Research Methods Flashcards
How can you sample aquatic animals?
Pond net, kick sampling, surber sampling, planktonic nets, colonisation media.
How can you sample plants?
Quadrats (point, grid and open frame)
How can you sample aerial and terrestrial animals?
Aerial:
Aerial Insect nets, suction samplers, light traps, sweep nets
Terrestrial:
Pitfall traps, suction samplers, sweep nets, beating trays, tullgren funnels, earthworm extraction (pit digging and soil flooding)
How can you sample earthworms?
- Soil Flooding - flood the soil and surrounding area in detergent
- Soil Pit Extraction - dig a pit of known volume and depth and hand-pick out the worms
When sampling, what is bias?
Deviation from results either due to systematic errors or flaws in study design leading to flawed data.
How can bias in sampling be avoided?
Standardisation
What should you consider when planning an experiment? (Acronym)
LCNTSSS
Location of samples
Count (% cover or population number etc)
Number of samples
Time
Standardisation
Size of sample
Statistical analysis
What types of sampling are there?
Random, systematic, stratified
What is stratified sampling?
Dividing the population into subpopulations and taking a proportionate number of samples from each subpopulation.
What is the difference between a transect line and a transect belt?
Transect belts use a quadrat along the line.
What are the drawbacks of a transect line?
It misses many species that don’t touch it
How does a transect belt fix the problem of transect lines?
It uses quadrats to widen the sample area
What is a preliminary study?
A test done before an experiment to determine how the experiment should be done
What can a preliminary study tell you?
It will give information about the success of the sampling techniques chosen plus the size and number of samples to be taken in order to get valid results.
What is a hypothesis?
A hypothesis is an explanation you can test statistically.
What is a null hypothesis?
This is a statement that says there is no effect or no relationship between variables or populations
How do you know how large to make intervals in a belt transect?
What is species density?
The mean number of individuals per unit area.
How can you measure species density?
What is species richness/diversity?
What is the Lincoln Index?
Used to estimate population sizes of individual species. Individuals are captured, marked, released back into the population and recaptured. Results are then put into the equation.
What is species frequency?
The likelihood of a particular species occurring in a quadrat.
What is species evenness?
How do you calculate species diversity?
Simpson’s diversity index
d = n(n-1)/total N(N-1)
What specialist techniques can you use to monitor populations?
– Tags/Marking
-CCTV/Infared cameras
– DNA databases
– Auditory marking/sonograms
– Position marking – radio/GPS/acoustic tracking (real time)
– Data recorders
– Sensor carrier systems
What indirect methods can be used to track populations?
Nests, tracks/trails, territorial marks and droppings
What is an example of systemic sampling?
Belt transect with quadrats
What is an example of random sampling?
Quadrats with random number generators for co-ordinates
What are the advantages of eDNA sampling?
More accurate identification of individuals (and population genetics), collection is less time consuming, less disturbance of the sight.
What are the limitations of eDNA sampling?
Takes longer to obtain DNA analysis results, DNA can degrade in warm conditions, may not have collected enough DNA in samples, doesn’t give indication of individual’s movement.
What is Simpson’s diversity index?
What is Lincoln’s index?
Pond Nets
Kick Sampling
Surber Sampling
Planktonic Drift Nets
Colonisation Media
Aerial Insect Nets
Suction Samplers
Light Traps
Sweep Nets
Pitfall traps
Beating Trays
Tullgren Funnels
How do you estimate the population size of a species?
Lincoln’s Index
How do you calculate species density in an area?
Simeon’s Diversity Index
