Sampling techniques Flashcards
(23 cards)
What is a pooter?
Used to catch small insects by sucking on a mouthpiece + drawing insects into the holding chamber
What are sweep nets?
Used to catch insects in long grass
What are pitfall traps?
Used to catch small, crawling invertebrates (beetles, slugs, etc)
Hole is dug in ground + insects fall into it
What is tree beating?
Used to take samples of invertebrates living in a tree or bush
Put white cloth under + shake tree
What is kick sampling?
Used to study organisms living in a river
River bank + bed is kicked to disturb substrate
What are the 2 main types of quadrats used to sample plants?
Point quadrat + frame quadrat
What is a point quadrat?
Frame containing a horizontal bar
Pushed into ground + each plant the pin touches is recorded
What is a frame quadrat?
Square frame divided into grid of equal sections
Type + num of species within each section of the quadrat is recorded
How do you estimate the size of an animal’s population?
Num of individual’s first marked + released (n1) x num if animals captured in 2nd sample (n2)
/ num if marked animals in 2nd sample (n3)
What are quadrats placed systematically along to study how distribution of species changes across an area?
A line or belt transect
What type of sampling is used to get a representative sample of an area using a quadrat?
Random sampling
Works by marking out an axis + using random numbers to make coordinates of where quadrat is placed
What are the different ways frame quadrats can be used to sample the population?
Density, frequency, percentage cover
How would we measure density?
If individual plants can be seen clearly, count number of them in 1m by 1m square quadrat
Absolute measure
How do we measure frequency?
Used where individual members of a species are hard to count
Use small grids within quadrat + count number of squares species is present in
Estimate measure
How do we measure percentage cover?
Used for speed since lots of data can be collected
Used when species is abundant or difficult to count, is an estimate measure
How do we calculate an estimate of the population of a whole area?
Multiply mean by total area
How do we measure species richness?
Use combo of sampling techniques to identify all species present in habitat, make list, then calculate total number of species
How do we measure species evenness?
Look in species area of habitat + count how many of each species are living in the habitat
How do we measure the abiotic (non-living conditions) factors in a habitat? (What sensors are used?)
Wind speed = Anemometer
Light intensity = Light meter
Relative humidity = Humidity sensor
pH = pH probe
Temperature = Temperature probe
O2 content in H20 = Dissolved O2 probe
Why are these being quick factors to measure an advantage?
- Rapid changes can be detected
- Human error in taking a reading is reduced
- High degree of precision can be achieved
- Data can be stored + tracked on computer
How do you calculate quadrat density?
Count number of plants in 1m by 1m square quadrat then divide by area of all quadrats
How do you calculate quadratic frequency?
Num of quadrats / total area x 100
How do you calculate percentage cover?
Quadrat divided into 100 squares then num if squares that species is found in is percentage civer
