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 328 毫秒
1.
南方稻田连作模式单一,盲目使用农药,稻田周边湿地淤积、废弃和填埋,致使面源污染消纳系统衰退,破坏了稻田生物多样性的发展空间。而生物多样性的破坏,已成为诱发稻田生物灾害的因素之一。目前,保护稻田周边湿地,构建稻田污染消纳系统;利用田埂荒地,构建生物群落;丰富连作模式,避免生物物种单一,对重建南方稻田的生物多样性具有十分重要的意义。  相似文献   

2.
新疆山地森林灾害类型及防灾减灾途径   总被引:1,自引:0,他引:1  
论述了新疆山地森林灾害类型和致灾因素,分析了造成山地森林灾害的主要原因,提出了恢复山地森林资源、改善生态环境和防止灾害发生的基本途径。  相似文献   

3.
砷的毒性及其环境卫生标准   总被引:6,自引:0,他引:6  
砷广泛分布于自然界,而且是一种重要的环境污染物,国内外曾多次发生过砷中毒事件。本文主要报道了砷的毒性,特别是致癌性,致突变性和致畸性,同时介绍了各国砷的现行环境卫生标准。  相似文献   

4.
本文在对泉州市山美水库水体富营养化现状进行评估的基础上,阐述了导致水库水体富营养化的污染物的主要来源以及水库发生富营养化的危害,并提出了防治对策。  相似文献   

5.
随着人们对铁细菌认识的突破,其应用也发生了巨大的变化。本文主要介绍了铁细菌在水处理方面的两个主要应用方向——酸性矿山废水的处理和城市用水的处理。同时综述了影响铁细菌生长的几个主要因素。  相似文献   

6.
稻瘟病(Pyriculariaoryzae)是影响水稻生产和发展的重要病害,在水稻幼苗至抽穗的整个生育期均有发生,其发生面积大,危害重,使米质下降。控制该病的主要措施仍是采取化学防治,筛选有效的防治稻瘟病药剂,是控制稻瘟病发生和流行的重要措施。作者选...  相似文献   

7.
题记:中国俗称滑坡为“走山”,称大规模的滑坡、崩坍为“山崩”,其主要发生在地质薄弱的断层带、植被受破坏的斜坡以及设计不周的工程点。本世纪最大的滑坡事件发生在中国海原(1920年),这次地震中丧生23.4万人,实际上大部分死于滑坡。1981年,四川盆地的洪水引发了6万多处滑坡和泥石流,灾民达北多万人。以往主要集中在我国西南山区和黄土高原的山崩、滑坡。近10年来.由于种种原因,在长江上游日渐频繁.近几年且有随大江东去之势。长江中下游的最新崩岸记录1996年,入汛之前,长江中下游频频发生滑坡、崩岸等灾情。有北门口崩岸一…  相似文献   

8.
近郊农村受城市化发展的影响,经济生产方式和社会结构发生了很大的变化,原有的循环系统被打破,产生了一系列的环境问题。生活废水任意排放、垃圾堆放无序、不合理的使用农药化肥等因素造成的面源污染已经成为我国农村环境污染的主要成因。本文以成都市金牛区为例,分析近郊农村存在的主要环境问题,并提出一些措施建议。  相似文献   

9.
金昌市沙尘暴中重金属Ni、Cu、Pb、Cd、As分布及污染分析   总被引:3,自引:0,他引:3  
就金昌市沙尘暴中的Ni、Cu、Ph、Cd、As的污染现状及污染特征进行了调查研究。分析结果表明,金昌市环境空气中Ni、Cu的污染水平较高,冶炼烟气是主要的污染源。另外,沙尘暴的发生加剧了重金属的污染程度,其污染源仍为本地工业污染。  相似文献   

10.
文章从青海省森林资源现状和森林病虫害严重发生的形势入手,列举和分析了森林病虫害测报、检疫、防治三大体系工作中存在的主要问题及原因,并从调整森防工作思路着眼,以育苗、造林、抚育环节为切入点,提出了加强森林病虫害防治工作的对策与措施。  相似文献   

11.
Value Orientation and Forest Management: The Forest Health Debate   总被引:2,自引:0,他引:2  
Among both forest practitioners and the general public, “forest health” has become an issue of contention. Whereas the debate over which treatments will best achieve healthy forests has been framed largely by the popular media and politicians as a struggle between industry and environmentalists, the views of the general public remain unexplored. Survey results from Oregon and Washington residents were used to assess the relationships between respondents’ self-described environmental or economic priorities and the following two variables: (1) acceptability of forest management practices and (2) perceived threats to forest health. Findings indicate that active management was generally accepted by a majority of respondents regardless of their environmental or economic orientation. Disagreement emerged, however, when the appropriateness of specific management practices within specific forest conditions was examined. Additionally, strong evidence was found for a relationship between self-described environmental or economic orientation and perceived threats to forest health. Those with an environmentally oriented viewpoint tended to perceive human-caused factors as the largest threats, whereas those with an economic orientation saw naturally occurring processes as the greatest threats. These findings suggest that the issue of contention is not active management per se. Rather, the major divisions in the forest health debate are defined by specific contexts and circumstances, as well as the management practices used.  相似文献   

