摘要
Macroinvertebrates areimportantcomponents of stream ecosystems,and are often used as indicator spe-cies for the assessment of river ecology.Numerous studies have shown that substrate is the primary physical envir-onmental variable affecting the taxa richness and density ofmacroinvertebrates.The aimofthiswork istostudythe effects of the characteristics of streambed substrate,such as grain size,shape,and roughness,on the composition and biodiversity of macroinvertebrates.A field experi-ment was done on the Juma River,a second-order moun-tain stream in northern China.Substrata of cobbles,hewn stones,pebbles,coarse sand,and fine sand were used to replace the original gravel and sand bed in a stretch of 30 m in length.The sampling results indicated that the macroinvertebrate assemblage is significantly affected by the grain size,porosity and interstitial dimension of the substrate,while it is rarely affected by the shape and the surface roughness of the experimental substrata.Macroinvertebrate compositions in cobbles and hewn stones were stable and changed least over time.The taxa richness and density of individuals in the substrata of cobbles,hewn stones,and pebbles are much higher than in those of the coarse sand and fine sand.
基金
This research was supported by the National Basic Research Program of China(973)(Grant No.2003CB415206)
the National Natural Science Foundation of China(Grant Nos.50779027
50221903-3)。
