Fuelwood assessment at micro-watershed level in Northeast Himalaya:a case study in Manipur,India

Fuelwood is one of the major sources of energy in the domestic sector across the rural areas,especially in the developing regions across the world.The Northeastern Himalayan state of Manipur is dominated by the tribal population that largely depends on fuelwood from the nearby forest area.The entire dependence on forests for energy resources is affecting the sustainability of the forest ecosystem in the region,thus indicating the livelihood conditions.Since land-use land-cover change is the key driver to the change in resource availability of a region,the present study has tried to analyze the landcover changes over a period 28 years.The second major component affecting resource availability is the increasing population pressure that leads to changes in the land dynamics,which directly affect the resource production.Based on the existing consumption pattern,the total consumption of fuelwood in the watershed ranges fiom a minimum of 289.992 tons/year to a maximum of 3545.719 tons/year with an average of 1561.956 tons/year in the year 2009 and simulated fuelwood consumption for the year 2021 is around 1469.260 tons/year.Nine different probable scenarios of resource are proposed to calculate the stress value that can be used by the policy-makers and planners for suitable policy implementation at the micro level with a complex social system.     

南亚热带土壤温度动态变化特征及其意义

根据定位系统观测资料，阐述了南亚热带山地常绿森林区、丘陵旱作区和平原水稻区多种土壤的温度变化与气温的关系。观测研究结果表明：低山常绿森林区温度的三维空间差异比丘陵区、平原区大，丘陵区又比平原区大；南亚热带林区的气温、地表温、30cm土温比中亚热带的高，比热带的低：南亚热带林区的谷地气温高于针叶林、混交林和阔叶林，谷地地表温低于针叶林而高于混交林和阔叶林，谷地20m土温低于针叶林、混交林而高于阔叶林；在气温一致的丘陵区栽植植物不同，其地表温、土温略有差异；在平原水稻土区，年气温、地表温、20cm土温差异不大，但30cm以下土温渐显差异；不同地貌单元的气温、地表温和土温的年际差异、年平均温度、各月及0～12～24时的温度动态变化各具特征。根据气温与植物生长的关系，拟把气温＞22℃的4～10月称热季、气温＜22℃的1～3月及11～12月称作凉季。可因地制宜，根据气温和土温的变化特征与土壤水分和作物生长的关系，采取措施调节温度，以利于作物生长。     

Assessment of decadal changes in sediment contamination in a large connecting channel (Detroit River,North America)

Concentrations of selected heavy metals (Cd, Cu, Hg, Pb, Zn) and organic contaminants (PCBs, PAHs) were investigated in samples from the Detroit River (Great Lakes, North America) in 1999 and 2008/09 collected using a stratified random sampling design. Getis–Ord geospatial analysis was used to further establish locations of areas demonstrating significantly high and low contaminant concentrations in the river. Based on the stratified random sampling design, a majority of the examined metals and organic contaminants demonstrated little or no trends with respect to regional sediment concentrations and river-wide mass balances over the investigated time interval. The Getis–Ord analysis revealed local scales of contaminated and clean areas which did not conform to the original strata used in the geostatistical sampling design. It is suggested that geospatial analyses such as Getis–Ord be used in the design of future sediment quality surveys to refine locations of strata that can simultaneously address sediment recovery over system-wide, regional and local spatial scales.     

环鄱阳湖区水足迹的动态变化评价

水足迹模型是计量水资源承载力的一个较新颖且日趋成熟的方法。水资源状况对鄱阳湖区生态系统的平衡、稳定以及生态系统良性循环有着重要意义。将水足迹模型运用于环鄱阳湖区进行实证研究，通过计量模型计算出环鄱阳湖区1989~2008年水足迹的时间序列值，并评价其承载状况。结果显示，近20 a来，环鄱阳湖区的水足迹需求由1989年的735亿m3增加至2008年的110亿m3，呈现出波动上升趋势。至今为止水足迹未超载，但盈余空间呈减少趋势。最后从优化水资源利用、倡导绿色消费和促进区域间贸易交流等降低水足迹的需求和增大水足迹供给的角度提出了提高水足迹承载力的对策。进而从水足迹的角度为环鄱阳湖区提高生态系统承载力提供理论依据，促进江西省鄱阳湖生态经济区的建设     

