生境破坏

Lesson Objectives
::经验教训目标

• Describe ways plants and animals, including humans, can impact the environment.
  ::说明植物和动物,包括人类,如何影响环境。

Lesson Vocabulary
::词汇表课程

• environment
  ::环境环境

• extinction
  ::灭绝

• habitat
  ::生境生境

• impact 
  ::影响影响

What's happening to this land?
::这块土地怎么了?

This does not look very pretty. It certainly is not how it used to look. Why does the land look this way? This picture was taken in southern Mexico. It shows land being cleared for agriculture. The forest has been cut down. The fallen trees have been burned to make room for a farm. Think about how many plants and animals used to live here. In comparison, think about what would happen if your city was burned down. Where would you go? How would you survive? In the case of this picture, many plants and animals lost their homes. This is an example of habitat destruction.
::这看起来不怎么漂亮。 它当然不是过去的样子。 为什么这块土地看起来这样看呢? 这张照片是在墨西哥南部拍摄的。 它显示土地被清除用于农业。 森林已被砍伐。 落下的树木已经被烧毁, 用来为农场腾出地方。 想想这里曾经住过多少植物和动物。 相比之下, 想想如果你们的城市被烧毁, 将会发生什么情况。 你会去哪里? 你将如何生存? 在这张照片中, 许多植物和动物失去了家园。 这是栖息地被摧毁的一个例子。

Habitat Destruction
::销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁 销毁

From a human point of view, a habitat is where you live. It might be your city, town, or neighborhood. Your habitat can be altered. Most people move a few times in their lives. But a plant cannot move. An animal may not be suited to live in another area. A  habitat  is the natural home or environment of an organism. Humans often destroy the habitats of other organisms. The loss of habitat can cause the extinction of species.  Extinction  is when a species disappears forever. Once a species is extinct, it can never be brought back. Humans cause habitat destruction in many ways. There are two common ways this happens. Land may be cleared. Another way is when an animal or plant is brought to an area where it does not belong. 
::从人类的角度来看,栖息地是你们居住的地方,可能是你们的城市、城镇或邻舍。你们的栖息地可以被改变。多数人在其生命中迁移几倍。植物不能移动。动物可能不适合居住在另一个区域。动物可能不适合在另一个区域居住。栖息地是生物体的自然家园或环境。人类常常破坏其他生物体的栖息地。栖息地的丧失可能导致物种灭绝。灭绝是指物种永远消失。物种一旦灭绝,就永远无法复活。人类以多种方式造成栖息地的毁灭。有两种常见的方式发生这种情况。土地可能被清除。另一种方式是动物或植物被带到不属于它的地方。

Land Loss
::土地损失

When land is cleared, habitats are lost. It may be cleared for agriculture. It may also be used for building new homes or businesses. Within the past 100 years, the amount of land used for agriculture has almost doubled. Land used for grazing cattle has more than doubled. Many wetlands have also been lost to agriculture ( Figure   ). The U.S. has lost almost all the natural tall-grass prairies. Thee areas of tall thick grass have virtually disappeared. These areas of land had thick fertile soil. Their grasses had very deep root systems. These deep and thick roots reduced the amount of soil erosion. They also were home to many plants and animals. Prairies were wonderful places. They were home to colorful flowers, prairie dogs, and herds of bison.
::当土地被清除后,生境就会消失。它可能会被清理为农业。它也可能被用于建造新的家园或企业。在过去的100年里,用于农业的土地几乎翻了一番。牧牛的土地已经翻了一番多。许多湿地也损失了农业(Figure ) 。美国几乎失去了所有的天然高草原。高厚的草地几乎已经消失。这些高厚的草地已经消失殆尽。这些土地有肥沃的土壤,它们的草有非常深的根基系统。这些深厚的根基减少了土壤侵蚀的数量。它们也是许多植物和动物的家园。草原是美妙的地方。它们住的地方有花朵、草地犬和野牛的家。

