A comparative study of benthic nematodes in two Chinese lakes with contrasting sources of primary production

Ecological studies on benthic nematodes were conducted in two small, shallo w lakes in the middle Yangtze basin, China; Lake Houhu, where the main sour ce of primary production is phytoplankton and Lake Biandantang where it is predominantly macrophytic in origin. Monthly sampling was carried out from April 1996 to March 1997. A total of 36 species of nematodes was found in L ake Houhu and 51 species in Lake Biandantang. The dominant trophic groups o f nematodes were algophages in Lake Houhu and bacteriophages associated wit h omniphages and phytophages in Lake Biandantang. Community analyses based on K-dominance curves, Shannon-Wiener and Simpson diversity indices, demons trate that the benthic nematodes are more diverse in Lake Biandantang than in Lake Houhu. The results suggest that the abundance of submerged vegetati on is essential for maintenance of habitat heterogeneity and biodiversity o f nematodes in shallow lakes.