Changes of Five Alpine Species’ Individual Growth Along Snowmelt Gradient

In a natural snowbed on the Eastern Tibetan Plateau,three portions were established along a snowmelt gradient.Environmental factors and plants’growth of five herbaceous species in each portion were measured and compared.The results showed that snowmelt timing,soil water content and amplitude of diurnal temperature variance at soil surface in March,April and May differed greatly,whereas no significant differences in soil nutrient contents(total N,total P,total K,soluble N,soluble P) and pH were found.According to individual growth along the snowmelt gradient,five species were divided into three groups.The first group included Carex atrofusca subsp.minor(Boott) T.Koyama and Astragalus fenzelianus Pet.-Stib.whose height,number of leaves per stem,area per leaf and aboveground biomass increased with increase in snow depth.The second included Pediculars longiflora Rudolph var.tubiformis(Klotz.) Tsoong and Pyrethrum tatsienense(Bur.et Franch.) Ling ex Shih.that decreased their height,leaves per stem,area per leaf and aboveground biomass with increase in snow depth.The last included only one species Leontopodium longifolium Ling that did not evidently change its individual growth along the same snow gradient.