Cultural impacts on macrophytes in the Yahara lakes since the late 1800s

Abstract

Vegetation changes in the Yahara lakes around Madison, Wisconsin, USA, are evaluated using historical data. Present vegetation is less diverse and less extensive, produces less biomass and is composed of more disturbance tolerant species than it was 80–100 years ago. Many changes are related to human impacts that began about 150 years ago which directly altered plant habitat, decreased water clarity, were toxic to plants, removed plant biomass or reproductive structures, or resulted from exotic invaders. The impacts are interrelated and overlap in time and space so change did not occur from simple cause and effect relationships. However, cumulative effects of the impacts are very evident. Management recommendations are made that are applicable to North American lakes with a similar history.