Abstract Herbivores have strong impacts on marine and terrestrial plant communities, but their impact is less well studied in benthic freshwater systems. For example, North American beavers (Castor canadensis) eat both woody and non-woody plants and focus almost exclusively on the latter in summer months, yet their impacts on non-woody plants are generally attributed to ecosystem engineering rather than herbivory. Here, we excluded beavers from areas of two beaver wetlands for over 2 years and demonstrated that beaver herbivory reduced aquatic plant biomass by 60%, plant litter by 75%, and dramatically shifted plant species composition. The perennial forb lizard’s tail (Saururus cernuus) comprised less than 5 % of plant biomass in areas open to beaver grazing but greater than 50 % of plant biomass in beaver exclusions. This shift was likely due to direct herbivory, as beavers preferentially consumed lizard’s tail over other plants in a Weld feeding assay. Beaver herbivory also reduced the Communicated by John Keeley
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.