 Quantitative Study of plants (and animals) of a sample area of the selected
ecosystem
Transfer Results to
• Diagrams
• Graphs
• Tables
• Histograms
• Other relevant mode
Quantitative Study relates to the number of organisms present
A Quadrat (used for quantitative studies of plants or sessile animals) is:
 A frame that forms a known area (often .5m x .5m = .25m2)
 Usually square shaped
 2 types: (i) Frame quadrat or (ii) Point quadrat (gridded)
 Used to measure Frequency (i)
or Percentage Cover (ii)
Using a FRAME quadrat
Using a POINT quadrat
Percentage Cover = the area of
ground occupied by aerial parts of a
named plant within the sample area
(expressed as a percentage of the
total area) – used for ‘cover plants
e.g. grass
Frequency = The chance of finding a
named organism within the sample area
1.
Throw the frame quadrat
(size must match
survey area for accuracy) randomly
in the
1.
sample area (safely? how? )
2.
for accuracy) randomly
Record the presence or absence of the
named organism within each quadrat
3.
Repeat for a number of throws
(size must match survey area
in the sample area (safely?
how?)
2.
Lower the needle at each of the 25 sampling
point s - i.e. where wires cross
(more
throws, more accuracy)
4.
Throw the point quadrat
3.
Record the number of hits at the sampling
points – i.e. if plant touches the needle at one
Tabulate results
of the 25 cross points that represents 4% cover
5.
Calculate using formula below: (can be
converted to a percentage by multiplying
(so multiply ‘hits’ by 4)
4.
by 100)
No. of quadratswith org. present
Frequency
No. of quadratsthrown
Repeat for a number of throws
accuracy) to
(more throws, more
get the average
5.
Tabulate results
6.
Calculate average percentage cover
Frequency table
Organism
1
2
3
4
Frequency
5
Quadrat throw
6
7
8
9
10 Total Frequency % Frequency
No. of quadratscontainingorganism
No. of quadratsthrown
If percentage is required multiply frequency by 100
Chart/Graph of Frequency
% Frequency
60%
50%
40%
% Frequency 30%
% Frequency
20%
10%
0%
Buttercup
Daisy
Dandelion
Plant name
Grass
Quadrat throw
Plant Name
Grass
1
2
3
4
5
6
7
8
9
Total no.
10 of Hits Total Points % Cover
250
250
% Cover 
No. of hits
 100
Τotal no. of point s
Pie Chart of Percentage Cover
Percentage (ground) Cover
Creeping
buttercup
others 10%
5%
Grass
85%