B6.1 Monitoring + Maintaining The Environment Flashcards
Define sampling
Taking observations or measurements from an area, which is representative of a larger area
What techniques can be used to sample different species?
Pooter
Quadrat
Kick sampling
Pitfall trap
Sweep nets
What is a pooter used for
Collecting insects
What are Quadrats used for
Plants / very slow moving animals (limpets)
What are sweep nets used for
Catching flying insects or those in grass
What are pitfall traps used for
Small invertebrates living in soil surface of leaf litter
What is kick sampling used for
Disturbs mud / vegetation
Hold a net downstream to capture any organisms released into flowing water
Quadrats can be used to measure abundance by recording…
- Number of individuals of a single species
- Total number of different species
- Percentage cover (% of Quadrat area in which an individual species is found + recorded)
Define random sampling
Position of a sample is not pre-determined; individuals are selected by chance
Define non-random sampling
Systematically choosing where to take a sample
How do you estimate percentage cover?
- Count number of squares covered by the species
- Divide this by total number of squares, multiply by 100
What is the process for mark release recapture
- Large sample of animal caught
- Counted and marked
- Released
- Mix with rest of population
- Second sample group captured
- Second group counted, + count how many are marked from first sample
Equation to work out population using mark-release-recapture?
Population = (total caught first time x total caught second time) / no of marked individuals in second sample
What assumptions are made in mark-release-recapture?
No death / reproduction / emigration
Identical sampling methods used for both samples
Marking does not affect survival rates
Define biodiversity
The variety of living organisms present in an area
How is biodiversity lost?
Deforestation
Agriculture - effect on plants + animals
Hunting / fishing
Air and water pollution
Accumulative - global warming
How does deforestation result in a loss of biodiversity?
80% of land based species live in forests
Destruction of forests is biggest driver of extinctions globally
Even localised / small scale deforestation can result in extinction
Why are hedgerows so important for biodiversity?
Provide food / shelter for birds, hedgehogs, nice etc
Without hedges organisms suffer - numbers decline, affecting ecosystem
What is bioaccumulation
Increase in concentration of a toxic chemical in an organism over time
(Each organism eaten contains dose of pesticide, pesticides stored in body tissues and build up in bodies of consumers, can be lethal to top carnivore)
What is overfishing and how does it impact biodiversity?
Catching more fish than can be naturally replaced through reproduction of the remaining population
Imbalance damages food web, threatens other species, many species are declining
What is land pollution
Landfill sites
Dumping rubbish in public / private places
What is air pollution
Combustion of fossil fuels - CO2
Sulphur dioxide + nitrogen oxide - acid rain
Can form smog
What is water pollution
Nitrate fertilisers washed into rivers + reservoirs
Pesticides can be washed into streams / rivers
Define conservation
The maintenance of biodiversity
