VOA慢速英语2021--帝王蝶种群即将灭绝

The Monarch¹ Butterfly Population Is in Danger of Disappearing

The warm coast of California is a place where many western monarch butterflies stay during the cold winter months in the United States. Researchers fear the record low number of monarchs² this year could mean the insects are in danger of disappearing in the near future.

Researchers from the Xerces Society said they found fewer than 2,000 orange-and-black butterflies in the yearly³ count this January. That number showed a big drop from the tens of thousands in recent years. In the 1980s, there were millions of them in trees from Northern California's Marin County⁴ to San Diego County near the Mexico border.

Every winter, western monarch butterflies fly south from the northwestern U.S. to California, going to the same places and even the same trees. They often stay together to keep warm. At the start of November, they usually arrive in California. The insects then spread across the country once warmer weather arrives in March.

On the eastern side of the Rocky Mountains, another monarch butterfly population travels from southern Canada and the northeastern United States to spend the winter in Mexico.

Scientists estimate⁵ the eastern monarch population has decreased by 80 percent since the mid-1990s. But the decrease in the western monarch population has been much greater.

The Xerces Society works⁶ on conservation efforts for insects. Last winter, it recorded around 29,000 butterflies in its yearly survey. That was similar to the winter before, when an all-time low of 27,000 monarchs was counted.

But the count this year is dangerously low. Pacific Grove⁷ is a city known for having monarch butterflies during the cold season. But volunteers did not see a single one this winter. Other well-known areas, such as Pismo State Beach, Monarch Butterfly Grove and Natural Bridges State Park, only had a few hundred butterflies, researchers said.

Scientists say there are several causes for the extremely low numbers of butterflies in the western states.

Homebuilding and chemical use have destroyed milkweed plants along their migratory⁸ path. The plants are needed for monarch butterflies to grow and develop. Climate change interferes⁹ with the growth of wild plants. And huge wildfires in the west may also have influenced their migration¹⁰.

A 2017 Washington State University study predicted that monarch butterflies would likely disappear within 10 to 20 years if the population dropped below 30,000 and nothing was done to save them.

Last December, U.S. federal¹¹ officials said the monarch butterfly is "a candidate¹²" for the threatened or endangered species¹³ list. The designation would provide protection for their food supply and environment, including their migratory path. However, they said no action would be taken for several years because many other species are still awaiting¹⁴ that designation.

The Xerces Society said it will keep working with other partners to protect the monarch. The organization added that people can help by planting flowers and milkweed along these butterflies' migratory path.

Words in This Story

conservation – n. the protection of animals, plants, and natural resources

milkweed – n. type of North American plant that has white juice

migratory – adj. moving from one place to another at different times of the year

endangered – adj. used to describe a type of animal or plant that has become very rare and that could die out completely

species – n. a particular group of things or people that belong together

1 monarch   

n.帝王，君主，最高统治者

参考例句：

• The monarch's role is purely ceremonial.君主纯粹是个礼仪职位。
• I think myself happier now than the greatest monarch upon earth.我觉得这个时候比世界上什么帝王都快乐。

2 monarchs   

君主，帝王( monarch的名词复数 )

参考例句：

• Monarchs ruled England for centuries. 世袭君主统治英格兰有许多世纪。
• Serving six monarchs of his native Great Britain, he has served all men's freedom and dignity. 他在大不列颠本国为六位君王服务，也为全人类的自由和尊严服务。 来自演讲部分

3 yearly   

adj.每年的，一年一度的；adv.一年一次地

参考例句：

• The flower show is a yearly event in our town.我们镇上的花展一年举行一次。
• The yearly rental of her house is 2400 yuan.她这房子年租金是2400元。

4 county   

n.县，郡

参考例句：

• When the good news reached there,the whole county rejoiced.喜讯传到那里时，全县的人都欢欣鼓舞起来。
• In that year county after county fell to the enemy.那一年一个又一个的县城沦入敌人手中。

5 estimate   

n.估计，估量；评价，看法；vt.估计，估量

参考例句：

• We estimate the cost to be five thousand dollars.我们估计费用为5000美元。
• The lowest estimate would put the worth of the jewel at ＄200.按最低的评估这块宝石也值200美元。

6 works   

n.作品，著作；工厂，活动部件，机件

参考例句：

• We expect writers to produce more and better works.我们期望作家们写出更多更好的作品。
• The novel is regarded as one of the classic works.这篇小说被公认为是最优秀的作品之一。

7 grove   

n.林子，小树林，园林

参考例句：

• On top of the hill was a grove of tall trees.山顶上一片高大的树林。
• The scent of lemons filled the grove.柠檬香味充满了小树林。

8 migratory   

n.候鸟，迁移

参考例句：

• Many migratory birds visit this lake annually.许多候鸟每年到这个湖上作短期逗留。
• This does not negate the idea of migratory aptitude.这并没有否定迁移能力这一概念。

9 interferes   

vi. 妨碍，冲突，干涉

参考例句：

• The noise interferes with my work. 这噪音妨碍我的工作。
• That interferes with my plan. 那干扰了我的计划。

10 migration   

n.迁移，移居，（鸟类等的）迁徙

参考例句：

• Swallows begin their migration south in autumn.燕子在秋季开始向南方迁移。
• He described the vernal migration of birds in detail.他详细地描述了鸟的春季移居。

11 federal   

adj.联盟的；联邦的；(美国)联邦政府的

参考例句：

• Switzerland is a federal republic.瑞士是一个联邦共和国。
• The schools are screaming for federal aid.那些学校强烈要求联邦政府的援助。

12 candidate   

n.候选人；候补者；投考者，申请求职者

参考例句：

• Voters like a candidate who has the common touch. 投票者喜欢那些平易近人的候选人。
• The local newspapers dressed up the candidate as a boxer.当地报纸把那个候选人描绘成一个拳击手。

13 species   

n.物种，种群

参考例句：

• Are we the only thinking species in the whole of creation?我们是万物中惟一有思想的物种吗？
• This species of bird now exists only in Africa.这种鸟现在只存在于非洲。

14 awaiting   

v.等候( await的现在分词 )；等待；期待；将发生在

参考例句：

• He is in custody awaiting trial . 他已被拘留候审。
• He spent a week in custody on remand awaiting sentence. 等候判决期间他被还押候审一个星期。 来自《简明英汉词典》