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 78 毫秒
1.
浙江省森林生物量动态   总被引:11,自引:0,他引:11  
张茂震  王广兴 《生态学报》2008,28(11):5665-5674
以浙江省1976至2004年森林资源连续清查资料为数据源,采用基于生物量与蓄积之间关系的生物量转换因子连续函数法,对全省林分生物量和包括林分在内的森林生物量动态进行估计。森林生物量为包括林分、疏林、灌木林、竹林、经济林和四旁树在内的所有林木生物量之和。结果表明,浙江省1976至2004年间森林生物量从1.00828×10^8Mg上升到2.44426×10^8Mg;其中,林分生物量由0.5712×10^8Mg上升到1.51128×10^8Mg。森林生物量和林分生物量的年平均增长速度分别为5.1%和9.1%。在1999至2004年间,森林生物量和林分生物量增长速度均明显加快,分别达到8.6%和10.1%。在1976至2004年间,全省森林面积年均增长速度为1.0%,森林平均生物量从16.50Mg·hm^-2上升到36.59Mg·hm^-2。但是,在森林资源总量不断增加的同时,全省林分质量仍维持较低水平。2004年全省林分单位面积生物量为38.40Mg·hm^-2,远低于全国平均水平(77.40Mg·hm^-2)。研究还表明,利用森林资源连续清查数据和基于单株测树因子的森林生物量模型能够估计大尺度范围内的森林生物量及其动态,但亟待在统一标准下建立和完善覆盖所有树种的生物量模型。  相似文献   

2.
汶川地震重灾区生态保护重要性评价与对策   总被引:9,自引:0,他引:9  
开展生态保护重要性评价,鉴定生态保护重要地区是地震灾区恢复与重建的前提与基础。选取水土流失敏感性、生物多样性保护重要性以及水源涵养重要性这3个指标,评价了地震重灾区51个县(市区)的生态保护重要性。研究表明,生态保护极重要地区面积约为3.5×10^4km^2,约占整个研究区域面积的26.7%,主要分布于邛崃山系北部的汶川与四姑娘山地区,以及岷山山系的大部分地区;而生态保护重要地区面积约为4.6×10^4km^2,约占整个研究区域的34.5%,主要分布于评价区的西部与东北部;其余地区为生态保护一般地区。建议在灾后重建时对生态极重要地区进行严格保护,禁止开展大型开发建设活动,并控制这些地区的人口规模。另外,生态保护重要地区的开发活动应该受到限制。并通过开展生态补偿,结合正在实施的天然林保护、退耕还林与流域综合治理等生态工程措施,促进灾区生态功能的恢复。  相似文献   

3.
张春敏  王根绪 《生态学报》2008,28(12):5833-5841
利用Landsat—TM/CBERS遥感数据和1:25万高程数据,分析汶川特大地震灾害前、后土地利用/土地覆被变化。为了研究地震对区域生态系统的影响,定量对比分析了重灾区青川、平武和茂县主要土地利用/土地覆被的特征,计算不同坡度和坡向影响下土地利用/土地覆被类型变化。得出以下结果:(1)地震后造成区域内有林地、草地和耕地面积减少;疏林地面积增加。有林地、草地和耕地分别减少了92.09、46.98km^2和30.81km^2;疏林地增加了98.81km^2。(2)研究区自然和耕地生态系统受地震影响明显。通过对3县自然和农田生态系统分析,青川林地、草地和耕地生态影响最严重;平武和茂县也存在不同程度影响。(3)在不同的坡度下,土地利用/土地覆被类型在〉35°坡度段受地震影响面积变化最大,依次是0~8°、15~25°、8~15°和25~35°坡段。这与震后诱发的崩塌、滑坡、水土流失等次生灾害,促使大量覆被携带山体、岩石整体或局部的、不规则的运动有关。在不同坡向下,土地利用/土地覆被类型在半阴坡坡向受地震影响面积变化最大,其次是半阳坡、阴坡和阳坡;这与区域内不同坡向上的土地利用/土地覆被类型优势度相关。  相似文献   

