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951.
提出了绿色财富核算的概念,对绿色财富核算的内容和范围进行了界定;在前人研究的基础上,对绿色财富各组成内容的核算方法进行了探索研究。以湖北省神农架林区为例,首次在国家区域层面对绿色财富进行了核算。研究结果表明:2004年神农架林区绿色财富总值为236.13亿元,自然资产总价值为46.91亿元,占整个绿色财富的比例为19.86%;生态服务功能总价值为189.23亿元,占整个绿色财富的比例为80.14%,生态服务功能价值高于自然资产价值约60个百分点;同时,神农架林区的绿色财富要远远高于物质财富,绿色财富大约是物质财富的4.6倍,高出物质财富约185亿元,绿色财富在总国民财富中发挥着重要作用。论文的研究方法和结论为国家自然保护区的生态补偿、财政转移支付、自然资源管理等政策的制定提供了定量分析基础。 相似文献
952.
三江源国家公园不同草地土壤微生物功能基因的差异性分析 总被引:1,自引:0,他引:1
土壤微生物在陆地生物地球化学循环过程中起着非常重要的作用。为了探索青藏高原高寒草地类型地上植被特性和地下土壤环境与土壤微生物功能基因之间关系,以三江源国家公园高寒草原、高寒沼泽化草甸及高寒草甸3种典型草地类型为研究对象,利用基因芯片(GeoChip 5.0)技术测定其微生物功能基因丰度,并分析它们之间的差异及影响因素。结果表明:(1)3种草地类型地上群落结构和地下土壤环境存在差异性,其中高寒草原物种多样性指数、pH值较高,沼泽化草甸中土壤含水量、微生物量碳、地上生物量、土壤速效氮含量较高,高寒草甸中则是土壤微生物量氮含量较高;(2)3种高寒草地类型的碳循环、氮循环、磷循环、有机修复的土壤微生物功能基因丰度存在显著差异,其中这些功能基因的丰度在高寒沼泽化草甸最高,高寒草甸、高寒草原次之;(3)地上植物物种多样性虽对功能基因丰度变化的解释率(r2)在57.1%-61.2%之间,但统计学上不显著(P>0.05),而微生物基因丰度随地上生物量的增加而增加,且解释率(r2)为77.5%-80.0%(P<0.05)。在pH、土壤含水量、土壤微生物量等地下土壤环境因子中,pH对功能基因丰度存在显著影响(P<0.01)解释率在83.4%-87.5%间,且土壤微生物功能基因丰度随土壤pH的增加而降低;土壤含水量、土壤微生物量对土壤微生物功能基因丰度的解释率分别为81.9%-83.1%(P<0.05)和76.8%-86.2%(P<0.05),微生物功能基因丰度随这两者含量的增加呈上升趋势。进一步运用RDA分析发现,pH、土壤微生物量、地上生物量是影响微生物功能基因丰度的主要因子,其中土壤微生物量是土壤有机质的重要组成部分,土壤有机质又是通过地上植被凋落物沉积所得到的。因此,地上植被特性的自上而下控制因子影响了土壤环境中自下而上的控制因子,间接的影响了微生物功能基因丰度。由此得出,地上植被特性和地下土壤环境因子共同作用控制了微生物功能基因丰度使其出现差异性。 相似文献
953.
南京市将发展为特大城市,城市空间的拓展已将江宁区、江浦县划为南京市的次区域中心。在分析两地发展功能转变及其与主城生态整合关系的基础上,提出产业生态化的主要建设领域及环境建设、生态保护对策。 相似文献
954.
Soil Quality: A Review of the Science and Experiences in the USA 总被引:2,自引:0,他引:2
An increasing human population is placing greater demand on soil resources, and as a result degradation is taking place in many regions of the world. This is critical because soils perform a number of essential processes including supporting food and fiber production, influencing air quality through interaction with the atmosphere, and serving as a medium for storage and purification of water. The soil quality concept was introduced to complement soil science research by making our understanding of soils more complete and helping guide the use and allocation of labor, energy, fiscal, and other inputs as agriculture intensifies and expands to meet increasing world demands. Soil quality thus provides a unifying concept for educating professionals, producers, and the public about the important processes that soils perform. It also provides an assessment tool for evaluating current management practices and comparing alternative management practices. Soil attributes comprising a minimum data set have been identified, and both laboratory and field methods have been developed for measuring them. A soil quality index is being developed to normalize measured soil quality indicator data and generate a numeric value that can be used to compare various management practices or to assess management-induced changes over time. Using previously published data, we evaluated the soil quality index as a tool to assess a wide range of management practices in the Northern Great Plains. The index ranked the treatments: grazed fertilized tame pasture > moderately grazed > ungrazed> heavily grazed > annual cropping with no-tillage > conventionally tilled crop-fallow which agrees with the way they were subjectively ranked in the publications. The soil quality index shows potential for use as a management assessment tool. 相似文献
955.
