B6.1 - Monitering & Maintaining The Environment Flashcards
Sampling
Taking observations & measurements from a small area, representative of a larger area to estimate
Apparatus & techniques to collect living animals:
- Pooters
- Sweep nets
- kick sampling
- tree beating
- pitfall traps
Pooters
- suck on mouthpiece to draw insects into holding chamber
- filter stops organisms entering mouth
Sweep nets
sweep large net through air to catch flying insects / insects in long grass
Kick sampling
- ‘kick’ river bank/bed to disturb mud/vegetation
- hold net downstream to capture organisms released into flowing water
Tree beating
- stretch large white cloth under tree/bush
- shake/beat tree to dislodge invertebrates, will fall into cloth
Pitfall traps
- dig hole in ground
- crawling invertebrates (beetles, spiders, slugs) will fall into
- cover hole with roof so trap doesn’t fill with rain water
Types of identification keys (to identify living organisms)
- branched key: answer yes/no for each question
- numbered key: correct answer to a question tells you which question to answer next
Capture-recapture technique
- Capture organisms from sample area
- Mark individual organisms, then release back into community
- At later date, recapture organisms in original sample area
- Record number of marked & unmarked individuals
- Estimate population size
Estimated population size equation (capture-recapture technique)
Estimated population size = (first sample size x seconds sample size) / no. of recaptured marked individuals
Quadrat, how do you sample plants
Square frame divided into a grid
- place it onto ground to take sample & record type & no. of organisms within each section
- take multiple samples & calculate mean average for accurate results
Random sampling
- position of sample not pre-determined
- individuals selected by chance
- prevents bias
Eg. Number generator to give random coordinates
Non random sampling
- systematically choosing where to take a sample
- transect: samples taken along line, place quadrat at fixed positions along line
Eg. To see how plant species change as move inland from sea
Why is biodiversity important
- species interconnected, so removal of 1 species can affect others
- essential for maintaining balanced ecosystem
- humans rely on biodiversity for raw materials (food, wood, oxygen)
How is biodiversity lost
increased need for food & materials due to increased population causes:
- deforestation
- agriculture
- hunting & fishing
- pollution
Deforestation
- removing forest provides wood for building/fuel & creates space for roads/buildings/agriculture
- reduces no. of trees & no. of supported animal species as food source & home lost, can also affect predator species
Agriculture
Many intensive farming techniques(for increased population):
- remove hedgerows to use large machinery & extra land for crops: reduces no. of plant species & destroys habitat of animals (mice/hedgehogs)
- pesticides to kill pests that eat crops/live on livestock: removes food source (pests) of other organisms, can ruin food chain, killing animals not targeted
- herbicides to kill plants growing where not wanted: reduces no. of plant species present & no. of animal species present (removes food/shelter)
Fishing
- overfishing = some fish populations decrease significantly/extinct in some area
- other marine species may be caught/killed
Hunting
- decreases target species population, removes food for other species (ruins food chain)
- allow unchecked growth of some plant species, outcompete other plants
Pollution
generally, more polluted area = fewer no. of species that can survive
Techniques to prevent biodiversity loss
- conservation
- seed banks
- captive/selective breeding
Conservation techniques
- controlled grazing (only allow animals to graze land for certain period of time, plant species have time to recover)
- restricting human access (providing paths, prevent plants being trampled)
- feeding animals (ensure organisms survive to reproductive age)
- reintroduction of species (adding new individuals of species to area where numbers decreases significantly / species haven’t survived)
Captive breeding
- breeding animals in human-controlled environments (zoo/aquarium)
- animals given shelter, nutritious food, veterinary treatment, predator-free environment
- suitable breeding partners imported from other zoos
Aim of captive breeding
- create stable, healthy population of species
- gradually reintroduce species back into its natural habitat