Epiphytic lichens in subtropical forest ecosystems in southwest China: Species diversity and implications for conservation

Anthropogenic disturbances can severely impact the abundant lichen epiphyte communities of subtropical forests due to habitat loss, fragmentation and alteration. To assess the potential of anthropogenic secondary forests as conservation sites for epiphytic lichens, we investigated epiphytic lichens in 120 plots of eight forest types that are representative for the subtropical Ailao Mountains, southwest China. A total of 217 epiphytic lichen species were recorded, with 83% occurring in primary forests and 97% in secondary forests. Total species richness was significantly higher in the primary Lithocarpus forest (PLF), the middle-aged oak secondary forest (MOSF), the Populus bonatii secondary forest (PBSF) and the Ternstroemia gymnanthera secondary forest (TGSF) compared to four other forest types. The PLF harbored the highest number of rare species, while the MOSF, the PBSF and the TGSF, which had more pioneer tree species, hosted all cyanolichens found in this area. The Sّrensen index of similarity between forest types ranged from 0.39 to 0.90. Ordination analysis showed a distinct lichen species composition in each forest type. Correlation analysis indicated that forest characteristics, such as canopy openness and host diversity, significantly influence lichen richness. These findings demonstrate the importance of primary forests for lichen epiphyte conservation, and suggest that the MOSF, the PBSF and the TGSF help preserve crucial components of the subtropical forest landscape and can play important roles in promoting lichen conservation. At a broad landscape scale, a mosaic of extensive primary forests and small secondary forest fragments is important for biodiversity conservation in subtropical regions.