Lecture 10: Habitat Loss - Deforestation

what is deforestation?

the cutting down, burning, and damaging of forests. can occur anywhere, but the most concentrated deforestation is occurring in the tropics

why are forests important?

provides medicine, food, timber, shelter for forest-dwelling species

what are some kinds of forests?

deciduous, coniferous, tropical

what are the consequences of deforestation/degredation?

• increase in global carbon emissions

• disruption of water cycles and increased flooding

• increasing soil erosion and sedimentation

• loss of habitat and biodiversity

• disruption or loss of livelihoods

how does deforestation increase global carbon emissions?

forests/trees are carbon sinks - forests absorb 30% of CO2 emissions. when they are cut/burned, some of the carbon they store escapes

how does deforestation disrupt water cycles?

water that seeps into the ground is taken up by trees in a process called transpiration, which leads to precipitation. when we don’t have trees to release water in the atmosphere, it disrupts the water cycle and may change rainfall and weather patterns.

transpiration processes from plants return large quantities of water to the atmosphere and is responsible for about ___% of global precipitation

62%

how does deforestation cause an increase in erosion and sedimentation?

tree roots stabilize the soil, and without them, the soil is not stable. rain will erode the soil, which will move down into waterways, causing sedimentation. also caused by the machinery, which compacts the soil.

how does deforestation contribute to loss of habitat & biodiversity?

over 75% of the world’s terrestrial species are found in forests. when a species loses their forest home, they are often unable to live in the small fragments of forested land left behind, which makes them more accessible to hunters/poachers, and their numbers begin to decline.

how does deforestation cause disruption/loss of livelihoods of indigenous communities?

many indigenous people live in the tropics, and they need forests for medicine, food, building homes, cultural/spiritual resources

what causes deforestation?

• logging/timber industry: illegal logging and clearcutting

• agriculture: croplands and grazing pastures

• urban development/infrastructure development

• natural disasters and wildfires

___% of deforestation is for cattle ranching and logging

80%

what are the 4 main commodities that drive deforestation?

• beef

• palm oil

• soy

• wood products

how is the beef industry a driver of deforestation?

need land to graze cattle. millions of cattle are still being grazed in protected areas. about 70% of deforestation in the Amazon has been linked to cattle ranching

how does the land footprint of animal products compare to the land footprint of plant products?

the land footprint of plant products is much, much smaller than that of animal products

how does the palm oil drive deforestation?

palm oil is the most common and productive crop that produces vegetable oil and is found in half of all packaged products. native forests and peatlands are cleared to grow the trees that produce palm oil. plantations have also been conn

how does the soy industry drive deforestation?

soy production has increased mroe than 13x in the paqst 50 years. biggest producer of soy is in Brazil (tropical region). 77% of soy is used as animal feed

how does the wood industry drive deforestation?

developed countries account for 70% of the total world production and consumption of indistrial wood products

what is clearcutting?

removing whole tracks of forests and letting them regenerate.

the presence of coarse woody debris correlates with ____

higher numbers of biodiversity

what is agroforestry?

many of original rain forest trees are left to provide shade for shade-loving crops like coffee or chocolate. when the farm is abandoned, the forest grows back very quickly because much of it was left unharmed in the first place

what are mangrove forests?

a type of wetland made up of salt tolerant trees along coastlines. they are hotspots of biodiversity.

it is estimated that the world has already lost over half of its mangrove forests. loss of mangroves has implications for biodiversity, conservation, and food insecurity.

why are mangrove forests important?

• breeding grounds for many fish

• carbon sinks

• keep soil from eroding

• protect coastal area from extreme weather

• people need them for food and other resources