Most species of insects, birds, and mammals require a specific habitat in order to survive. The habitat provides food and nesting or breeding grounds. When habitats are destroyed, many species die out. The two main causes of habitat destruction are that which is caused by human activity, such as building and farming, and destruction caused by nature, such as in the form of fires, earthquakes, and other natural disasters.
A habitat is made up of specific native plants and conditions that provide a home and breeding area for birds, mammals, and insects. Many habitats are specific to the area and climate, and are very fragile. Wetlands, for instance, are particularly rich in flora and fauna and also susceptible to damage. Likewise, rainforests provide rich habitats for countless species. Other habitats include temperate woodlands, meadows, and prairies.
One of the main causes of habitat destruction is deforestation. Deforestation affects temperate, subtropical, and tropical areas. Deforestation occurs when most or all of the trees in an area are cut down either to clear the land for building, for agriculture, or for the wood itself. Many delicate ecosystems, particularly in the tropics, are destroyed every day through deforestation.
Filling in wetlands to build homes and other structures is a major cause of habitat destruction as well. A single pond can create a unique environment that supports many different species. If a developer, city, or home owner fills in the pond, the habitat will be destroyed and the species that relied on it displaced.
Agriculture also causes habitat destruction when forests are clearcut to make room for farming and raising livestock. Use of fertilizers and pesticides can also cause habitat destruction when the chemicals wash into local waterways and spread throughout ecosystems, changing the often delicate balance. The large quantities of manure produced by farm animals also enters waterways, further adding to the pollution. Many species rely on lakes, streams and rivers for habitat, and when these areas are tainted, the habitat is lost. Dams also cause habitat destruction by preventing migratory fish from retuning to their spawning grounds.
Human activity is not the only cause of habitat destruction. Nature itself is constantly shifting and changing, and when change occurs, often entire habitats are lost. Wild fires started by lightning, for instance, can wipe out forest and grassland habitats.
Additionally, floods change the delicate dynamic of freshwater streams, rivers, and wetlands, and overtime habitats gradually shift. A wetland area, for example, can dry out and become grassland, destroying the former habitat but creating a new one. Likewise, grasslands can turn to swamplands.
Human interference, however, causes the most damage to ecosystems and habitats. Even planting a garden full of exotic and non-native plants reduces the amount of habitat available for local species. As such, many gardeners plant native plants in their gardens to help reestablish the habitat lost during development.