12.
森林旅游是生态旅游的重要形式之一,开展森林旅游已成为一种新的消费时尚,也是当今世界旅游的热点.介绍了神山国家森林公园优越的自然条件、丰富的森林旅游资源和人文旅游资源,分析了目前建设森林公园存在的问题,提出了发展森林旅游的建议.  相似文献   

13.
Ji L  Wang Z  Wang X  An L 《Environmental management》2011,48(6):1107-1121
According to the Seventh National Forest Inventory (2004–2008), China’s forests cover an area of 195.45 million ha, or 20.36% of the total land area. China has the most rapidly increasing forest resources in the world. However, China is also a country with serious forest pest problems. There are more than 8,000 species of potential forest pests in China, including insects, plant diseases, rodents and lagomorphs, and hazardous plants. Among them, 300 species are considered as economically or ecologically important, and half of these are serious pests, including 86 species of insects. Forest management and utilization have a considerable influence on the stability and sustainability of forest ecosystems. At the national level, forestry policies always play a major role in forest resource management and forest health protection. In this paper, we present a comprehensive overview of both achievements and challenges in forest management and insect pest control in China. First, we summarize the current status of forest resources and their pests in China. Second, we address the theories, policies, practices and major national actions on forestry and forest insect pest management, including the Engineering Pest Management of China, the National Key Forestry Programs, the Classified Forest Management system, and the Collective Forest Tenure Reform. We analyze and discuss three representative plantations—Eucalyptus, poplar and Masson pine plantations—with respect to their insect diversity, pest problems and pest management measures.  相似文献   

14.
奥地利森林发展经历了完好、破坏、保护、可持续发展等四个历史阶段.由于政府高度重视,加强投入,用可持续发展的原则指导林业建设,特别是提出了科学的建设近自然林的方针,奥地利林业建设已经走上了健康的可持续发展的轨道.目前奥地利森林覆盖率已达46.2%,有2/3的森林为近自然林,采伐量大大低于生长量.其林业发展理论、法规和政府的扶持政策对我国具有重要的借鉴意义.  相似文献   

15.
Forest networks   总被引:1,自引:1,他引:0  
Summary A study beyond the political boundaries in planning strategies for long-term management of the global forest estate is presented. Three alternative forest networks are proposed: (1) the genetic-evolutionary network, based around common evolutionary features, thus delineating similar forest types where conservation and management issues are likely to be compatible; (2) the current ecological and environmental network, based around the role that forests play in the wider ecosystem, including regular and irregular migration pathways, networks to absorb the impact of climate change, water filters etc; (3) the human impact network, based on the history of human involvement in the forest and its implications. The practical policy significance of the various networks is discussed in turn.This paper was researched as part of a project carried out for the World Wide Fund for Nature (WWF). Nigel Dudley is an ecologist, based in the UK, with 15 years experience as a consultant for NGOs, local government and international organizations. He is a former director of the Soil Association and now works with Equilibrium Consultants at the above address. For the past five years he has worked closely with WWF on forest conservation projects and has written several reports for the organization, includingForests in trouble: a review of the status of temperate forests worldwide.  相似文献   

16.
17.

News And Comments

Forest fire salvaged  相似文献   

18.
The article analyses the possibilities of developing an integrated indicator and a model of the assessment of forests naturalness using the data from the database of mountainous spruce forests situated in the Western Carpathians of Slovakia. The article presents two variants of such a model, one based on discriminant analysis, while the second one using an additive approach. The analysis of the data from mountainous spruce forests revealed significant indicators of forest naturalness degree: the arithmetic mean of the ratio between crown length and tree height, the deadwood volume, the coverage of grasses, the coverage of mosses and lichens, and the aggregation index. In addition, the coefficient of variation of tree diameters was included in the final model, since its presence in the model had a positive influence on the correctness of the classification of the forest naturalness degree. The correctness of the classification of the proposed discriminant model was 74.5%. For the additive model, the ranges of the values of the integrated indicator were defined for every degree of forest naturalness by taking into account the error ranges of the arithmetic mean values and the percentiles of the values in individual degrees of forest naturalness. The overall correctness of the classification with the additive model was 63.4%. In the second step, the scheme how to apply the classification model of the forest naturalness degree in the decision-making process of designating as a forest protected areas was proposed. In this scheme, the degree of forest naturalness is considered as a basic criterion for the determination of nature-conservation value of forest ecosystems. As further decision-making criteria we identified the possibility to restore, or the possibility to improve the naturalness of less natural forest ecosystems, which are designated as protected; the occurrence of the endangered species; and the occurrence of other natural values.  相似文献   

19.
秦皇岛海滨森林公园森林景观改造探讨   总被引:1,自引:0,他引:1  
秦皇岛海滨森林公园是秦皇岛沿海防护林的重要组成部分,也是秦皇岛重要的城市森林公园之一。针对秦皇岛海滨森林公园阔叶树多、针叶树少、树种单一、林龄老化、景观单调的现状.探讨了森林公园景观改造的原则、措施和技术,并描绘了景观改造后的效果。  相似文献   

20.
本文回顾广元林业十五年的增长和发展,总结经验,展望面向二十一世纪的林业发展。  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