Towards a protocol for stream macroinvertebrate sampling in China.

Standard protocols are critical for maximizing data comparability and aggregation in national monitoring programs, and taxa richness is a common indicator of site condition and biological diversity. There are two general approaches for sampling stream macroinvertebrate assemblages: targeted richest habitat and site wide. At seven sites, we compared three methods: Ontario Benthic Biomonitoring Network (OBBN), Environmental Monitoring and Assessment Program (EMAP), and Rapid Bioassessment Protocol (RBP). The OBBN method produced a biased sample at a site with a single small riffle, the RBP method produced the most total taxa, and the EMAP method produced the most taxa at four sites and the most individuals at six sites. The RBP method produced asymptotes for percent tolerant individuals, percent chironomid individuals, and Hilsenhoff Biotic Index score after five to ten stations. The EMAP method produced asymptotes for those metrics after 10 to 20 stations per site. The EMAP method typically required half the number of stations as the RBP method to obtain 70-90% of true taxa richness as estimated by the Jaccard coefficient. We conclude that the EMAP method is preferable because of its greater precision in taxa richness estimates.