Consequences of Human Lakeshore Development on Emergent and Floating-Leaf Vegetation Abundance

Abstract

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 clear-water 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.