Balance ofNature大自然的生态平衡

ot many years ago, some American farmers began to complain about hawks (鹰) 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，一些美国农民开始抱怨起鹰来，因为它们在捕杀小鸡。这些农民不知道该怎么办，于是他们向政府官员求助。政府官员说：“你们每杀死一只鹰，我们都会给你们钱。”

然后这些农民开始猎杀，许多鹰被杀掉了。但是随后农民们又面临了一个新的问题：田鼠大量繁殖，它们吃掉农民的玉米。

鹰不仅吃鸡，还吃田鼠。而它们吃得更多的是田鼠，而不是鸡。那些农民如果早知道这一点，他们就不会杀死鹰了，田鼠也会更少。

在美国的一个地方生长着以野生玫瑰为食的鹿，而山里的饿狮子却以鹿为食。如果人们不去管它，这些鹿、山狮、野生玫瑰的数量将不会有大的变化。如果有太多的鹿，狮子数量将会相应增加，它们会吃掉更多的鹿。如果有太多的狮子，鹿的数量将会减少，野生玫瑰就会更多。

因此人们总要维持大自然的生态平衡。为了保护鹿，政府曾经杀死了所有的狮子。不久大量的鹿吃掉了所有的野生玫瑰。然后它们开始吃小树的绿叶。而这些树对于农民来说是很重要的。因此农民试图保护那些树，使其免受鹿的伤害。鹿找不到食物吃，有许多鹿都被饿死了。

政府从大自然那里得到了深刻的教训。