Here is your essay on Ecological Indicators !
Since, specific factors often determine rather precisely what kinds of organisms will be present in a particular habitat; we can turn the situation around and judge the kind of physical environment from the organism present. It is found that certain species of micro-organisms, 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 indicate some very specific condition of the environment. Some of the Indian plant species which serve as ecological indicators have been tabulated in (Table: 171):
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Table: 17-1. Certain ecological indicators of plant species:
Name of species | Indicator (s) of |
1. Utricularia, Chara. Wolffia, Oltelia alismoides | Water pollution |
2. Peiridium sp. | Burnt and highly disturbed coniferous forest |
3. Argemone maxicana | Recently disturbed or flooded soil |
4. Rumex acetcsella | Acid grassland soil |
5. Carissa spinarum and Capp ris spinosa | Intense soil erosion |
6. Enicostema liuorale | Well drained soil |
7. Saccharum spontaneum | Poorly drained soil |
8. Ziryphus rotundifola | Soil deposition |
9. Andropogon sccparium | Sandy loam type soil |
10. Lippia nodiflora and Rumex sp. | Nitrate rich soil |
11. Woodfordio foribunda and Chlorii virgata | High lime content of soil |
12. Airiplen, Salsola, and Saueda | Saline water condition |
13. Hydrilla veriic llcta and Cerato- phyllum demersum | Hard water |
14. Watheria indica ste cutiasceae | Copper, lead and zinc rich soil |
15. Equisetum plebejum and E. arvense | Gold rich soil |
16. Silene cobahicola and Crotalaria eobaliicola | Cobalt rich soil |
17. Spermacoce stricta | Iron rich soil |
18. Pines and junipers | Uranium rich soil |
In fact, Central Arid Zone Research Institute, Jodhpur has made the use of certain plant communities of Indian deserts to indicate the salinity and depth of groundwater (Table 17 2).
Table 172. Certain ecological indicators for groundwater of Indian deserts (Chatterjii arid Bharkar, 1977):
Plant Community | Indicated depth to water in meters (m) | Indicated total soluble salt contents in pph) in groundwater |
1. Euphorbia caducifolia | 12 to 18 m | 1500 to 7000 |
2. Acacia Senegal—Anogeissus pendula | 12 to 18 m | 500 to 1500 |
3. Salvadora persica—Tainarix sp. | 6 m | 1500 to 3200 |
4. Salvadora oleoides—Prosopis cineraria | 10 to 20 m | 500 to 2000 |
5. Prosopis cineraria—Ziz vphus nummularia, Capparis decidua | 6 to 18 m | 5000 to 10,000 |
6. Salvadora oleoides. Capparis decidua | 6 to 12 m | -do- |
7. Salvadora oleoides—Zizyphus nummularia | IS to 28 m | -4C- |
8. Panicum lurgidum—CaHigonium polygonoides | 6 to 18 m | 1500 to 3200 |
9. Panicum lurgidum—Zizyplius complex | 6 to 18 m | 5000 to 10,000 |
10. Crotahria burhia—Lepladenia pyrotechnica | 6 to TO m | 5000 to 3200 |
11. Suaeda fruiicosa—Aebtropkms lagopiJes | 6 m | 11.000 »o 12.000 |
12. Capparis decidua | 12 to 20 m | 180 to 15000 |
13. Acacia indica—Nilothica sp.— Prosnp; s cineraria—Salvado ru oleoides | P. to 20 m | 400 to 1500 |
Besides plants, certain micro-organisms serve as ecological indicators. For example, Escherichia coli, a bacterium, is an index organism for aquatic pollution. Some species of diatoms (Arphidinae) indicate the degree of sewage pollution of lakes. The presence of Fusilinids (protozoans) in the soil indicated the petroleum deposits.
Similarly, certain animal species serve as 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.
Emigration and consequent disappearance of certain Indian fish species as Catla catla I abeo gonius, Labeo bata, Labeo rohita, Notopterus notopterus, etc., from Kalinadi river near Mansurpur Sugar Factory, indicate industrial pollution of water, as these fishes are found to be very sensitive to aquatic pollution (Verma, 1971).