LITTER DECOMPOSITION IN AN INDIAN MONSOONAL WETLAND OVERGROWN WITH PASPALUM-DISTICHUM

After the removal of domestic cattle and water buffalo in 1982, the monsoonal wetlands of the Keoladeo National Park, India were rapidly overgrown by the grass Paspalum distichum L. We studied the decomposition of above-ground litter of Paspalum distichum and that of ten submersed, floating-leaved, free-floating and emergent species, including the dominants in these wetlands prior to 1982. The only species that had decomposition rates as low as those of Paspalum were the emergents, Pseudoraphis spinescens (R. Br.) Vickery and Typha angustata Bory & Chaub, which had very restricted distributions both before and after 1982. All the previous dominants had much higher decomposition rates. The turnover time for Paspalum litter was estimated to be greater than one year, while litter of the previous dominants all had turnover times of less than one year. Thus, a permanent litter layer could develop in these wetlands that had not been present previously.