Management of Half Moon Lake, Wisconsin, for Improved Native Submersed Macrophyte Growth

摘要

Direct biomass control programs (i.e., herbicide, biocontrol, mechanical) that target non-native macrophyte species may not always produce the desired goal of restoring native macrophyte community dominance in shallow aquatic systems. Native reestablishment is often complicated by eutrophic conditions, enhanced nutrient recycling, and frequent nuisance algal blooms that result in poor light penetration and limited colonizable macrophyte habitat. Half Moon Lake is a eutrophic, urban oxbow lake exhibiting high densities of the non-native Potamogeton crispus in early summer followed by high chlorophyll, total phosphorus, and light attenuation. These patterns are, unfortunately, typical for many lakes located in agricultural regions of the upper midwestern United States. Although Half Moon Lake is shallow and supports a native submersed macrophyte community, poor underwater light conditions limit their growth and propagation. The purpose of this research was to examine algal, nutrient, light attenuation characteristics, and underwater light habitat for submersed macrophyte growth and to project changes in these variables and improvement in light penetration as a result of managing the lake to control internal phosphorus loads.