What are Biological Indicators or Ecological Indicators?

Biological Indicators or Ecological Indicators with example

Certain species of microorganisms, plants and animals have one or more specific requirements and they become very much limited in their distribution. Thus the occurrence of such species in a particular area indicates special habitat conditions, and such species are called biological or ecological indicators., since they indicates some very specific condition of the environment.

Equisetum arvense-Indicator of gold rich soil

Certain Ecological indicators of plant species

No	Name of species	Indicator (s) of
1	Petridium sp	Burnt and highly disturbed coniferous forest
2	Pines and junipers	Uranium rich soil
3	Spermacoce strica	iron rich soil
4	Crotalaria cobalticola and Silene cobalticola	Cobalt rich soil
5	Equisetum plebejum and E arvense	Gold rich soil
6	Zizyphus rotundifolia	soil deposition
7	Lippia nodiflora and Rumex sp	Nitrate rich soil
8	Atriplen, Salsola and Saueda	Saline water condition
9	Woodfordio foribunda and Chloris virgata	High lime content soil
10	Rumex acetosella	Acid grassland soil

Besides plants, certain microorganisms serve as ecological indicators

For example, Escherichia coli, a bacterium, is an index organism for aquatic pollution.Some species of diatoms indicate the degree of sewage pollution of lakes. The presence of fusilinids in the soil indicate the petroleum deposits.

Certain animal species serve are ecological indicators.Chironomid larvae and maggots increase in number as the pollution increases. Burrowing may fly Hexagenia serves as indicator for well oxygenated aquatic environments.