Bryophyte Flora in Alpine Grasslands of the Qinghai-Tibet Plateau Based on Plot Sampling

The species number of bryophytes is the second highest among land plants. Alpine grasslands on the Qinghai-Tibet Plateau (QTP) are the largest among global alpine biomes. However, bryophyte flora in alpine grasslands on the QTP remains poorly explored relative to its large geographic extent. A total of 347 plots were surveyed across the QTP, and 149 bryophyte taxa in 24 families and 49 genera were recorded in alpine grasslands. The largest family was Pottiaceae, followed by Bryaceae and Brachytheciaceae. The most species-rich genus was Bryum, followed by Didymodon and Brachythecium. The dominant species were Didymodon tectorus, Didymodon fallax, Bryum caespiticium, Didymodon constrictus, and Didymodon ditrichoides. The Jaccard similarity indexes of bryophyte compositions between alpine meadow and alpine steppe at the family, genus, and species levels were 0.375, 0.367, and 0.282, respectively. Turf was the most common life-form (75.2%), followed by weft (16.1%) and cushion (5.4%). Endemic species to China accounted for 8.05% of the total taxa. Bryophyte diversity in alpine grasslands on the QTP is exceptional and irreplaceable. The changes in species composition and life-forms between different grassland types reflect the adaptations of bryophytes to harsh environments.