The vegetative cover in semi-arid lands typically occurs as patches of individual species more or less separated from one another by bare ground. We have adapted two methods to quantify the spatial pattern of such cover from measurements across patches on transects.Transects were laid in several directions across digital maps of the land surface or across the land itself, and the distances between successive patch boundaries were measured. The distances were ranked in order, and their cumulative distributions were computed and modeled with gamma functions. The parameters of the model provided estimates of the mean distance across patches. The means for different directions were further tested for anisotropy. Transitions between classes on the transects estimate the probabilities with which the different species occur next to others (and to bare ground) and so describe the arrangement of the patches occupied by the different species.The methods were tested with data from mosaic patterns at three semi-arid sites dominated by the tussock grass Stipa tenacissima. The differences in the estimated mean boundary spacings from site to site accorded with prior qualitative assessment, as did the estimated anisotropy. The transition matrices and the estimated proportions of cover showed the dominance of the bare soil with which all the individual species are intimately associated. The transitions also suggest the presence of both positive and negative relations among the main species. Those between Stipa tenacissima and Brachypodium retusum seem to be facilitative, as do those between this grass and the shrub Anthyllis cytisoides. In contrast, Globularia alypum seems to inhibit the other species.We also estimated transition probabilities geostatistically by summing the indicator variograms of the individual species. Standard variogram models were then fitted to describe the ordered series of values, and these again produced results that accorded with visual impressions. 相似文献
956.
城市生态环境 总被引:11,自引:0,他引:11
周毅 《城市环境与城市生态》2003,16(4):46-48
在自然生态环境基础上,描述了城市生态环境发展规律和特征。包括与城市生态系统的辩证关系、城市生态环境的整体性、开放性和负荷能力等。分析城市生态环境效应,探讨城市生态环境容量、结构与功能。 相似文献
957.
居住区绿色空间的生态规划与设计——以珠海华发新城为例 总被引:2,自引:0,他引:2
居住区绿色空间是城市绿色空间的重要组成部分,它对提高居民的生活环境质量,增进居民的身心健康至关重要,具有重要的生态服务功能。从生态学的角度出发,提出了居住区绿色空间生态规划的8项原则,并以珠海华发新城为例,从滨河公园、住区外围防护绿色空间、建筑组团外围和庭院绿色空间、建筑架空底部绿色空间、屋顶和垂直绿化等方面进行了规划设计。 相似文献
958.
959.
丝状真菌基因功能研究的方法 总被引:2,自引:0,他引:2
近年来不少丝状真菌全基因组测序已完成或正在进行,基因功能研究成为真菌研究的一个热点.多种基因功能研究方法都已应用到丝状真菌领域,为丝状真菌的基因功能研究提供了许多不同的技术策略.本文总结了目前丝状真菌基因功能研究中常用的方法,如转座子标签法、基因敲除技术、RNA干扰、超表达及酵母杂交系统等,并对各方法在丝状真菌研究中的优缺点进行了阐述.参42 相似文献
960.
Objectives for Multiple-Species Conservation Planning 总被引:2,自引:0,他引:2
Abstract: The first step in conservation planning is to identify objectives. Most stated objectives for conservation, such as to maximize biodiversity outcomes, are too vague to be useful within a decision-making framework. One way to clarify the issue is to define objectives in terms of the risk of extinction for multiple species. Although the assessment of extinction risk for single species is common, few researchers have formulated an objective function that combines the extinction risks of multiple species. We sought to translate the broad goal of maximizing the viability of species into explicit objectives for use in a decision-theoretic approach to conservation planning. We formulated several objective functions based on extinction risk across many species and illustrated the differences between these objectives with simple examples. Each objective function was the mathematical representation of an approach to conservation and emphasized different levels of threat. Our objectives included minimizing the joint probability of one or more extinctions, minimizing the expected number of extinctions, and minimizing the increase in risk of extinction from the best-case scenario. With objective functions based on joint probabilities of extinction across species, any correlations in extinction probabilities had to be known or the resultant decisions were potentially misleading. Additive objectives, such as the expected number of extinctions, did not produce the same anomalies. We demonstrated that the choice of objective function is central to the decision-making process because alternative objective functions can lead to a different ranking of management options. Therefore, decision makers need to think carefully in selecting and defining their conservation goals. 相似文献