四川省西昌市邛海湿地外来入侵物种的生态危害及防治对策

目前,外来入侵物种已成为一个全球性的热点、难点问题,它对生态环境和生物多样性造成了严重的影响和破坏,这种影响和破坏是长期的、持久的。文章分析了邛海湿地外来入侵物种的产生和危害,并提出了防控外来入侵物种的对策措施。     

撩开神秘的面纱——首批16种外来入侵物种简介

n近日，国家环保总局公布了首批入侵我国的外来物种。随着与国际交往的逐步扩大，外来入侵物种也逐年增多，有的已对我国生物多样性和生态环境造成了严重的危害，同时也给我国造成巨大的经济损失。据专家估计，我国每年仅几种主要外来入侵物种造成的经济损失就达５７４亿元人民币（美国高达１５００亿美元）。了解外来入侵物种，有针对性地对其防治和进行综合治理，对于减少外来入侵物种所造成的损失具有重要的意义。国家环保总局公布的首批外来入侵物种分别是：■１．紫茎泽兰（Ewpatoriumadenophorum），原产中美洲，约在２０世纪５０年…     

对外来物种入侵的现状、对策的探究

随着经济全球一体化步伐的加快,国内外贸易往来越来越频繁,生物入侵的几率也大大增加,有害生物入侵已成为当前全球性的环境问题。外来物种入侵对全球生态环境和生物多样性已经造成了严重的影响。我国地域辽阔,其优越的自然环境为外来物种入侵提供了理想的条件,目前,外来入侵物种已达数百种,已对我国的生态环境、经济发展、生活质量构成严重威胁和影响。本文分析了外来物种入侵的现状,提出了防控外来物种入侵的对策措施。     

警报:外来物种入侵

“外来物种入侵”,是指物种从自然分布区通过有意或无意的人类活动引入其他地区,在自然或半自然生态系统中形成自我再生能力,并给当地的生态系统造成了明显损害的现象。通俗地说,就是外来物种“反客为主”赶走了当地的“主人”。     

外来物种入侵:中国生物安全大敌

在2002年5月22日的联合国环境日大会上,“生物多样性与外来入侵物种管理”已被确定为新世纪第一个“国际生物多样性日”的主题。这表明人类开始广泛关注外来入侵物种及对生物物种多样性的影响,同样也表明外来物种入侵的危害之巨大。外来物种入侵有两层意思,第一,物种必须是外来     

外来物种入侵：中国生物安全大敌

现在，已经频繁发生的外来物种入侵事件一次次在中国上演，越来越多的国人和组织开始认识到，外来物种入侵对生物多样性，人类健康，农业潜力，经济发展和许多其它利益的迫切威胁，环保官员和生物安全专家警告——     

生物入侵的危害及其对策

本文阐述了生物入侵的概念,并从生物入侵导致本地物种的濒危和灭绝,入侵物种威胁人类健康,生物入侵造成的经济损失,以及防止外来物种入侵的对策等方面进行了讨论,希望引起人们对此方面问题的高度重视。     

外来物种入侵的规模、危害与发展趋势

外来物种入侵最根本的原因是人类活动把这些物种带到了它们不应该出现的地方．因此．我们称这些物种是“有害的”,实际上对这些物种而言是不公平的,它们只是呆错了地方,而造成这种错误的原因常常是人类的一些对生态环境安全不负责任的活动．外来入侵物种问题的关键是人为问题．     

外来物种入侵及其危害

所谓外来物种入侵,指由于人为的或自然的因素,使原产于外地的生物进入本地生态系统,并在本地快速生长繁衍,种群不断增大、分布区不断扩展,对当地的生物多样性和生态环境造成严重危害,并造成巨大的经济损失的现象。2001年,世界自然保护联盟发表一份关于人类活动携带的外来物种影响当地生态环境的研究报告．报告列举了100种影响最大的外来物种,并认为生物入侵已成为全球性的环境问题。国家环保总局和中国科学院也于2003年联合发布我国第一批16种外来入侵物种名单。     

零距离调查“生物入侵者”

凤眼莲原产南美,1901年作为花卉引入我国,五六十年代还作为猪饲料推广。但是这种生物的大肆繁衍已经成为人们的心腹之患,昆明滇池之所以被列入国家环保治理重点项目,凤眼莲“功不可没”。滇池曾经一度有10平方公里的水面被凤眼莲占据,不仅堵塞了交通,破坏了当地水生植被,而且给渔业和旅游业造成了重大损失。损害生物入侵究竟每年给人类造成多大的损害?据统计,美国每年因外来物种入侵造成的经济损失高达1500亿美元,印度每年的损失为1300亿美元,南非为800亿美元。我国因外来物种入侵造成的损失也相当惊人,每年仅几种主要外来入侵物种造成的经…     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.