Quantitative Characters - Population Density

Density denotes the average number of individuals of a particular species in a unit area. In other words, it represents the numerical strength of a species in a community. A study of density makes it possible to have accurate and direct comparisons of the abundance of species between different areas. Density also gives an idea of the degree of competition between the members of the same species as well as of one species with the other. It is calculated as follows:

Density = Total number of individuals of a species in all the sampling units / Total number of sampling units studied

The value thus obtained is expressed as number of individuals per unit area.

• Crude density - is the density of individuals of a species throughout the habitat and is determined by random sampling.
• Ecological density - refers to the density of individuals of a species.