章节大纲

  • Deforested land in southern Mexico, showing stumps and burned vegetation from agriculture.

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

    This picture, taken in southern Mexico, shows land being cleared for . The forest has been cut down and burned to make room for a farm. In the process, homes  of many plants and were destroyed. This is an example of habitat destruction.
    ::这张照片在墨西哥南部拍摄, 显示土地正在被清除, 森林已被砍伐和烧毁,

    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, go to school, and go to have fun. Your habitat can be altered, and you can easily adapt. Most people live in a few different places and go to a number of different schools throughout their life. But a plant or animal may not be able to adapt to a changed habitat. A habitat is the natural home or environment of an organism . Humans often destroy the habitats of other organisms. Habitat destruction can cause the extinction of . Extinction is the complete disappearance of a species. Once a species is extinct, it can never recover. Some ways humans cause habitat destruction are by clearing land and by introducing non-native species of plants and animals.
    ::从人类的角度来看,栖息地是指你居住的地方,上学的地方,去玩乐的地方。你的栖息地可以被改变,你可以很容易地适应。大多数人住在几个不同的地方,在他们一生中都到不同的学校学习。但植物或动物可能无法适应改变的栖息地。栖息地是有机体的自然家园或环境。人类经常破坏其他生物的栖息地。生境的破坏可以造成灭绝。生境的毁灭可以造成物种的完全消失。物种一旦灭绝,就永远无法恢复。人类破坏生境的方式有:清理土地,引进非自然的动植物物种。

    Land Loss
    ::土地损失

    Clearing land for agriculture and is a major cause of habitat destruction. Within the past 100 years, the amount of total land used for agriculture has almost doubled. Land used for grazing cattle has more than doubled. Agriculture alone has cost the United States half of its wetlands ( Figure ) and almost all of its tallgrass prairies. Native prairie , with their thick fertile soils, deep-rooted grasses, diversity of colorful flowers , burrowing prairie dogs, and herds of bison and other animals, have virtually disappeared ( Figure ).
    ::过去100年来,农业用地的总数几乎翻了一番,牧牛用地增加了一倍多,仅农业就使美国一半的湿地(图 ) 、 几乎全部高草原付出了代价。 土著草原及其肥沃的土壤、根深蒂固的草地、多彩花朵的多样性、耕种草犬以及野牛和其他动物的牧群几乎消失(图 ) 。

    Aerial view of wetlands in Cape May, New Jersey, showing diverse habitats and waterways.

    Wetlands such as this one in Cape May, New Jersey, filter water and protect coastal lands from storms and floods.
    ::诸如5月在新泽西州五月角的这一次湿地,过滤水,保护沿海土地免受暴风雨和洪水的侵袭。

    Tallgrass prairie habitat showing golden grass under a clear blue sky in the Flint Hills.

    The Flint Hills contain some of the largest remnants of tallgrass prairie habitat remaining in North America.
    ::弗林特山丘含有北美留下的一些最大的高草草原栖息地。

    Herd of bison grazing in tallgrass prairie habitat in the Flint Hills.

    Herds of bison also made up part of the tallgrass prairie community.
    ::野牛的牧群也构成高草草原社区的一部分。

    Slash-and-Burn Agriculture
    ::刀耕火农业

    Other habitats that are being rapidly destroyed are forests, especially rainforests. The largest cause of deforestation today is slash-and-burn agriculture (shown in the opening image). This means that when people want to turn a forest into a farm, they cut down all of the trees and then burn the remainder of the forest. This technique is used by over 200 million people in tropical forests throughout the world.
    ::其他正在被迅速摧毁的生境是森林,特别是雨林,今天砍伐森林的最大原因是刀耕火种的农业(如开阔图象所示),这意味着当人们想将森林变成农场时,他们就砍掉所有树木,然后烧掉其余的森林,全世界2亿多热带森林中的人都使用这一技术。

    As a consequence of slash-and-burn agriculture, nutrients are quickly lost from the soil . This often results in people abandoning the land within a few years. Then the top soil erodes and desertification can follow. Desertification turns forest into a , where it is difficult for plants to grow. Half of the Earth’s mature tropical forests are gone. At current rates of deforestation, all tropical forests will be gone by the year 2090.
    ::由于刀耕火种的农业,土壤中的养分迅速丧失,这往往导致人们在几年内放弃土地。 然后,顶层土壤侵蚀和荒漠化会随之而来。 荒漠化将森林变成难以生长的植物。 地球上一半成熟的热带森林已经消失。 按照目前的毁林速度,所有热带森林都将在2090年之前消失。

    Non-native Species
    ::非本地物种

    One of the main causes of extinction is introduction of exotic species into an environment. These exotic and new species can also be called invasive species or non-native species . These non-native species, being new to an area, may not have natural predators in the new habitat, which allows their to easily adapt and grow. Invasive species out-compete the native species for resources. Sometimes invasive species are so successful at living in a certain habitat that the native species go extinct ( Figure ).
    ::灭绝的主要原因之一是将外来物种引入环境,这些外来物种和新物种也可以称为外来物种或非本地物种。这些非本地物种对于一个地区来说是新鲜的,在新的栖息地中可能没有自然捕食者,因此它们可以容易地适应和成长。入侵物种比本地物种更具有资源竞争力。有时,入侵物种在某种生境中生活得非常成功,以致本地物种灭绝(图 )。

    Recently, cargo ships have transported zebra mussels, spiny waterfleas, and ruffe (a freshwater fish) into the Great Lakes ( Figure ). These invasive species are better at hunting for food. They have caused some of the native species to go extinct.
    ::最近,货轮将斑马贝类、脊椎水面鱼和ruffe(淡水鱼类)运入大湖(图 ) 。 这些入侵物种更擅长寻找食物,导致一些本地物种灭绝。

    Invasive species can disrupt , carry disease, prey on native species directly, and 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、携带疾病、直接捕食本地物种、以及超过本地物种的有限资源,如食物。 所有这些影响都可能导致本地物种灭绝。

    Close-up of a brown tree snake with its tongue visible, showcasing its features.

