Vol.:(0123456789) Biodiversity and Conservation https://doi.org/10.1007/s10531-019-01782-z 1 3 ORIGINAL PAPER Microclimatic variations and their efects on photosynthetic efciencies and lichen species distribution along elevational gradients in Garhwal Himalayas Nayan Sahu, et al. [full author details at the end of the article] Received: 21 May 2018 / Revised: 7 May 2019 / Accepted: 27 May 2019 © Springer Nature B.V. 2019 Abstract Climate change efects on Himalayas are expectedly more pronounced than any other mountainous ecoregion of the world with expected threat of meltdown by the year 2100 if efective checks are not imposed. The impacts of this climate warming in the geologi- cally fragile Himalayas has started to show its efects on shifting precipitation patterns, increasing temperatures, glaciers meltdown, species richness patterns and overall unpre- dictable microclimatic conditions. For measuring such impacts of current climate warming in Himalayan ecosystems, need of ecological substitutes has been stressed on by diferent United Nation conventions. Lichens in contrast to vascular fora have long been proved to act as cost efective global indicators for measuring ecosystems responses to environmen- tal climate. The variations in microclimatic attributes and their efects on photosynthetic efciency and distribution were studied in geologically fragile ecosystem of Govind Pashu Vihar National Park in Garhwal Himalayas. Total 217 species of lichens comprising 80 genera and 35 families were found along diferent elevations. Among the diferent habitat groups, corticolous lichens showed their dominance (123 species) followed by saxicolous (65 species) and terricolous (29 species) lichens. Corticolous forms were dominated by crustose while saxicolous and terricolous were mostly fruticose growth forms. Mostly large number of species showed a narrow distribution with maximum species richness observed in mid elevation zones (1950–2200 m) followed by a gradual decline towards higher ele- vations. Phaeophyscia hispidula, Parmotrema reticulatum and Flavoparmelia caperata showed wider ecological amplitude. Out of these species, P. hispidula and F. caperata were further subjected to chlorophyll fuorescence measurements with a pulse amplifed modulated fuorometer to access photosynthetic quenching efciencies. Maximum electron transport rates (ETR; 96 ± 5.76 μmol e − m −2  s −1 ) were observed in Phaeophyscia hispidula (1550 m) while F. caperata showed nearly 21% lower ETR. Photochemical quenching (qP; 0.5 ± 0.01) was maximum at 1550 m elevation in F. caperata while P. hispidula showed maximum qP values at 2200 m elevation, showing it’s higher tolerances towards extreme light stresses. F. caperata showed higher (0.102 ± 0.003) non photochemical quenching (NPQ) in comparison to P. hispidula (0.062 ± 0.001) at extreme elevations of 3508 m. P. Communicated by M. D. Behera, S. K. Behera and S. Sharma. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1053 1-019-01782-z) contains supplementary material, which is available to authorized users.