Consequences Of Human Lakeshore Development On Emergent And Floating-Leaf Vegetation Abundance

Vegetation abundance along undeveloped and developed shorelines of Minnesota lakes was compared to test the hypothesis that development has not altered the abundance of emergent and floating-leaf vegetation. Aerial photographs of clear-water lakes dominated by centrarchids and walleyes Stizostedion vitreum were analyzed for vegetation. Vegetative coverage was estimated in 12 randomly selected 935-m2 digitized photograph plots for both developed and undeveloped shorelines of 44 lakes representing a gradient of development. Vegetative cover in littoral areas adjacent to developed shores was less abundant than along undeveloped shorelines. On average, there was a 66% reduction in vegetation coverage with development. The estimated loss of emergent and floating-leaf coverage from human development for all Minnesota's clearwater centrarchid–walleye lakes was 20–28%. Significant correlations were detected between occurrence of emergent and floating-leaf plant species and relative biomass and mean size of northern pike Esox lucius, bluegill Lepomis macrochirus, and pumpkinseed Lepomis gibbosus (Spearman's rank correlation, P , 0.05). Current shoreline regulatory policies and landowner education programs may need to be changed to address the cumulative impacts to North American lakes.