US Army Corps of Engineers
Buffalo District

USACE, ERDC complete Walnut Beach project, new stakeholder needed to continue efforts

U.S. Army Corps of Engineers, Buffalo District
Published Nov. 22, 2019

BUFFALO, NY -- The Walnut Beach Aquatic and Riparian Invasive Plant Species Control Demonstration Project was completed in September at Walnut Beach on Lake Erie in Ashtabula, Ohio. Now, the U.S. Army Corps of Engineers Buffalo District is hoping for a new regional stakeholder to continue the habitat restoration work that began in 2014.

The Corps of Engineers along with the U.S. Army Engineer Research and Development Center’s Aquatic Plant Control Research Program, Ecology and Environment, Inc., and Davey Resource Group designed the 5-year project.

“The goal of the project was to test new and improved methods for controlling invasive plants in order to validate applicability to other Great Lakes restoration projects,” said Tim Noon, project manager for the Buffalo District. “In doing so, we also controlled invasives on site at Walnut Beach and protected tributary resources, which aligns with the goals of the Great Lakes Restoration Initiative.”

Testing involved a combination of mechanical and three chemical treatments across three test areas on the 43-acre site. The treatments targeted the Common reed, European black alder, and Mugwort.

Mechanical control treatments included mowing and hand-cutting at all testing areas during years one through three. The project site had a combined 98 tons of invasive species debris removed during the mechanical treatment years with 92 tons being removed the first year.

“Mechanical cutting wasn’t done the fourth and fifth year because of Lake Erie’s high water levels,” said Noon. “The increase of water during the growing season inhibited the growth of Phragmites.”

Chemical treatments were applied every year from 2014 through 2018 using three variable herbicide applications.

The combination of mechanical and chemical treatments proved to be successful. The density of the Common reed went from approximately 16.3 acres having more than 60 percent coverage during the first year to .2 acres having 60 percent coverage by the fifth year.

“In looking at treatment effectiveness, we are pleased not just with the results, but also with the ability to share this information to other projects moving forward,” said Noon.

The Mature European black alder was practically eliminated from the site. Even though seedlings and stump-sprout regeneration did occur in years two through five, there was still a reduction in most years. Mugwort was eliminated in year 1, but reappeared in low densities in other areas of the project during years two through five.

“The success of Walnut Beach stands on the foundation of this restoration effort, but due to the highly invasive nature of plants like Common reed (Phragmites), long term success will not be possible without an engaged stakeholder to carry on stewardship,” Noon emphasized. “We also know that rare plants such as the native bur reed have potential to increase at Walnut Beach if we can engage a stakeholder to continue stewardship.”

In addition to treating invasive plants, surveys for birds and rare plants were conducted prior to treatments to identify potential for effects on birds and to avoid adverse impacts to birds and rare plants during site treatments.

“The rare type of coastal wetland habitat restored at Walnut Beach is critical for certain bird species and ultimately contributes to a functioning and healthy ecosystem,” Noon said. “Without these sustained critical habitats, the sustainability of certain bird populations are at risk.”

Three bird surveys were also conducted during year five’s spring migration, along with two surveys during the breeding season, and three during the fall migration. Overall, approximately 180 different bird species were observed over the five years. The amount of birds using the site during the spring and fall migration increased from years one through five.

Restoration planting started in year three and continued throughout the duration of the project. Trees, shrubs, fascines, live stake and bare roots, and herbaceous plugs were planted inside a constructed exclosure, as well as outside. The exclosure was constructed to protect the plants against herbivory.

“The plants in the exclosure had a higher survival rate compared to the plants that were not protected against herbivory,” said Noon. “That being said, flooding and wave action from the fluctuating water levels ended up being a bigger threat to the plants survival than heribvory.”

The restoration plantings along with chemical and mechanical treatments of the invasive plants paid off in the end. More than 240 plant species have been recorded at the site, and half of those species were not recorded in year one.

The organizations used AIS spatial mapping, vegetation monitoring transects, vegetation meander surveying, and images taken from fixed-point photo-monitoring stations to assess the progress and success of the treatments, evaluate responses of vegetation and bird communities, and direct efforts for future project years.

With the project in the final year, the two organizations have been busy constructing a “playbook” for the future regional stakeholders. The playbook will include the technical and monitoring data from the project along with lessons learned for managing the restoration of the site into the future.

“The successful restoration activities we’ve completed are Act I in the story of long-term success,” said Noon. “The stage is set for a successful and long-term Act II if a stakeholder can be identified to work with the landowners in carrying out future stewardship.”