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1.
生物质是一种丰富易得的清洁能源,具有大幅减少温室气体排放的潜力。与以玉米及其他谷物为原料的生物质能源生产技术相比,由于纤维生物能源生产消耗的化石能源较少(化石能源与碳的比值低)而备受关注。然而,生物燃料生产系统并非简单,受到多种因素的影响,如能量供应、农村的经济发展水平、土地和生态系统的保护、温室气体减排的可能性以及社会培训等。本文简要综述生物质能源开发的经济与环境影响。根据区域气候和生态条件,不同地区具有各自的生物质种类或能源作物的优化组合。在不久的将来,生物质能源开发的生物技术所面临的挑战包括:生物质形成与细胞壁分解过程的认识与操控,生物质预处理技术,糖产量高的植物变种的选育,用于纤维素降解的酶和微生物的大规模筛选与选育等。除强调生物质能源开发的环境安全和公共健康的重要性之外,生物质能开发还需要解决生命周期评价(LCA)、可持续性的标准和指标的建立等问题。 相似文献
2.
Yabello牧场是埃塞俄比亚博拉纳的一个半干旱地区的牧场,目前面临着草场退化的严重挑战。植被覆盖的变化、过度放牧和季节性变化极大地影响了Yabello牧场的牧草组成和生物量。本文评估了植被覆盖、放牧和季节对Yabello牧场的牧草组成和生物量的影响。首先采用1 m×1 m的随机样方进行实验,根据植被覆盖类型和放牧变化选择样点,并对季节影响进行评估。使用SAS统计软件和MicrosoftExcel分析牧草组成、牧草高度和质量数据。本研究总共记录了26种草种,其中Chloris roxburghiana, Chrysopogon aucheri和Chrysopogon aucheri草种均表现出最高的平均单种覆盖高度和生物量产量。因此,建议将这些草种用于研究区域退化草地的恢复。研究结果还表明,植被覆盖类型、放牧和季节变化是决定牧草种类组成、牧草高度和生物量产量的关键因素。最后,研究结论还认为控制灌木丛植被并平衡放牧水平的可持续管理对于该地区的可持续牧草生产和生物多样性保护至关重要。 相似文献
3.
Animal husbandry and crop farming are specialized for development in separate areas on the Tibetan Plateau. Such a pattern of isolation has led to current concerns of rangeland and farming system degradation due to intensive land use. The crop-livestock integration, however, has been proven to increase food and feed productivity thorough niche complementarity, and is thereby especially effective for promoting ecosystem resilience. Regional synergy has emerged as an integrated approach to reconcile rangeland livestock with forage crop production. It moves beyond the specialized sectors of animal husbandry and intensive agriculture to coordinate them through regional coupling. Therefore, crop-livestock integration (CLI) has been suggested as one of the effective solutions to forage deficit and livestock production in grazing systems. But it is imperative that CLI moves forward from the farm level to the regional scale, in order to secure regional synergism during agro-pastoral development. The national key R & D program, Technology and Demonstration of Recovery and Restoration of Degraded Alpine Ecosystems on the Tibetan Plateau, aims to solve the problems of alpine grassland degradation by building up a grass-based animal husbandry technology system that includes synergizing forage production and ecological functioning, reconciling the relationship between ecology, forage production and animal husbandry, and achieving the win-win goals of curbing grassland degradation and changing the development mode of animal husbandry. It is imperative to call for regional synergy through integrating ecological functioning with ecosystem services, given the alarming threat of rangeland degradation on the Tibetan Plateau. The series of papers in this issue, together with those published previously, provide a collection of rangeland ecology and management studies in an effort to ensure the sustainable use and management of the alpine ecosystems. 相似文献
4.
