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Quotes Rapid habitat loss is the single most primary cause of endangerment. Most of the planet has now been modified by human activity, a trend that continues to accelerate. The consequenses may be disasterous.  Humans are depleting the soils of the earth, irradicating its forest, causing the extinction of fish and various marine animals, and changing global climate conditions by releasing greenhouse gases. Wild lands are quickly being converted to housing and farmland. Space once home to plants and animals are being elliminated at an alarming pace. []

As the human population grows, its effect on habitats grows. The effects may be good or bad. We alter habitats to fit our own needs for food, materials, and space. Mining, filling in wetlands for buildings and farming, and making roads and new towns change wildlife habitat, often causing harm. When a wetland is filled, ducks can't feed or nest. Other animals lose their homes, too. Habitat management includes building nest boxes. It includes planting trees and grasses in some places, and cutting trees in other places. Cutting trees to open forests helps white-tailed deer but not some owls, warblers, and woodpeckers. Burning prairie land helps prairie chickens, but not wild turkeys.
 * Habitat management** is the science and art of changing habitat. The goal of habitat management is to increase wildlife populations. We must take care of the habitat that is left so we don't lose plants and animals from the earth forever.


 * Ecologists** study the links between plants and animals and their environments. Some study habitat restoration (putting the habitat back together). Many habitats have been changed by humans through pollution, construction, mining, or farming. Some ecologists study different ways to restore and improve habitats so there will be homes for more animals.

http://www.extension.umn.edu/distribution/youthdevelopment/components/DA5762chapter1.html

People can also cause the extinction of plants and animals. The main reason that many species are endangered or threatened today is because people have changed the homes or **habitats** upon which these species depend. A habitat includes not only the other plants and animals in an area, but all of the things needed for the species' survival -- from sunlight and wind to food and shelter. The United States has many habitats, from ocean beaches to mountain tops. Every species requires a certain habitat in order to live. A cactus, for example, needs the sunny, dry desert in order to grow. A polar bear, on the other hand, would not live in a desert, because it could not find enough food and water. Pollution can also affect wildlife and contribute to extinction. The [|Nashville crayfish] is endangered mainly because the creek where it lives has been polluted by people living nearby. [|**Pesticides**] and other chemicals can poison plants and animals if they are not used correctly. The [|bald eagle] is one bird that was harmed by pesticides. In the past, a pesticide called DDT was used by many farmers. Rains washed the pesticide into the lakes and streams where it poisoned fish. After eating the poisoned fish, the eagles would lay eggs with very thin shells. These eggs were usually crushed before they could hatch. Today, people are not allowed to use DDT, and this has contributed to the bald eagle being moved from endangered status up to threatened status. People can also endanger plants and animals by moving, or **introducing**, new species into areas where they do not naturally live. Some of these species do so well in their new habitat that they endanger those species already living there, called the native species. These introduced species are called **invasive species**. For example, when some fish are introduced into a lake or stream, they may prey upon, or eat the food of the native fish. The native species may then have to find a new source of food or a new home, or face becoming endangered or extinct. Another way that people harm animals and plants is by taking them from the wild. Some people might catch an insect like the [|Mission Blue Butterfly] for a butterfly collection. Others might capture a wild animal for a pet, or pick a flower because it's pretty. In addition, some people illegally hunt animals for food, skins, or fur. In the past, lots of American crocodiles were killed so that their skins could be made into shoes and other clothing. This crocodile is now an endangered species.

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