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791.
792.
本文简要叙述了建立三峡工程环境生态监测网络的必要性,以及它的主要职能和任务,并对监测的主要内容、监测网的组成、监测网成员单位的隶属关系等作了较详细的说明,同时建议把三峡工程环境生态监测中心设在重庆。 相似文献
793.
工业化学品的日益增多和广泛使用,给环境带来了很大的压力。工业化学品的风险评价问题,对环境管理至为重要,国家环保局及国内的工业企业正在讨论有关化学品毒性的控制问题。该文讨论了化学品风险评价的常用术语及基本程序,对生态毒性在评价中的地位特别予以强调,并提出了与其相关的评价程序,即理化参数分析;毒性扫描;亚急性毒性试验和慢性毒性试验或微生态系统试验。 相似文献
794.
Elizabeth A. Tibbetts 《Behavioral ecology and sociobiology》2007,61(12):1877-1883
Social insects are popular models for studying the evolution of cooperation. Casteless taxa where individuals have the flexibility
to either nest alone or cooperate are particularly valuable for understanding the causes and consequences of cooperative behavior.
For example, some ‘workers’ from Polistes paper wasp nests disappear from their natal colony soon after pupal emergence and nest independently. However, little is
known about dispersal behavior. In this paper, I compare predispersal behavior of wasps who leave their natal colony soon
after emergence with behavior of individuals who remain on the natal colony as true workers. I found that P. dominulus females with short nest tenure behave much like gynes (reproductive-destined offspring produced at the end of the season),
as wasps with short nest tenure are behaviorally selfish while on the natal colony. They spend a smaller proportion of their
time foraging and a larger proportion of their time resting than workers with long nest tenure. In addition, I assessed the
factors that may favor early dispersal. Nest environment strongly influenced dispersal; large colonies had a smaller proportion
of females with short nest tenure. Queen turnover also increased dispersal behavior perhaps because queen turnover reduces
relatedness between a colony’s current and future offspring, thereby reducing the kin-selected benefits of cooperation. Therefore,
casteless social insects exhibit a surprising degree of reproductive flexibility. Individuals may use information about their
internal state and nest environment to optimize their behavioral strategies. 相似文献
795.
介绍了模糊综合评价方法,并应用该方法对青藏铁路(西格段)沿线的环境影响,尤其是生态环境影响进行了评价.实例表明,被评价范围内的生态环境敏感性为中等,青藏铁路(西格段)增建第二线的工程对原有地形植被、生态环境造成了一定影响.模糊综合评价方法对于生态环境影响分析与评价具有重要的参考意义和应用价值. 相似文献
796.
本世纪末,许多工业企业在对付环境问题的广度牙,逐步放弃传统的对工业废弃物进行处理的作法,转而致力于各种废料的产生。工业界应大力实施清洁生产工艺战略,它即可降低生产成本,又可达到环境效果。该战略要求企业在设计和生产产品时谅充分考虑事前如何控制废料产生和环境污染的问题。 相似文献
797.
Correspondence between spatial patterns in fish assemblages in ohio streams and aquatic ecoregions 总被引:5,自引:0,他引:5
David P. Larsen James M. Omernik Robert M. Hughes Christina M. Rohm Thomas R. Whittier Andrew J. Kinney Alisa L. Gallant Daniel R. Dudley 《Environmental management》1986,10(6):815-828
Land classification systems can be useful for assessing aquatic ecosystems if relationships among them exist. Because the character of an aquatic ecosystem depends to a large extent upon the character of the landscape it drains, spatial patterns in aquatic ecosystems should correspond to patterns in the landscape. To test this hypothesis, the US state of Ohio was divided into four aquatic ecoregions based on an analysis of spatial patterns in the combination of land-surface form, land use, potential natural vegetation, and soil parent material. During the period July–October 1983, fish assemblages were sampled in 46 streams that were representative of the ecoregions, and that had watersheds relatively undisturbed by human activities. Spatial patterns of the fish assemblages were examined relative to the ecoregions; distinct regional differences were identified. The assemblages differed most between the Huron/Erie Lake Plain region and the Western Allegheny Plateau region; assemblages in the Eastern Corn Belt Plains and the Erie/Ontario Lake Plain-Interior Plateau regions were intermediate. This pattern also reflects the gradient in landscape character as one moves from the northwest to the southeast of Ohio. 相似文献
798.
A paradigm for ecological risk assessment 总被引:6,自引:0,他引:6
Joshua Lipton Hector Galbraith Joanna Burger Daniel Wartenberg 《Environmental management》1993,17(1):1-5
The 1983 National Academy of Sciences paradigm for conducting human health risk assessment is considered with respect to ecological
risk assessment. This four-step paradigm fails to capture key intrinsic differences between the two types of analysis, specifically:
identity of risk targets and receptors; identity of the appropriate level of ecological organization at which the risk is
expressed; variability of endpoint with respect to risk receptor; and the existence ofrisk cascades through ecological feedback loops. We propose an alternative paradigm that includes a preliminary step,receptor identification, in which chemical partitioning is combined with a conceptual model of the ecosystem to identify appropriate risk targets.
In addition, we propose formal inclusion ofendpoint identification and explicit consideration of risk cascades in arelationship assessment in which interactive feedback loops are considered in an iterative process. The proposed paradigm preserves the steps of
hazard identification, exposure assessment, dose-response assessment (renamedresponse assessment) and risk characterization, although specific modifications are recommended. 相似文献
799.
黄土高原地区农林牧业生态系统中主要灾害及减灾对策 总被引:1,自引:1,他引:1
农林牧业在黄土高原地区国民经济发展中占有十分重要的位置。本文根据全区的生态特点,对农业系统的生态环境恶化的几种主要形式进行了分析,同时提出了农林牧业整体建设的综合整治对策。 相似文献
800.
Forests and competing land uses in Kenya 总被引:1,自引:0,他引:1
Indigenous forests in Kenya, as in other developing countries, are under heavy pressure from competing agricultural land uses and from unsustainable cutting. The problem in Kenya is compounded by high population growth rates and an agriculturally based economy, which, even with efforts to control birth rates and industrialize, will persist into the next century. Both ecological and economic consequences of these pressures need to be considered in land-use decision making for land and forest management to be effective. This paper presents one way to combine ecological and economic considerations. The status of principal forest areas in Kenya is summarized and competing land uses compared on the basis of ecological functions and economic analysis. Replacement uses do not match the ecological functions of forest, although established stands of tree crops (forest plantations, fuel wood, tea) can have roughly comparable effects on soil and water resources. Indigenous forests have high, although difficult to estimate, economic benefits from tourism and protection of downstream agricultural productivity. Economic returns from competing land uses range widely, with tea having the highest and fuel wood plantations having returns comparable to some annual crops and dairying. Consideration of ecological and economic factors together suggests some trade-offs for improving land allocation decisions and several management opportunities for increasing benefits or reducing costs from particular land uses. The evaluation also suggests a general strategy for forest land management in Kenya.The views and interpretations expressed in this article are those of the authors and should not be attributed to the World Bank, its affiliated organizations, or any individual acting on their behalf. 相似文献