Biomass dynamics of grassland vegetation in Kenya

Abstract

SummarySeasonal changes in plant biomass in the herb layer were measured at Nairobi National Park and Masai Mara Game Reserve in Kenya from January 1980 to February 1981. Plant biomass fluctuated in response to seasonal rainfall, and live biomass was correlated with rainfall and soil moisture at both locations. Peak values for live biomass at Nairobi National Park occurred at the end of the long rains during the June 1980 sample and ranged from 138 to 197gm‐2. Minimum values for live biomass at Nairobi occurred during a dry season in February 1981 and ranged from 8 to 39 g m‐2. The standing dead and litter compartments were larger than the live compartment during every sample period at Nairobi National Park, and together often comprised more than 80% of the total above‐ground biomass. Probably as a result of higher rainfall, peak values for live biomass at Masai Mara Game Reserve were higher than those at Nairobi. Again, peak biomass occurred during June following the long rains, and ranged from 218 to 294 gm‐2. Minimum values for live biomass occurred during February 1981, and ranged from 10 to 48 g m‐2. Standing dead and litter compartments were much smaller than at Nairobi National Park, reflecting more intense herbivore pressure and a greater frequency of fires at Masai Mara compared with that at Nairobi National Park.