Human Impact On The Environment Flashcards
Endangered species caused by
Natural selection Habitat destruction Pollution Oil spillage Overhunting and collecting Overfishing and agricultural exploitation Competition from introduced species
Conservation
Involves the management of habitats to enhance biodiversity
Why is conservation important
Ethical reasons - preserve environment, not damage
Maintaining a healthy gene pool helps future - proof populations against environmental change
Agriculture has selectively bred crops from wild varieties
Conservation methods
Seed banks - hold seeds from rare and traditional varieties in controlled environments, to protect against extinction of species
Sperm banks - store sperm from threatened species and are used in captive breeding to ensure genetic variety with populations
Ecotourism - e.g safaris, provides education and raises money to fund local conversation efforts by employing local people
Agricultural exploitation
Refers to the way in which food production has had to increase efficiency and intensity to maximise crop yields in order to feed a growing populations
Causes conflict between conservation and the need to mass produce food
Monoculture
By growing a single species of crop e.g wheat to further increase yields
Disadvantages of monoculture
Reduces biodiversity as there is only one habitat
Provides an ideal environment for pests, so pesticides and herbicides have to be used
Farming reduces the flow of recycling of nutrients as when plants die and decompose their constituent elements are returned to the soil, but farmers often remove crop residue and there minerals from soil
Causes of deforestation
Use of land Palm oil Soya bean Biofuels Cattle ranching Timber extraction
Consequences of deforestation
Habitat loss Soil erosion Increase in sedimentation Climate change Less transpiration by trees Loss of plant species Desertification
Overfishing
Occurs when the rate at which fish are harvest exciters the rate at which they reproduce
Methods of overfishing
Fishing quotas Enforcing exclusion zones Restricting mesh size of nets- only ‘correct’ age fish caught Return young fish to the sea Forced reduction in fleet size Enforcing fishing seasons Allow some to return for breeding
Fish farming
Farms are densely stocked, so disease can spread easily, could spread to wild fish
Overuse of antibiotics and pesticides may cause resistance
Pesticides used to control fish parasites
Fish can outcompete native species for food if they escape
Methods of sustainability
Monitoring air quality to identify possible risks to human health
Monitoring soil structure, drainage pH, organic matter, and the diversity of living organisms
Monitoring water quality in terms of chemical composition species composition and microbial counts
EIAs
Planet boundaries
The limits between global systems must operate to prevent abrupt and irreversible environmental change
Climate change boundary
CROSSED
Due to large amounts of greenhouse gases
Use of biofuels is seen as a way to achieve this, as they remove CO2 from the atmosphere during photosynthesis
Take up too much land
Types of biofuels
Bioethanol
Biodiesel
Biogas is methane
The biosphere integrity boundary
Crossed
Caused by habitat destruction, pollution and climate change are all responsible for reducing biodiversity
The land system change boundary
E.g deforestation for agriculture, livestock rearing, and the cultivation of biofuel crops
Represents the misuse of land resulting in too little food bring produced
The biogeochemical flows boundary
Cycling of minerals though cycles like the carbon, phosphorus and nitrogen cycles. Overuse of nitrogen and phosphorus-based fertilisers means that this boundary has already been crossed
Cycle no longer self sustaining
The stratospheric ozone boundary
Destruction by CFCs found in propellants and refrigerants prior to 1987
The ocean acidification boundary
The pH of the oceans has fallen from 8.16 to 8.03 in the pant 3 centuries which represent 30% decrease
Fresh water use boundary
Avoidable if fresh water use is reduced
Reduced due to irrigation for agriculture, deforestation, water pollution, drainage wetlands, increasing population size and per capita use
Methods to increase availability
Using water-efficient appliances
Reclaiming waste water for irrigation and industrial use
Stop irrigation non-good crops
Irritate crops by using drip-irrigation systems
Capture storm water run-off for recharging reservoirs
Desalinate salt water
The atmospheric aerosol loading boundary
Represents the atmospheric microscopic particles from fossil fuels and dust from quarries. These particles worsen respiratory diseases like asthma, and settle on plant leaves blocking sunlight
Not been quantified
