七条美国牛蛇被放生
文章来源:未知 文章作者:enread 发布时间:2012-05-08 06:40 字体: [ ]  进入论坛
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On May 1, USDA Forest Service, U.S Fish and Wildlife Service, Louisiana Department of Wildlife and Fisheries, the Memphis Zoo, and other partners released seven young Louisiana pine snakes on a restored longleaf pine stand in the Kisatchie National Forest in Louisiana. The release is the fourth in 2 years, part of a plan to restore a very rare snake to its range in Louisiana. Last year the partners released 20 newly hatched snakes; this year's snakes are 6 months old and about 3 feet long. Four to 5 feet long as an adult and covered with a striking pattern of black, brown and beige, the Louisiana pine snake is a rare sight in its native range in east-central Texas and across Louisiana. Craig Rudolph, Forest Service Southern Research Station research ecologist and a member of the reintroduction team, has monitored the species for decades, and concurs1(同意,一致) with other herpetologists that it well may be one of the rarest snake species in the United States. Snakes released for the restoration effort are hatched and raised in zoos, and are the offspring of Louisiana pine snakes captured from the wild.

Already listed as threatened in Texas and a candidate for listing under the Federal Endangered Species Act, the Louisiana pine snake population has declined because of alterations2 to the its native pine longleaf pine habitat and that of its prey3.

A nonvenomous species, the Louisiana pine snake spends most of its time underground in burrows4 of its favorite prey, the Baird's pocket gopher. The ideal habitat for both species consists of dry, sandy-soiled ridges5 covered with longleaf pine trees and an open understory of the grasses and forbs the pocket gophers feed on. This habitat largely disappeared due to commercial logging in the late 19th and early 20th centuries and subsequent fire suppression. "Without fire, these upland pine savannahs rapidly develop a midstory that shades out the grassy6 understory that pocket gophers need," says Rudolph. "The release site on the Kisatchie, which was intentionally7 restored for red-cockaded woodpecker habitat, should also support pocket gophers and Louisiana pine snakes."

Only time will tell whether the Louisiana pine snake can be sustainably restored to longleaf pine ecosystems8 in its native range.

Researchers implanted each of the snakes released on May 1 with a passive integrated transponder (PIT) that allows them to be tracked by recorders installed on the site. "So far we've not had much success with the recorders, which are dug into the ground in four places on the release site," says Rudolph. "We've recorded activity in the first weeks, but nothing later on. This is not unexpected, since these snakes have a large home range and probably leave the immediate9 area. We need to get good population estimates for the areas we've released in, but the only way to get data is by trapping, which is very time-consuming and expensive."

The animal's biology presents another constraint10 to its survival. While most other snakes produce large clutches of eggs, the Louisiana pine snake lays only three to five eggs, and in captive breeding programs, sometimes only one or two eggs per clutch hatch. This low reproductive rate means that the species might not recover quickly in the wild. Rudolph worries that breeding programs, which rely on the progeny11 of only 16 founder12 individuals caught in the wild, may be producing snakes that are not genetically13 diverse enough to survive when released. "In the best-case scenario14, there would still be Louisiana pine snakes out there that we've never caught that can breed with the released snakes," says Rudolph. "We have traps operating for thousands of trap days a year in Texas, for instance, and haven't caught a single snake in three years. When we find better ways to monitor our releases, perhaps we'll find some additional populations."



点击收听单词发音收听单词发音  

1 concurs fbb2442ed8793bdb8942c47540e10367     
同意(concur的第三人称单数形式)
参考例句:
  • Gilardi concurs that the newly compiled data is a powerful tool. 吉拉迪认同新汇集的数据是一个强有力的工具。
  • Curtin concurs that it's been a blessing and a reward. 柯廷也同意这是一种祝福和奖励。
2 alterations c8302d4e0b3c212bc802c7294057f1cb     
n.改动( alteration的名词复数 );更改;变化;改变
参考例句:
  • Any alterations should be written in neatly to the left side. 改动部分应书写清晰,插在正文的左侧。 来自《简明英汉词典》
  • Gene mutations are alterations in the DNA code. 基因突变是指DNA 密码的改变。 来自《简明英汉词典》
3 prey g1czH     
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨
参考例句:
  • Stronger animals prey on weaker ones.弱肉强食。
  • The lion was hunting for its prey.狮子在寻找猎物。
4 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
5 ridges 9198b24606843d31204907681f48436b     
n.脊( ridge的名词复数 );山脊;脊状突起;大气层的)高压脊
参考例句:
  • The path winds along mountain ridges. 峰回路转。
  • Perhaps that was the deepest truth in Ridges's nature. 在里奇斯的思想上,这大概可以算是天经地义第一条了。
6 grassy DfBxH     
adj.盖满草的;长满草的
参考例句:
  • They sat and had their lunch on a grassy hillside.他们坐在长满草的山坡上吃午饭。
  • Cattle move freely across the grassy plain.牛群自由自在地走过草原。
7 intentionally 7qOzFn     
ad.故意地,有意地
参考例句:
  • I didn't say it intentionally. 我是无心说的。
  • The local authority ruled that he had made himself intentionally homeless and was therefore not entitled to be rehoused. 当地政府裁定他是有意居无定所,因此没有资格再获得提供住房。
8 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
9 immediate aapxh     
adj.立即的;直接的,最接近的;紧靠的
参考例句:
  • His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
  • We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。
10 constraint rYnzo     
n.(on)约束,限制;限制(或约束)性的事物
参考例句:
  • The boy felt constraint in her presence.那男孩在她面前感到局促不安。
  • The lack of capital is major constraint on activities in the informal sector.资本短缺也是影响非正规部门生产经营的一个重要制约因素。
11 progeny ZB5yF     
n.后代,子孙;结果
参考例句:
  • His numerous progeny are scattered all over the country.他为数众多的后代散布在全国各地。
  • He was surrounded by his numerous progeny.众多的子孙簇拥着他。
12 Founder wigxF     
n.创始者,缔造者
参考例句:
  • He was extolled as the founder of their Florentine school.他被称颂为佛罗伦萨画派的鼻祖。
  • According to the old tradition,Romulus was the founder of Rome.按照古老的传说,罗穆卢斯是古罗马的建国者。
13 genetically Lgixo     
adv.遗传上
参考例句:
  • All the bees in the colony are genetically related. 同一群体的蜜蜂都有亲缘关系。
  • Genetically modified foods have already arrived on American dinner tables. 经基因改造加工过的食物已端上了美国人的餐桌。 来自英汉非文学 - 生命科学 - 基因与食物
14 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。
TAG标签: pine snakes Louisiana
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