Ecosystem Threats and

Environmental Risks.

“Ranching in Brazil”

“Ranching in Brazil”

“Ranching in Brazil”

“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.• Humidity balance affected and area was at

risk of erosion.• Many animals disappeared.• Soil destroyed and nutrients were lost.• 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.• Large species need large areas (forced

inbreeding).• Wind and weeds threaten perimeter area.• 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 climate• 60-100mm falling during 1-3 months of

the year• Droughts are common

►Causes of desert advancement:• Fragile environment• Agricultural practices• Population 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.