IELTS Listening Part 4: Sea Otters and Kelp Forests

Part Four. You will hear a lecture about sea otters and kelp forests.

第四部分。你将听到一场关于海獭和海藻森林的讲座。

You have some time to look at questions thirty-one to forty.

你有一些时间阅读第三十一至第四十题。

Now listen carefully and answer questions thirty-one to forty.

现在请仔细听，并回答第三十一至第四十题。

Good afternoon. Today's lecture is about one of my favourite animals, the sea otter.

下午好。今天的讲座讲的是我最喜欢的动物之一：海獭。

Yes, they're adorable. But they're also surprisingly important!

没错，它们很可爱。但它们也重要得出人意料！

Sea otters live along the coasts of the North Pacific.

海獭生活在北太平洋沿岸。

They spend almost their whole lives in the water, often floating on their backs.

它们几乎一生都在水里度过，常常仰面漂浮。

They even hold hands while they sleep, so they don't drift apart!

它们睡觉时甚至会手牵手，以免漂散！

Their home is the kelp forest, an underwater forest of giant seaweed.

它们的家是海藻森林，一片由巨型海藻组成的水下森林。

Kelp can grow up to half a metre in a single day.

海藻一天之内最多能长半米。

So why do otters matter so much to these forests?

那么，海獭为什么对这些森林如此重要？

The answer is sea urchins.

答案是海胆。

Urchins eat kelp, and without predators, their numbers explode.

海胆吃海藻，没有天敌的话，它们的数量会暴增。

Whole forests can disappear, leaving what scientists call urchin barrens.

整片森林可能消失，只留下科学家所说的“海胆荒漠”。

Sadly, in the eighteenth and nineteenth centuries, otters were hunted for their fur.

遗憾的是，在十八和十九世纪，海獭因为毛皮遭到捕杀。

By 1911, only around two thousand were left in the world.

到1911年，全世界只剩下大约两千只。

And as the otters vanished, so did many kelp forests.

随着海獭消失，许多海藻森林也跟着消失了。

Fortunately, hunting was banned, and the otters slowly returned.

幸运的是，捕猎被禁止了，海獭慢慢回来了。

And wherever they came back, the kelp forests recovered too!

而且海獭回到哪里，哪里的海藻森林就恢复了！

This is why ecologists call the sea otter a keystone species.

这就是生态学家把海獭称为关键物种的原因。

A keystone species has a huge effect on its environment, compared to its numbers.

关键物种对环境的影响，与它的数量相比非常巨大。

Remove it, and the whole system can collapse.

一旦把它移除，整个系统都可能崩溃。

Next time, we'll ask whether wolves played a similar role in Yellowstone.

下次课，我们来探讨狼在黄石公园是否也扮演了类似的角色。

Right, that's all for today. Thank you!

好，今天就到这里。谢谢大家！

That is the end of Part Four.

第四部分到此结束。