Although F. candida was most abundant in the experiment, E. crypticus had the largest impact on the community response, probably because besides being abundant it was also more sensitive to changes in both temperature and Cu as confirmed in single species testing for temperature by Briones and for Cu by e.g. (Amorim et al., 2005; Maraldo et al., 2006; Scott-Fordsmand et al., 2008). This temperature dependency was in agreement with previous studies where Enchytraeid population size has been shown to depend on temperature and water content (Abrahams, 1971; Springet et al., 1970). E.crypticus was more affected by Cu at higher than at low temperatures, which is in line with studies by Khan et al. (2007) who showed that the CuLT50(lethal time) of Lumbricus terrestris was lower with increasing temperatures (from 10 to 22◦C).