Forests under threat Flashcards
Why is biodiversity high in tropical rainforests
- Equatorial climate (hot and wet all year around)
- Species have evolved over millions of years
- Multiple layers of vegetation
What are some adaptions made by organisms in the rainforest
- Hardwood trees - large buttress roots to support the weight of trees and leaves and branches are only found at the top where they get more light
- Lianas that use the tree to climb up to the sunlight in the canopy
- Birds have strong beaks to open nuts
- Primates such as monkeys use their tails for balance and live in the canopy where most food is found
Why is the nutrient cycle rapid in tropical rainforests
- Large biomass store (dense vegetation)
- A small litter store (rapid decay)
- A small take-up of nutrients (rapid plant growth)
- A larger supply of nutrients (weathering)
- A larger loss of nutrient (throughflow)
Features of the taiga biome
Low biodiversity
Harsh, cold climate
How have living organisms adapted to the taiga biome
- Mammals have thick, oily fur to retain heat
- Some animals hibernate in the winter
- Some birds and animals migrate in colder months
How are trees adapted to the taiga biome
- Trees are coniferous (evergreen)
- The trees are cone shaped to allow snow to slip off and not build up and snap branches
- They have waxy needles instead of leaves to reduce water loss
Why does the nutrient cycle in the taiga biome occur a lot slower than in tropical rainforests
Most nutrients found in the litter because decay happens much slower in cold temperatures
The biomass store is small because trees can only grow for a few months of the year
Precipitation is lower
Why are rainforests being increasingly deforested in developing countries
- Cattle ranching (increasing global demand of beef)
- Poverty (locals cut down trees for subsistence farming and fuelwood)
- Debt (countries export timber and grow cash crops to pay off debts)
- Development (urbanisation, HEP stations and palm oil plantations)
- Demand (the need for timber, oil, gas, iron ore and gold)
How is climate change a threat to rainforests
- Main indirect threat to tropical rainforests
- Droughts in the amazon rainforest are becoming more common
- Dry leaf litter reduces decomposition and dying leaves in the canopy reduces food supply, affecting food webs
Why is deforestation greatest in countries with taiga biome?
- Paper (comes from fir and pine)
- Construction (softwood used for roofs)
- Mining (clearing forests for minerals)
- Fossil fuels (extraction of oil and gas)
- HEP (building dams also destroys taiga)
How is climate change affecting taiga
- Forest fires - hot and dry summers make the forest prone to fires from lightening strikes
- Pests and diseases - warmer temps increase insect infection and diseases in coniferous trees
- Acid rain - Burning of fossil fuels releases sulphur dioxide into the air, acid rain weakens trees by reducing photosynthesis and damaging soil
Two main global actions to protect rainforests
CITES
REDD
What is CITES
An international treaty adopted by 180 countries that protects species
But does not prevent deforestation and global warming
What is REDD
A UN project that aims to stop deforestation with governments and TNCs funding projects to conserve forests in developing countries.
However it is difficult to police so illegal logging often takes place
Positives and drawbacks of sustainable management of tropical rainforests
Ecotourism provides jobs for local people and educates tourists
Agroforestry maintains biodiversity allowing crops to grow between trees
However, population growth will increase urbanisation and deforestation
