Plant biomass, species diversity and net primary production in a central Himalayan high altitude grassland

Abstract

(1) Plant biomass, species diversity and net primary production are presented for a high altitude grassland of Central Himalaya, India. (2) The time-series of live shoot biomass exhibited a unimodal growth pattern during each of the two years of study. The peak live shoot biomass, which was attained in August, ranged between 382 and 409 g m^-2. (3) The relative growth rate of live shoots ranged between 8 and 42 mg g^-1 day^-1, the maximum rate occurring during the early part of the growing season. Rise in temperature which caused the snow-melt in mid-April was followed by vegetation growth. Snow-melt provided the plant-available moisture as well and shoot growth began at a rapid rate during April-May. Biomass accumulation was sustained by monsoon rainfall in June-August. (4) Species diversity declined from a maximum in June to a minimum in October. Danthonia cachemyriana showed increasing dominance with advancement of the growing season. (5) The minimum annual net shoot production ranged between 453 and 527 g m^-2 and the minimum total below-ground net production between 284 and 449 g m^-2. (6) The total dry matter disappearance almost balanced the total net organic matter input within the annual cycle indicating that the system is in equilibrium.