潮间带湿地碳循环及其环境控制机制研究进展

有高等植被覆盖的潮间带湿地（红树林沼泽、盐沼）植被生产力高,有机碳分解速率低,CH4排放较弱,碳沉积速度快,是单位面积碳封存速率最高的生态系统之一。作为全球“蓝色碳汇”的主要贡献者,潮间带湿地在减缓含碳温室气体排放,降低全球温室效应方面具有重要潜力。潮间带湿地大多地处经济发达和人口密集的河口海岸地区,近年来其碳汇功能受到了越来越多人为干扰的威胁,正在发生着的气候变化则更增加了这种碳汇功能的不确定性。在全球变化背景下,对潮间带湿地碳循环及其环境控制机制的深入了解可以帮助更好地管理这种具有重要碳减排潜力的生态系统。文章综述国内外的相关研究,分析了潮间带湿地碳循环的基本过程和环境影响因素,探讨了多种人为干扰和气候变化要素对潮间带湿地碳循环的影响。潮间带湿地碳循环的基本过程主要包括垂直方向土壤（水）-大气界面和植被-大气界面CO2、CH4交换和沉积过程驱动的碳封存,以及水平方向与近海的碳交换。潮间带湿地的碳循环主要受潮汐/流、光合有效辐射、温度、盐度、水位、植物群落特征等非生物和生物因素的影响。围垦、富营养化、放牧很可能削弱潮间带湿地的碳汇功能,而外来植物入侵却可能在一定程度上增加其碳汇潜能。海平面上升、气温升高会增加潮间带湿地碳汇功能的脆弱性,CO2浓度升高的作用依赖于优势植物群落的光合作用途径,而多种并存气候变化要素的作用则更为复杂。全球范围内大量潮间带湿地已经遭受破坏甚至丧失,水文调控是对受损潮间带湿地碳汇功能进行修复和重建的有效措施。未来的研究需要更好的理解多种并存气候变化要素,及人为干扰和气候变化同时存在对潮间带湿地碳循环的交互效应,利用过程模型预测不同人为干扰和气候变化情境下潮间带湿地碳收支变化规律,并完善受损潮间带湿地碳汇功能修复的基础理论和实施方法。     

菹草腐解-金鱼藻生长耦合作用对水质及植物生长的影响

通过室内实验模拟沉水植物季相交替过程,分析菹草腐解-金鱼藻生长耦合作用对水质变化影响,探讨菹草不同残体量腐解对金鱼藻生长的影响.结果表明,不同残体量条件下,金鱼藻均能将水体营养盐及有机质保持在相对较低水平,且实验第29 d后基本保持稳定,其中DTN0.514 mg·L-1,TN0.559 mg·L-1,TP0.080 mg·L-1,DTP0.014 mg·L-1,TOC13.94mg·L-1,Chl-a26.546 mg·L-1,菹草腐解-金鱼藻生长耦合作用对水质的改善效果明显,其中在20 g残体条件下处理效果较好,对水体TN、DTN、TP、TOC和Chl-a的去除率分别达到89.67%、52.51%、94.99%、55.59%和98.55%;不同残体量条件下金鱼藻的叶绿素、可溶性蛋白、丙二醛含量均比初始值增加,残体释放的营养盐促进了金鱼藻生长,在20 g残体条件下其对金鱼藻生长的促进作用最好.结果表明在水体含有20 g残体条件下,菹草腐解-金鱼藻生长耦合作用对水质的改善及植物生长的促进效果最显著.     

基于氢氧稳定同位素的黄土高原云下二次蒸发效应

根据GNIP提供的1985年1月至2004年12月黄土高原8个站点的409个降水同位素数据及同期的气象资料,结合HYSPLIT 4.9模型,分析了该区δ18O和d的时空分布特征,计算了二次蒸发的比率,并对不同气象因子影响二次蒸发的程度作了探讨,得到以下结论:1冬季风和夏季风期间,在黄土高原内由南向北δ18O呈上升趋势,d呈下降趋势;自东向西δ18O仅在夏季风期间有上升趋势,而在冬季风期间呈现下降趋势,d总呈现下降的趋势,δ18O和d的变化幅度可以指示季风的路径.2该区全年存在二次蒸发效应,夏季风期间最为明显,蒸发比率介于1.51%~5.88%之间,平均值为3.87%.冬季风期间蒸发比率总体较低,介于1.06%~5.46%之间,平均值也降为3.03%.黄土高原边缘站点蒸发比率受季风变化影响较大,而中部站点受季风变化影响较小.3温度对二次蒸发的影响较大,降水量和水汽压其次,相对湿度较小.此外,风速和海拔对二次蒸发的影响较弱.     

