How Humans Threaten Wildlife Flashcards
How do humans deliberately exploit wildlife? (unsustainably)
Deforestation
Eutrophication
Mining/ resource extraction
Overfishing/ bottom trawling/blast fishing
Agriculture/ food production
Examples of unsustainable exploitation for food:
Steller’s sea cow - hunted to extinction
Dodo - relied on by sailors - eaten by invasive species brought on boats
Mammoths
Bison
Examples of unsustainable exploitation for fashion:
snake skin
ivory
leather
tortoise shell
coral jewellery
bear skin
leopard skin
How and why have humans exploited snow leopards?
poached for illegal trade
bones are used in traditional medicine
killed by farmers because they prey upon livestock
captured as pets for entertainment
deforestation has lead to habitat loss
How many skins are needed to make a snow leopard coat? How much are they worth?
seven
£7,000
Examples of unsustainable exploitation for pets and entertainment:
circuses
sea world
bullfighting
safari parks
horse racing
Yellow headed parrot case study: where?
Mexico and Central America
Yellow headed parrot case study: why?
Imitates human speech
Yellow headed parrot case study: what?
population decreased by 90%
half of all birds captured are thought to die in the process
threatened by habitat loss
Yellow headed parrot case study: how are they protected?
nest monitoring and protection
illegal to trade them
What does CITES stand for?
Convention on International Trade in Endangered Species of Wild Fauna and Flora
CITES: appendix 1
all of the species that cannot be traded internationally
CITES: appendix 2
trade of these species is closely monitored and restricted - varies depending on the population in the area
Examples of unsustainable exploitation for furniture and ornaments:
Taxidermy
Leather - seating
Mahogany - wooden furniture
Animal skin - rugs
Examples of unsustainable exploitation for traditional medicines:
Pangolins - keratin - scales and bones
Tigers - whiskers/eyes/teeth - treats malaria and insomnia
Sharks - fins - prevent heart disease/lower cholesterol
Reasons for the eradication of predators and pests
herbivores = damage crops
diseases vectors (badgers - TB, mosquitoes - malaria)
protected livestock
protecting plants from damage via pesticides
to protect human life/self-defense - e.g. from wolves/sharks/crocodiles
Unintentional harm to nature caused by other activities:
trampling
roadkill
by-catch
ghost fishing
combustion of fossil fuels - climate change
eutrophication
How have invasive species been introduced to non-native areas?
boats - intentional/unintentional (ballast water)
ornamental plants
accidental transport with food
escaped/abandoned pets
species that have been used for food production (fish farms)
Invasive species examples: American Mink
used in UK for furr farms
escaped in 1960s
affected water voles and seabirds
destroyed nests/eaten eggs
increased competition
Invasive species examples: Cane Toad
introduced in Australia in 1935 as a biological control of beetles
moved over 200km from introduced site
affected northern quolls and large goannas
produce a poison
lay up to 50,000 eggs at a time - 15x the amount of the native toad
Invasive species examples: Grey Squirrel
1870s - introduced to a park in Cheshire
predated upon red squirrels
brought squirrel pox
damage trees
increased competition for resources
impacts were reduced by monitoring red squirrel populations and by re-introducing pine martin (eat grey squirrels)
Invasive species examples: Signal Crayfish
1970s - brought from North America
farmed for food
escaped from farms into fresh water
carried crayfish plague
grow faster than indigenous crayfish - grow larger
tolerant of changing conditions
Invasive species examples: Rhododendron
1890s - added to gardens
affected oak trees/beech trees
out compete plants for nutrients and light
poisonous leaves - damage herbivores
fast growing
Invasive species examples: New Zealand Flatworm
1960s - brought over in plants accidentally
affect earthworms, birds, badges, voles
disrupt food chain - slow decomposition - lower soil quality - lower crop yield - increase food risk
Categories of Invasive Species: Competitors
rhododendron - compete for light
Categories of Invasive Species: Predators
New Zealand Flatworm - ate native UK earthworm
Categories of Invasive Species: Pathogens
Grey squirrels - carried squirrel pox
Crayfish - carried crayfish plague
Chalara Ash Dieback - spread amongst trees
Categories of Invasive Species: Species that hybridise
Sika deer (introduced) hybridise with red deer (native)
Categories of Invasive Species: Species that change abiotic features
rhododendron - change light availability
beavers - change nutrient availability
What does biotic mean?
living features of an ecosystem
What does abiotic mean?
non-living features of an ecosystem
How humans change abiotic factors: Water Availability
increased population
agriculture - irrigation
urbanisation - surface runoff
climate change - melt ice caps
reservoir
How humans change abiotic factors: Dissolved oxygen
lowers = eutrophication, power stations (release warm water)
increases = temperature decrease
How humans change abiotic factors: Temperature
climate change
industry - releasing hot fluids
building reservoirs - moderates temperature
How humans change abiotic factors: pH
combustion of fossil fuels - ocean acidification (CO2 + H20 makes carbonic acid)
burning of coal - acid rain
mining - acid mine drainage
How humans change abiotic factors: Water Turbidity
increase = litter, sewage, dredging
lower = build dams
How do we cause acid rain?
combustion of coal releases sulphur
sulphur + oxygen = sulphur oxides
SO2 + H2O = sulphuric acid
acid falls in the rain
How does acid rain affect living organisms?
kills plants and trees
leaches nutrients from the soil
dissolves organisms with calcium carbonate structures (coral reefs)
How humans change biotic features: Pollinators
neonicotinoids - kill bees
climate change - migration
habitat loss - loss of wildflowers
How humans change biotic features: Seed Dispersers
Habitat loss
Hunting - rhinos, elephants, hippos
How humans change biotic features: Food Chain Impacts
overfishing sand eels led to a decrease in puffin
collecting turtle eggs led to an increase in jellyfish population
How do humans destroy habitats?
destructive fishing methods
urbanisation
wildfires
resource extraction/ mining
eutrophication/ oil spills
combustion of fossil fuels - climate change
agriculture
HEP / offshore wind farms
