Niche and Interspecific Association of Terricolous Macrolichens in Tuoli Taste District of Barluk Mountain National Nature Reserve, Xinjiang, China

Based on investigating 15 sample plots along the altitude gradient, and 25 quadrats (0.5 m × 0.5 m) in each of the sample plots, we aimed to analyse interspecific associations and the niche of the 20 main terricolous macrolichens in the Tuoli Tasite district of Barluk Mountain National Nature Reserve, Xinjiang, China. We studied these aspects by calculating niche breadth, niche overlap, variance ratio, Pearson correlation coefficient, and Spearman’s rank correlation coefficients. The results showed a total of 20 terricolous macrolichen species belonging to 5 genera, with Cladonia being the dominant genus (13 species, accounting for 65%). Fruticose lichens were the main growth form (14 species, accounting for 70%). Regarding niche breadth, C. gracilis subsp. turbinata had the largest niche breadth (Levins index: 4.609; Shannon-Wiener index: 1.693), while P. muscigena had the smallest (Levins index: 1.241; Shannon-Wiener index: 0.434). For niche overlap, the overlap value between species ranged from 0 to 0.94, with 26 species pairs showing no overlap and 46 species pairs having an overlap value less than 0.1. The overall interspecific association of the community was positive (VR = 3.653, P < 0.05). Spearman’s rank correlation analysis indicated that 51% of species pairs were positively associated (3 pairs extremely significant, 10 pairs significant) and 49% were negatively associated. In conclusion, the terricolous macrolichen community in the study area has formed a relatively stable structure through niche differentiation and moderate interspecific associations, which is closely related to their adaptation to the extreme environment.