REQUIREMENTS
Definite size of quadrat (50cm x 50cm), notebook, pencil, graph paper.
THEORY
The important value index. shows a complete or overall picture of ecological importance of all species in a community. In any heterogeneous plant community, data of frequency, density and the cover of species does not yield a total picture of ecological importance independently. Adding the values of relative density (RD), relative frequency (RF), and relative coverage (RC) provides the overall picture of a species’ ecological importance in relation to the entire community structure. The important value index of the species is called the total value out of 300.
IVI= RD + RF + RC
PROCEDURE
A quadrat was laid in the specific study area. Plants occuring there were noted with names and the value of relative frequency, relative density and relative Coverage were found by above mentioned formula. IVI. was calculated by adding these three values. The dates were plotted in the graph.
OBSERVATION TABLE
| S.N. | Name of plant species | R.D | R.F | R.C | IVI |
| 1. | Alternanthera | 22.22 | 19.15 | 21 | 62 |
| 2. | Monocot Grass | 5.56 | 6.38 | 16 | 28 |
| 3. | Equisetum | 5.56 | 10.65 | 15 | 31 |
| 4. | Oxalis | 5.56 | 4.25 | 12 | 22 |
RESULT
In terms of IVI, Liphest IVI species is Alternanthera.
In terms of IVI, the lowest IVI species is Oxalis.