Unit 3

1. Unit 3 Human Impact

2. Land cover is what you find on a patch of land, and it often depends on how the land is used. • For example, land cover might be a forest, a field of grain, or a parking lot.

4. Land that is covered mainly with buildings and roads is called  Urban • Land that contains relatively few people and large areas of open space are rural areas.

5. Rural

6. Suburban sprawl • Development characterized by houses and strip malls that spread out around cities.

7. Urban • Urbanization The growth of cities as people move from rural to urban areas.

8. Urban Development • An estimated 5 billion people worldwide will be living in cities and towns by the year 2025. Problems • The development of land for the growth of urban areas has many impacts on the environment. • Lack of sanitation ( increase solid wastes) • Destroys natural habitats • Erosion of topsoil.

9. Urban Solutions • Educate people • Pass laws to protect environment • Landfill regulations • Bioremediation cleans up toxic wastes by the use of organisms.

10. Nile River in Egypt

11. Agriculture • In natural ecosystems, there is a wide variety of species  biodiversity • Those with high biodiversity tend to be more stable because of their ability to recover from harmful events. • However land gets cleared for food production.

12. Agriculture • Monoculture planting one species in a field. • However it can easily be destroyed as well from parasites or disease. • Ex: corn easier for farmer to take care of.

13. Agriculture • Problems: • Increased erosion from removals of natural cover. • Pesticides • Pollute water • Insects can become resistant • Solutions • Use methods to preserve topsoil. • Monitor runoff when spraying fertilizer and pesticides. • Only use when necessary

14. Harvesting Trees • Cutting down trees for uses like paper, furniture, lumber etc.

15. Deforestation • Problems • Deforestation cutting down trees and not replacing them. • Removing trees increases erosion. • Why is this? • Destroys ecosystems Amazon

16. Solutions • Solutions • Selective Logging marking which trees to cut and which to leave alone. Prevents erosion. • Buffer zones trees being left alone along stream banks • Reforestation Replacing the trees that have died or have been cut down.

17. Overgrazing • Rangelands grasses and shrubs used by ranchers for grazing animals such as cattle, sheep and goats. • Problems • Overgrazing when too many animals graze in an area too long that they damage the grass beyond the ability to recover. • Solution • Maintain the range limiting animal herds to sizes the land can support.

18. Overgrazed area (left) and ungrazed area (right) on the Carrizo Plain Ecological Reserve, October 2009

19. Traditional (Conventional)Agriculture • Positives: • Mass production of food lowers prices to make affordable to poor people/regions. • Negatives: • Use of fertilizers and chemical pesticides, • Conventional and genetically modified seeds • Depends on nonrenewable fossil fuels • Produces significant air and water pollution • Uses antibiotics and growth hormones to produce meat and meat products • Export-oriented.

20. Sustainable Agriculture • Positives: • Emphasizes prevention of soil erosion, • Utilizes crop rotation and biological pest control, • Reduces fossil fuel use, • Less air and water pollution, • Does not rely on pesticides and growth hormones, • Regionally/locally orientated • Negatives: • Lower yields • Requires more labor

22. Aquaculture • World’s fastest-growing type of food production • Fishing with fleets depletes fisheries and uses many resources • Advantages • High efficiency • High yield • Low fuel cost • High profits • Reduced over harvesting of fisheries • Disadvantages • Large inputs of land, feed and water • Large waste output • Loss of estuaries • Some species fed with grain and fish meal • Dense population vulnerable to disease

24. SolutionsMore sustainable aquaculture • Protect mangrove forests and estuaries • Improve management of wastes • Reduce escape of aquaculture species into the wild • Raise some species in deeply submerged cages • Set up self sustaining aquaculture systems that combine aquatic plants, fish and shellfish