Effects of leaf-litter decomposition of exotic plants on benthic macroinvertebrate species diversity and functional feeding groups
外来植物凋落物分解对底栖动物多样性及其摄食功能群的影响

Leaf litter decomposition rates and benthic macroinvertebrates colonizing on leaf litters of the dominant native (Castanopsis hystrix and Coix chinensis) and exotic (Eucalyptus torelliana and Lantana camara) plants were compared in a second-order subtropical stream. Breakdown rates (k) of leaf-litters of native species were 0.02 d-1 for C hystrix and 0.056 d-1for C. chinensis, and the rates of exotic leaves were 0.038 d-1 for E. torelliana and 0.041 d-1 for L. camara. Total numbers of macroinvertebrate species colonized on leaves of exotic and native plants were 21 and 24, respectively and no statistical differences were observed in macroinvertebrates density (P>0.05) between exotic and native leaves. Proportions of each functional feeding group on litters of native plants showed that collectors-filterers (73.5%) was the most abundant group, followed by shredders (10.9%), predators-piercers (8.7%) and scrapers-grazers (6.8%); the composition of functional feeding groups on litters of exotic plants was collectors-filterers (67.6%), shredders (13.9%), scrapers-grazers (12.1%) and predators-pierces (6.1%); there were no apparent differences between the exotic and native plants according to the proportions of functional feeding groups. The results indicated that leaf-litter decomposition of two exotic plants in our investigation may not affect benthic macroinvertebrate diversity and functional feeding groups.