White clover (Trifolium repens) introduced in the 1970s has become the most important fodder legume in Bhutan and there is some concern about its possible negative influence on native plant communities. Detailed plant and soil observations were made across 27 sites (2,600–4,000 m) to evaluate the effects of white clover on plant community, P dynamics, and fodder quality. Arundinella hookeri was the dominant species up to 3,500 m. Other important species with wide distribution were Eragrostis nigra, Brachypodium sylvaticum, Potentilla spp. and Schizachyrium delavayi. An increasing presence of white clover reduced the proportion of biomass from other species, the frequency of A. hookeri and Potentilla spp., and the proportion of bare ground. Biomass harvested from spots with high white clover presence had 70% higher N and 17% higher P content when compared to biomass from spots with no white clover. Soil available P (Bray) was 2.68 mg/kg for patches without white clover and 6.21 mg/kg for patches with high white clover presence. There is no indication that white clover could become a weed in permanent grassland environments of Bhutan.