4.
破坏性地震往往给社会经济和自然生态环境造成极大的损失。定量化评价地震造成的损失,对灾后恢复重建具有重要意义。应用3S技术对云南省彝良县"9.7"地震的次生灾害进行空间分析,应用影子工程法和成本价值法对地震造成的破坏进行定量评价,采用生态经济学的方法对地震造成的生态系统服务价值损失进行评估。结果表明:"9.7"彝良地震共引发698处地质灾害,损失房屋4587间,直接损失和修复成本为50655.00万元。地震对洛旺乡、角奎镇和洛泽河镇的破坏最为严重,3个乡镇的经济损失占全县的48%。森林生态系统在地震中破坏严重,其受损面积占总损失面积的82.4%。森林生态系统服务价值损失为36175.09万元,农田生态系统服务价值损失2198.83万元。研究结果可以为震后恢复重建提供重要的理论依据。  相似文献   

5.
滨州市生态系统服务价值与生态风险时空演变及其关联性   总被引:8,自引:0,他引:8  
李俊翰  高明秀 《生态学报》2019,39(21):7815-7828
以山东省滨州市为研究对象,利用2000、2005、2010年和2015年4期遥感影像数据划分土地利用类型,基于3km×3km评价小区格网化重采样,核算生态系统服务价值和生态风险指数,分析二者动态变化特征及时、空关联性。结果表明:(1)2000-2015年滨州市生态系统服务价值总量由168.06×108元持续增长到205.30×108元,生态风险指数呈现缓慢降低趋势,总体下降5.86%,区域生态安全问题有所改善;(2)单位面积生态系统服务价值和生态风险指数具有较强的正向等级相关性,并存在一定的正向空间关联性;(3)生态系统服务价值变化相对于生态风险指数具有一定的滞后性,高等级生态风险区域的生态系统服务价值存在极大的减小变化的可能性。研究有助于为区域生态安全格局建设和环境保护政策的制定提供参考。  相似文献   

6.
汶川大地震滑坡体遥感识别及生态服务价值损失评估   总被引:7,自引:0,他引:7  
花利忠  崔胜辉  李新虎  尹锴  邱全毅 《生态学报》2008,28(12):5909-5916
利用遥感技术,提出了综合遥感指数、非监督分类和监督分类的自动识别滑坡体的方法:先构建4个遥感指数(植被指数SAVI、水体指数MNDWI、建筑指数NDBI和云指数NDCI)合成新影像图,用SAVI指数阈值分割新影像图确定无植被区,最后对无植被区进行非监督分类和监督分类区分滑坡体的方法。以TM/ETM+影像为数据源,应用此方法提取了地震重灾区——汶川县的滑坡体,分类精度达93%,进而研究了滑坡体空间分布特征并对其造成的生态服务价值损失进行了评价。结果表明,滑坡体面积随着坡度的增加呈现先增后减的趋势,30~40°之间的滑坡体面积最大;地震共产生滑坡体206.5km^2,汶川-茂县,映秀-北川两大断裂带之间的区域受地震影响最大,成为滑坡灾害最为严重的区域,其中映秀镇15.9%的乡镇面积被滑坡体所掩埋;地震造成全县151.08km^2林地、16.13km^2草地和5.11km^2耕地丧失,崩塌的滑坡体填充的河流面积达3.45km^2;各类生态系统服务总价值损失22646万元,其中林地生态系统服务价值损失最大,占89.8%,虽然耕地价值损失所占比重不大,但滑坡灾害使人均耕地减少45.6m^2,加剧了该县耕地面积短缺的局面。  相似文献   

7.
水坝对河流生态系统服务功能影响评价   总被引:8,自引:0,他引:8  
客观评价水坝对河流生态系统服务功能的影响问题,对完善我国水利工程环境影响评价和保护河流生态系统具有重要意义。根据水坝对河流生态系统服务功能影响的特点,建立了评价指标体系,以2002年为评价基准年份,对全国水坝对河流生态系统服务功能影响进行了评估。结果表明,防洪和水力发电是水坝的主要功能,两者分别占其正面影响的53.94%和26.77%;供水、减少有害气体排放和内陆航运等,也是水坝的重要功能。水库泥沙淤积的负面影响最大,年损失值为-508.63×10^8元;其次是水库淹没,从生态系统的角度进行核算,年损失值为-56.65×10^8元;水坝对河流生态系统的占据也是其重要的负面影响,年损失值为-10.43× 10^8元。  相似文献   