This study was conducted in the arid Mediterranean Reserve located in northern Jordan, representing a continuous grazed arid rangeland ecosystem. Quantitative analyses on species diversity in addition to phytogeographical analysis were conducted. Some ecological parameters such as, life forms, growth forms, species density and frequency were investigated. A total of 93 vascular plant taxa belonging to 78 genera and 26 families were reported. This constitutes about 4.3% of the total flora of Jordan. Reported taxa include 13 species of grasses, 69 forbs and 10 shrubs and semi-shrubs. The botanical survey pointed to the presence of four rare species in Jordan. Plant species were classified into 28 functional groups. Pairwise correlation analyses among the most abundant species, showed that neutral associations dominated (75%) those communities, followed by positive associations (19%), while only (6%) showed negative association. Positive association may be attributed to direct facultative mutualism, or to physical environmental heterogeneity. Such a positive cooperation in the plant community can significantly maintain species diversity in adverse environments.The relationship between primary productivity and species richness showed a humpbacked pattern. Maximum richness corresponded to a biomass level of 300–400 g m−2. However, a sinusoidal curve-fitting model explained the relationship between graminoids biomass and species richness. These findings pointed to the adaptation of plant taxa to livestock grazing and to the small-scale spatial and environmental heterogeneity in arid Middle Eastern Mediterranean rangelands. Results suggest that optimal biodiversity conservation for the arid Middle Eastern grazing lands should consider their high level of spatial heterogeneity. Rangeland managers should adopt grazing plans that apply a range of grazing pressure across the area so as to maintain diversity at local and regional scales. 相似文献
5.
6.
内蒙伊盟牧场利用与沙漠化及其防治 总被引：1，自引：0，他引：1
本世纪七十年代以来, 沙漠化问题在世界范围内引起了广泛的注意。沙漠化对社会生产和人类的生活与生产是一个严重的威胁。内蒙古自治区伊克昭盟是一个沙漠化比较严重的地区, 迄一九七七年, 全盟流沙面积达27, 666平方公里, 比解放初扩大1.3倍。伊盟牧业在国民经济中比重很大, 牧区约占全盟面积72%。在沙漠化成因中, 牧场的利用不合理是一个主要的方面。因此, 研究牧场利用与土地沙漠化的关系, 总结牧民合理利用牧场的经验, 并提出防治沙漠化的途径, 对于解决这个地区的沙漠化问题, 是十分重要的。 相似文献
7.
Rangeland degradation on the Qinghai–Tibetan Plateau is a growing concern, often attributed to climate change and overgrazing. A minority of researchers have suggested instead that degradation may be caused by changes in land management, particularly enclosures and the contracting of long-term rangeland use rights to households. However, these claims have been hampered by a lack of empirical evidence. This field experiment is the first to compare rangeland conditions over time in the case of different management regimes on the Qinghai–Tibetan Plateau, specifically single-household versus multi-household management. A survey of vegetation properties in Maqu County, Gansu province in 2009, and repeated in 2011, examined the differences between single- and multi-household management in terms of vegetation biomass, cover, and species richness. In 2009, the biomass of the sedge group under multi-household management was significantly higher than that under single-household management. In 2011, biomass, vegetation cover, and species richness were all significantly higher under multi-household management than single-household management. These data suggest the flaws of the tragedy of the commons assumptions underlying single-household management. 相似文献
8.
Many of the complex issues worldwide regarding environmental management and sustainable develo-pment require integrating the social and natural sciences. Nevertheless, while theoretical discussions have been increasingly developed, operative issues are still major barriers to integrated social–ecological analysis. The aim of this paper was to assess regional forage production in semi-arid rangelands as a key feature in social-ecological analysis, by using human organizational units (i.e. counties). We used these state-administrative units to explore demographic and farming indicators in order to address socio-productive implications of different regional forage production dynamics. We studied the forage spatial and temporal dynamics in two different large ecological regions: Monte and Patagonia, under a single administrative unit (i.e. province). Since forage production estimations in arid rangelands are not trivial, we tested two different methods. We found that inter-annual variability in forage production explained the main differences between regions. At a regional level, zones with higher temporal variability in forage production registered less rural residents and farm numbers, but inverse situations were registered at sub-regional scales. We found a non-linear relationship between forage production variability and rural population density. We proposed differentiated policy recommendations regarding rangeland management and animal husbandry, considering both the social and ecological contexts. 相似文献
9.
J.W. Fan K. Wang W. Harris H.P. Zhong Z.M. Hu B. Han W.Y. Zhang J.B. Wang 《Journal of Arid Environments》2009,73(4-5):521-528
Biomass was measured at 48 undefoliated grassland sites on a 1900-km transect in Inner Mongolia. Above-ground biomass was separated into leaf, stem, flower and fruit, and dead matter, and into the five dominant species at each site. Below-ground biomass was measured to a depth of 30 cm and separated into 10-cm layers. Changes of these biomass components and their ratios were examined in relation to gradients of temperature and precipitation, and to the classification of the sites into five grassland types. Total biomass decreased markedly as site mean annual temperature increased and to a smaller extent as mean annual precipitation decreased. Averaged over all sites 92% of biomass was below ground. The proportion of below-ground biomass increased as temperature decreased, and was least and distributed more deeply in desert grassland. As aridity of the grassland types increased, the proportion of biomass in the first dominant species and in stem relative to leaf tissue increased. The biomass measurements provide baseline data required for monitoring sustainable use of Inner Mongolia grassland for livestock production and its storage of carbon. 相似文献
10.