Social and economic impacts of carbon sequestration and land use change on peasant households in rural China: a case study of Liping, Guizhou Province

Numerous innovative approaches to mitigate effects of excessive emission of greenhouse gases (GHGs) on global climate change are being proposed and formulated. Sequestering carbon to terrestrial ecosystems represents one of the important clean development mechanisms. Reforestation through converting various non-forest lands to forests is undoubtedly an important dimension of carbon sequestration. Using Liping County in Guizhou Province as a case region, this study examines the perceived change in social and economic livelihoods of peasants and the factors responsible for the variations in the changes. The results of the study reveal that socio-economic changes associated with the government-financed project are multifaceted and profound. Because of the financial subsidies provided by the central government, this environmental action in many aspects can be regarded as a poverty reduction measure in the underdeveloped area where rural poverty is widespread. A majority of peasant households have benefited from project participation. The land conversion project with continued financial support also contributes to the social transformations of traditional rural society in remote areas to a more mobile, less subsistence agriculture-based, and open society.     

Comparison of vegetation conditions along two backcountry trails in Mount Robson Provincial Park, British Columbia (Canada)

Vegetation conditions, i.e., plant cover, species richness, and the presence of exotic species, are compared along a high-use trail (Berg Lake Trail--BLT) and a low use trail (Mt. Fitzwilliam Trail--FWT) in Canada's Mt. Robson Provincial Park. We established 71 paired quadrats (1 m x 1 m), and assessed the amount of vegetation cover and species richness by four main lifeforms, i.e., woody species, herbaceous species, ferns, and moss, lichen and fungi. The following hypotheses were tested: (1) differences exist between control and trailside quadrats in vegetation cover, species richness and floristic diversity, and (2) differences exist between the high and low-use trails in the above-mentioned three parameters. Results show that for the majority of variables the differences between the control and trailside quadrats are statistically not significant. Variables showing significant differences are relative vegetation cover (for BLT only), exposed soil (BLT and FWT), herbaceous cover (FWT), moss, lichen and fungi cover (BLT), overall species richness (BLT), and herbaceous species richness (BLT). Ruderal and exotic species are present but only on trailside quadrats of the high-use trail. Results indicate that the Park administration's strategy to disperse use in the Mt. Robson Provincial Park should be examined critically, and some guidelines for acceptability of changes should be developed.     

Spatial and temporal relationships between precipitation and ANPP of four types of grasslands in northern China

Precipitation is considered to be the primary resource limiting terrestrial biological activity in water-limited regions. Its overriding effect on the production of grassland is complex. In this paper, field data of 48 sites （including temperate meadow steppe, temperate steppe, temperate desert steppe and alpine meadow） were gathered from 31 published papers and monographs to analyze the relationship between above-ground net primary productivity （ANPP） and precipitation by the method of regression analysis. The results indicated that there was a great difference between spatial pattern and temporal pattern by which precipitation influenced grassland ANPP. Mean annual precipitation （MAP） was the main factor determining spatial distribution of grassland ANPP （r^2 = 0.61, P 〈 0.01）; while temporally, no significant relationship was found between the variance of AN PP and inter-annual precipitation for the four types of grassland. However, after dividing annual preeipitation into monthly value and taking time lag effect into account, the study found significant relationships between ANPP and precipitation. For the temperate meadow steppe, the key variable determining inter-annual change of ANPP was last August-May precipitation （r^2 = 0.47, P = 0.01）; for the temperate steppe, the key variable was July precipitation （r^2 = 0.36, P = 0.02）; for the temperate desert steppe, the key variable was April-June precipitation （r^2 = 0.51, P 〈 0.01）; for the alpine meadow, the key variable was last September-May precipitation （r^2 = 0.29, P 〈 0.05）. In comparison with analogous research, the study demonstrated that the key factor determining inter-annual changes of grassland ANPP was the cumulative precipitation in certain periods of that year or the previous year.