The influence of golf course operation and construction on benthic algal communities in headwater streams on the Precambrian Shield was investigated using a reference condition approach. Streams were sampled for water chemistry and epilithic benthic algae on operational golf courses, on courses under construction, and from nearby minimally impacted reference locations. Epilithic diatom community structure was different in reference streams than in operational golf course streams, the latter indicating nutrient enrichment, higher pH, and disturbance. Full counts of diatoms and soft algae revealed that there was a lower proportion of diatoms relative to other algal groups, cyanobacteria in particular, in operational golf course streams compared with samples from reference locations. Dominance by a single taxon was also significantly higher in operational golf course streams. Although differences relative to the reference streams were less marked for the streams on courses under construction, full counts of diatoms and soft algae provided evidence of disturbance and nutrient enrichment. In particular, high proportions of filamentous green algae were recorded. Overall, our results indicate that golf course land management on the Shield is associated with significant differences in the abundance of certain benthic algal taxa in headwater streams.Key words: diatoms, periphyton, biomonitoring, golf courses, canonical correspondence analysis (CCA), Precambrian Shield.
Climate-induced changes in bottom-up and top-down processes independently alter a marine ecosystem