Effects of flow regulation on bryophytes in north Swedish rivers Original Research Article

We sampled bryophytes in 52 rapids in regulated and unregulated north Swedish rivers to quantify effects of flow regulation on taxonomic richness and abundance of bryophytes. Predictive models based on the conditions at unregulated sites were used to predict richness and abundance at impacted sites and the residuals were used as a measure of the effect of regulation. Taxonomic richness was 22% lower than predicted at sites with reduced flow and 26% at sites with regulated but unreduced flow. The overall abundance of bryophytes was not significantly different from predicted. However, an analysis of the five most abundant species showed that the abundances of two species, Fontinalis antipyretica and F. dalecarlica, was lower than predicted at sites with reduced flow, while the abundance of Blindia acuta and Schistidium agassizii was higher than predicted at sites with regulated but unreduced flow.