Western Ghats and parts of central India are most vulnerable to projected impacts of climate change, while Northeastern forests are more resilient. Thus our study points to the need for developing and implementing adaptation strategies to reduce vulnerability of forests to projected climate change.  相似文献   

5.
6.
India being a developing economy dependent on climate-sensitive sector like agriculture is highly vulnerable to impacts of global climate change. Vulnerability to climate change, however, differs spatially within the country owing to regional differences in exposure, sensitivity, and adaptive capacity. The study uses the Hadley Centre Global Environment Model version 2-Earth System (HadGEM-ES) climate projections to assess the dynamics in vulnerability across four climate change exposure scenarios developed using Representative Concentration Pathways (RCPs). The analysis was carried out at subnational (district) level; the results were interpreted and reported for their corresponding agro-ecological zones. Vulnerability of each district was quantified using indicators capturing climatic variability, ecological and demographic sensitivity, and socio-economic capacity. Our analysis further assigns probabilities to vulnerability classes of all the 579 districts falling under different agro-ecological zones. The results of the vulnerability profile show that Western plains, Northern plains, and central highlands of the arid and semi-arid agro-ecological zones are the most vulnerable regions in the current scenario (1950–2000). In the future scenario (2050), it extends along districts falling within Deccan plateau and Central (Malwa) highlands, lying in the arid and semi-arid zones, along with regions vulnerable in the current scenario, recording the highest vulnerability score across all exposure scenarios. These regions exhibit highest degree of variation in climatic parameters, ecological fragility, socio-economic marginality, and limited accessibility to resources, generating conditions of high vulnerability. The study emphasizes on the priority to take up adaptive management actions in the identified vulnerable districts to not only reduce risks of climate change, but also enhance their inherent capacity to withstand any future changes in climate. It provides a systematic approach to explicitly identify vulnerable regions, where regional planners and policy makers can build on existing adaptation decision-making by utilizing an interdisciplinary approach in the context of global change scenario.  相似文献   

7.
The conservation of traditional fruit orchards might be considered to be a fashion, and many people might find it difficult to accept that these artificial habitats can be significant for overall biodiversity. The main aim of this study was to identify possible roles of traditional fruit orchards for dead wood-dependent (saproxylic) beetles. The study was performed in the Central European landscape in the Czech Republic, which was historically covered by lowland sparse deciduous woodlands. Window traps were used to catch saproxylic beetles in 25 traditional fruit orchards. The species richness, as one of the best indicators of biodiversity, was positively driven by very high canopy openness and the rising proportion of deciduous woodlands in the matrix of the surrounding landscape. Due to the disappearance of natural and semi-natural habitats (i.e., sparse deciduous woodlands) of saproxylic beetles, orchards might complement the functions of suitable habitat fragments as the last biotic islands in the matrix of the cultural Central European landscape.  相似文献   

8.
9.
Throughfall measurements are very often used to calculate the atmospheric input to ecosystems. Such attempts are normally complicated by canopy interaction processes which are difficult to assess. This study presents an approach to calculate dry deposition and canopy leaching of Ca2+, Mg2+ and K+ to forests. The calculations are based on throughfall measurements in a forest edge of a spruce stand and by use of Na+ as a model substance for dry deposition of particles. This ‘forest edge approach’ is compared with an approach based on equal Na+ to base cation ratios in wet and dry deposition (‘wet/dry ratio approach’), which has been widely used in the literature. Our calculations show that the wet/dry ratio approach may overestimate the dry deposition of Ca2+, Mg2+ and K+ by up to 100% and leaching will correspondingly be underestimated. The assumptions underlying the different approaches and the use of throughfall measurements to estimate dry deposition are discussed and it is suggested that throughfall measurements in forest edges may be a valuable improvement to studies of atmospheric deposition in forests.  相似文献   

10.
An important goal of vulnerability assessment is to create an index of overall vulnerability from a suite of indicators. Constructing a vulnerability index raises several problems in the aggregation of these indicators, including the decision of assigning weights to them. The purpose of this paper is to demonstrate a method of aggregating vulnerability indicators that results in a composite index of vulnerability, but that avoids the problems associated with assigning weights. The investigators apply a technique based on Pareto ranking to a complex, developed socioeconomic landscape exposed to storm surges associated with hurricanes. Indicators of social vulnerability to this hazard are developed and a principal components analysis is performed on proxies for these indicators. Overall social vulnerability is calculated by applying Pareto ranking to these principal components. The paper concludes that it is possible to construct an effective index of vulnerability without weighting the individual vulnerability indicators.  相似文献   

