Quantitative tolerance values for common stream benthic macroinvertebrates in the Yangtze River Delta, Eastern China Chun-Yan Qin & Jin Zhou & Yong Cao & Yong Zhang & Robert M. Hughes & Bei-Xin Wang Received: 7 November 2013 /Accepted: 8 May 2014 # Springer International Publishing Switzerland 2014 Abstract Aquatic organisms’ tolerance to water pollu- tion is widely used to monitor and assess freshwater ecosystem health. Tolerance values (TVs) estimated based on statistical analyses of species-environment relationships are more objective than those assigned by expert opinion. Region-specific TVs are the basis for developing accurate bioassessment metrics particularly in developing countries, where both aquatic biota and their responses to human disturbances have been poorly documented. We used principal component analysis to derive a synthetic gradient for four stressor variables (total nitrogen, total phosphorus, dissolved oxygen, and % silt) based on 286 sampling sites in the Taihu Lake and Qiantang River basins (Yangtze River Delta), China. We used the scores of taxa on the first principal component (PC1), which explained 49.8 % of the variance, to esti- mate the tolerance values (TV r ) of 163 macroinverte- brates taxa that were collected from at least 20 sites, 81 of which were not included in the Hilsenhoff TV lists (TV h ) of 1987. All estimates were scaled into the range of 1–10 as in TV h . Of all the taxa with different TVs, 46.3 % of TV r were lower and 52.4 % were higher than TV h . TV r were significantly (p <0.01, Fig. 2), but weakly (r 2 = 0.34), correlated with TV h . Seven biotic metrics based on TV r were more strongly correlated with the main stressors and were more effective at discriminating refer- ences sites from impacted sites than those based on TV h . Our results highlight the importance of developing region-specific TVs for macroinvertebrate-based bioas- sessment and to facilitate assessment of streams in China, particularly in the Yangtze River Delta. Keywords Bioassessment . Biomonitoring . Streams . Yangtze River . Macroinvertebrate Introduction Bioassessment plays a key role in water resource and water quality management (Rosenberg and Resh 1993; Barbour et al. 1999 ; Birk and Hering 2006 ). Macroinvertebrate-based multimetric indices have been widely used for stream assessments (Rosenberg and Resh 1993; Karr and Chu 1999). Of these indices, biotic metrics based on the tolerance values (TVs) of taxa, such as those described by Armitage et al. (1983) and Hilsenhoff ( 1987), are among the most sensitive. Several macroinvertebrate TV lists have been applied beyond the region for which they were originally de- rived. For example, TVs derived for the USA and Environ Monit Assess DOI 10.1007/s10661-014-3826-2 C.<Y. Qin : J. Zhou : Y. Zhang : B.<X. Wang (*) Laboratory of Aquatic Insects and Stream Ecology, Department of Entomology, Nanjing Agricultural University, Nanjing 210095 Jiangsu, People’ s Republic of China e-mail: wangbeixin@njau.edu.cn Y. Cao Illinois Natural History Survey, Institute of Natural Resource Sustainability, University of Illinois at Urbana-Champaign, 1816 South Oak Street, Champaign, IL 61820, USA R. M. Hughes Amnis Opes Institute and Department of Fisheries and Wildlife, Oregon State University, 200 SW 35th Street, Corvallis, OR 97333, USA