Edible biomass production from some important browse species in the Sahelian zone of West Africa 总被引：1，自引：0，他引：1
Acacia senegal, Guiera senegalensis and Pterocarpus lucens, browse species important in the Sahelian zone of Burkina Faso were studied by the estimation of their phenological variation over time and the evaluation of edible biomass production, total and accessible directly to animals. Biomass production was also estimated using dendrometric parameters. All the three species started the foliation phase as soon as the rains started. A. senegal and P. lucens flowered before G. senegalensis and A. senegal lost leaves earlier. The fruiting phase lasted 6–7 months for all species. Accessible edible biomass varied according to the animal species, the plant species and the height of plants. G. senegalensis showed the highest proportion of accessible biomass, but P. lucens had higher total edible biomass. Goats browsing at higher height had more edible biomass at their disposal. The accessible edible biomass was weakly correlated with tree parameters, while crown diameter was the best parameter to predict total edible biomass production, with R2 varying from 90% (G. senegalensis) to 98% (P. lucens) in log10 transformation of dependent and independent variables. The single species models developed could be applied in similar agro-ecological zones, taking into account the height stratification of plants. Further investigations on others species are needed to be able to estimate total biomass available for browsing. 相似文献
11.
豫北平原的沙质草地分布于黄河多次泛滥改道冲积形成的沙丘、沙地。其主要类型有:①以白茅、达乌里胡枝子为主的草从草地;②刺槐、杨树等林地下层以藜、白茅、茜草等为主的林下草地;③以碱茅、狗牙根等为主的低湿草地。沙质草地的主要特征为种类组成简单,牧草产量低(<2 000 kg·hm-2)且利用过度。但多种优良栽培牧草在沙地生长良好,可获较高产量。在沙地开发中,应针对各草地类型采取相应措施改造为人工、半人工草地。同时应结合沙地多种林木、果树和经济作物种植,建设农牧林复合经营的系统。畜牧业开发应以产业化为主导,发展适应市场需求的优良畜种,实行适度规模经营。 相似文献
12.
根据中国首次北极科学考察的资料 ,分析了楚科奇海浮游动物的物种和生态类群以及群落结构的多样性 ,报道了浮游动物不同群落的地理位置 ,生态属性及其主要种的差异 ,阐述了浮游动物数量的平面和垂直分布特征以及各主要类别的百分组成 ,探讨了本区浮游动物分布特征与环境因子的相关性 ,同时还就本区浮游动物的物种多样性和生物量等指标与相关海区进行比较。结果表明 ,在已记录的 84种浮游动物中 ,4种生态类群同时共存 ,它们以差异悬殊的数量比分别在测区 70°N以南和以北浅水区以及东北部深水区形成 3个生态属性各异的群落结构 ,其分布状况可与测区内不同海流、水团的动态相互佐证。在平面分布上 ,总生物量呈深水区低、浅水区高 ,尤以浅水区南端最高的分布格局 ,在垂直方向上 ,傍晚深水区总生物量高值层出现于 2 0 0 m以浅 ,尤以 5 0 - 0 m层最高 ,2 0 0 m以深逐层下降 ,而物种多样性则由浅到深逐层增加 ,但 80 0 -5 0 0 m层略有减少。与相邻的中、低纬度的海域相比 ,本区浮游动物总生物量均值明显较高 ,但物种多样性却明显贫乏 ,此外 ,物种多样性的垂直分布与热带海域的分布特征完全相反 相似文献
13.
