Historical records from Lake Winnebago show minimal macrophyte growth; however, reports from recent years claim that macrophyte growth in some areas of the lake has reached nuisance levels. This study aimed to investigate the species of macrophytes present and their abundances in four near-shore locations, as well as measurements of multiple water quality conditions. Rake sampling was used to identify species and quantify their abundances and distributions. In addition, data were collected on light penetration, Secchi depths, and suspended algae chlorophyll concentrations at each site. These data from shallow near-shore sites reveal trends in changing water clarity and light penetration when compared to past and current data from deep-water sites. Macrophytes find habitats with increased light penetration advantageous for growth and competition; this suggests that the macrophyte species may have flourished recently due to comparatively better water clarity. In addition to two dominant native species, Coontail and Wild Celery, we also observed two invasive species (Eurasian Watermilfoil and Curly-leaf Pondweed). Eurasian Watermilfoil was found in high abundances in three out of the four sampling sites. Possible causes of increased water clarity, in particular the invasion of zebra mussels, will also be discussed. This study provides baseline data on the current macrophyte communities and will facilitate further exploration of recent changes in growth conditions that have resulted in such high abundances of macrophytes.
Level of Honors
Bart De Stasio
Kessenich, Mackenzie, "Macrophyte Communities of Lake Winnebago: Baseline Study of Species Composition with Abundances and Water Quality Conditions" (2012). Lawrence University Honors Projects. Paper 9.