Characterization of benthic macroinvertebrate communities in a restored stream by using self-organizing map

The Self-Organizing Map (SOM) was used for revealing the ecological states of streams in recovery through patterning of benthic macroinvertebrate communities. SOM was capable of showing different clusters of the sample sites in a small scale according to changes in environmental variables such as water velocity, depth, substrate roughness and the amount of silt. Community abundance correspondingly varied in different clusters of the sample sites. Within each cluster, data for community abundance were further grouped according to temporal changes in water quality. The patterns of benthic macroinvertebrate communities in the trained SOM were efficient in assessing recovery processes in the polluted sample sites, revealing the effects of river restoration projects in stream ecosystems. The study showed that spatial heterogeneity at the local level plays an important role in characterizing community patterns and consequently biological water quality assessment.