tropical rainforests Flashcards
characteristics - climate
-temp between 20 and 28 degrees, suns energy is more intense near the equator
-rainfall very high, 2000mm per year
characteristics - plants
-most trees are evergreen
-tall trees, vegetation cover is dense
-epiphytes, plants that grow on other living plants
characteristics - soil
-not very fertile
-heavy rain washes nutrients away
-surface nutrients due to decayed leaf fall
characteristics - animals
-contains more animal species than any other ecosystem
what is an interdependent ecosystem
all of the parts of the ecosystem are dependent on each other, if one changes, they are all affected
interdependence between CLIMATE and PLANTS
warm and wet climate helps fungi and bacteria on the floor to decompose dead plant material rapidly, making the surface soil high in nutrients, allowing plants to grow
interdependence between PLANTS and SOIL
plants pass on their nutrients when eaten by animals, dense vegetation increases the animal population, when the animals die their nutrients is returned to the soil
4 layers of the rainforest
-emergent trees
-main canopy
-undercanopy
-shrub layer
how have trees adapted
-compete for sunlight by growing tall
-smooth, thin bark as there is no need to protect the trunk from cold temps
-large stable roots support tall trees
how have plants adapted
-thick, waxy leaves with pointed drip-tips (no standing water)
-climbing plants use tree trunks to reach sunlight
-plants drop their leaves gradually throughout the year
why do animals have strong limbs
so that they can move around the canopy quickly
why do birds have short pointed wings
easily manoeuvre between dense trees
why are some animals nocturnal
feed at night when its cooler, helps them save energy
main threats to biodiversity in rainforests
-mining causing water pollution
-unsustainable timber harvesting
-development of roads and settlements
causes of deforestation (7)
-commercial farming
-subsistence farming
-commercial logging
-mineral extractions
-energy developments
-population growth
-road building
commercial farming - deforestation
-forest cleared for cattle grazing and plantations
subsistence farming - deforestation
-forest cleared by small-scale farmers faring for themselves and families
commercial logging - deforestation
logging of valuable hardwood trees by legal and illegal businesses
mineral extraction - deforestation
gold, iron ore and copper are mined and exported to help boost countries’ development
energy development - deforestation
building hydroelectric dams floods large areas
population growth - deforestation
Brazilian gov. offers land in rainforest to poor people from overcrowded cities, puts pressure on the forest
road building - deforestation
4000km trans-amazonian highway connects Brazilian coast to Ecuador, Peru and Colombia through the rainforest. new roads built for logging
impacts of deforestation
-climate change
-soil erosion
-economic
impacts of deforestation - climate change
-trees remove CO2 from the atmosphere
-deforestation releases CO2, causing global warming
how many tonnes of carbon does the Amazon store
140 billion
impacts of deforestation - soil erosion
-with less tree canopy to intercept rainfall and fewer tree roots to absorb it, more water reaches the soil, reducing fertility as the nutrients are washed away
impacts of deforestation - economic
-economic development has brought wealth to many amazonian countries
-mining industry creates jobs
-logging contributes, but can destroy resources the country depend on
what products are sourced from the rainforest
rubber, coffee, chocolate and medicines
what do rainforests regulate
climate and water cycle
strategies to maintain the rainforest sustainably (7)
-selective logging
-replanting
-ecotourism
-education
-conservation
-reducing debt
-international hardwood agreements
strategies to maintain the rainforest - selective logging
-only some trees are felled
-less damaging than clearing a whole area, keeps the structure of the forest
-horse logging
strategies to maintain the rainforest - replanting
-new trees replace old ones
-some countries have laws to make logging companies replant when they clear an area
strategies to maintain the rainforest - ecotourism
-minimises damage to the area and benefits local people
-provides jobs and income for local people
strategies to maintain the rainforest - education
-encourages people to buy products from sustainable sources
-teaches how to make money alternative ways
strategies to maintain the rainforest - conservation
-national parks and nature reserves within rainforests, restricted areas
strategies to maintain the rainforest - reducing debt
-reducing debt in exchange for the money being spent on conservation
strategies to maintain the rainforest - international hardwood agreements
-international agreements prevent illegal logging and promote the use of hardwood from sustainably managed forests