8.
目的:筛选出毒力较强的金黄色葡萄球菌、大肠杆菌、无乳链球菌作为制苗菌株,制成多联菌苗,预防及治疗奶牛乳房炎。方法:通过菌株的分离、纯化、鉴定试验及毒力试验获得毒力较强的菌株,制成金黄色葡萄球菌类毒素及菌体蛋白、大肠杆菌和无乳链球菌灭活菌苗,合理配伍制成多联菌苗,进行安全、异常毒性及免疫力试验。结果:所选金黄色葡萄球菌、大肠杆菌、无乳链球菌的最小致死量分别是3.0×10^8/ml、1.5×10^8/ml、9.0×10^8/ml,多联苗安全、异常毒性试验合格,对免疫组小白鼠保护率为83.3%。结论:该多联菌苗具有安全、无毒、高效的特点,可以用来预防及治疗奶牛乳房炎。  相似文献   

9.
应用响应面法优化嗜热脂肪土芽孢杆菌培养基   总被引:1,自引:0,他引:1  
目的:筛选并优化嗜热脂肪芽孢杆菌CHB1液体发酵培养基。方法:通过Plackett-Burman试验和响应面分析方法,确定培养基的主要影响因素和最佳浓度。结果:利用SAS软件进行分析,确定对响应值影响最大的3个因素为豆粕、酵母粉、K2HPO4。最佳培养基组成为0.51%、豆粕浓度为0.425%、K2HPO4浓度为0.994%。根据模型预测得到的理论最大菌数为2.94×10^8cfu。在初始条件下实验,菌数为2.40×10^8cfu,在优化的最佳培养基条件下,实际的菌数为3.06×10^8cfu。菌数比优化前提高了27.3%。试验值与预测值的误差为4.08%。结论:实验值与模型预测值拟合良好。  相似文献   

10.
刺参养殖池塘水体中浮游病毒的丰度   总被引:1,自引:0,他引:1  
姜北  周遵春  邓欢  陈仲  徐晓虹  谭克非 《生态学报》2008,28(11):5506-5512
运用荧光显微技术,于2007年3~11月,对大连市附近4个地区的刺参养殖池塘及相应的海域进行了浮游病毒丰度的监测和分析,对刺参养殖池塘生态系统的浮游病毒丰度在时间、空间分布上的变化进行了探讨。荧光显微观察结果显示,刺参养殖池塘浮游病毒在时间和空间分布上均存在极显著差异(P〈0.01),8月中旬平均丰度达到峰值,为2.54×10^10个/L,7月下旬浮游病毒的平均丰度最低,为1.43×10^9个/L。复州湾海域的浮游病毒丰度显著高于其他地区,该地区浮游病毒丰度平均达到1.17×10^10个/L,夏家河子地区浮游病毒丰度最低,平均为3.89×10^9个/L。同一刺参养殖池塘中部区域的浮游病毒丰度高于进水和排水口。刺参养殖池塘水体中浮游病毒丰度与养殖池塘所处的海区位置、养殖池塘的密度密切相关。  相似文献   

11.
通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.  相似文献   

12.
Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m−2 s−1. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to Pfr.  相似文献   

13.
The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.  相似文献   

14.
15.
龙胆科药用植物化学成分的研究现状   总被引:16,自引:0,他引:16  
龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。  相似文献   

16.
A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.  相似文献   

17.
18.
真菌类遗传学分析的知识结构教学   总被引:5,自引:2,他引:3  
罗桂花 《遗传》2002,24(3):349-350
本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.  相似文献   

19.
Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H2-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H2 with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD+, FMN+, and NAD(P)+ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H2OCO2+2H++2e- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation  相似文献   

20.
Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)8 barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)8 structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive ET and active ER. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive ET and active ER represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.  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