Drowning in a Sea of Invasive Species When Vegetation Planning
Gina Levesque
5 Smooth Stones Restoration
Hadley, MA
Brad Fairly
Five Smooth Stones Restoration
Livermore, CO,
David Bidelspach
Five Smooth Stones Restoration
Livermore, CO
An invasive species is defined as one that outcompetes other species for space in an ecosystem often becoming dominant (most frequently encountered). While many native plant species can become invasive given the proper conditions, our focus is directed keenly on those that are non-native. Non-native invasive plants have unique advantages that natives do not. They can be particularly problematic in riparian habitats due to seed dispersal via flowing water. Their elimination at restoration sites can be imperative due to establishment of native vegetation being the desired outcome. Occasionally a project site can become so over-ran with aggressive non-native invasives that the task of elimination seems overwhelming.
We encountered such a site in Alabama where Chinese Tallow Tree (Triadica sebifera) and Chinese privet (Ligustrum sinense) were by far the dominant vegetation on site. Our choices were to either work with them as part of our vegetation plan or design a plan that would eliminate those in the immediate area and give native plantings an opportunity to establish. Governmental agencies involved with the project made that decision for us by mandating that they be eliminated on the project site. Growth patterns of these species made their elimination particularly challenging.
Our plan to deal with these plants evolved into a three-pronged approach. Prong one was girdling trees. Girdling was decided upon as an efficient method of dealing with mature members of these two species. The second prong was planting larger and more mature container plants that would hopefully begin rooting and outcompeting invasives immediately. Last, but not least, was periodic monitoring for sprouts of non-natives and spraying to prevent their maturation. While this approach did not completely eliminate either the Chinese Tallow Tree or Chinese Privet from the area it will hopefully provide native species an opportunity to establish at the project site.
About Gina Levesque
Gina Crowder Levesque has worked with endangered species and habitats as a professional biologist for 35+ years. She holds degrees focused on restoration ecology/conservation biology from Purdue University and the University of Arkansas, with additional graduate work from Oklahoma State University. She is currently a riparian ecologist with Five Smooth Stones Restoration.
About David Bidelspach, PE
Mr. Bidelspach is a nationally recognized river restoration specialist with a broad range of experience restoring damaged ecosystems. Mr. Bidelspach’s academic and research background includes five years with the Stream Restoration Program at North Carolina State University (NCSU), where he provided assessment, design, and construction oversight services on many restoration projects and taught courses related to river assessment, restoration design, and construction administration. He also worked for nine years as the river restoration technical leader for a large engineering consulting firm. He has completed more than 100 river restoration/stabilization projects in 29 states, 6 Canadian Provinces/Territories, and Costa Rica. Mr. Bidelspach was mentored at NCSU by Dr. Greg Jennings and at Wildland Hydrology by Dr. Dave Rosgen. He specializes in using Natural Channel Design (NCD) coupled with a traditional engineering framework for river restoration designs to achieve optimal project goals and objectives. The MCDA framework has been utilized and taught by Mr. Bidelspach and incorporates NCD, three-dimensional (3-D) stream design, limiting factors analysis for fisheries, flood risk, geomorphic assessment, river resiliency, cost analysis, changing points of diversion, and stakeholder involvement into a design optimization scheme.