11.
基于韧性理念的海岸带生态修复规划方法及应用   总被引:4,自引:4,他引:0  
生态修复是海岸带空间规划的重要组成部分,而韧性理念中有关规划-吸收-恢复-适应的演化规律对于海岸带生态修复具有重要的指导意义。以沙化较为典型的海南木兰湾海岸带区域为例,开展海岸带国土空间生态修复规划的方法及应用研究,基于沙化脆弱性和生态系统服务的空间耦合分析划分不同类型空间,并分区制定生态修复规划方案。研究结果表明:(1)沙化脆弱性高的区域主要是旱地和沙地,面积达21.8%,生态系统服务高的区域主要是林地、水域、湿地,面积达67.5%。(2)重建修复区主要位于鱼塘、旱地一带,占总面积的16.4%;人工辅助修复区主要位于旱地以及迎风面一带,面积达5.5%;适度开发区多为基本完全沙化区域,面积为15.8%。相关评估结果和生态修复规划方案能够揭示生态系统各关键因子之间的胁迫-响应机理,为海岸带沙化区域的生态修复及恢复提供科学支撑。  相似文献   

12.
A flexible procedure for the development of a multi-criteria composite index to measure relative vulnerability under future climate change scenarios is presented. The composite index is developed using the Weighted Ordered Weighted Average (WOWA) aggregation technique which enables the selection of different levels of trade-off, which controls the degree to which indicators are able to average out others. We explore this approach in an illustrative case study of the United States (US), using future projections of widely available indicators quantifying flood vulnerability under two scenarios of climate change. The results are mapped for two future time intervals for each climate scenario, highlighting areas that may exhibit higher future vulnerability to flooding events. Based on a Monte Carlo robustness analysis, we find that the WOWA aggregation technique can provide a more flexible and potentially robust option for the construction of vulnerability indices than traditionally used approaches such as Weighted Linear Combinations (WLC). This information was used to develop a proof-of-concept vulnerability assessment to climate change impacts for the US Army Corps of Engineers. Lessons learned in this study informed the climate change screening analysis currently under way.  相似文献   

13.
Measurements are presented of the flux of cloud droplets, as a function of particle size to a forest canopy (Sitka spruce) before and after a light snowfall. The results are compared to the predivtions of the model of Slinn. Good agreement is found provided that appropriate values for the effective target diameter are chosen, both before and after the snowfall. It is shown that the snowfall results in a considerable reduction in the flux of cloud water to the forest canopy (by a factor of about 2). The snow reduces the surface roughness of the canopy but the most important effect is that it increases the effective target diameter for the droplets impacting on the tree. This effect may considerably reduce the deposition of phytotoxic chemical species to forests at high altitude where snow cover and low cloud are common in winter.  相似文献   

14.
This paper describes a comparative study of four different cases on vulnerability, hazards and adaptive capacity to climate threats in coastal areas and communities in four developing countries: Bangladesh, Brazil, Cameroon and Uruguay. Coastal areas are vulnerable to sea-level rise (SLR), storm surges and flooding due to their (i) exposure, (ii) concentration of settlements, many of which occupied by less advantaged groups and (iii) the concentration of assets and services seen in these areas. The objective of the paper is twofold: (i) to evaluate current evidence of coastal vulnerability and adaptive capacity and (ii) to compare adaptation strategies being implemented in a sample of developing countries, focusing on successful ones. The followed approach for the case evaluation is based on (i) documenting observed threats and damages, (ii) using indicators of physical and socioeconomic vulnerability and adaptive capacity status and (iii) selecting examples of successful responses. Major conclusions based on cross-case comparison are (a) the studied countries show different vulnerability, adaptive capacity and implementation of responses, (b) innovative community-based (CBA) and ecosystem-based adaptation (EbA) and (c) early warning systems are key approaches and tools to foster climate resilience. A recommendation to foster the resilience of coastal communities and services is that efforts in innovative adaptation strategies to sea-level rise should be intensified and integrated with climate risk management within the national adaption plans (NAPAs) in order to reduce the impacts of hazards.  相似文献   

15.
科学评估国土空间脆弱性与恢复力并解释其时空分布特征,能为国土空间开发与保护相关决策提供参考。采用综合指数法和有序加权平均(Ordered Weighted Averaging, OWA)法分别评价和模拟长江经济带市域国土空间脆弱性及国土空间恢复力,并对二者的组合情况进行综合分析。结果表明:(1)2008-2017年间长江经济带国土空间脆弱性指数有明显下降趋势,累计下降率为16.49%,脆弱性指数从西向东逐步下降;(2)长江经济带“生态优先型”“维持现状型”“开发优先型”政策情景下国土空间恢复力分别处于较高(占47.22%)、中等(占35.19%)、低恢复力(占99.07%)水平;(3)长江经济带国土空间以低脆弱性-中等恢复力、低脆弱性-较低恢复力为主导,占30.63%,国土空间整体脆弱性低,恢复力处于较低至中等水平。  相似文献   

