Sampling Techniques Flashcards
How can we improve the reliability when using quadrats ?
Place them randomly in an area
What can pitfall traps be used to sample ?
Small invertebrate animals living on the soil surface or in leaf litter
Why is it essential to check pitfall traps regularly?
Predation and scavenging can occur within traps if left too long
What do stones on pitfall traps prevent ?
Rain flooding the trap or birds or other predators from removing the trapped animals
What do qualitative results show ?
If a species is present or absent in the sampling area. Able to use quadrats/ pitfall traps to give qualitative results
What are quantitative results ?
The results can be converted into actual figures
What are quadrats used to sample ?
Low growing plants and very slow moving organisms
Give 3 examples of limitations when quadrat sampling ?
Generally only suitable for low-growing, rooted plants
Quadrat size
Reliability limited by number of samples possible
Give 3 examples of limitations when pitfall trap sampling ?
Generally only suitable for small, surface-crawling invertebrates.
Pitfall trap size
Reliability limited by number of traps set
Give possible sources of error when quadrat sampling ?(4)
Quadrats may not be placed randomly or according to the planned method.
Inappropriate size of quadrat selected
Too few quadrats used
Plants misidentified or overlooked
Give examples of possible sources of error when pitfall trap sampling ?(4)
Traps may not be placed randomly or according to the planned method.
Inappropriate size of trap selected
Too few traps used
Traps badly set or not emptied on time; invertebrates misidentified or lost from sample
Possibly source of error when measuring abiotic factors ?
Remember to clean and dry probes between samples and to read scales accurately
