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101.
矿业可持续发展与无废开采 总被引:3,自引:0,他引:3
矿山开采排出废水、废气、废矸石等废弃物对环境造成污染,对生态产生破坏,对经济造成损失。为使矿业持续发展,维护经济效益、社会效益和环境效益的统一,必须采取有效措施,实行矿山无废开采。使矿产资源开发和矿区发展走可持续发展的健康之路。 相似文献
102.
上海城市绿地景观异质性分析 总被引:15,自引:0,他引:15
选取贯穿上海外环线内绿地景观的8条样线,借助数学的方法,研究绿地景观要素的构成、线性分布等特征,从而找出了上海城市绿地景观的异质性状况,并对今后的规划建设提出了建议。 相似文献
103.
建设项目景观环境影响评价因素的确定 总被引:9,自引:0,他引:9
建设项目对景观的影响应作为环境影响评价的一项内容,在开展该项工作前要确定影响因素。通过各类建设项目对景观环境的影响进行系统的分析和说明,并建立评价的因素体系,对展开建设项目的环境影响评价有一定作用。 相似文献
104.
景观生态学在水库环评中的应用--以周公宅水库为例 总被引:3,自引:0,他引:3
生态完整性的判定是生态影响评价的基础,可从生态体系的结构和功能两个方面考虑进行评价。分别从景观结构、植被生物量和植被分布的空间异质性三个角度对宁波市周公宅水库库区景观生态体系的结构和功能状况进行了评价。 相似文献
105.
DANNY A. P. HOOFTMAN REGULA C. BILLETER BERNHARD SCHMID MATTHIAS DIEMER 《Conservation biology》2004,18(4):1043-1051
Abstract: The area of Caricion davallianae alliance in Switzerland has been considerably reduced and fragmented during the last 150 years. We assessed the genetic variability, inbreeding level, and among-population differentiation of two common habitat-specific plant species, Carex davalliana SM. and Succisa pratensis Moench, in 18 Caricion davallianae fen meadows subjected to fragmentation. We used a spatial field design of fen systems (six systems total), each consisting of one large habitat island and two small habitat islands. We used allozyme electrophoresis to derive standard genetic parameters ( A, P, HO , HE, FIS, FST ). In Carex we identified a consistently lower A in isolated habitat islands; furthermore, HE was lower in small habitat islands than in large habitat islands. In Succisa we identified a lower HO in small habitat islands than in larger ones. Small habitat islands were marginally significantly differentiated ( FST ) from large islands for Succisa . For both species, no effects were evident for FIS ; therefore, we argue that genetic drift rather than inbreeding is the main cause of the observed differences. The genetic structure of Carex and Succisa in small habitat islands differed from that in large habitat islands, but differences were small. It appears that the observed differences in genetic variability among fen meadows correspond to observed differences in fitness and demographic traits. We show that habitat fragmentation affects not only the rare species in an ecosystem but also reduces the survival probabilities of common species. One of the main goals of conservation should be to mitigate fragmentation of natural habitats in order to increase population sizes and connectivity. 相似文献
106.
Guoliang Liu Shijie Han Xiuhai Zhao John D. Nelson Hongshu Wang Weiying Wang 《Ecological modelling》2006
We compared genetic algorithms, simulated annealing and hill climbing algorithms on spatially constrained, integrated forest planning problems. There has been growing interest in algorithms that mimic natural processes, such as genetic algorithms and simulated annealing. These algorithms use random moves to generate new solutions, and employ a probabilistic acceptance/rejection criterion that allows inferior moves within the search space. Algorithms for a genetic algorithm, simulated annealing, and random hill climbing are formulated and tested on a same-sample forest-planning problem where the adjacency rule is strictly enforced. Each method was randomly started 20 times and allowed to run for 10,000 iterations. All three algorithms identified good solutions (within 3% of the highest found), however, simulated annealing consistently produced superior solutions. Simulated annealing and random hill climbing were approximately 10 times faster than the genetic algorithm because only one solution needs to be modified at each iteration. Performance of simulated annealing was essentially independent of the starting point, giving it an important advantage over random hill climbing. The genetic algorithm was not well suited to the strict adjacency problem because considerable computation time was necessary to repair the damage caused during crossover. 相似文献
107.