    An exotic species, the brown tree snake, hitchhiked on an aircraft to the Pacific Islands, causing the extinctions of many bird and mammal species which had evolved in the absence of predators.
    ::一种外来物种,棕树蛇,搭乘飞机前往太平洋岛屿,导致许多鸟类和哺乳动物物种灭绝,这些物种是在没有掠食动物的情况下演变而来的。

    Zebra mussels covering walls of the Arthur V. Ormond Lock on the Arkansas River.

    These zebra mussels, an invasive species, live on most man-made and natural surfaces. Here they have infested the walls of the Arthur V. Ormond Lock on the Arkansas River. They have caused significant damage to American waterways, locks, and power plants.
    ::这些斑马贝壳是一种入侵物种,生活在大多数人造和自然表面。 它们在这里侵袭了阿肯色斯河上的Arthur V. Ormond Lock的墙壁,对美国水道、锁和发电厂造成了重大破坏。

    Other Causes
    ::其他原因 原因

    Other causes of habitat destruction include poor fire management, overfishing, mining ( Figure ), pollution, and storm damage. All of these can cause irreversible changes to a habitat and ecosystem.
    ::生境破坏的其他原因包括火灾管理不当、过度捕捞、采矿(图 ) 、污染和风暴破坏,所有这些都可能对生境和生态系统造成不可逆转的改变。

    Strip coal mining site showing extensive land alteration and ecosystem destruction.

    Strip coal mining, pictured here, has destroyed the entire ecosystem.
    ::这里所描绘的采煤业已经摧毁了整个生态系统。

    Examples of Habitat Destruction
    ::生境销毁实例

    A habitat that is quickly being destroyed is the wetland . By the 1980s, over 80% of all wetlands in parts of the U.S. were destroyed. In Europe, many wetland species have gone extinct. For example, many bogs in Scotland have been lost because of human development.
    ::迅速被摧毁的生境是湿地。 到1980年代,美国部分地区80%以上的湿地被摧毁。 在欧洲,许多湿地物种已经灭绝。 比如,苏格兰的许多沼泽因人类发展而消失。

    Another example of species loss due to habitat destruction happened on Madagascar’s central highland plateau. From 1970 to 2000, slash-and-burn agriculture destroyed about 10% of the country’s total native plants. The area turned into a wasteland. Soil from erosion entered the waterways. Much of the river ecosystems of several large rivers were also destroyed. Several species are almost extinct. Also, some coral reef formations in the Indian Ocean are completely lost.
    ::马达加斯加中部高原也发生了因生境破坏而导致物种损失的又一个例子。 从1970年到2000年,刀耕火种的农业摧毁了全国10%的原生植物。 该地区变成了荒地,土壤因侵蚀而进入水道,许多大河流的河流生态系统也遭到破坏。 几个物种几乎灭绝。 此外,印度洋的一些珊瑚礁形成也完全消失。

    Summary
    ::摘要

    • There are many causes of habitat destruction, including clearing of land and introduction of invasive species.
      ::生境破坏的原因很多,包括清理土地和引进入侵物种。
    • Slash-and-burn agriculture can lead to desertification, meaning the fertile top soil is lost.
      ::刀耕火种的农业可能导致荒漠化,这意味着肥沃的顶层土壤丧失。

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

    Explore More I
    ::探索更多

    • Suburban Growth Stresses Streams at
      ::快速增长的快速增长
    1. How does the loss of trees along streams affect steam ecosystems?
      ::溪流中树木的流失如何影响蒸汽生态系统?
    2. Loss of trees has destabilized some stream banks. How are aquatic insects affected by this situation?
      ::树木的丧失破坏了一些溪流的支流。 水生昆虫如何受到这种情况的影响?
    3. How have urban areas affected the diversity of fish in streams? What types of fish are being selected for?
      ::城市地区如何影响溪流中鱼类的多样性?选择哪类鱼类?

    Explore More II
    ::探索更多情况二

    • The Ecology of Climate Change at (8:07)
      ::《气候变化生态学》(8:07)
    1. What types of trees dominate boreal forests?
      ::北方森林以哪类树木为主?
    2. How is climate change affecting the amount of fires occurring in Alaska? How is this affecting the ecosystem?
      ::气候变化如何影响阿拉斯加火灾的数量?这如何影响生态系统?
    3. How do conifer forests differ from deciduous forest in their effect on carbon? How may this feed into climate change?
      ::细木林在对碳的影响方面与衰落的森林有何不同?这如何能成为气候变化的诱因?
    4. How may the thawing of permafrost affect the Global Carbon Cycle? How is the carbon in the permafrost similar to the carbon in fossil fuel?
      ::永久冻土的解冻会如何影响全球碳循环?永久冻土中的碳与化石燃料中的碳有何相似之处?

    Review
    ::回顾

    1. What is a habitat?
      ::什么是栖息地?
    2. What are the primary ways that humans destroy habitats?
      ::人类破坏生境的主要方式是什么?
    3. 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?
    4. Describe slash-and-burn agriculture.
      ::描述刀耕火种的农业。