AN ASSESSMENT OF AIR QUALITY USING LICHEN DIVERSITY OF DEHRADUN CITY, UTTARAKHAND, INDIA

Lichens are the symbiotic form of two micro-organisms, viz. alga and fungus, and are excellent bioindicators of environmental conditions and climate change in an area. This is an exceptionally successful group of symbiotic organisms, exploiting various habitats and relying on nutrients accumulated from the air. Due to loss of vegetation, vehicular pollution, and other anthropogenic actions, the overall picture of lichen diversity and distribution indicates that most species are pollution tolerant taxa and show their dominance over the sensitive ones. The localities which fall within the city center showed a complete absence of lichens followed by poor growth of pollution tolerant lichens in localities situated in the middle. The peripheral borders had normal growth of both sensitive and tolerant species. This study establishes the utility of lichen diversity and their distribution in long-term monitoring studies, as an effective method for air quality assessment in an area at an almost no-cost basis. It is assumed that any changes occurring in the environment significantly affect the biota. Thus, the data collected on the distribution of lichen flora will act as reference data for conducting biomonitoring studies in the future.