Ecosystem Threats and Environmental Risks.

“Ranching in Brazil”

► Pg. 120 – Question 7 (a) & (b) ► 7 (a) How has ranching disrupted fragile relationships in the tropical rainforest ecosystem? ANS: Big areas of forest were cut down, and area was replanted with non-native grasses. Big areas of forest were cut down, and area was replanted with non-native grasses. Humidity balance affected and area was at risk of erosion. Humidity balance affected and area was at risk of erosion. Many animals disappeared. Many animals disappeared. Soil destroyed and nutrients were lost. Soil destroyed and nutrients were lost. The forest could not regenerate or sustain itself. The forest could not regenerate or sustain itself.

► 7 (b) The governments of some tropical countries now regularly set aside fragments of rain forests as conservation reserves. What problems do you see in this attempt at protecting the rain forest ecosystem? ANS: Isolated forests do not protect life forms living in the area. Isolated forests do not protect life forms living in the area. Large species need large areas (forced inbreeding). Large species need large areas (forced inbreeding). Wind and weeds threaten perimeter area. Wind and weeds threaten perimeter area. Empty, outside area allows more access and disruption of the ecosystem. Empty, outside area allows more access and disruption of the ecosystem.

► Desertification – the spread of desert-like conditions in semi-arid environments.

Climate Zones and Environmental Risk The following climate zones are particularly fragile and are considered at risk. ► Tropical Climates ► Dry Climates ► Polar Climates ► Highlands Climate

Tropical Climates ► Tropical Climates are considered at risk because of the threat of deforestation. If the vegetation is cut down the hot temperatures cause soils to dry out quickly. This dried out soil will then often wash away with the normal heavy tropical rains.

Dry Climates ► Dry climates are considered to be at risk because of the threat of desertification. Overuse of existing lands can destroy soil. Planting crops that cannot be sustained, grazing too many animals on farms that are too small, and clear-cutting the limited trees will destroy soil quality making it dry out and easily blow away.

Polar Climates ► Polar climates are considered to be at risk mostly due to negligent human use. Due to the extreme cold weather growing seasons are very short. Land that is disturbed takes years to regrow and regenerate. Mining, oil and gas exploration, and the building of infrastructure are all detrimental to polar climates. It takes decades just for tundra soil to recover from footprints and tire tracks.

Highlands Climate ► Highlands climates are also vulnerable. Since they are really possibly a combination of all climate zones everything from deforestation, to desertification, to simple soil disruption put this climate zone at risk of destruction.

Climate change ► The general global climate change also puts all climate zones at risk. ► As the climate changes and glacial areas begin to melt, there is a much greater threat of flooding and then eventual drought risks as the ice disappears. ► Dry climates are getting drier speeding up desertification. ► Heavy rains and stronger storms leads to more flooding which in turn washes away soils and farmlands.

This is a recent satellite image of the United Kingdom, France and Beligium. The arrow is pointing at areas in the English Channel where the River Thames empties out. Due to severe flooding all this winter there is a high soil content in the water. This means a loss of prime top soil from farms in the South of England. It also muddies the fishing grounds in the Channel and The North Sea.

“Desertification in the Sahel” ► Sahel is located along the Sahara Desert. ► Natural Environment: Hot, dry climateHot, dry climate mm falling during 1-3 months of the year60-100mm falling during 1-3 months of the year Droughts are commonDroughts are common ► Causes of desert advancement: Fragile environmentFragile environment Agricultural practicesAgricultural practices Population growthPopulation growth

Analyze value positions taken on environmental issues. How would each of the following feel about a gold mine being developed in a local wilderness area – what is their position? 1.President of a local environmental group. 2.Owner of Regal Goldfields – mine developer. 3.Owner of a local hunting lodge. 4.Chief naturalist for the wilderness area. 5.President of the local Fish and Wildlife Association. 6.An unemployed fisherman. 7.The wife of the fisherman – a part-time fish-plant worker. 8.The mayor of a local town. 9.The owner of a local trucking company. 10.The owner of a local restaurant.