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Loyola University Chicago

Department of Biology

Abigail Jacobs Thesis Defense: Project Description

Title: History of Freshwater Invasions in Illinois: Learning From the Past to Inform the Future


Increasing globalization has caused rates of worldwide species invasions to increase at an accelerating rate over the last century,with freshwater ecosystems being particularly highly impacted. Illinois straddles the divide between the Laurentian Great Lakes and Mississippi drainages. Many non-native aquatic species have breached this divide by traveling through Illinois, and the goal of preventing future species movements is an important regional and continental priority. We assembled a comprehensive database of known occurrences of aquatic non-native species in Illinois inland waters (n=99). We determined their vector, location, and stage in the invasion sequence (introduction, establishment, and ecological impacts).

The arrival of non-native species has increased at an accelerating rate since 1873, and the number of established species has a nearly significant increase in establishment rate over time. The Great Lakes Basin has been the main source of established aquatic non-native species into Illinois. Established species that are not native to North America (n=43) have been delivered to the continent historically through deliberate releases (e.g., fish stocking), and unintentional release (e.g., solid ballast of ships). Over the last two and a half decades unintentional release (e.g. shipping)  has been dominant. Sixty of the 99 introduced species have established reproducing populations. Eighteen established species were assessed by experts as having high or very high ecological impacts. Assessing ecological impacts by surveying trained ecologists that have experience with these species in the field is a novel type of impact assessment and is a quick way to assess impacts of numerous species.

Spatially, established aquatic non-native species are more likely to be recorded, and first recorded, along the invasion corridor in Illinois (counties that contain the waterways that make up the aquatic link between the Great Lakes and Mississippi River basins). Established species are spreading into and through the invasion corridor faster than they can be transported via recreational boating activities. Ten established aquatic non-native species are recorded in more than 50% of Illinois counties while six established species are only found in one county.

We recommend a multi-vector management and policy approach, increasing early detection efforts along the invasion corridor, broad sampling of counties with low number of records, and increasing efforts to control and slow the spread of established aquatic non-native species in Illinois that are causing the highest ecological impacts. Because Illinois acts as a conduit of aquatic invasive species between the Great Lakes and Mississippi River Basins, it is a key player in management across North America. Only with cooperation at regional, national, and international scales, can we properly address the increasing introduction, establishment, spread, and potential impacts of aquatic non-native species.



A grant from the Illinois Department of Natural Resources to Dr. Reuben Keller supported this thesis.  I would like to thank my advisor Dr. Reuben Keller and my committee members Dr. Martin Berg and Dr. Timothy Hoellein for all of their time spent advising me and their comments that helped me conduct and improve this research. I would like to thank David Treering for his help with ArcGIS. I'd also like to thank Keller lab members Ellen Cole and Kevin Scheiwiller for their help in various parts of this thesis. And finally, I couldn't complete this research without the willingness of institutions and data contributors to share their records and to complete my ecological impacts survey, so thank you for your knowledge and data.



Abigail Jacobs was born and raised in Ashtabula, Ohio. She graduated from Lakeside High School in 2006. She earned a Bachelor of Science in Marine Science from the University of Maine in 2010. After completing an aquarium internship and working as a research technician, she started the Master's in Science Biology program in August 2012.


Committee Members 

Dr. Reuben Keller (Thesis Director)

Dr. Martin Berg

Dr. Timothy Hoellein





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