Slash-and-Burn Agriculture
::刀耕火农业

Types of habitats that are rapidly being lost include forests. This is especially true for tropical rainforests. The largest cause of this loss is  slash-and-burn agriculture . To gain farmland, people cut down trees. They then burn the area. This technique is used in many areas around the world. It is very damaging. 
::迅速消失的生境类型包括森林,热带雨林尤其如此。这种损失的最大原因是刀耕火种的农业。为了获得农田,人们砍伐树木,然后烧掉树木,然后烧掉该地区。这种技术在世界各地许多地区使用。非常有害。

What happens due to the use of slash-and-burn methods? First, nutrients are quickly lost from the soil. This often results in people abandoning the land within a few years. Then, the top soil erodes. What is left is not well suited for life. Very few things can grow in the soil.  Desertification  turns forests into a desert. Plants have adapted for wet and shady conditions. They may not survive in drier and heavily sunlit areas. Half of the Earth’s mature tropical forests are gone. At this rate, it does not look good for rainforests. Given the current rate of deforestation, all tropical forests will be gone by the year 2090!
::使用刀耕火种的方法会有什么后果? 首先,养分会很快从土壤中消失,这往往导致人们在几年内放弃土地。然后,顶层土壤侵蚀。留下的东西并不适宜生命。 很少有东西可以生长在土壤中。 荒漠化会把森林变成沙漠。 植物已经适应了湿和阴暗的条件。 它们可能无法在干燥和严寒的地区生存。 地球上一半成熟的热带森林已经消失。 照这个速度计算,雨林看起来并不好。 鉴于目前的毁林速度,所有热带森林都将在2090年之前消失。

Non-native Species
::非本地物种

Imagine you are in a baseball league. The league is made up of several schools. All the players on the teams are the same age. Now imagine a new team joins the league. This teams has students that are much older. They may be bigger and stronger. This new team certainly has an advantage. Their pitcher can throw the ball faster. Their hitters can hit the ball farther. This isn't fair to the other teams. This is sort of what it can be like when a new species is introduced into an animal's habitat.
::想象一下你在棒球联盟中。 联盟由几所学校组成。 所有球队的球员都是同龄人。 现在想象一个新球队加入球队。 这些球队的学生年龄要大得多。 他们可能更强大。 这个球队肯定有优势。 投球者可以更快投球。 球手可以打得更远。 这对其它球队来说不公平。 这有点像新物种被引入动物栖息地。

Habitats are changed by new members. These new members are called non-native species. Non-native means they are not from this area. You can think of them as uninvited guests. They may not have natural predators. In most habitats there is a balance. This balance controls the size of groups of animals. Invasive species have an unfair advantage over their rivals. They are able to out-compete the native species for resources. At times, invasive species are very successful. In some areas, they have taken over the habitat. In this case, the native species goes extinct ( Figure   ). 
::栖息地由新成员改变。 这些新成员被称为非本地物种。 非本地物种意味着它们不是来自这个区域。 您可以把它们视为不邀请的客人。 它们可能没有自然的掠食者。 在大多数生境中, 这种平衡控制着动物群的规模。 入侵物种比它们的对手有不公平的优势, 它们能够比本地物种更胜于资源。 有时, 入侵物种非常成功。 在某些地区, 它们已经占领了栖息地。 在这种情况下, 本地物种灭绝了( 图 ) 。

Recently, cargo ships have transported new species to the Great Lake. These include the zebra mussel, spiny waterflea, and ruffe (a freshwater fish)( Figure   ). These new species are better at hunting for food. They have caused some of the native species to go extinct.
::最近,货轮将新物种运到大湖,其中包括斑马贝、脊椎水面和ruffe(淡水鱼类)(图 ) 。 这些新物种更擅长寻找食物,它们导致一些本地物种灭绝。

