Niche width and diversity pattern in different landscapes of an alpine grazingland in Garhwal Himalaya, India.
Data are presented on niche width/location, species diversity, β-diversity, equitability, P×F (presence × frequency) index and CI (continuum index) for important herbs and graminoids in 5 sample stands in an alpine grazing land in Panwali Kantha (Garhwal, Western Himalaya, Uttar Pradesh). The stands were at different aspects (SW, SE or E.) and altitudes (3400-3600 m) and included 2 Carex-forb communities, a Danthonia-forb community, a Poa-Trachydium community and a Poa-Agrostis community; assessments were made over 2 successive growth periods (May-October 1995-96). Among the graminoids Phleum alpinum exhibited maximum niche width, and Bupleurum lanceolatum and Taraxacum officinale showed maximum niche location. Higher β-diversity and equitability values in one of the Carex-forb communities indicated rapid change in species composition and community heterogeneity according to species adaptability and growth requirements. CI values demonstrated the impact of environmental gradients on the vegetation well.