The Clean Beaver

The Clean Beaver

干净的海狸

One day some scientists looked around and saw that the rivers were very dirty, and that there were less fish to catch. They also noticed that there were fewer birds and dragonflies, and that the trees were starting to die. They couldn’t find what was causing the problem. But they noticed something else was missing—the beaver. So scientists decided to study how beavers live so that they can bring them back to the rivers.

一天，一些科学家环顾四周，发现河流很脏，可捕的鱼也少了。 他们还注意到鸟类和蜻蜓减少了，树木开始死亡。 他们找不到引起问题的原因。但他们注意到还有一样东西不见了——海狸。 所以科学家们决定研究海狸是如何生活的，这样他们就可以把它们带回河流。

Wherever beavers live, they make big changes to nature. In fact, the only creatures who affect nature more are humans! However, unlike humans, the changes that beavers make are good for the other animals and plants around them. Once a beaver finds an empty spot on a stream or river, it builds a dam.

无论海狸生活在哪里，它们都会对自然环境做出巨大的改变。事实上，唯一对自然影响更大的生物是人类! 然而，与人类不同的是，海狸所做的改变对它们周围的其他动物和植物是有益的。 一旦河狸在小溪或河流上找到一个空的地方，它就会筑起水坝。

As soon as the dam is built, the land upstream begins to fill with water. The extra water changes the land behind the dam into a wetland. A wetland is a wide area of mud and water, and wetlands are very important habitats. In fact, over half of North America’s endangered species need wetlands to survive. Once a beaver makes its dam, it takes care to make sure the water level around the dam stays high.

大坝一建成，上游的土地就开始被水填满。 多余的水把大坝后面的土地变成了湿地。 湿地是一大片泥和水，湿地是非常重要的栖息地。 事实上，超过一半的北美濒危物种需要湿地才能生存。 一旦海狸建好了水坝，它就会小心翼翼地确保水坝周围的水位保持在高位。

The beaver does this to protect its home, but it also protects nature. The dam slows down a river, which helps make the water cleaner. And instead of the river carrying good soil away to the ocean, the dam keeps the soil in the forest. Even though beavers cut down trees to make their dams, they actually help the trees to grow.

海狸这样做是为了保护它的家园，也是为了保护大自然。水坝减缓了河水的流速，使河水更加清澈。 而不是河流带着好的土壤到海洋，大坝保持土壤在森林。 尽管海狸砍伐树木来建造水坝，但它们实际上帮助树木生长。

A beaver’s favorite trees for eating and building are cottonwoods and aspens. Both of these trees make hundreds of baby trees every year. However, if all the baby trees lived, they would eventually get too crowded, and they all would die. But when the beaver takes out some of the trees, it gives the rest more room to grow. This helps keep the forests healthy. Beavers eat only plants, and this makes its other animal friends happy.

海狸最喜欢的食物和建筑树木是杨树和白杨。 这两种树每年都能结出数百棵小树。 然而，如果所有的幼树都存活下来，它们最终会变得太拥挤，所有的树都将死亡。 但是当海狸砍掉一些树时，其余的树就有了更多的生长空间。这有助于保持森林的健康。 海狸只吃植物，这让它的其他动物朋友很高兴。