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Systematic sampling
Aims for todayTo carry out a belt transectTo learn how to measure abiotic factorsTo assess percentage cover of plant speciesTo present this data in an acceptable wayTo develop and awareness of how abiotic
factors may influence plant distribution
We record data to:
Find out about the conditions an organism needs
Keep track of seasonal variationsRecord the effects of different treatments in
different areas eg fertilisers
SAMPLINGCan be systematic or randomA transect is an example of systematic
samplingIt is a line through a habitat along which
organisms are sampledIt is useful for studying areas of gradual
change
Describing Vegetation
What can we measure
• Density
• Percentage Frequency
• Percentage Cover• Subjective
• Objective
• Biomass
• Height
• Leaf Length, Width or Area
• Stomatal Density
QuadratsQuadrats can be used in a controlled way to
provide information about the distribution of species.
Results will need to be recorded from several quadrats in a sample area.
They can be placed randomly to remove bias, using a gridded map and random numbers, or used systematically in a belt transect
Quadrats are useful for:
Comparing species in one area with those in another (plants and stationary animals)
Different sizes of quadrats can be used for different species
Data can be recorded in a variety of ways (frequency, percentage cover)
Ecological Coursework Investigations
Estimate the percentage cover
How close was your estimate?
Sampling
How wide is my transect?
How wide is my transect?
How wide is my transect?
How long should a transect be?
Species A Species B
Transect 1
Transect 2
Transects
Species A Species B
Transect 1
Transect 2
Transect 3
Doing a transect – safety pointsAlways LOOK carefully where you are placing your
quadrat/tape measure, there may be rubbish and/or animal waste in the undergrowth!
Don’t go into the long grassy areas unless you’re wearing full shoes and trousers
Treat the environment with respectBe careful of nettles and brambles, some people are
also allergic to ivy
Doing the transectPlace the 10 m tape across an area of change, 5 m
in each area. Place a quadrat every 2m and record the % cover of
species in that areaRecord the abiotic factors of temperature and light
intensity at each 2m pointRemove a SMALL soil sample into the sample bags
at each point – we will measure the pH of these in the lab
Transects
0
20
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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1000% CoverLight Int. / lux
0
20
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Tufted Hair-grass
Moss
Dogs Mercury
-50.0
-25.0
0.0
25.0
50.0
-50.0
-25.0
0.0
25.0
50.0
-50.0
-25.0
0.0
25.0
50.0
How do we record the data?