16.
杨立伟 《环境科学与管理》2011,36(12):173-179,194
基于SPOT_VGTNDVI时序数据和LandsatTM数据,提出了生态脆弱性遥感评价方法,获取了黄山区植被覆盖和土地覆被信息,分析了黄山~2001—2008年生态脆弱性动态变化情况,结果表明,黄山区在这一时期生态脆弱性呈现波动性,但总体上趋于平稳。此外,利用黄山区统计年鉴数据,采用层次分析法对黄山区生态脆弱性进行评价,结果与基于遥感技术的方法基本一致,证明所提出的遥感方法在生态脆弱性研究中具有可行性。  相似文献   

17.
由于浅层地下水的污染以及承压水的开采,导致受到污染的浅层地下水越流补给深层承压水,增大了承压含水层受到污染的风险,如何评价承压含水层受到污染的可能性是迫切需要解决的问题。论文根据承压含水层受污染的特点将承压含水层脆弱性分为固有脆弱性和扰动脆弱性两个方面,同时根据脆弱性大小具有相对性这一特性,将研究区内承压含水层各脆弱性评价指标归一化,根据信息熵反映实测数据的效用值计算评价指标权重,而后加权求和得到反映脆弱性的综合指数,从而避免了构建脆弱性分级和定额的主观性。以济宁市承压含水层脆弱性评价为例,对评价方法的可靠性进行了分析,通过与数值模拟结果进行对比验证了方法的可靠性。该方法具有概念清晰、操作简便等特点,对无法建立地下水流数值模型和溶质运移模型的地区开展承压含水层脆弱性评价有一定的应用前景。  相似文献   

18.
基于景观格局的三峡库区生态脆弱性评价   总被引:10,自引:0,他引:10  
三峡库区是我国的生态环境敏感脆弱区,进行生态脆弱性评价对于掌握其生态脆弱特征和识别生态环境问题具有重要意义. 基于遥感 (RS)和地理信息系统(GIS)空间分析技术,综合考虑景观格局和区域生态2类影响因素,进行三峡库区生态脆弱性评价. 结果表明:①景观类型中,脆弱度由高到低依次为水体、林地、旱地、草地和水田. ②景观破碎度与区域生态脆弱性之间的相关性显著,反映了人类活动对三峡库区生态环境的干扰剧烈. ③三峡库区生态脆弱区可划分为——Ⅰ区(0.171 500≤EVI<0.191 225),Ⅱ区(0.191 225≤EVI<0.210 950),Ⅲ区(0.210 950≤EVI<0.230 675),Ⅳ区(0.230 675≤EVI≤0.250 400). 其中,Ⅲ区和Ⅳ区生态脆弱程度较高,主要分布在水域及其岸边带、高海拔区域和岩溶地貌区域. 特殊的地形地貌是三峡库区生态环境敏感脆弱的重要因素,而人类行为干扰是造成生态环境退化的决定性因子.   相似文献   

19.
Fire is an important community wetland management tool in Indonesia, but its increasing use in the wetlands of southern Sumatra is degrading the landscape and diminishing household incomes and livelihood options. We studied evolving community land and fire use, resource and livelihood impacts on two sites of roughly 250 km2 each using satellite image analysis and biological and socio-economic surveys. Uncontrolled fire use expanded over time in relation to sonor or swamp rice cultivation, logging, fishing, grazing, and annual cropping on drained wetlands. As a result, most of the landscape has been subject to repeated fires of varying intensities, more extensive in El Niño years. Direct burning by companies played a smaller transitory role in fire ignition over the two decades. But company activities and other large-scale developments contributed to expanding community fire-based land use by bringing in more people, improving access to remote wetlands or making them more flammable. Widespread, repeated fires have transformed the landscape from mature high swamp forests to uniform stands of fire-resistant Gelam (Melaleuca cajuputi) forests and thickets, open savannas and grasslands. These new types of land cover are also degrading. Local communities have rapidly adapted to the changing resources and new opportunities. Logging and fishing declined in importance, and sonor and harvesting of Gelam expanded. But resource depletion has led to falling incomes and fewer livelihood options. The impacts extend beyond local areas as workers migrate into neighbouring forests to extract resources. Large-scale developments, community fire-based management practices and landscape transformation are spreading from accessible to formerly more remote wetlands.  相似文献   

20.
格式栲天然林水源涵养功能的研究   总被引:27,自引:0,他引:27  
本文通过对三明莘口格式栲天然林与人工林的林冠层,林木植被层和林褥层及林下土壤层的持水量,土壤渗透性能差异等的研究。结果表明:格式栲天然林林分持水总量比格式持和楠木人工林分别增加 225.131t/ha 和 296.558t/ha;土壤稳渗值高达 8.09 mm/min,分别是格式栲和楠木人工林的3.3倍和25.3倍。格式栲天然林具有良好的水源涵养功能。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号