Invasive species can disrupt food chains. They can carry disease. They may also prey on native species directly. More importantly, they out-compete native species for limited resources, like food. All of these effects can lead to extinction of the native species.
::入侵物种可以扰乱食物链,可以携带疾病,也可以直接捕食本地物种,更重要的是,由于有限的资源,如食物,它们比本地物种更具有竞争力。 所有这些影响都可能导致本地物种灭绝。

Other Causes
::其他原因 原因

Above were just a few things that caused habitat loss or change. There are many ways in which living organisms can affect their ecosystem. In some areas, it is because of fire management. Fire is a natural event, so managing fire correctly is very important.  
::以上只是造成生境丧失或变化的少数事物。 生物生物可以以多种方式影响其生态系统。 在一些地区,这是因为火灾管理。 火灾是自然事件,因此正确管理火灾非常重要。

In other areas, fisherman have taken too many fish from one area. This places the species at risk of extinction. It also affects other living things that may rely on these fish for food. 
::在其他地区,渔民从一个地区捕捞的鱼太多,使物种濒临灭绝,还影响到可能依赖这些鱼类作为食物的其他生物。

The image below shows a picture of a mine. Mining changes the Earth's surface. This area may once have been a forest or a prairie. Think about how many plants and animals may once have lived here. Now it is a giant hole in the ground. 
::下面的图像显示了地雷的图片。 采矿改变了地球的表面。 这个区域可能曾经是森林或草原。 想想有多少动植物可能曾经住在这里。 现在它变成了一个巨大的地洞 。

Pollution is also a major factor in habitat loss and change.  
::污染也是生境损失和变化的一个主要因素。

Examples of Habitat Destruction
::生境销毁实例

One type of habitat that is under great threat is  wetlands . By the 1980s, most of the U.S. wetlands were lost. Things are even worse in Europe. In their wetlands, many species have already gone extinct. One country that is known for its wetlands is Scotland. In Scotland, these wetland areas are called  bogs.  Many of Scotland's bogs have been lost due to human development. 
::一种受到严重威胁的生境是湿地。到1980年代,美国大部分湿地都丧失了。欧洲的情况更糟。在湿地中,许多物种已经灭绝。一个以湿地著称的国家是苏格兰。在苏格兰,这些湿地被称为沼泽。苏格兰的许多沼泽由于人类发展而丧失。

Another example of species loss happened in Madagascar. From 1970 to 2000, slash-and-burn agriculture was used. Over time, 10% of the country’s total native plants were lost. The area turned into a wasteland. The soil was exposed to the forces of water. Soil from erosion entered the waterways. Much of the country's river ecosystems have since been destroyed. Several fish species are almost extinct. The runoff from the erosion has also affected ocean life. Some coral reef formations in the Indian Ocean are completely lost. 
::另一个物种损失的例子发生在马达加斯加。从1970年到2000年,马达加斯加使用了刀耕火种的农业。随着时间的推移,该国全部本地植物中有10%的损失。该地区变成了荒地。土壤受到水力的污染。土壤因侵蚀而进入水道。该国许多河流生态系统被摧毁。一些鱼类濒临灭绝。侵蚀的径流也影响到海洋生物。印度洋的一些珊瑚礁形成完全消失。

Lesson Summary
::经验教训摘要

• There are many causes of habitat destruction. These include clearing of land and introduction of invasive species.
  ::生境破坏的原因很多,其中包括清理土地和引进入侵物种。

• Slash-and-burn agriculture can lead to desertification. This means fertile top soil is lost.
  ::刀耕火种的农业可能导致荒漠化,这意味着肥沃的地表土壤丧失。

Lesson Review Questions
::经验回顾问题

Recall
::回顾

1. What is a habitat?
   ::什么是栖息地?

1. What are the primary ways that humans destroy habitats?
   ::人类破坏生境的主要方式是什么?

1. Why may invasive species thrive in a new area? Why is this an issue?
   ::为什么入侵物种会在新的地区繁衍兴旺?为什么这是个问题?

1. Describe slash-and-burn agriculture.
   ::描述刀耕火种的农业。