Balance ofNature大自然的生態平衡

ot many years ago， some American farmers began to complain about hawks (鷹) because the hawks were killing chickens. The farmers didn’t know what to do. They went to the government officials and asked for help. The officials said， “We’ll pay you for each hawk you kill.”

Then the farmers began to kill the hawks， many hawks were killed. But the farmers now had another problem: the field mice were growing in great number， and they were eating up the farmers’ corn.

Hawks eat not only chickens but also field mice(老鼠). They eat more field mice than chickens. If the farmers had known that， they would have not killed the hawks. And there would have been fewer field mice.

In one part of the United States， there are deer that eat a kind of wild rose. And the mountain lions kill the deer (鹿) for food. The number of deer， mountain lions， and wild roses will not change much if people stay away from them. If there are too many deer， mountain lions will grow in number. They will have to kill more deer. If there are too many mountain lions， there will be fewer deer， and there will be more roses.

So people always need to keep the balance of nature. The government once killed almost all the mountain lions to protect the deer. Soon there were so many deer that they ate up all the wild roses. Then they began to eat green leaves of young trees. These trees were very important to the farmers. So the farmers tried to protect the trees from the deer. The deer had nothing to eat and many of them died.

The government learned a good lesson from nature.

前些年，一些美國農民開始抱怨起鷹來，因為它們在捕殺小雞。這些農民不知道該怎么辦，于是他們向政府官員求助。政府官員說：“你們每殺死一只鷹，我們都會給你們錢?！?/p>

然后這些農民開始獵殺，許多鷹被殺掉了。但是隨后農民們又面臨了一個新的問題：田鼠大量繁殖，它們吃掉農民的玉米。

鷹不僅吃雞，還吃田鼠。而它們吃得更多的是田鼠，而不是雞。那些農民如果早知道這一點，他們就不會殺死鷹了，田鼠也會更少。

在美國的一個地方生長著以野生玫瑰為食的鹿，而山里的餓獅子卻以鹿為食。如果人們不去管它，這些鹿、山獅、野生玫瑰的數量將不會有大的變化。如果有太多的鹿，獅子數量將會相應增加，它們會吃掉更多的鹿。如果有太多的獅子，鹿的數量將會減少，野生玫瑰就會更多。

因此人們總要維持大自然的生態平衡。為了保護鹿，政府曾經殺死了所有的獅子。不久大量的鹿吃掉了所有的野生玫瑰。然后它們開始吃小樹的綠葉。而這些樹對于農民來說是很重要的。因此農民試圖保護那些樹，使其免受鹿的傷害。鹿找不到食物吃，有許多鹿都被餓死了。

政府從大自然那里得到了深刻的教訓。