Decomposition of grasses in Nairobi National Park, Kenya.

The litter-bag technique was used to estimate decomposition rates of standing-dead grass and grass litter in Nairobi National Park. Decomposition was extremely slow. After almost 2 years standing-dead and litter had lost 40% and 50% of dry weight, respectively (equivalent to 45% and 65% of ash-free dry weight, respectively). Ash concentration (mainly silica) was exceptionally high, reaching 40% in the litter within 9 months. There was no net loss of nitrogen from the bags during the study. Weight loss was not statistically correlated with rainfall received between sampling dates. The pattern of decomposition, rates of decomposition in other grasslands and the implications of the results for park management are discussed.