MnDOT Puts Technology to Work on Invasive Species
By Ken Graeve, Minnesota Department of Transportation
Picture a vine growing at the edge of the woods, reaching out and wrapping around the nearest tree trunk, spiraling up like the stripe on a candy cane. Eventually the vine can strangle the tree it is climbing, and can grow large enough to topple full-sized trees or even bring down patches of forest.
Oriental Bittersweer growing on a no
w horizontal Birch tree.
Photo Credit: Tina Markeson, MnDOT
A Newly Destructive Plant
It may sound like something out of the Amazon rainforest, but this is Oriental Bittersweet, a non-native invasive species right here in Minnesota. This is the scene that greeted staff from the Minnesota Departments of Agriculture (MDA), Natural Resources (MNDNR), and Transportation (MnDOT) when they visited an Oriental Bittersweet infestation in Winona last winter. An additional infestation was reported in Red Wing this past spring, and is clear evidence of another emerging threat to Minnesota’s ecosystems. Reports from eastern states suggest that Oriental Bittersweet has great potential to cause havoc in Minnesota forests. It is likely to be more difficult to control than the invasive shrub Common Buckthorn.
MnDOT first noticed Oriental Bittersweet in Minnesota in the summer of 2010 in the Twin Cities metro area. These small infestations were quickly removed from the roadsides and treated with herbicides. But the infestation discovered in Red Wing is much larger, extending through the surrounding woodlands. MnDOT right-of-way includes several irregular parcels on the bluffs along Highway 58, but the amount of afflicted right-of-way was unknown.
Tackling Questions with GIS
A number of questions immediately emerged upon discovery of the infestation. Was it small enough for maintenance crews to handle or was it going to require contractors? Who were the neighboring property owners? Were they interested in doing some cooperative weed control? Unless they were also controlling Oriental Bittersweet on their property, it would be futile to try to eradicate it from public property. Where was the infestation the worst, with the largest bank of seeds in the soil waiting to re-sprout? Where were the edges of the population, where we might be able to contain it and prevent further spread? A simple weed problem gets a bit complicated when multiplied by dozens of acres, steep terrain and multiple property owners.
To understand the size of the infestation and to develop a more effective control strategy, MnDOT turned to technology. The first step was to map the extent of the infestation along roadsides using GPS. Layering the GPS-collected data together with Farm Service Agency air photos illustrated where the infestation was heaviest and where the leading edges were. Next, digital parcel data provided by Alan Laumeyer at Goodhue County gave a quick approximation of right-of-way lines and highlighted the potential movement of Oriental bittersweet between infested roadsides and adjacent forest cover. This increased our understanding of the scale of the problem, which will guide control efforts.
A next step may be to use the parcel data to begin a dialogue with neighboring landowners. Identifying which neighbors will be proactive in controlling Oriental Bittersweet will help prioritize the application of limited control resources. In a case like this, MnDOT may explore opportunities with interested landowners to collaborate on organizing volunteer help or hiring contractors.
GIS technology has allowed MnDOT to take a daunting problem and put it into perspective. Understanding the context of the Oriental Bittersweet infestation is crucial to being able to strategize where control efforts will be the most cost-effective and where partnership opportunities exist. MnDOT is increasingly using GIS technology to guide more efficient use of resources in vegetation management. Hopefully efforts such as these can help prevent scenes of tree-toppling vines from becoming commonplace in Minnesota.
For further information please contact Ken Graeve at MnDOT’s Office of Environmental Stewardship at firstname.lastname@example.org