Tropical Rain Forests - Biomes Flashcards
Biomes Comparison Case Study
Climate
Hot and wet all year
Temperature
20-28 degrees C
Sun overhead all year round
Rainfall
- High all year round
- 2000mm per year
- Rains every day
- Usually in afternoon (high temps create convectional rainfall)
Convectional Rainfall
- Sun warms ground.
- This conducts heat to air above and evaporates surface water.
- Warm air can hold lots of water vapour.
- Warm wet air rises.
- As rises, it cools.
- Cool air can hold less water vapour.
- Water condenses to form clouds and rains.
Soil Moisture Budget
- The balance between water inputs and outputs in the soil.
- High because precipitation is higher than potential evaporation.
Rainforest Soils
Latosols
Very nutrient poor because:
- Leaf litter & organic matter broken down so quickly (warm & wet climate)
- Growing season continues all year – as soon as dead organic matter broken down, nutrients re-absorbed by plants. Few nutrients remain in soil.
- Nutrients leached down the soil column by heavy rainfall.
Plant adaptations - Emergent
- 40m
- Tallest trees.
- Poke out of main canopy layer.
- Straight trunks
- Branches and leaves only at top (where they can get light)
- Buttress roots to support trunks
Plant adaptations - Main canopy
- 30m
- Continuous layer of trees
- Only have leaves at top
- Dense layer of leaves shades rest of forest
Plant adaptations - Undercanopy
- 20m
- Younger trees (yet to reach their full height)
- Only survive in breaks in canopy where light can get through
Plant adaptations - Shrub Layer
- 10m
- Quite dark
- Shrubs have large, broad leaves to absorb as much light as possible
Plant adaptations - Leaves
- Waxy leaves – helps repel rain
- Drip tips – channel water to run off
Means:
- Weight of water doesn’t damage plant.
- No standing water for fungi & bacteria to grow / leaf to rot.
Plant adaptations - Lianas
Root in soil & clime up trees searching for light
Plant adaptations - Epiphytes
- Grow on trees
- E.g. orchids and bromeliads
- Help plants reach light
Animal adaptations - Canopy
- Live in canopy
- Plenty of food
- E.g. flying squirrels (flaps of skin for gliding between trees)
Animal adaptations - Nocturnal
- Jaguars, sloths, vampire bats
- Save energy by sleeping in hot day.
- Feed at night when cooler
Animal adaptations - Low light
- Underneath canopy
- E.g. Tapirs and anteaters
- Excellent sense of smell and hearing to detect predators
Animal adaptations - Swimming
- Many TRF animals can swim
- Allows them to cross river channels and cope with forest floor flooding
Deforestation
- Small Scale Farming
- Cattle Farming
- Commercial Agriculture
- Commercial Logging
- Other
Deforestation - Small Scale Farming
- Trees cleared to set up small subsistence farms.
- Often slash & burn
- Vegetation cut down, left to dry, then burnt.
Deforestation - Cattle Farming
Forest cleared to make room for cattle grazing
Deforestation - Commercial Agriculture
Trees felled for planting crops.
Soya and palm oil
Deforestation - Commercial Logging
- Wood used for timber, pulp, paper.
- Road building for logging also makes new areas accessible for agriculture
Deforestation - Other
- Mineral extraction (gold & iron ore)
- New settlements
- Building dams for hydroelectric power floods large areas of forest
Deforestation - Environmental Impacts
- Habitat loss –> reduced biodiversity
- Decreased interception so more water in soil –> reduces soil fertility & flooding more likely.
- Evapotranspiration rates decreased –> less water vapour in atmosphere, less rain falls.
- Global warming –> fewer trees = EGE.