Teaching English through Geography: Ecosystem Balance

 

The ‘YellowStone’ National Park mystery

Could you ever imagine that the disappearance of large predators like wolves are considered responsible for the change of the landscape and absence of poplars along the banks of the Yellowstone lake in Montana?This fact brought about flooding in the lake and the erosion of land which sank into the lake.

Researches revealed that there had been a widening of the shore, resulting in an important piece of land being vanished, since waters could not be restrained, and it was land which they couldn't afford to sacrifice.

Old photos of the lake showed that there used to be poplars along the shore of the lake. But, how had the poplars vanished?

At  first it was thought that global warming was responsible, a claim which proved false, because of the presence of poplars a short distance away from the lake.

Moreover, since poplars are known to flourish after arsons, there should be affluent trees, due to a large arson in the area in the late 20's.

Indeed, research in the trunk of the remaining poplars proved their age; all these trees were no more than 70 years old, which meant that poplars indeed flourished after the arson.

However, biologists realised a strange coincidence:

In the 30s, there was a big campaign of capturing all the wolves in the area and taking them away, because inhabitants complained that wolves hunted their sheep. But how the capturing of the wolves could be connected with the absence of poplars?

Scientists were close to the solution and in an effort to prove the truth of their words, they released 30 wolves back to the ‘YellowStone’ lake area, in 1995.

Indeed, a year later, new poplar seedlings made their appearance. How was that?

 Can you imagine the solution to the mystery?

1. Match the following words from the text with their meaning

1. Predators 1.controlled

2. Restrained 2.made free, let go of

3. Vanished 3.happening by accident

4. Flourished 4. disappeared

5. Coincidence         5.young plant

6. Affluent 6.hunting animal

7. Released 7.thrived, developed well

8. Seedlings 8.a lot of

9. Arson 9.fire Read the passage and answer whether the statements are (T) true, (F) false or (NM)not mentioned

1. The profile of the ‘YellowStone’ National Park has changed a lot during the recent years.

2. Yellowstone National Park wasn’t affected by erosion.

3. Climate change was considered responsible for the landscape change in YellowStone National Park  

4. Certain types of trees benefit from fires.

5. Wolves were kept in ranches.

6. Reintroduction of the wolves in Yellowstone brought a balance to the ecosystem.Wolves shouldn’t have been brought back because they kill animals.

      3. Answer the questions

1. How did the reintroduction of wolves impact the tree population in Yellowstone park?

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2. Follow up: What is the moral we get from this true story?

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The answer to the mystery:

Wolves were after elk for food, so deer, almost exclusively fed with poplars, were not free anymore to eat them to the root, as they were after the wolves had been removed from the area.

This gives us a clear and daunting idea of how a missed link in the environmental chain can influence the balance on the earth and what detrimental consequences it can have.