Biodiversity sampling methods Flashcards
What is random sampling?
Sampling where each individual has an equal chance of being picked. Often done using a marked out grid and a random number generator to sample from random coordinates.
What is opportunistic sampling?
Non random sampling where the most conveniently available organisms are sampled.
Unreliable but easy and fast.
What is stratified sampling?
The population is separated into subgroups (strata) and then random sampling is used within each strata.
What is stratified sampling used for?
Used to see the differences between different groups in a population e.g: male/female
What is systematic sampling in biology?
The use of a line or belt transect to see how the abundance of species changes.
What is systematic sampling used for?
Used to see the differences in distribution and abundance of species between different areas of a habitat.
What is a pooter used for?
To collect individual insects.
What is a sweep net used for?
To catch lots of insects from one area.
What is a pitfall trap used for?
To collect a sample over time with little maintenance.
What is tree beating used for?
To collect a sample from a whole tree quickly.
What is kick sampling used for?
To sample organisms living in rivers/water.
What is a point quadrat?
A horizontal bar with regularly spaced pins.
What is a point quadrat used for?
To sample plants over an area of ground.
What is a frame quadrat used for?
To sample species in an area across a transect.
What is the concept behind capture mark release?
Mark captured individuals, release back into the community, then take another sample.
The more marked individuals recaptured -> the smaller the population.
What are examples of abiotic factors?
How are they measured?
Wind speed (anemometer) Light intensity (light meter) Temperature (temperature probe) Humidity (humidity sensor) pH (pH probe) Oxygen content (dissolved oxygen probe)
What are 3 ways of calculating abundance of a species?
Abundance scale
Count each one
Percentage cover
What is the abundance (ACFOR) scale, and when is it used?
Abundant, Common, Frequent, Occasional, Rare
This is a subjective, qualitative method which is used because it is quick, and easily transferable to different situations.
How is percentage cover used to calculate abundance?
Split quadrat into smaller squares and calculate percentage cover (take an average of multiple quadrats)
What is Simpson’s index of biodiversity used to represent?
Species biodiversity, it is an index of both species richness and evenness.
What does a value of Simpson’s index close to one represent?
The habitat shows high species richness and evenness, the habitat has high species biodiversity.
What does a value of Simpson’s index close to zero represent?
The habitat shows low species richness and evenness (low species biodiversity).
What is the significance of low species biodiversity in a habitat?
Environmental change may have drastic consequences as the community is less able to adapt to new pressures.
What is the significance of greater species evenness?
The community is more stable.
The community can better cope with abiotic and biotic changes.
What is a tullgren funnel used for?
To extract living organisms (particularly insects) from a sample of soil.
