Floristic Diversity And Morphological Characterisation Of Lichens As Bio-Indicators Of Environmental Health In Eastern India: A First Systematic Multi-Zone Assessment

A lichen is a stable symbiotic association between a fungal partner (mycobiont) and a photosynthetic partner (photobiont), forming a single composite thallus. Lacking a protective cuticle, lichens absorb water and nutrients directly from the atmosphere, making them sensitive to air quality and widely used as bio-indicators of environmental health. The lichen flora of Jharkhand remains critically understudied, with no prior systematic, multi-zone survey of morphological characterisation for the state. This study addresses that gap by documenting lichen diversity across four spatial zones in Ranchi representing an urbanisation and pollution gradient: Industrial (Tupudana), Commercial (Nayatoli/Main Road), Residential (Tagore Hill/Morabadi), and Peri-urban Forest (Jagannathpur Hill). Lichen thalli were surveyed by stratified random sampling on standardised phorophytes using a 20 cm × 20 cm quadrat at 1-1.5 m trunk height. Morphological identification used a hand lens, stereomicroscope, and standard taxonomic keys. Both foliose and crustose growth forms were recorded, and three species were confirmed: Parmotrema reticulatum (foliose), Pyxine cocoes (foliose), and Lecanora muralis (crustose). Shannon-Wiener and Simpson indices revealed a clear gradient: Zone 2 recorded the highest diversity and evenness (H′ = 0.694; 1−D = 0.556), while Zone 4 recorded the lowest (H′ = 0.325; 1−D = 0.200). Foliose lichens were largely restricted to less-disturbed zones, whereas pollution-tolerant crustose forms persisted in high-traffic and industrial corridors, consistent with lichen desert phenomena reported from other urban centres. This study establishes a first systematic floristic baseline for lichen diversity in Jharkhand, demonstrating the utility of lichen biomonitoring as a cost-effective tool for assessing urban environmental health on the Chota Nagpur Plateau.