human impact Flashcards
(147 cards)
what % is the human population growing per year
1.1% (135 million births and 55 million deaths)
what is the most invasive form of habitat loss
deforestation
how to limit effects of deforestation
- variable retention: leave representative old growth in each block (doesn’t work always)
- selective cutting - removal of single trees by helicopter (best but costly)
how big defines clear cutting
12ha to 2000ha
soil and lemur population
- in madagascar forests were comprised for profit
- lateritic soils (leached of silica after deforestation)
- concentration of iron, manganese, aluminum, nickle
- leaked into the ocean and killed coral reefs
- lemurs still exist but will go extinct
amazon deforestation
- deforestation for cattle export
- burned/slashed agriculture
- larges cattle farm in the world, sent cattle to 170 countries (3x export in the past 3 years)
what country has the highest rate of deforestation per year?
Brazil
- protest by indigenous ppl
- little response by the educated class
Brazil’s new laws about deforestation
- remission of penalties in landowners who illegally remove native vegetation
- reduce the areas classified as “requiring restoration”
- injustice in the population
- means that insect collectors are charged with high fines but landowners receive no punishment for illegal reforestation
amazon sugar cane article
- can’t cultivate sugar cane
- # of sugar canes have increased
- cane has been shown to decrease biodiversity
- Brazil wants to open the amazon region to sugar cane (in biodiversity hot spots)
Why shouldn’t they plant sugar cane in the amazon
- amazon plays important role in rainfall
- will harm Brazil itself (agriculture and biofuel production)
What did the Ecuadorian government announce
- recent signings of 2 new oil concessions in Yasuni National park
- piplines, wells, drilling platforms etc.
what percentage of worlds temperate rainforest have been cut
55% forest due to deforestation
what ecosystem has the greatest biomass/ha
coastal temperate rainforests
which countries have the highest percentage of deforestation?
nigeria and viet nam
55%
washington, oregon, california (how much of their ancient forest is gone)
95%
what is remaining of BC’s coastal temperate rainforest?
1/4
Gribbrell Island
- government clearcut river
- this was main source of salmon for bears
- 80% reduction of their major protein source for bears (4300kg/y to 300 kg/y)
Haida Gwaii logging
70% of the best forest gone
- spokes person said there is more old-growth forest now than 100 years ago… not true??
- 1967 = first clear cutting. all large trees are now gone except in protected areas
what are grasslands used for
- they all differ from their original state
- used for crops that increases population growth
where are the only natural grasslands left
alberta and saskatchewan
where is the highest species diversity and of vertebrates and richness
coral reef
what are coral reefs impacted by (7)
- warming of oceans
- cyclones
- ocean acidity
- coliform bacteria
- artisinal fishing
- commercial fishing
- aquaria trade
what % of coral reefs have degraded and declined?
75%
how much has the great barrier reef declined since 1980?
50% reduction in corals
- 90% reduction of northern GBR