Sampling Biodiversity Flashcards
Planning Sampling
=> Ensure suitable clothing, equipment, sampling and recording apparatus is carried
=> Keys to identify plants
=> plans to minimise environmental impact like trampling
Random Sampling + Quadrats
=> random generation can be used to select the coordinates of representative number of squares in grid
=> each squares can then be sampled - either counting or percentage cover for dense species
Random walking
=> involves a random number between 0 and 360 to act as a compass bearing
=> then choose another random to go to next point to sample
Systematic sampling
samples are taken at fixed intervals across the habitat
=> Line transects: useful for examining effects of change of habitat on biodiversity - line drawn through area to be examined + any species touching the line is recorded
=>Belt transects: same but records density as well unlike line
Opportunistic sampling
sampling decisions made based on researchers prior knowledge or during process of collecting data
=> researcher may deliberately sample an area that they known contains certain species
Evaluating opportunistic sampling
Despite easier + quicker than random
=> may be biased as presence of large/colourful species may entice researcher to include species
=> may lead to overestimate of its importance + therefore an overestimate of biodiversity
Evaluating systematic sampling
PRO: particularly useful often the habitat shows clear gradient in some environmental factor
CON: only species on the line or within the belt can be recorded => other species may be missed and underestimate biodiversity
Stratified sampling
Dividing a habitat into areas which appear different and sampling each area seperately
Evaluating stratified sampling
PRO: ensures all areas of habitats are sampled + species aren’t underrepresented due to random possibly missing certain areas
CON: possible this may lead to over representation of some areas in sample if disproportionate number of samples are taken in small areas
