Variations of community structure of functional feeding groups of aquatic insects along a check dam

[[abstract]]In order to understand the effects of check dams on the transportation of organic matters and functional compositions of aquatic insects, six sampling sites were selected around the most upstream dam in the Tong-Hou Stream. Environmental variables and aquatic insects were sampled in February, March, May and July 2008, and the habitat characters of each site were recorded as well. This study showed that stream width, depth, discharge and canopy carried out a significantly differed between upstream and downstream of check dam. The coarse and fine particulate organic matter ratio, the ratio of abundances of gathering- and filtering- collectors was presented a significantly differed between two sites just above and under the check dam. Furthermore, the community structure of FFG have distributed with discontinuous patterns just above the check dam. Although the disturbed ranges only focus in 50 meter scopes of the check dam, the discontinuity results were still in accordance with dams.