Name of the activity- To determine the population density of plants at a place by the quadrant method.
Materials Required-Meter scale
or quadrate ( ) of size 1m2,
String, nails, paper and pencil
Theory- The quadrate of size 1m2 is prepared by use of meter scale or by simply throwing the metal quadrat of size 1m2.The ecological factors determine the number of plants to be found in that area. The number of plants of one species found per square meter area is called it’s population density.
Number of plants of that species
Population density of a plant species = ---------------------------------------------
1m2 area
Procedure-The quadrate is thrown randomly in the grass field/park/cultivated field to know the population density of any species of plant. Further, the quadrat is divided into 16 sub-grids for ease of counting the plants in each sub-grid. Then all the plants are added to get the number of plants of any species in 1m2 area.
This experiment is repeated at three different places. The number of plants of different species was also counted.
Observation-
|
S.N. |
NAME OF PLANT SPECIES |
NUMBER OF PLANTS IN QUADRAT OF SIZE 1m2 |
TOTAL PLANTS |
AVERAGE |
||
|
1st Experiment |
2nd Experiment |
3rd Experiment |
||||
|
1. |
Euphorbia hirta |
2 |
4 |
3 |
9 |
3 |
|
2. |
Cynodon dactylon |
4 |
5 |
6 |
15 |
5 |
|
3. |
Chrysanthemum species |
5 |
3 |
3 |
11 |
3.67 |
|
4. |
Parthenium hysterophorus |
3 |
4 |
5 |
12 |
4 |
|
5. |
Stenotaphrum secundatum |
4 |
3 |
3 |
11 |
3.67 |
Calculation- Population density of a plant species is the average number of plants species found in that area of size 1m2.
Total number of plants of that species in all the three experiments
Population density of a plant species = ---------------------------------------------------------------------------
3 X 1m2 area
Total number of plants of a species
Population density of a plant species = -------------------------------------------------
Total number of quadrant studied
Conclusion-Population
density of plant Cynodon dactylon is highest and of Euphorbia hirta
is lowest.
Precautions-
a. Only one plant species is taken into consideration at a time.
b. Measurements of the field area for the study should be chosen carefully.
c. Quadrats should be selected in vicinity. Otherwise, there may be chance of variation in reading.
d. The string should not be very thick or thin. Alternatively, quadrats of iron rods can also be used.
Area= 1m X 1m
