Freshwater crabs 'feel the pinch' 淡水蟹“面临绝迹”
文章来源:未知 文章作者:meng 发布时间:2009-07-28 06:29 字体: [ ]  进入论坛
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Two thirds of all species of freshwater crab1 maybe at risk of going extinct, with one in six species particularly vulnerable, according to a new survey.

一项新调查显示,所有种类的淡水蟹有三分之二面临绝迹,其中六分之一特别容易受到伤害。

Geothelphusa ancyclophallus has little defence against habitat destruction
Geothelphusa ancyclophallus has little defence against habitat destruction

That makes freshwater crabs2 among the most threatened of all groups of animals assessed(估定值) so far.

The study is the first global assessment3 of the extinction4 risk for any group of freshwater invertebrates5(无脊椎动物).

Crab species in southeast Asia are the most at risk, from habitat destruction, pollution and drainage(排水系统).

Scientists from the Zoological Society of London and Northern Michigan University led the survey, which produced the first World Conservation Union (IUCN) Red List assessment of the 1280 known species of freshwater crab.

Of those, the survey found that 227 species should be considered as near threatened, vulnerable(易受伤害的,有弱点的), endangered or critically endangered.

For another 628 species, not enough data exists to adequately assess their future, says the survey published in the journal Biological Conservation.

However, while the most optimistic scenario6(情节,剧本) is that 16% of all species are at risk, the worst case scenario suggests the figure could be as high as 65%, or two-thirds of all species.

Keystone species

Freshwater crabs are essential to many freshwater ecosystems7. Some feed on fallen leaves and algae8(水藻,海藻), while other species help cycle nutrients10 by eating vast quantities of detritus(碎石,碎屑).

The crabs themselves are an important source of food for a range of birds such as herons(苍鹭) and kingfishers(翠鸟), reptiles11(爬行动物) such as monitor lizards12 and crocodiles and amphibians13(两栖类) such as frogs and toads14(蟾蜍). Mammals that like to dine on(吃) freshwater crabs include otters15(水獭), mongooses(猫鼬), civets(麝猫) as well as wild boar(野猪) and even macaque(短尾猿) monkeys.

Because most species require pristine16(原来的,古时的) water to survive, they are also excellent indicators17 of good water quality.

But species are increasingly being impacted by habitat destruction and pollution.

Most vulnerable are crabs living in southeast Asia, which is also home to the greatest diversity of species.

For example, 40 of 50 species living in Sri Lanka are threatened.

Those species that live a semi-terrestrial life, breathing air, living in burrows18(地洞) and dividing their time between water and land, appear most at risk, possibly because their habitats are most easily disturbed by human activities.

No species are yet known to have gone extinct, but some species such as the terrestrial crab Thaipotamon siamese and the waterfall crab Demanietta manii from Thailand have not been seen alive for over a century, and their original habitats have since been built over by urban developments.

The loss of natural forest to land development and agriculture has also impacted almost every habitat in which freshwater crabs live, the report notes.

The proportion of freshwater crabs threatened with extinction is equal to that of reef-building corals, and exceeds that of all other groups that have been assessed except for amphibians.

"We must set clear goals to reverse these trends and ensure that our enduring legacy19(遗赠物) is not to wipe out the small things that provide us with great benefits, such as nutrient9 cycling," says Ben Collen, one the survey scientists from the Zoological Society of London.