Using embodied HANPP to analyze teleconnections in the global land system: Conceptual considerations
Helmut Haberl Karl-Heinz Erb Fridolin Krausmann Stefan Berecz Nikolaus Ludwiczek Joan Martínez-Alier 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):119-130
Geografisk Tidsskrift—Danish Journal of Geography 109(2):119–130, 2009 In our rapidly globalizing world economy activities in one region have increasingly important effects on ecological, economic or social processes elsewhere, an effect which we here denote as ‘teleconnections’ between different regions. Biomass trade, one of the causes behind such teleconnections, is currently growing exponentially. Integrated analyses of changes in the global land system are high on the agenda of sustainability science, but a methodological framework for a consistent allocation of environmental burdens related to the consumption and production of biomass between regions has not been put forth to date. The concept of the ‘embodied human appropriation of net primary production’ (abbreviated ‘embodied HANPP’ or ‘eHANPP’) allows for the assessment of the ‘upstream’ effects on ecosystem energetics associated with a particular level of biomass consumption or with a given biomass-based product. This concept is based on HANPP and its two components: (1) productivity changes resulting from land conversion (ΔNPPLC), and (2) harvest of biomass in ecosystems (NPPh). HANPP, defined as the sum of ΔANPPLC and NPPh in any given territory, is indicative of the intensity with which humans use the land for their purposes. eHANPP is defined as the NPP appropriated in the course of biomass production, encompassing losses along the production chain as well as productivity changes induced through land conversion or harvest. By making the pressure exerted on ecosystems associated with imports and exports visible, eHANPP allows for the analysis of teleconnections between producing and consuming regions. This article puts forward the eHANPP concept, illustrates its utility for integrated socioecological land-change research based on top-down data on global HANPP and biomass consumption, and discusses the possibilities and challenges related to its quantification in bottom-up approaches. 相似文献
14.
Annual above-ground net primary production (ANPP), evapotranspiration (ET) and water use efficiency (WUE) of rangeland have the potential to provide an objective basis for establishing pricing for ecosystem services. To provide estimates of ANPP, we surveyed the biomass, estimated ET and prepared a water use efficiency for dwarf shrublands and arid savanna in the Riemvasmaak Rural Area, Northern Cape, South Africa. The annual production fraction was surveyed in 33 MODIS 1 km2 pixels and the results regressed against the MODIS fPAR product. This regression model was used to predict the standing green biomass (kg DM ha−1) for 2009 (dry year). Using an approach which combines potential evapotranspiration (ET0) and the MODIS fPAR product, we estimated actual evapotranspiration (ETa). These two models (greening standing biomass and ETa) were used to calculate the annual WUE for 2009. WUE was 1.6 kg DM mm−1 ha−1 yr−1. This value may be used to provide an estimate of ANPP in the absence of direct measurements of biomass and to provide a comparison of the water use efficiency of this rangeland with other rangeland types. 相似文献
15.
2008年7月～2009年5月,分别于平水期（7月）、枯水期（10月）和丰水期（5月）对新疆阿勒泰地区5个盐池进行了大型底栖动物及相关环境因子的调查,共采集到底栖动物23种,其中水生昆虫18种,软体动物4种,环节动物1种。优势种为羽摇蚊（IV=59.00%）、水蝇幼虫（IV=6.86%）、扁蜷螺（IV=6.67%）、Diplocladius sp.(IV=4.69%）和卵萝卜螺（IV =4.34%）。新疆阿勒泰地区盐池大型底栖动物的平均密度和生物量分别为316.36±117.27 ind/m2和4.09±2.73 g/m2。对大型底栖动物和相关环境因子的CCA分析结果显示,新疆阿勒泰地区盐池大型底栖动物物种分布在很大程度上受到环境因子的影响,种类与环境因子排序轴的相关系数高达0.992和0.990。盐度和电导率是影响大型底栖动物分布的两个主要因子,海拔、pH和温度对大型底栖动物的分布也有一定程度的影响。 相似文献
16.
泛绿色设计是处理解决各种环境问题的新理念和新技术路线.泛绿色设计不是为解决单一环境问题而进行的工程建设,而是多目标的协调和共赢,尤为关注的是对人类行为的规范化设计,系统地、综合地、集约化地解决多方面的环境和生态问题.针对大庆油田受损湿地的现状和存在的各种问题,运用泛绿色设计理论与方法,在对受损湿地的修复方面,提出了一些新的对策与实施途径:首先从转变思想观念入手,进行规范油田生产行为的绿色设计,提出了构建油田生产活动绿色作业体系的新思路.在此基础上,提出了要开展遵循油田湿地生态系统内部结构特征的绿色设计;综合运用生态工程的绿色设计;城市湿地公园的绿色设计;生物质能生产基地建设的绿色设计等一系列工程技术措施.泛绿色设计所实行的软件工程与硬件工程相结合的新理念和技术路线,在大庆油田受损湿地修复上的运用,现已初见成效,并为创建绿色油田奠定了有利基础. 相似文献
17.
