Students Study Invasive Bush Honeysuckle

The Shew lab at Lewis and Clark Community College’s National Great Rivers Research and Education Center (NGRREC) continues to engage undergraduates in research projects involving an ongoing honeysuckle project, which is a major theme in the lab.

Amur honeysuckle (Lonicera maackii), commonly referred to as bush honeysuckle, is an invasive shrub species that has degraded many woodlands and forests of the Midwest and reduces habitat quality for many kinds of wildlife. It outcompetes many native wildlife flowers and shrubs that would normally inhabit the forest floor, by growing early in the growing season before many of the native plant species.

Addis Moore and Jacob Decker, both graduates of Lewis and Clark Community College and now continuing their education at Southern Illinois University Edwardsville, conducted separate projects on honeysuckle. Both projects have the potential to help land managers, volunteer groups and agencies manage and monitor honeysuckle more efficiently.

Dr. Justin Shew, who leads the lab, stated, “Addis Moore and Jacob Decker have done a wonderful job making these projects their own and I am truly pleased to see how they have grown professionally over the course of their multiple NGRREC internships.” Shew hopes their projects can improve management decisions surrounding this common invasive. Hear Moore and Decker talk about their projects in their own words in a recent interview.

Honeysuckle Eradication and Restoration Through Chemical Injection and Seeding

Addis Moore’s study reintroduces the use of the EZ-Ject lance™, a rarely used technology that can simplify the eradication process as users inject a dry herbicide capsule into the honeysuckle. This technique eliminates the need for extensive training, reduces physical exertion, eliminates chemical exposure to users, and eliminates the possibility of overspraying herbicide on to non-target native species. He is also seeding native plants following honeysuckle injections to study how native species may prevent the establishment of other invasive species such as garlic mustard (Alliaria petiolata).

To assess the effectiveness of the EZ-Ject™ system on killing honeysuckle with subsequent woodland seeding, Moore conducted a study at Lewis and Clark Community College’s campus woods, a common restoration area and field-learning space utilized by the school’s Restoration Ecology Program. He set up 36 study plots within heavily infested honeysuckle areas. These plots were randomly assigned one of four treatments: winter injection, winter injection and fall seeding (black-eyed Susan – Rudbeckia hirta; northern spicebush – Lindera benzoin; inland wood oats – Chasmanthium latifolium), fall seeding, and a control group with no injection or seeding. He quantified honeysuckle before and after treatments and conducted fine-scale surveys, with plant identification support from iNaturalist, to assess plant species richness and diversity.

So far EZ-Ject winter injections appear to be successful at significantly reducing foliar honeysuckle cover and Moore expects a positive correlation between seedling survival and reduced honeysuckle cover from injection.

Moore has been an intern under Dr. Justin Shew for over a year, and said this about his experience, “Coming into my internships at NGRREC, I had little knowledge in environmental science and wildlife ecology. Dr. Shew has taught me so much and has helped introduce me to new experiences in the field of science. This research project has taken me over a year and I look forward to our hard work paying off. Most of all, I am excited to work on trying to publish our research.”

Honeysuckle Monitoring Through Satellite Imagery

Jacob Decker’s study focused on using Google Earth Engine, a free cloud-based analysis platform utilizing remote sensing satellite imagery and geospatial datasets, to quantify honeysuckle coverage in different areas. Quantifying honeysuckle this way could significantly reduce the time and people power compared to using traditional boots-on-the-ground field monitoring techniques.

To help validate this technique, Decker used field-collected honeysuckle coverage data from multiple locations across southwestern Illinois relating to an earlier game camera study he set up for a previous internship. Using Google Earth Engine, he used satellite images of the study areas from the same time period to produce a plant phenology-based vegetation index by taking advantage of honeysuckle’s extended green leaf period in the late fall. Decker discovered a strong correlation between the honeysuckle coverage he collected in the field and those calculated using satellite imagery.

Finding the perfect satellite image (with no cloud cover) to help quantify honeysuckle can be challenging. The time frame was verified by camera-trap photos from Lewis and Clark Community College, as shown in the photo below.

Decker has interned under Dr. Justin Shew since 2021 and hopes to continue this project further, and possibly on other areas that are in desperate need of honeysuckle eradication and management.

He had this to say about his experience, “I have interned and worked with NGRREC for most of my undergraduate career and I can be nothing but grateful with the knowledge and experience I have gained in doing so. From going out in the field doing restoration management and collecting quantifiable data of invasive bush honeysuckle, to now being able to independently utilize new technology to quantify the presence of the invasive has been rewarding. This project’s use of remote sensing and geospatial operations will without a doubt be beneficial to my development of my ecological career.”

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Addis Moore attends Southern Illinois University Edwardsville and will complete his bachelor’s in environmental management in Spring of 2024. Addis is a graduate of Lewis and Clark Community College with an associate’s degree in science. His future plans are to graduate SIUE and start a career in the natural resources field or other environmental field.

Jacob Decker is going into his last year of undergraduate studies at Southern Illinois University of Edwardsville, Illinois. He is a major in biological sciences, with a concentration in ecology, evolution, and conservation, along with a minor in geographical information systems. After graduation he plans on continuing his ecological career development within the field of terrestrial forest ecology in relation to invasive species management.

Justin J. Shew manages the National Great Rivers Research and Education Center’s Conservation Programs including the Land Conservation Specialist Program and Habitat Strike Team and is currently a member of The Illinois Chapter of the Wildlife Society. His research focuses on wildlife associations to multi-scale habitat, with emphasis on conducting research that may inform wildlife management decisions. An example of his work can be found here.