Moose Grazing Decreases Aquatic Plant Diversity

ABSTRACT We excluded moose from ten 2×2 meter areas of Feldtmann Lake on Isle Royale, Michigan, USA, in the beginning of the summer and measured total biomass, plant species richness, and plant species diversity in the three exclosures that were still intact at the end of the summer. Plant biomass, species richness, and species diversity all were lower in grazed areas compared to non-grazed exclosures. Thus, herbivory by moose has the potential to significantly affect both standing biomass and species composition of macrophytes in certain aquatic systems.