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1 crab xoozE     
n.螃蟹,偏航,脾气乖戾的人,酸苹果;vi.捕蟹,偏航,发牢骚;vt.使偏航,发脾气
参考例句:
  • I can't remember when I last had crab.我不记得上次吃蟹是什么时候了。
  • The skin on my face felt as hard as a crab's back.我脸上的皮仿佛僵硬了,就象螃蟹的壳似的。
2 crabs a26cc3db05581d7cfc36d59943c77523     
n.蟹( crab的名词复数 );阴虱寄生病;蟹肉v.捕蟹( crab的第三人称单数 )
参考例句:
  • As we walked along the seashore we saw lots of tiny crabs. 我们在海岸上散步时看到很多小蟹。 来自《简明英汉词典》
  • The fish and crabs scavenge for decaying tissue. 鱼和蟹搜寻腐烂的组织为食。 来自《简明英汉词典》
3 assessment vO7yu     
n.评价;评估;对财产的估价,被估定的金额
参考例句:
  • This is a very perceptive assessment of the situation.这是一个对该情况的极富洞察力的评价。
  • What is your assessment of the situation?你对时局的看法如何?
4 extinction sPwzP     
n.熄灭,消亡,消灭,灭绝,绝种
参考例句:
  • The plant is now in danger of extinction.这种植物现在有绝种的危险。
  • The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。
5 invertebrates 7e45dc289993d00de9b9f14a70e51319     
n.无脊椎动物( invertebrate的名词复数 )
参考例句:
  • Insects and worms are all invertebrates. 昆虫和蠕虫都是无脊椎动物。 来自辞典例句
  • In the earthworm and many other invertebrates, these excretory structures are called nephridia. 在蚯蚓和许多其它无脊椎动物中,这些排泄结构称为肾管。 来自辞典例句
6 scenario lZoxm     
n.剧本,脚本;概要
参考例句:
  • But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • This is a totally different scenario.这是完全不同的剧本。
7 ecosystems 94cb0e40a815bea1157ac8aab9a5380d     
n.生态系统( ecosystem的名词复数 )
参考例句:
  • There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
  • Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样,从雨林到半荒漠等不一而足。 来自辞典例句
8 algae tK6yW     
n.水藻,海藻
参考例句:
  • Most algae live in water.多数藻类生长在水中。
  • Algae grow and spread quickly in the lake.湖中水藻滋蔓。
9 nutrient 3vpye     
adj.营养的,滋养的;n.营养物,营养品
参考例句:
  • Magnesium is the nutrient element in plant growth.镁是植物生长的营养要素。
  • The roots transmit moisture and nutrient to the trunk and branches.根将水分和养料输送到干和枝。
10 nutrients 6a1e1ed248a3ac49744c39cc962fb607     
n.(食品或化学品)营养物,营养品( nutrient的名词复数 )
参考例句:
  • a lack of essential nutrients 基本营养的缺乏
  • Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》
11 reptiles 45053265723f59bd84cf4af2b15def8e     
n.爬行动物,爬虫( reptile的名词复数 )
参考例句:
  • Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
  • Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》
12 lizards 9e3fa64f20794483b9c33d06297dcbfb     
n.蜥蜴( lizard的名词复数 )
参考例句:
  • Nothing lives in Pompeii except crickets and beetles and lizards. 在庞培城里除了蟋蟀、甲壳虫和蜥蜴外,没有别的生物。 来自辞典例句
  • Can lizards reproduce their tails? 蜥蜴的尾巴断了以后能再生吗? 来自辞典例句
13 amphibians c4a317a734a700eb6f767bdc511c1588     
两栖动物( amphibian的名词复数 ); 水陆两用车; 水旱两生植物; 水陆两用飞行器
参考例句:
  • The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
  • Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。
14 toads 848d4ebf1875eac88fe0765c59ce57d1     
n.蟾蜍,癞蛤蟆( toad的名词复数 )
参考例句:
  • All toads blink when they swallow. 所有的癞蛤蟆吞食东西时都会眨眼皮。 来自《简明英汉词典》
  • Toads have shorter legs and are generally more clumsy than frogs. 蟾蜍比青蛙脚短,一般说来没有青蛙灵活。 来自辞典例句
15 otters c7b1b011f1aba54879393a220705a840     
n.(水)獭( otter的名词复数 );獭皮
参考例句:
  • An attempt is being made to entice otters back to the river. 人们正试图把水獭引诱回河里去。 来自《简明英汉词典》
  • Otters are believed to have been on Earth for 90 million years. 水獭被认为存活在地球上已经9千多万年。 来自互联网
16 pristine 5BQyC     
adj.原来的,古时的,原始的,纯净的,无垢的
参考例句:
  • He wiped his fingers on his pristine handkerchief.他用他那块洁净的手帕擦手指。
  • He wasn't about to blemish that pristine record.他本不想去玷污那清白的过去。
17 indicators f46872fc1b5f08e9d32bd107be1df829     
(仪器上显示温度、压力、耗油量等的)指针( indicator的名词复数 ); 指示物; (车辆上的)转弯指示灯; 指示信号
参考例句:
  • The economic indicators are better than expected. 经济指标比预期的好。
  • It is still difficult to develop indicators for many concepts used in social science. 为社会科学领域的许多概念确立一个指标仍然很难。
18 burrows 6f0e89270b16e255aa86501b6ccbc5f3     
n.地洞( burrow的名词复数 )v.挖掘(洞穴),挖洞( burrow的第三人称单数 );翻寻
参考例句:
  • The intertidal beach unit contains some organism burrows. 潮间海滩单元含有一些生物潜穴。 来自辞典例句
  • A mole burrows its way through the ground. 鼹鼠会在地下钻洞前进。 来自辞典例句
19 legacy 59YzD     
n.遗产,遗赠;先人(或过去)留下的东西
参考例句:
  • They are the most precious cultural legacy our forefathers left.它们是我们祖先留下来的最宝贵的文化遗产。
  • He thinks the legacy is a gift from the Gods.他认为这笔遗产是天赐之物。
TAG标签: crab freshwater extinct
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