珠江三角洲典型区景观生态聚类分析 总被引:7,自引:2,他引:7
珠海是珠江三角洲地区一个海陆交互作用与人类干扰活动频繁的典型区域。文章以2000年TM数据为基础数据源,编制珠海地区景观类型图,并以镇(区)为基本空间单元将珠海划分为20个景观生态子区,在GIS与景观斑块分析软件Patch Analyst 2.0支持下计算各子区的景观特征指数。通过各子区的景观指数对比分析,探讨研究区范围内景观格局的空间差异,揭示人类活动、自然干扰等各种景观生态机制对区域景观生态的影响。根据各指数反映的景观特征信息,选择平均斑块大小(MPS)、斑块大小变异系数(PSCOV)、边缘密度(ED)、面积加权分维数(AWMPFD)、破碎度指数(F)、多样性指数(SDI)及人为干扰指数(DT)进行珠海景观生态聚类分析,根据聚类分析结果可多层次客观地对珠海地区进行景观生态类型区划分。 相似文献
108.
This article presents an investigation of relationships between organic farming and landscape composition in Denmark. Landscape composition was analysed in terms of density of uncultivated landscape elements (I), number of land uses per hectare (II), diversity of land use (III) and mean field size (IV). Two analytical approaches were used. The first was based on an examination of the national agricultural registers for 1998, 2001 and 2004. The second approach used aerial photo interpretation for an analysis of 72 conventional and 40 organic farms within three sample areas for 1982, 1995 and 2002. The national analysis indicated that organic farming has a direct effect on landscape composition. In 2001, organic farms were characterised by a higher number of land uses per ha, a higher land use diversity and smaller mean field sizes. From 1998 to 2004, conversion to organic farming was related to an increasing number of land uses per ha, increasing land-use diversity and decreasing mean field sizes. Relationships between organic farming and landscape composition were independent of variations in regional location, farm size or farm size change. At the level of sample areas, a significant relationship between organic farming and landscape composition was only found for densities of small biotopes. However, when differences in farm size and physical geographical conditions between conventional and organic farms were taken into account, several significant differences in landscape composition were clarified in two of the three sample areas. Furthermore, changes in landscape composition following conversion to organic farming were largely biased by the characteristics of the sample areas. Thus, in contrast to the national level, the sample area study indicated that differences in landscape composition between organic and conventional farms were not a direct implication of organic farming practices, but were related to variations within other parameters and to the location of organically farmed land. 相似文献
109.
K.M.S. Sundaram 《Journal of environmental science and health. Part. B》2013,48(2):295-312
Abstract Effects of azadirachtin (isomer A, AZ‐A) and tebufenozide (TF) on freshwater algae were investigated using indoor aquatic microcosms. AZ‐A and TF were dosed at different concentrations to 10‐L microcosms. Chlorophyll and protein contents of the algae, and the concentrations of the insecticides in water and algae were monitored at intervals of time up to 20 d. Chlorophyll and protein contents in algae were inhibited at treatment levels of 3.0 and 4.5 μg AZ‐A/mL, whereas at 1.5 μg/mL, the chemical stimulated the chlorophyll production. The partition of AZ‐A between water and algae was reversible, and the bioconcentration factor (BCF) was low. In contrast, TF dosed at 0.25 to 0.75 μg/mL stimulated algal growth, probably due to its utilization of carbonaceous and nitrogenous intermediates and other breakdown products of TF as nutrients. The BCF was high and the organism functioned as a sink for the chemical. Extension of the laboratory findings to complex outdoor systems are discussed. 相似文献
110.
Landscapes as highly complex systems are subject to many different assessment procedures despite the fact that their development is not really predictable. Every synthetic model of landscape functioning will probably fail in demonstrating the landscape behaviour due to the decreasing precision and relevance of its output with increasing complexity. Two approaches are presented here which use deductive methods to describe landscape behaviour as indicated by its spatial structure. The one is a correlative concept which is characterized by all the advantages and disadvantages of statistical regression methods. It is strongly dependent on data quality. In the second study an expert knowledge system is developed. Fuzzy set theory is applied to transfer rules of landscape ecological experience to image parameters derived from satellite data. Both approaches are compared regarding the problems faced in the work during implication. Theoretical restrictions and the applicability in landscape assessment is discussed. 相似文献