human impact Flashcards
what is extinction?
the loss of species and a decrease in biodiversity
what is an endangered species?
a species that is seriously at risk of extinction
what are the reasons for species becoming endangered due to human impact?
- destroying habitats
- pollution of the environment
- introduction of alien species to an ecosystem
- monoculture
- building roads, houses or factories
- unsustainable harvesting
what is conservation?
the principles and practise of the science of preventing species extinctions
why can alien species disrupt an ecosystem?
- they may out-compete native species for food and space
- they might have no natural predators to control the population
- may also carry diseases that affect native population
how is conservation achieved?
- habitat protection by nature reserves and SSSI
- international co-operation between governments and organisations
- restricting activities and passing legislations that threaten endangered species
- breeding programmes
- sperm banks and seed stores
- reintroduction programmes
- pollution control
what is the SSSI?
sites of special scientific interest
how are gene pools conserved in the wild?
rare breeds, frozen zoos and sperm/seed banks
how are gene pools conserved in captivity?
captive breeding programmes which ensure the diversity of the species by maintaining the genetic diversity of the stocks of captive animals
why is conservation so important?
some organisms may have alleles that are useful to humans
- our domestic animals and plants all have wild relatives that have useful alleles that could be bred back into the domestic varieties and confer
- many plants also have medicinal properties
why is it important that genetic diversity is maintained?
it is critical for species to survive changing environments as natural selection is dependent on variation in the species
what is agriculture?
the means of producing food for human consumption in order to meet demand.
how do agriculturalists meet the growing demand of human consumption?
- created larger fields by removing hedges
- cultivated monocultures
- increased their use of fertilisers and pesticide.
why are hedges so important for wildlife?
they are valuable habitats and contain some pest species and their predators.
- also allows mobile species to travel to different areas to disperse species and find mates.
what is the advantages of using monoculture crops?
- grow crops that are easy to harvest mechanically
- guaranteed to yield disease-free seeds
what is the disadvantages of using monocultures?
- if pest species invade, this will spread rapidly
- reduces biodiversity of the area
what is a gene pool?
the sum of all the alleles for all the genes in a population
what is an example of a reintroduction programme?
red kite programme in wales
what are 3 of the legislations passed for conservation?
- the protection of endangered species
- prevention of over-grazing/fishing, hunting, collecting birds eggs and picking wild flowers
- international co-operation restricting trade e.g. ivory, whaling
how do agriculturalists meet the growing demand of food production?
- creating larger fields by removing hedges
- cultivated monocultures
- increased use of fertilisers and pesticide
what is the issue with fertilisers?
can cause eutrophication of nearby water bodies as any excess will leach into rivers
issues with pesticides?
they harm beneficial species and pests, and can cause them to decline in numbers
consequences of deforestation
- loss of habitats and biodiversity
- soil erosion > removal of vegetation
- lowland flooding (leaf litter usually acts as a sponge to soak up heavy rainfall)
- climate change
- less photosynthesis
- combustion of trees
management techniques for sustainability (forestry)
- coppicing
- selective cutting
- long rotation time
- planting trees
- protected areas
what is coppicing?
cutting trees/shrubs to allow for regrowth and supply timber sustainably
- enables light to reach forest floor and encourage biodiversity
what is selective cutting?
when individual trees are removed, leaving space for remaining trees to grow. the habitat is largely left in place
what is a cause of deforestation?
- palm oil
- soya beans
- biofuels
- cattle ranching
- use of land for agriculture
what is the issue with overfishing?
the numbers within the population cannot be maintained so there will be a decline in fish stocks
how to reduce the impact of overfishing
- fishing quotas
- reduced fishing fleets size
- restricting mesh sizes for fishing nets
- banned fishing from exclusion zones
- fish farming
what is fish farming?
growing/breeding fish in managed conditions, the animals are fed and treated with chemicals to stay pest and disease free and are then harvested
issues with fish farming
- overuse of antibiotics leads to resistance in pathogenic bacteria
- non specific pesticides can leak out and affect marine food chains
- fish in netted-off area can be overcrowded so disease and pests can spread rapidly
issues with farmed salmon
- kept very densely stocked
- contain high levels of dioxins and PCB’s
- poor texture and flavour
why do farmers plough land?
to improve aeration of soil.
- enables the process of nitrification
issue with digging drainage ditches
they have a detrimental effect on habitats
- results in reduced biodiversity
effects of management techniques in farming
- beetle banks to encourage predators of pests
- wild-life friendly farming
- buffer ditches to encourage more wildlife
types of things being environmentally monitored:
- air, soil and water quality
- Chemicals such as pH, carbon dioxide, nitrates and ammonium
- animals and plants, especially those that are sensitive to change.
- Radiation
- Microbes for recreation areas
what is environmental monitoring?
the physical and biological measurements that are made over a period of time
why is environmental monitoring necessary?
they help political bodies to make decisions based on scientific data about the impact of projects on the environment and to consider alternatives
what methods are used for environmental monitoring?
may involve transects or random sampling of areas
- often need to repeat experiments and at different seasons to assess impact
forestry environmental monitoring techniques
- forest mapping
- planting/re-planting campaigns
- monitoring of deforestation/illegal logging
forestry management techniques
- pruning of shrubs to prevent succession
- coppicing on rotation to provide different habitats for organisms
coastal management techniques
- erosion monitoring
- storm damage assessment
- beach replenishment planning
plant conservation techniques
- species identification
- plant health/stress analysis
- biomass estimation
who should be informed by the info gained from environmental monitoring?
- governments
- citizens
- world forums
what are planetary boundaries?
the safe operating space for humanity to prevent abrupt and irreversible environmental change
what are the 9 planetary boundries?
biosphere integrity, climate change, chemical pollution, ozone depletion, aerosol loading, ocean acidification, biochemical flows, freshwater consumption and land system change
Which planetary boundaries have already been crossed?
the biodiversity, climate change and biogeochemical flows boundaries
which planetary boundaries may be prevented?
land use, ocean acidification and fresh water
which planetary boundary has been avoided?
the ozone boundary
which planetary boundaries have not been quantified?
chemical pollution and aerosol boundary
what are the three types of biofuels?
- bioethanol (made via alcoholic fermentation)
- biodiesel (made from vegetable oils)
- biogas (methane from the digestion or plant and animal waste)
what are biofuels useful for?
growing biofuels removes CO2 from the atmosphere which reduces climate change
what reduces biodiversity/ biosphere integrity?
habitat destruction, pollution and climate change
what is the biosphere integrity boundary?
this represents biodiversity of ecosystems
what is the land system change boundary?
this represents the misuse of land, resulting in too little food being produced
What is the stratospheric ozone boundary?
represents the destruction of stratospheric ozone by CFC’s found in propellants and refrigerants
how was the ozone boundary reversed to safe levels?
montreal protocols banned their manufacture after discovering the hole in ozone layer over Antarctica
