Implications of sampling frequency for detecting temporal patterns during environmental effects monitoring

摘要

To estimate the effects of sampling frequency on detecting temporal patterns during environmental effects monitoring, we used multivariate analyses and data subsampling to investigate long-term(spanning 20 years)patterns in ben- thic invertebrate community structure downriver of a large pulp mill in south- ern British Columbia. Patterns in invertebrate abundance sampled yearly were related to long-term patterns in several physicochemical variables measured in the river using multidimensional scaling ordination. The only available physic- ochemical variables that were significantly correlated with invertebrate commu- nity structure over the 20-year period were the mill outputs of total phosphorus and suspended solids, and these were associated with increased abundances of five families of mayflies, stoneflies and caddisflies.