3.6 Human impact on the environment deforestation Flashcards
What does extinction mean?
The total loss of a species
What does endangered mean?
At risk of becoming extinct
Why are species becoming endangered?
-Habitat destruction
-Natural selection
-Overfishing/hunting
Why is extinction worrying?
-Reduction in gene pool
-Loss of food source
-Loss of useful organisms (medicinal plants)
What are the 3 methods of deforestation?
-Slash and burn
-Logging
-Conversion to farmland
Describe slash and burn
-Used to produce more fertile soil
-Problems:
.Land exposed to elements & leeching
.Reduced soil fertility
.Harsh environment to recolonise
Describe logging
-Timber for building and clear areas for building
-Problems:
.Increased usage of machinery
.Soil erosion
.Loss of habitat
Describe conversion to farmland
-Provides more food to increasing population
-Problems:
.Loss of habitat & biodiversity
.Contributes to global warming
What are the consequences of deforestation?
-Habitat destruction
-Wildfires
-Drought
-Flooding
-Disruption to water cycle
What are the benefits of coppicing?
-A crop is available each year
-Rich variety of habitats
-Range of different age shoots (New stems fast)
-Can be repeated
-Roots prevent soil erosion
How is rotational felling carried out?
-Leave forest areas for years before reharvesting
-Don’t harvest adjacent sectors (prevents constant migration)
What is monoculture?
When genetically identical crops are grown in a defined area
What are the problems of monocultures?
-fossil fuels (machinery)
-Soil degradation
-Overuse of pesticides
-Decrease soil fertility (same length root, same minerals)
What are the advantages of tree removal?
-Straightforward
-Increases light levels, ground plants can grow
What are the disadvantages of tree removal?
-Increased light levels can cause pest species
-Can be resisted by conservationist and locals
-Creates waste, biomass not returned to soil
-Has to avoid breeding bird season
