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区系次生度和生态次生度在生物多样性评价中的应用研究 被引量:8
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作者 杜凡 杨宇明 +3 位作者 王娟 李俊清 孙鸿雁 孙玺雯 《西部林业科学》 CAS 北大核心 2012年第1期41-45,共5页
在分析Patrick、Simpson、Shannon-Wiener及Pielou均匀度等生物多样性评价指数的基础上,提出了区系次生度(F)和生态次生度(E)等指标,定义区系次生度(F)是生态系统中已进入的外来种及已丧失的原生种的种类的百分比,它只与这些物种的种类... 在分析Patrick、Simpson、Shannon-Wiener及Pielou均匀度等生物多样性评价指数的基础上,提出了区系次生度(F)和生态次生度(E)等指标,定义区系次生度(F)是生态系统中已进入的外来种及已丧失的原生种的种类的百分比,它只与这些物种的种类变化有关而与它们的植株数量变化无关,即F={[a/(b1+a)+b2/(b1+b2)]÷2}×100%;定义生态次生度(E)由系统中外来种的重要值与系统中现存每个种的重要值之和的比值,以及由系统中已经丧失的原生种的重要值与系统中曾经拥有的原生种的重要值之和的比值构成,即E={[i∑=s 1 Ai/(i∑m=1 B1i+i∑=s 1 Ai)+i∑=n 1 B2i/(i∑m=1 B1i+i∑=n 1 B2i)]÷2}×100%。通过在滇西北研究的实例分析,说明引入区系次生度和生态次生度等新指数的合理性和必要性。采用系统中外来入侵种的种类和数量及原生种的种类和数量的变化,用较为直观和易于获得的指标评价系统的生物多样性质量,为生物多样性评价、保护和管理提供更多的依据。 展开更多
关键词 生物多样性质量 区系次生度 区系原生度 生态次生度 生态原生度
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Changing Wetland Environment Based on Water and Soil Quality Analysis of Selected Wetlands, Assam, India
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作者 Dharma Ram Deka Pradip Sharma 《Journal of Environmental Science and Engineering(A)》 2012年第2期228-235,共8页
Wetland environment of Assam is fast changing due to encroachments, dumping of solid and liquid wastes, excessive use of wetland water, over exploitation of wetland resources, overgrazing, over fishing, hunting, poach... Wetland environment of Assam is fast changing due to encroachments, dumping of solid and liquid wastes, excessive use of wetland water, over exploitation of wetland resources, overgrazing, over fishing, hunting, poaching, unscientific construction of engineering structures across and along the wetlands, unscientific land use in surrounding areas and various human interferences. On the other hand wetlands play an important role in charging ground water table, sinking of carbon, providing livelihood to thousands of people through fishing, collecting edible plants, agriculture, irrigation and commercial fisheries, besides enrich biodiversity and maintaining environmental quality of a region. The life of wetlands depends on the quantity and quality of water. Any change in water quality and quantity affect the biotic regime of the wetlands. Fish and other aquatic animals and plants found in all levels (floating, rooted, submergent and emergent etc.) are affected by the changes, which are taking place in wetland water. The present study concerns in understanding the environmental quality of the wetlands in Dimoria region of Kamrup (Metro) district, Assam based primarily on the water and soil quality of selected wetlands viz. Jiong, Parkhali, Bomani and Duani. 展开更多
关键词 BIODIVERSITY water quality soil quality.
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Biomass-derived carbon materials with structural diversities and their applications in energy storage 被引量:20
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作者 江丽丽 盛利志 范壮军 《Science China Materials》 SCIE EI CSCD 2018年第2期133-158,共26页
Currently, carbon materials, such as graphene,carbon nanotubes, activated carbon, porous carbon, have been successfully applied in energy storage area by taking advantage of their structural and functional diversity. ... Currently, carbon materials, such as graphene,carbon nanotubes, activated carbon, porous carbon, have been successfully applied in energy storage area by taking advantage of their structural and functional diversity. However, the development of advanced science and technology has spurred demands for green and sustainable energy storage materials.Biomass-derived carbon, as a type of electrode materials, has attracted much attention because of its structural diversities,adjustable physical/chemical properties, environmental friendliness and considerable economic value. Because the nature contributes the biomass with bizarre micro structures,the biomass-derived carbon materials also show naturally structural diversities, such as OD spherical, 1D fibrous, 2D lamellar and 3D spatial structures. In this review, the structure design of biomass-derived carbon materials for energy storage is presented. The effects of structural diversity, porosity and surface heteroatom doping of biomass-derived carbon materials in supercapacitors, lithium-ion batteries and sodium-ion batteries are discussed in detail. In addition, the new trends and challenges in biomass-derived carbon materials have also been proposed for further rational design of biomass-derived carbon materials for energy storage. 展开更多
关键词 biomass-derived carbon materials supercapacitors lithium-ion batteries sodium-ion batteries
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