Plant Communities and Factors Responsible for Vegetation Pattern in an Alpine Area of the Northwestern Himalaya

The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species distribution.We placed random plots covering different habitats and altitude to record species composition and environmental variables.Vegetation was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with Canonical Correspondence Analysis.Four communities,each in alpine shrub and meadows were delineated and well justified in the ordination plots.Indicator species for the different communities were identified.Maximum species richness and diversity were found in community IV among shrub communities and community II among the meadows.Studied environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in meadows.Soil variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and meadows.Altitude,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum variation.About 40% variations left unexplained.Latitude and species diversity among the other variables had significant correlation with ordination axes.Study showed that altitude and C/N ratio played a significant role in species composition.Extensive sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.

Net Primary Productivity and Species Diversity of Herbaceous Vegetation in Banj-oak (Quercus leucotri-chophora A.Camus) Forest in Kumaun Himalaya,India

Net primary productivity and species diversity of herbaceous vegetation of banj-oak （Quercus leucotrichophora A. Camus） forest in Kumaun Himalaya, India were analyzed. Across different growth forms （tall forbs, short forbs, cushion and spreading forbs, grasses）, short forbs were most dominant component during rainy season （1VI=152） and winter season （IVI=167） and grasses during the winter season （IVI=148）. Maximum above-ground production occurred during rainy season （132.5 g m-2） and minimum during winter season （2.8 g m-~）. Below-ground production was maximum （85.9 g m-x） during winter season and minimum （14.9 g m-x） during summer season. Annual net shoot production was 15o g m-~ and below-ground production was 138 g m-~. Of the total input 61% was channeled to above- ground parts and 39% to below-ground parts.

Seasonal variations in species diversity, dry matter and net primary productivity of herb layer of Quercus leucotrichophora-Pinus roxburghii mixed forest in Kumaun Himalaya, India

Plant biomass, species diversity and net primary productivity are presented for herb layer of banj oak （Quercus leucotrichophora A. Camus）-chir pine （Pinus roxburghii Sarg.） mixed forest in Kumaun, central Himalaya, India. The species diversity declined from a maximum （3.56） in September to a minimum （2.11） in December. The monthly live shoots biomass exhibited a single peak growth pattern with highest live shoot biomass of 185 g·m^-2 in August. The seasonal pattem showed that the maximum above-ground production （131 g·m^-2） occurred during the rainy season and the minimum （1 g·m^-2） during winter season. The be- low-ground production was maximum during winter season （84 g·m^2） and minimum during summer season （34 g＇m＇2）. The annual net shoot production was 171 g·^2m^-1 and total below-ground production was 165 g·m^2. Of the total input 61% was channeled to above-ground parts and 39% to below-ground parts. Transfer of live shoots to dead shoots compartments and that of dead shoots to litter compartments was 61% and 66%, respectively. The total dry matter disappearance was 61% of the total input within annual cycle. The herb layer showed a net accumulation of organic matter, indicating the seral nature of the community.