human impact on environment Flashcards
what is the 6th mass extinction
the holocene extinction mainly due to human activity
what happened to the dodo
most famous extinct species no reason to be scared were eaten couldn't fly humans destroyed habitats
what happened to the quagga
heavily hunted
extinct in the wild by 1878
EX
extinct
EW
extinct in the wild
CR
critically endangered
EN
endangered
VU
vulnerable
NT
near threatened
LC
least concern
DD
data deficient
NE
not evaluated
what are the main reasons that species are threatened
- natural selection
- non contiguous population
- loss of habitat
- overhunting by humans
- competition from introduced species and accidental introduction
- pollution
what is conservation
sensible management of the biosphere to maintain habitats and enhance biodiversity allowing human activity
what is charismatic mega fauna
gets people interested conserving animals
using ‘prettier’ animals
what are the different conservation animals
seed banks = to conserve plants (used for medicine)
zoos = to conserve animals (educates people and scientific research)
captive breeding programmes
what are captive breeding programmes
need to maintain or increase genetic diversity
increase pop. numbers
stud books (record of animals mating)
sperm banks/AI/IVF/surrogacy
what are reintroduction programmes
reintroducing captive animals into the wild
- is the habitat still intact
- protected sites/wildlife reserves
- ‘hacking out’ - released into a fenced area as similar as possible to natural habitat. will gradually reduce food and increase living space
what is intensive farming
open system, net loss of nutrients as large yields are being exported from the farms which then has to be related by fertilisers
animals farmed at high densities which increase the chance of catching diseases due to dress and overcrowding, this leads to antibiotics being added to their food
what is monoculture
the growth of large numbers of genetically identical crops plants in a defined area for economic efficiency
what are the effects of monoculture
soil condition
field size
shelter
habitats
environment impact of increased use of pesticides and chemical fertilisers in relation to species diversity and loss of stability
loss of biodiversity
unstable ecosystem at risk from interspecific competition
machinery compacts soil
(squeezes air pockets - nitrogen fixing bacteria prefer aerobic conditions)
what is soil erosion
removal of topsoil which contains valuable nutrients
invasions of pests
what is toxic pollution
-eutrophication = loss of biodiversity
species present in large numbers due to lack of interspecific competition in polluted habitats
what do pesticides do
kill non target species
target species evolve resistance to insecticide
some insecticides become concentrated up food chains
what do PCBs and heavy metals do
egg shell thinning
interference with mammalian reproduction
damage to immune system
carcinogenic
what are hedgerows
narrow belt of vegetation dominated by shrubs and occasional trees
what are hedgerows used for
barrier to movement of livestock
marking property boundaries
why do hedgerows have a high landscape and conservation value
provide foraging and nesting sites for birds
rich in plants and animals
source of beneficial insects
wildlife corridors through hostile landscapes
advantages of hedgerow removal
acts as refuge for weeds
reduces loss of yield
decreases land needed for turning machinery
disadvantages of hedgerow removal
increases soil erosion
reduce crop yield through loss of beneficial insects species
predators for pest control
pollinators
what is deforestation
removal of forests for
timber
agricultural use of land
increasing housing development
what is caused by deforestation
loss of vegetation and roots lead to soil erosion
water floods from higher to lower levels
water runs off soil instead of being retained
water evaporates more easily from soil leading to desertification
how can we solve deforestation
coppicing - tree trunk is cut , leaving a stool a few cm high. new shoots emerge from buds and from into poles which thicken they are cut on rotation to produce timbers. a long rotation increases sustainability which favours diversing wildlife
selective cutting - steep slopes where total removal of trees would leave soil very vulnerable to erosion. also maintains nutrients in soil and minimises amount of soil washed away
how does overfishing happen
nets with small mesh catch young fish that are sexually mature overtime there are fewer individuals left to reproduce so population size decreases
what is drift netting
pelagic fish live in surface water. swim into a net suspended between two boats. but non target species are caught e.g. turtles and dolphins
what is trawling
