What percent of Earth do tropical forests cover?
What about Wet tropical forests?
What are other types of tropical forests?
48-51%
32%
Deciduous and Dry
What percent of biomass is living in tropical forests vs boreal forests vs temperate forests?
55 (over half) –> take up lots of CO2 from atmosphere 262/471
32
14
Major Tropical Forest Regions
- Central and South America = Neotropics –> not brazilian atlantic forest though
- Africa = West Central Africa = old world tropics
- Madegascar
- SE Asia = Sundaland and Wallacea
- India
- New Guinea and Australia
- Oceana and Pacific Islands, including Hawaii
Possible reasons why Africa has less diversity than other area?
- less rainfall
- different planetary history
- highest level of extinction
Where, specifically are the tropical regions in Central america, africa, and Australia
- Atlantic side
- middle, west side –> mostly congo
- narrow band along east coast
What’s significant about the Neotropics?
Which areas does it encompass?
- It is the largest contiguous rainforest
- it makes up 50% of all global rainforests
It encompases:
- Amazon Basin
- Brazilian Atlantic forests
- Pacific coast of Ecuador through Central America to Mexico
- Carribean Islands
Topography of Neotropics
- Isthmus of Panama
- did and didn’t exist at different times depending on sea levels
- marine barrier disappeared 3 mya (that just means it became a land mass)
- frequent tropical cyclones
- connects central and south america - Andes Mountains
- formed 25 mya
- happened at meeting of 2 plates
- prevents rain from reaching the west coast –> causes disjunction
- traps rain in the Amazon Basin
- salt flat with lithium salt
Why are the Old World Tropics significant and what do they encompass?
-2nd largest contiguous rainforest
Encompasses
- Congo River Basin
- West African Forests (much lost from ivory coast, liberia, ghana, and nigeria)
- “Islands” on Rift Valley Mts (remnants of forests covering whole continent until 30 mya)
Topography of Old World Tropics
- Rift Valley
- traps rain, preventing accumulation in the West
- warm, dry winds make the tropical savanas - Congo Basin
- transpiration maintains rainforests
-mostly isolated from tropical cyclones and monsoons (except madagascar)
What’s significant about Madegascar?
- 3rd largest tropical island (beat by New Guinea and Borneo)
- rainforest confinded to 120 km strip on the east side
- wet mountains and coastal valleys
Madagascar topography
- Steep plateau escarpment
- traps rain in the east
- creates dry tropical forests and arid climates in the west - Close to Tropics of Capricorn
- more variation of temp and more dry months
- SE tradewinds and westerlies create tropical cyclones and monsoons
What’s significant about India?
It has 3 remnant forests:
- Peninsular india = Western Ghats (mt range) and orissa state
- Greater Assam region in NE
- Western Sri Lanka
Indian Topography
- West coast is abrupt 100m cliff
- traps rainfall in the west, but monsoon sea winds drench the west coast - Closer to tropics of Cancer
- Moist, deciduous forests, but wetter at higher elevations - Himalayas make the rest of India too dry to support rain forests
