Phytodiversity Estimation of High-altitude Pastureland Above Yonphula, Kanglung Gewog, Trashigang Dzongkhag

High altitude pasturelands (Tsamdro) are important grazing grounds of livestock in Bhutan. Pasturelands are degrading due to overgrazing and shrub encroachment along with climate change. The lack of floristic knowledge of such pastureland would mean permanent loss of phytodiversity if not studied timely. This floristic study was conducted for two seasons using quadrat method of vegetation analyses. Phytodiversity was determined using different biodiversity indices. A total of 83 species in 60 genera belonging to 35 families were recorded from the pastureland including two endemic species, Halenia elliptica D. Don and Viola bhutanica H. Hara. Asteraceae, Rosaceae and Gentianaceae are species rich families. Species indicated a high richness with 2.17, dominance index was 0.92 for species like Elsholtzia strobilifera (Benth) Benth, Swertia spp., Fragaria nubicola (Lindl. ex. Hook.f.) Lacaita, Potentilla sp., Trifolium repens L., Euphorbia griffithii Hook. f., and Plantago erosa Wall. The diversity value was 2.97, indicating low diversity with even distribution (0.91). Similarity index of 0.70 indicated fairly similar floristic composition in autumn and spring seasons. This study provides basic information on floristic composition and phytodiversity of pastureland, which can be incorporated for pastureland management and conservation.