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。你將聽到一場關於海獺和海藻森林的講座。

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

你有一些時間閱讀第三十一至第四十題。

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

現在請仔細聽，並回答第三十一至第四十題。

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

午安。今天的講座要談我最喜歡的動物之一：海獺。

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

對，牠們很可愛。但牠們也重要得出乎意料！

Sea otters live along the coasts of the North Pacific.

海獺生活在北太平洋沿岸。

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

牠們幾乎一輩子都待在水裡，常常仰躺著漂浮。

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

牠們睡覺時甚至會手牽手，免得漂散！

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

牠們的家是海藻森林，一片由巨型海藻構成的水下森林。

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

海藻一天之內最多能長半公尺。

So why do otters matter so much to these forests?

那麼，海獺為什麼對這些森林這麼重要？

The answer is sea urchins.

答案是海膽。

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

海膽吃海藻，沒有天敵的話，數量就會暴增。

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

整片森林可能消失，只剩下科學家所說的「海膽荒原」。

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

可惜的是，在十八和十九世紀，海獺因為毛皮而遭到獵捕。

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

到了1911年，全世界只剩下大約兩千隻。

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

隨著海獺消失，許多海藻森林也跟著消失了。

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

幸好獵捕被禁止了，海獺慢慢回來了。

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

而且海獺回到哪裡，哪裡的海藻森林就恢復了！

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

這就是生態學家把海獺稱為關鍵物種的原因。

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

關鍵物種對環境的影響，和牠的數量相比非常巨大。

Remove it, and the whole system can collapse.

一旦把牠移除，整個系統都可能崩潰。

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

下次上課，我們來探討狼在黃石公園是否也扮演了類似的角色。

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

好，今天就到這裡。謝謝大家！

That is the end of Part Four.

第四部分到此結束。