塔里木河下游荒漠植物多样性、地上生物量与地下水埋深的关系 总被引：2，自引：0，他引：2
样带是研究植物群落沿环境因子梯度变化的重要方法。用样带法研究了塔里木河下游荒漠植被群落物种多样性和地上生物量在垂直河道方向随地下水埋深梯度变化的关系。结果表明：（1）样带植物群落物种多样性与地下水埋深极显著负线性相关（P〈0.01）,Margalaf指数、Pielou指数、Shannon-Wiener指数和Simpson指数均随地下水埋深增大而减小,地下水埋深是影响群落组成和物种多样性的重要因素。（2）单一乔木层、灌木层、草本层地上生物量和乔灌草地上总生物量与地下水埋深均极显著负相关（P〈0.01）,地下水埋深从3 m增大到7 m时,地上总生物量由912.2 g·m-2减少到不足30 g·m-2,地下水埋深是制约荒漠植被地上生物量和分布的主要因素。（3）群落多样性与地上生物量之间显著正线性相关（P〈0.05）,即随多样性增加,地上生物量呈增加趋势。 相似文献
18.
HUANG Yuqing YUAN Weiyuan MO Ling XU Guangping ZHANG Zhongfeng ZENG Danjuan HE Chengxin GU Daxing 《资源与生态学报(英文版)》2015,6(4):269-275
Dragon fruit (Hylocereus undulates) was planted in a large area of karst region in recent years. To understand whether karst drought may impact on its physiological process is important and useful for planning and management of this fruit. In this study, we contrasted with a relative species Hylocereus undatus, and set up experiment to study physiological and biochemical trait and its response to different karst soil water level deficiency, so as to understand the mechanism of H. undulates and H. undatus in adaptation to karst drought condition. The results showed that, trends of physiological and biochemical response to drought was similar between two species. With the intensive of soil water deficiency, such toxin substance as malonaldehyde (MDA) increased, but meanwhile, two protective enzymes superoxide dismutase (SOD) and peroxidases (POD) and osmotic adjustment Proline (Pro) increase as well. Under relative water content (RWC) >50% condition, the enzyme can effectively protect the cells from toxin MDA injure, and Pro can also maintain the water needs through osmotic adjustment. However, under RWC < 40% condition, protective enzymes were not enough for cleaning MDA. Biomass was largest under RWC=70%–80%, with low root shoot ratio and high aboveground biomass. Biomass significantly decreased under RWC 30%–40%, which decline by 73.28% and 73.56% in H. undulates and H. undatus respectively. Therefore, RWC=70%–80% would be an optimal soil moisture while developing dragon fruit in karst, which is favor to fruit production. Under moderate drought e.g. RWC=50%–60%, plants may regulate by metabolic process and balance unfavorable substance, but it allocated much more biomass to root, reduced the aboveground biomass, which is not advance for fruit production. 相似文献
19.
生物量是植物积累能量的主要体现,其在各器官中的分配是植物对环境适应的结果,反映了植物的生长策略。生物量分配会影响不同碳库之间的碳周转,进而影响陆地生态系统碳循环。选取腾格里沙漠东南缘荒漠草地的4种优势灌木种,采用全挖法在个体水平上研究了各器官的生物量以及地下-地上生物量关系(根冠比R/S),试图揭示生物量在各器官中以及地下-地上的分配格局。结果表明:不同物种生物量在地上部分各器官中的分配策略不同;R/S也不相同,其中红砂（Reaumuria soongarica）最大(中值为0.972),珍珠（Salsola passerina） (中值为0.744）和驼绒藜（Ceratoides latens）(中值为0.670)次之,盐爪爪（Kalidium foliatum）最小(中值为0.179),这表明4种灌木具有各自独特的生长策略。随着灌木的生长,冠幅和生物量不断增大,R/S呈下降趋势,说明植物在开始生长阶段对限制性的水分和养分可能有更高的竞争需求。4种灌木的根系分布在不同种间也存在差异,盐爪爪根系较浅(主要分布在0～30 cm土层),其次是珍珠（主要分布在0～50 cm土层),驼绒藜和红砂的根系分布较深(主要分布在0～70 cm土层)。驼绒藜、红砂和珍珠的地下-地上生物量分配模式支持等速生长假说,而盐爪爪的地下-地上生物量分配模式则不支持该假说。4种灌木的地上生物量与地下生物量(经对数转换)均呈极显著的线性相关关系(p<0.001),决定系数介于0.81~0.93之间,这一相关关系可以应用于对荒漠草地地下生物量的估算。本结果有助于进一步研究荒漠生态系统的生物量分配格局和碳循环。 相似文献