Discuss the significance of lichens as bioindicators in the context of forest ecosystem monitoring, with reference to recent taxonomic discoveries in the Western Ghats.

Q. Discuss the significance of lichens as bioindicators in the context of forest ecosystem monitoring, with reference to recent taxonomic discoveries in the Western Ghats. (15 marks, 250-350 words)

Lichens are symbiotic associations of a fungus with algae or cyanobacteria [1]. Lacking roots and a protective cuticle, they absorb moisture and nutrients directly from the atmosphere, which makes them acutely sensitive to pollution and habitat change — and therefore reliable biological indicators of forest health.

Why lichens function as bioindicators - Direct atmospheric dependence: pollutants accumulate in their tissues, so decline in lichen cover signals deteriorating air quality even before trees show stress [1]. - Microclimate sensitivity: they respond to humidity, canopy cover and light, tracking forest degradation and fragmentation. - Sessile and long-lived: unlike mobile fauna, they integrate site conditions over years, allowing long-term monitoring at low cost.

Significance for forest ecosystem monitoring - Species records help delineate ecologically sensitive zones and support evidence-based conservation planning in biodiversity-rich landscapes [1]. - Provide a cheap, non-invasive complement to instrument-based air and forest-health monitoring, useful for baseline data in remote terrain. - Feed into conservation prioritisation — but only if the underlying taxonomy is sound, since monitoring requires correctly identified species.

Recent Western Ghats discoveries - MACS-Agharkar Research Institute, Pune (an autonomous institute of the Department of Science & Technology), described five new Allographa species — A. keralensis, A. nayakae, A. paraconsanguinea, A. persistinspersa and A. semicarbonisata — from Western Ghats forests [1]. - The team used integrative taxonomy*: morphology and chemistry combined with multi-locus DNA sequencing (mtSSU, nrLSU, RPB2), showing that morphologically similar lichens may be evolutionarily distant [1]. - This builds on Allographa effusosoredica, the first Indian Allographa* confirmed by molecular data [2], underlining how incomplete India's lichen inventory** still is.

That new species continue to emerge from an intensively studied hotspot shows both the richness of the Western Ghats and the gap in our monitoring baseline. Strengthening molecular taxonomic capacity, digitised herbaria and long-term lichen monitoring plots would convert these discoveries into usable conservation tools — advancing India's commitments under the Convention on Biological Diversity and SDG 15 (Life on Land).

(~330 words)

Sources: 1. Five new species of Allographa discovered in the Western Ghats — DST/PIB (2026) — lichen symbiosis and bioindicator role; five new Allographa species; ARI Pune under DST; integrative taxonomy with mtSSU, nrLSU, RPB2; ecologically sensitive zone delineation 2. New Lichen species reveals ancient symbiosis in the Western Ghats — Department of Science & Technology — Allographa effusosoredica as the first Indian Allographa confirmed by molecular data