An Assessment of Aquatic Invasive Plants in the Illinois River: water hyacinth surveillance, mapping, persistence, and potential seed dispersal Annual Progress Report Period 1 May 2014 – 30 April 2015

Objectives:1.Documenting the current distribution of mature water hyacinth plants in the Illinois River/CAWS corridor and comparing with historical records and sightings. 2.Comparing seed densities and frequencies in seed banks and dispersal in areas where dense colonies of water hyacinth occur and non-occupied areas (i.e., control) in the main Illinois River channel and associated backwaters. 3.Concurrently assessing the temporal and spatial overlap between recurring stands of water hyacinth and the presence of their seeds in their underlying seed bank4.Developing and evaluating a rapid aerial survey technique to detect and map locations of water hyacinth along the Illinois River Water hyacinth (Eichhornia crassipes) is becoming a reoccurring problem in the Illinois River –Chicago Areas Waterway System(CAWS), but the current extent and potential for future intensification are largely unknown in this system. Regular reoccurrence of water hyacinth represents a significant threat to the recreation, fisheries, and wildlife resources, economy, and ecological processes of both the Great Lakes and the Illinois & Mississippi River systems. We conducted aerial surveillance flights and boat surveys of floating-leaved vegetation with visual signatures of water hyacinth from Hennepin, IL to Joliet, IL along the Illinois River twiceduring the summerand fall 2014. We collected sediment cores in random sitesthroughout the Dresden and Starved Rock reaches, and at water hyacinth bed locations. We collected and assessed diets of 26 Common Carp (Cyprinus carpio) to determine evidence of water hyacinth seed presence. We discovered a total of 14water hyacinth beds in 2014. We located fivebedsof water hyacinth while conducting aerial surveillance, and an additional ninewater hyacinth beds via ground surveillanceyielding a 35.7% detection rate of water hyacinth beds. We found water hyacinth seed densities were greatest beneath water hyacinth beds and least in random samples. We determined that frequency of water hyacinth seed (whole or partial) in common carp diets was 30.8% of the total carp assessedwhile mean seed density was 1.7seeds/carp. We determined that although water hyacinth seeds are present in the seed bank and within dispersal vectors (i.e., common carp), water hyacinth in Illinois likely relies on annual reintroductionas seed germination rates were extremely low.