11.2

• Sampling is useful for: estimating size, measuring characteristics, making generalisations
• Opportunistic sampling is the weakest form of sampling
• Stratified sampling is where the population is separated into strata and a sample taken from each stratum
• Systematic sampling is where different areas are sampled separately at evenly distributed points
• Systematic sampling can use line or belt transects
• A Line transect is a line between two poles
• A Belt transect is two parallel lines
• A Pooter is an animal sampling technique where you suck on a mouthpiece to draw small insects into a holding chamber
• A Sweepnet is an animal sampling technique to catch insects in long grass
• A Pitfall Trap is an animal sampling technique where a hole is dug in the ground which insects fall into, and is covered with a roof structure to prevent it filling with water
• Kick Sampling is an animal sampling technique where the bed/bank of a river is kicked to disturb the substrate while a net is held downstream
• Tree Beating is an animal sampling technique where a large white cloth is stretched out under a tree as it is shaken
• A Point Quadrat is a plant sampling technique using a frame containing a horizontal bar with long pins pushed through it at set intervals to collect plants
• A Frame Quadrat is a plant sampling technique using a frame divided into a grid of equal sections (10x10)
• Belt Transects allow calculation of density