Southeastern Wisconsin Invasive Species Consortium, Inc.


Shop Local

Roadside Survey: what we learned in 2011 and revving up for 2012!

Nearly 150 volunteers collaborated to map four non-native invasive plant species in eight southeastern Wisconsin counties last summer, and the data keeps pouring in.

Eight County Leaders were selected to recruit mapping teams of two for each township in the SEWISC region. Team members received training, data sheets and maps which were provided by County GIS Departments and the University of Wisconsin-Milwaukee American Geographic Society Library. The volunteers collectively surveyed more than 11,000 miles of roadways, devoting over 1,200 hours to the project.

SEWISC's 2011 Invasive Plant Roadside Survey covered all roads with lane markings within Sheboygan, Washington, Ozaukee, Waukesha, Milwaukee, Walworth, Racine and Kenosha Counties. Township Mapping Teams also performed surveys focusing on areas in or near primary and secondary environmental corridors and isolated natural resource areas.

Giant reed grass (Phragmites australis) was mapped in 799 locations, common and cut-leaved teasel (Dipsacus sylvestris and D. laciniatus) were mapped in 1,125 locations and Japanese knotweed (Polygonum cuspidatum) was mapped in 133 locations.

These species were selected because they are, 1) common, but still in early stages of infestation in our region, 2) not uniformly spread throughout the region, 3) spreading along roadways, and 4) easy to recognize throughout the year. Although these species have limited distribution in southeastern Wisconsin, each has the potential to spread rapidly along roadsides and rights-of-way. With training, these species were safely identified and mapped by teams of two or more travelling on foot, bicycle or by vehicle.

A very brief summary of the survey instructions is as follows:

invasive species population pie chart• Participants completed survey protocol training and submitted a liability release.

• Survey teams of at least two were required for each township. One team member was charged with safely driving the car while the passenger navigated and recorded populations on the map and data form.

• All populations visible from the road were recorded. A special effort to survey environmental corridors was made.

• Populations were recorded with a dot on the map and labeled with a number. Species and population size codes corresponding to that number were recorded on the data sheet. Populations which were located within the right-of-way were noted.

• All roads surveyed were marked with a highlighter on the map. Maps and data sheets were submitted to SEWISC and the survey data was entered into a digital geodatabase.

The majority of the mapped populations were relatively small, and teasel populations were, on average, smaller than either Japanese knotweed or Phragmites.

It was clear from the mapped populations of the species that they were not uniformly distributed throughout the eight-county region.

survey map


invasive species population pie charts

invasive population mappedJapanese knotweed was the least common of the species, but had a concentration of populations in north-central Sheboygan County in the northern part of our region.

The teasels were very common, had a very high concentration in southern Ozaukee County, and were nearly absent from the northern part of the eight-county area.

Timely eradication of small populations of teasel in the northern part of the region can still prevent teasels from becoming a major problem there.

Phragmites was widely scattered, but tended to be found in concentrations where it must have first established, and from which it is spreading, including the I-94 highway corridor south of Milwaukee.

Data from this survey will increase the effectiveness of SEWISC's Invasive Species mapping and Management Workshops.

It will also provide the information park and right-of-way managers will need for planning efforts to control the establishment and spread of these species.

This project served to increase public awareness of the threats posed by invasive species, and to provide valuable information to guide future funding of control efforts.

Feedback from the volunteers also indicated that the survey was just plain fun!

Although an additional goal of the survey was to develop a network of dedicated volunteers needed to build a strong and sustainable invasive control program, an unexpected outcome was the subsequent formation of an "adopt-a-township" program.

Township Team Members continue to submit new (or missed) populations in their assigned mapping areas as they go about their daily business. All four of the 2011 target survey species can be easily identified throughout the winter, making them difficult for a seasoned mapper to ignore.

Using the GIS database we can produce detailed maps of population locations for any specific area of interest.

As surveyors and others transition from mapping to controlling populations, we will be able to provide them with detailed maps of the species that includes some information about population size.

That information will enable them to first target small and isolated populations to prevent further spread and quarantine the species to where it is already well established.

The data submitted by our mapping teams are entered into a Geographic Information System (GIS) database, which was developed by two University of Milwaukee-Wisconsin student interns majoring in Geography.

Initial inventory data were shared with two University of Milwaukee-Wisconsin students (one graduate and one undergraduate) for special geospatial class projects during the fall 2011 semester. Funding by a USEPA/US Forest Service Great Lakes Restoration Initiative Assistance Agreement. allowed SEWISC to hire Marc White, White Ecological, as Coordinator to help design and manage the project.

The GIS database is continually updated as new populations are reported and the information will soon be shared with government agencies. The SEWISC Board of Directors will soon choose one new species to map in 2012, so the teams will hit the road again this summer.

If you'd like to learn more about this project or if you are interested in volunteering, send an email to Please include your name, address and a daytime phone number.

invasive species map