Species Diversity and Elevational Patterns of Saxicolous Lichens in the Eastern Pamir Plateau, China

Saxicolous lichens are crucial elements of alpine ecosystems and are involved in soil formation, rock weathering, nutrient cycling, and environmental monitoring. However, little is known about their distribution patterns and diversity on the eastern Pamir Plateau of China. This study looked at the variety and elevational distribution of saxicolous lichens in China’s eastern Pamir Plateau’s Taxkorgan Nature Reserve. Six transects spanning an elevational range of 3500–4500 m were used for field studies in July and August of 2025. Stratified sampling was used to gather lichen specimens, which were then identified by morphological, anatomical, chemical (thin-layer chromatography), and molecular investigations. Lichens communities’ similarity across altitudes was evaluated using Sørensen’s index, and diversity indices such as Simpson, Shannon–Wiener, and Pielou’s consistency were computed. A total of 69 saxicolous lichen species from 12 families and 27 genera were identified. With 95.6% of all species, crustose lichens predominated, whilst foliose and fruticose forms were uncommon. Acarosporaceae and Megasporaceae were the most species-rich families, accounting for over half of total recognized species. In the study region, Aspicilia and Acarospora dominated at the genus level. Saxicolous lichen species richness exhibited a unimodal elevational pattern, peaking at 4101–4300 m with pronounced community turnover across altitudes, as supported by Sørensen similarity values (0.253–0.561). Additionally, substrate type affected lichen distribution, with siliceous rocks hosting richer lichen communities than calcareous substrates. In general, the richness and distribution of saxicolous lichens in the alpine ecosystems of the eastern Pamir Plateau are mostly determined by elevation and rock type. This work provides essential baseline data for lichen biodiversity in the region and highlights the potential use of lichens as bio-indicators for monitoring environmental change in high-mountain ecosystems.