fish living in deeper water. caught by a large net dragged through water. equipment damages the ocean bed which destroys habitats
what are the effects of overfishing on other wildlife
trawlers catch capelin but important prey for cod fish (contributes to decline of cod stocks)
harvesting antarctic krill - primary consumers main food of whales and seals, heavily fishing affects the food web
methods to regulates fishing and allow stock to recover
- mesh size but allow young fish to swim through
- quotas to only allow a certain mass of fish
- prohibit fishing in areas at certain times to allow reproduction
- legislation controlling size of fishing nets
- legislation controlling number of days at sea
what is fish farming
bred and grown to maturity in ponds and lakes
sometimes farmed in a pod (large steerable device)
fish convert their food into protein more efficiently
greater proportion of fish are edible
lower carbon footprint
what can fish farming cause
- diseased fish = densely stocked huge doses of antibiotics
- pollution = ecological balance of waterways may be upset, eutrophication, fish excreta carried into water around pens
- escaped fish = rapid growth of farm fish which out competes wild fish for food transmits parasites
- resource use = farmed salmon are carnivorous and eat 3x their body weight in fish food
- environmental toxins = more concentrated toxins than wild salmon although concentration so small that doesnt outweigh health benefits of eating fish
what are the 9 planetary boundaries
1) biosphere integrity boundary
2) land system change
3) biogeochemical flow
4) stratospheric ozone
5) ocean acidification
6) fresh water use
7) aerosols
8) introduction of novel entities
9) climate change
which boundaries have been crossed
climate change
biosphere integrity
land system change
biogeochemical flow
which boundaries have been avoided
stratospheric ozone
which boundaries are avoidable
ocean acidification
fresh water use
which boundaries are not quantified
aerosols
novel entities
what is the climate change boundary
higher atmospheric c02 linked to higher global temp
increases sea level by 7m
combatting climate change –>
- kyoto protocol signed by 84 countries
- COP21 signed by 174 countries
keep global temp well below 2 degree above pre industrial temp
limit greenhouse gases to human activity to what can be naturally absorbed
help poorer nations to adapt
what is the biosphere integrity boundary
habitat destruction leads to species becoming extinct 1 species lost per year in a million to natural selection boundary - 10 per million per year current rate - 100 per million per year must increase public awareness
what is the land system change boundary
problems - natural ecosystems used for urban development, raising livestock
pollutants derived from agriculture and other human activity
production of biofuel crops and crops grown for export means not enough food for local use
solutions - no more than 15% ice free land should be used for crop growing and human habitation
eat less meat
what is the biogeochemical boundary
fertilisers use - atmospheric nitrogen is fixed in the haber process
combustion of fossil fuels
led to -
- eutrophication
- acidification (co2 forming carbonic acid in rivers)
current - 150 million tonnes
boundary - no more than 62 million
what is the stratospheric ozone boundary
hole in ozone layer in 1970
measures taken - use of chlorinated hydrocarbons was banned
boundary - 276 dobson units
current - 300 dobson units
what is the ocean acidification boundary
was pH 8.16 –> now pH 8.03 h+ ions are 30 times more complicated
decreases internal pH of phytoplankton
less o2 produced less co2 removed
gas exchange in fish is less efficient
calcium leaches out of the calcium carbonate skeletons od corals out of the shells of molluscs and arthropods current 2.9:1
boundary 2.7:1
what is the freshwater boundary
2.5% fresh water on earth 61% is frozen not all fresh water is drinkable human activity reduces water - - irrigation systems - polluting water - increased human population leads to - - desertification - rivers fail to reach seas - fisheries are destroyed boundary = 4000 km y-1 current = 2600 km y-1 solutions = stop irrigating non food crops drip irrigation for food crops reduce reuse recycle
what is the atmospheric aerosol boundary
atmosphere contains minute particles. some are natural consequences = 800,000 premature deaths soot absorbs heat sulphate reflects heat no boundary
what is the introduction of novel entities boundary
synthetic organic pollutants radioactive materials genetically modified organisms nano materials no bigger than 100nm boundary = - ddt is banned - pcb controlled as its toxic and reports of it being carcinogenic few have been properly assessed
