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Human Impact on Biomes and Ecosystems

Prezi addressing the environmental degradation of the world's major biomes

Katie Jeffress

on 27 January 2013

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Transcript of Human Impact on Biomes and Ecosystems

photo credit Nasa / Goddard Space Flight Center / Reto Stöckli Human threats to the world's major biomes Biomes: Human Impact Deserts The desert is very fragile in many ways because of the scarcity of water and plants. Most plants that live in the desert take a long time to grow. For example, the saguaro cactus takes two centuries to grow. Once plants are destroyed, it will take many years for them to grow back. Since soil in the desert is held down by the plants roots, once plants are destroyed the soil is, too. The soil will quickly erode away in the strong winds. Grasslands A quarter of Earth was once covered by grasslands, but much of these have now been turned into farms. This has resulted in a widespread loss of wildlife habitat.

Grassland soil is rich, and almost anything can be grown there. But poor agricultural practices can ruin soil and turn grassland into lifeless, barren spaces. If crops are not rotated properly, nutrients in the soil are stripped out, and nothing can be grown for several years. Compared to grassland, cropland provides few or no resources for breeding birds. Grazing livestock destroy grassland as well. Only 5 percent of the original prairie in the United States remains. Forests Marine Ecosystems Freshwater Biome Pollution from towns and cities, industry and agriculture directly affect water supplies for people and freshwater ecosystems. The shifting climate has spurred global change. An overall increase in temperature has been blamed for earth's shrinking glaciers, melting permafrost, and rising ocean levels. As the earth adjusts to the new era of change, it is imperative that mankind adopts sustainable practices to halt the degradation of the natural environment. Only by advocating awareness can we preserve our planet for generations to come. "Off Roading" Out in the desert, a single tire track can scar the land for decades. Just one off road vehicle or motorcycle driven in the wrong place can tear up plants and crush the burrows of threatened desert tortoises or other animals. Large numbers of these vehicles can damage plant and animal habitats so severely that they will never recover. Threats to Grasslands Continued global warming could turn current marginal grasslands into deserts as rainfall patterns change.

Land once incompatible with row-crop agriculture, but which provided a living to ranching families and habitat for prairie wildlife, is being converted to row crops.

Development of urban areas is increasingly cutting into grassland habitat.

Drought-hardy, cold-resistant, and herbicide-tolerant varieties of soybeans, wheat, and corn allow crops to expand into native grassland.

Where only one crop is grown, pests and disease can spread easily, creating the need for potentially toxic pesticides. The collapse of a tailing lagoon at a gold mine near Baia Mare in Romania washed 100,000 m3 of waste water containing cyanides and heavy metals into the Danube river basin, killing fish life and disrupting public water supplies. Diversion of water for agriculture and industry is destroying freshwater lakes and rivers In just 30 years, the Aral Sea - formerly the fourth largest lake in the world and a major fishery - has shrunk to less than half of its size, and has become as salty as the ocean. The diversion of irrigation water for agriculture and for power generation led to severely reduced inflows, leaving an area of almost four million hectares of polluted soils and caused widespread economic losses and human suffering. Freshwater species are disappearing Scientists generally acknowledge that species dependent on freshwater ecosystems are the world’s most endangered group of plants and animals.
More than 20% of the world’s 10,000 freshwater species have become extinct, threatened or endangered in recent decades (CBD2005). Freshwater environments tend to have the highest proportion of species threatened with extinction (MA 2005).
According to the WWF Living Planet Report 2006, the analysed 344 representative tropical and temperate freshwater species populations declined by about 30% overall between 1970 and 2003. Freshwater birds appear to have relatively stabilised while other freshwater species have declined on an average by about 50% The Changing Biosphere
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