VOA科学技术2024--Monarch Butterfly Population Declines in Mexico

Monarch¹ Butterfly Population Declines in Mexico

　　The Monarch butterfly population has dropped to its second-lowest number on record in Mexican forests this winter. The forests are the insects' winter home. The population decrease is worrisome as the butterfly group is already considered at risk of disappearance².

　　Mexico's government and the non-profit World Wildlife Fund (WWF) recently issued findings of their yearly joint³ study on the butterflies. The research shows that the monarch butterfly presence has shrunk to less than a hectare of forest area.

　　In the mid-1990s, monarch butterflies could be found on around 18 hectares of the forest.

　　The findings represent an almost 60 percent decrease in the monarch butterfly population compared to last year's study. It is also the second-lowest population finding since the first study took place more than thirty years ago.

　　Biologists blame the drop on higher-than-usual temperatures and dry conditions in the northwestern U.S. where the butterfly reproduces.

　　The weather conditions affect the growth of milkweed, the plant where the butterflies lay their eggs. When the young arrive, milkweed is their food for a time.

　　In one of the planet's famous wildlife migrations⁵, the butterflies travel south as many as 4,500 kilometers from places as far north as Canada. They spend the winter in warmer Mexico, where millions of the insects stay in trees that protect them from the rain and cold.

　　Monarch butterfly populations change year to year. As recently as 2021, the same study showed a 35 percent increase to cover around 2.8 hectares.

　　Officials and activists⁶ called for more action to help the species. Such calls include the need to reduce threats posed by herbicides that destroy milkweed and the need to protect forests.

　　"We can't lower our guard," Jorge Rickards, head of WWF's Mexico office, told reporters after releasing the latest data.

　　Words in This Story

　　species – n. a group of animals that are similar and can produce young animals

　　migration⁴ – n. to move from one area to another

　　herbicide – n. a chemical used to destroy plants

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 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

3 joint   

adj.联合的，共同的；n.关节，接合处；v.连接，贴合

参考例句：

• I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤，肩膀脫臼了。
• We wrote a letter in joint names.我们联名写了封信。

4 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。

5 migrations   

n.迁移，移居( migration的名词复数 )

参考例句：

• It foundered during the turmoils accompanying the Great Migrations. 它在随着民族大迁徙而出现的混乱中崩溃。 来自辞典例句
• Birds also have built-in timepieces which send them off on fall and spring migrations. 鸟类也有天生的时间感应器指导它们秋春迁移。 来自互联网

6 activists   

n.（政治活动的）积极分子，活动家( activist的名词复数 )

参考例句：

• His research work was attacked by animal rights activists . 他的研究受到了动物权益维护者的抨击。
• Party activists with lower middle class pedigrees are numerous. 党的激进分子中有很多出身于中产阶级下层。 来自《简明英汉词典》