Loyola University Chicago

Department of Biology

Kelsey Berke Project Description

Title: Nutrient Removal and Vegetation Recovery through Successive Harvesting of the Invasive Hybrid Cattail (Typha x glauca) in Great Lakes Coastal Wetlands


Nutrient enrichment poses a threat to water quality and ecosystem biodiversity and function in the Laurentian Great Lakes. Excess nutrient levels have led to invasive hybrid cattail (Typha × glauca) dominance in many Great Lakes coastal wetlands, resulting in shifts in plant community structure and decreased native plant diversity. T. × glauca’s ability to alter wetland structure and function has made it a target invasive species with respect to Great Lakes coastal wetland restoration. Harvesting (cutting and removing the biomass) has been shown to provide an effective invasive species management approach with multiple combined benefits through the physical removal of nutrients sequestered in the biomass, reducing invasive plant dominance, and recovering native plant diversity. This study investigates the effect of mechanical harvesting invasive T. × glauca biomass on nutrient removal and plant diversity recovery in Great Lakes coastal wetlands. Large-scale T. × glauca experimental harvest treatments at Cheboygan Marsh which include control, single harvest, double harvest, crush, and two-year below-water harvest treatments were used to quantify the amount of nutrients removed with each treatment and assess the post-treatment effects on nutrient conditions and plant community responses. Harvesting T. × glauca had greater impact on phosphorus removal than nitrogen, but a longer timeframe and further harvesting efforts would be necessary to significantly detect changes in nutrient conditions and plant community composition. However, each treatment likely had an impact on T. × glauca’s regrowth response post-treatment. By understanding the likely response to T. × glauca harvesting, I was able to outline implications for management on how to best achieve the desired goals of nutrient removal and/or increased plant diversity in degraded wetlands, ultimately improving the functioning of these coastal systems.



I would like to thank my thesis advisor, Dr. Nancy Tuchman, Director of the Institute of Environmental Sustainability (IES) who welcomed me into “Team Typha” and introduced me to Great Lakes coastal wetland research. I am beyond grateful for your support and encouragement and for finding me the means to pursue my graduate studies. She allowed me to use my own ideas for this project, but guided me in the right direction when necessary. I would also like to acknowledge my remarkable team members – Shane Lishawa, Brendan Carson, and Andrew Monks. Your expertise, passion, and mentorship throughout the years made this an unforgettable experience and has contributed to my new love of Great Lakes coastal wetland research.

I would like to extend my gratitude to Dr. Martin Berg of the Biology Department, Dr. Reuben Keller, and Shane Lishawa of IES for your time and serving as my committee members. Your guidance and suggestions throughout the course of my study have contributed tremendously to my scientific knowledge and understanding. I would also like to thank Loyola University Chicago’s Biology Department for their mentorship and support throughout my program. I would especially like to acknowledge Zhenwei Zhu of IES for his training and assistance with the nutrient analyses for this project. And to the faculty and staff of the Biology Department and IES, thank you for your assistance throughout my time at Loyola.

Other Team Typha members I owe a huge thank you to include Dr. Brian Ohsowski, Dr. Beth Lawrence, Dr. Dennis Albert, Gabrielle Habeeb, Corinn Rutkoski, Daphne Sugino, Sean Ooi, Olivia Johnson, Kate Wellons, Matt Unitis, Moriah Young, Samantha Keyport, Matthew Conners, Sarah Ostwald, and Logan Pawlowski. Your patience, positive attitudes, and countless hours in the field and lab have not gone unnoticed. I have never spent so much time laughing and singing in a wetland. Thank you, Team, for the unforgettable memories.

This project would not have been possible without funding from the Environmental Protection Agency’s Great Lakes Restoration Initiative (Grant No. EPAR5-GL00E01293), Loyola University Chicago’s IES for the financial means to complete my graduate studies, and the University of Michigan Biological Station for project funding and the extraordinary scientists, researchers, teachers, and students who surrounded me every field season. It was an honor to have shared valuable knowledge with you over the past few years.

Finally, special recognition goes out to my parents, Eddie, family, and friends for their endless love, support, and willingness to let me explore new opportunities. You have provided endless encouragement and helped me stay focused.



Kelsey’s completed her B.S. in Environmental Science at the University of Manitoba. While completing her undergraduate studies, she conducted aquatic sampling concerning deteriorating water quality aboard the MV Namao on Lake Winnipeg. Before moving to Chicago from Kola, Manitoba, she was involved in the upstream oil and gas industry conducting environmental site reclamation and restoration projects. Her M.S. research in Dr. Nancy Tuchman’s Lab at Loyola University Chicago is a partial continuation of her research with the Environmental Protection Agency’s Great Lakes Restoration Initiative (GLRI) directed towards restoring coastal wetlands within the Great Lakes watershed.


Committee Members

Dr. Nancy Tuchman

Dr. Martin Berg

Dr. Reuben Kelly

Shane Lishawa, BS, MS