外来昆虫使关岛铁树几近灭绝
文章来源:未知 文章作者:enread 发布时间:2012-08-06 05:59 字体: [ ]  进入论坛
(单词翻译:双击或拖选)
The beautiful, endemic(地方性的) and endangered cycad(苏铁属植物), Cycas micronesica was once a dominant1 forest tree on the island of Guam, but recent plant mortality predicts extirpation2(消灭,根除) from Guam habitats by 2019. This dire3 prediction by scientists at the Western Pacific Tropical Research Center (WPTRC), University of Guam is validated4 by the research of Thomas E. Marler and John H. Lawrence, which has concluded that Cycas micronesica is the only native host for the invasive scale insect Aulacaspis yasumatsui. "The potential cascading5 ecosystem6 responses are yet to be completely understood," says WPTRC research scientist Marler. The armored scale insect A. yasumatsui attacks several cycad genera, but only members of the Cycas genus are killed by the pest. Around twenty years ago the insect was unintentionally introduced to an area in southern Florida known for the production and exportation of Cycas revoluta. The scale was documented in Hawaii in 1998 and in Guam in 2003, and by 2005 it was found in native limestone7 forest habitat close to the initial outbreak site.
 
"We looked for native habitats that would be representative of the general cycad populations where we could study population-level response to the devastating8 scale pest. Our data showed the number of months for juvenile9 plants to reach 100% mortality was dependent on size and other demographic features," says Marler.
 
Just like the human body, plants exposed to constant stresses eventually become weakened and unable to withstand additional stresses that by themselves would not be fatal. After the scale invasion, mature C. micronesica trees began to succumb10 to(屈服于) other pressures. These other factors contributing to the plant mortality include two other invasive insects that enjoy eating cycad salads for dinner: the cycad blue butterfly (Chilades pandava) and a tiny moth11 (Erechthias sp.).
 
"During the time frame of our study, cycad scale has been found in Rota in 2007 and in Palau in 2008," says Marler. "The spread of A. yasumatsui in the region underscores the importance of empirical studies to inform conservation efforts on Guam and the rest of Micronesia."


点击收听单词发音收听单词发音  

1 dominant usAxG     
adj.支配的,统治的;占优势的;显性的;n.主因,要素,主要的人(或物);显性基因
参考例句:
  • The British were formerly dominant in India.英国人从前统治印度。
  • She was a dominant figure in the French film industry.她在法国电影界是个举足轻重的人物。
2 extirpation 24e80f0b67cdcaab1a1ccb18d37d9d8e     
n.消灭,根除,毁灭;摘除
参考例句:
  • Gamma Knife surgery has recently been tried as an alternative to surgical extirpation. 伽玛刀治疗最近被尝试作为手术根治之外的另一种选择。 来自辞典例句
  • Gamma Knife surgery (GKS) has recently been tried as an alternative to surgical extirpation. 伽玛刀治疗(GKS)最近被尝试作为手术根治之外的另一种选择。 来自互联网
3 dire llUz9     
adj.可怕的,悲惨的,阴惨的,极端的
参考例句:
  • There were dire warnings about the dangers of watching too much TV.曾经有人就看电视太多的危害性提出严重警告。
  • We were indeed in dire straits.But we pulled through.那时我们的困难真是大极了,但是我们渡过了困难。
4 validated c9e825f4641cd3bec0ba01a0c2d67755     
v.证实( validate的过去式和过去分词 );确证;使生效;使有法律效力
参考例句:
  • Time validated our suspicion. 时间证实了我们的怀疑。 来自《现代英汉综合大词典》
  • The decade of history since 1927 had richly validated their thesis. 1927年以来的十年的历史,充分证明了他们的论点。 来自辞典例句
5 cascading 45d94545b0f0e2da398740dd24a26bfe     
流注( cascade的现在分词 ); 大量落下; 大量垂悬; 梯流
参考例句:
  • First of all, cascading menus are to be avoided at all costs. 首先,无论如何都要避免使用级联菜单。 来自About Face 3交互设计精髓
  • Her sounds began cascading gently. 他的声音开始缓缓地低落下来。
6 ecosystem Wq4xz     
n.生态系统
参考例句:
  • This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
  • We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
7 limestone w3XyJ     
n.石灰石
参考例句:
  • Limestone is often used in building construction.石灰岩常用于建筑。
  • Cement is made from limestone.水泥是由石灰石制成的。
8 devastating muOzlG     
adj.毁灭性的,令人震惊的,强有力的
参考例句:
  • It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
  • Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。
9 juvenile OkEy2     
n.青少年,少年读物;adj.青少年的,幼稚的
参考例句:
  • For a grown man he acted in a very juvenile manner.身为成年人,他的行为举止显得十分幼稚。
  • Juvenile crime is increasing at a terrifying rate.青少年犯罪正在以惊人的速度增长。
10 succumb CHLzp     
v.屈服,屈从;死
参考例句:
  • They will never succumb to the enemies.他们决不向敌人屈服。
  • Will business leaders succumb to these ideas?商业领袖们会被这些观点折服吗?
11 moth a10y1     
n.蛾,蛀虫
参考例句:
  • A moth was fluttering round the lamp.有一只蛾子扑打着翅膀绕着灯飞。
  • The sweater is moth-eaten.毛衣让蛀虫咬坏了。
TAG标签: tree insect cycad
发表评论
请自觉遵守互联网相关的政策法规,严禁发布色情、暴力、反动的言论。
评价:
表情:
验证码:点击我更换图片