IPAW and The Great Lakes Indian

Fish and Wildlife Commission

Collaborate to Conduct an Invasive Plant Survey

The Invasive Plant Association of Wisconsin (IPAW) and The Great Lakes Indian Fish and Wildlife Commission (GLIFWC) have developed a survey to gather observations from people working in the field, on the impact and ecology of invasive plants. One of the immediate goals of IPAW is to develop official working lists of Invasive and Potentially Invasive plants of Wisconsin. Based on this working list of Invasive Plants, some of IPAW’s primary efforts will be to, 1) develop educational materials and programs, 2) work to help formulate and influence public policy, 3) support and encourage control and management, and 4) help foster research on invasive plants. An initial step for these efforts is development of a working list of invasive plants.

Creation of a list of invasive plants can sometimes become controversial or politically charged, because of the commercial (agricultural and horticultural) value of some invasive species. It is important that IPAW’s working list of invasives be developed based on as much quantitative data as is available, and based on the observations and experience of as many naturalists and land managers as possible. The credibility of the list will depend, in part, on the involvement of a large number of people who have experience with Wisconsin’s native plant communities. Since direct studies of the effects of invasive species on native communities are often lacking, the collective observations of a wide variety of naturalists is essential to support the validity of the list.

GLIFWC has been working to develop a database of the published characteristics of plants that might be considered invasive. Some of the characteristics currently in the GLIFWC database when they are available for individual species, include: 1) North American distribution, 2) presence on state invasives lists and availability of published fact sheets, 3) life history and longevity, 4) growth form and growth rate, 5) fire tolerance, 6) minimum length of growing season, 7) shade tolerance, 8) seed longevity, and 9) ability to spread vegetatively, etc. The results of the direct observations of invasiveness gathered through the IPAW/GLIFWC survey will be added to the database to generate a score that summarizes the relative invasiveness of the species. The approach is adapted from the Alien Plant Ranking System (Hiebert, R.D. and J. Stubbendieck. 1993. Handbook for ranking exotic plants for management and control. USDI National Park Service Natural Resources Report NPS/NRMWRO/NRR-93/08).

Many of you are familiar with the concept of developing an “index of conservatism” for native plants by averaging the opinions of a panel of experts. Similarly, the median responses from this survey will be calculated and combined with data derived from published literature and plant databases to develop an “index of invasiveness” of the invasive plants of Wisconsin. People who volunteer to complete the survey will be asked to answer questions only about those species with which they have personal experience, and will constitute a large “panel of experts” on the invasive plants of the state. The questions that the survey asks for each species are summarized in the column on the left side of this page.

The survey includes a list of over 300 non-native species, and almost 30 native species that may be considered invasive in some situations. This initial comprehensive list was formed by combining the U.S. Forest Service’s list of invasive plants for the Eastern Region, and the University of Wisconsin Herbarium’s list of ecologically invasive plants. Many of the species on the list may not occur in the state, but may be considered Potentially Invasive in Wisconsin. Other species on the comprehensive list will be shown by the survey to be Weeds, but not Invasive Plants (see definitions below). The results of the completed survey will produce a ranked or categorized list of Invasive and Potentially Invasive Plants of Wisconsin. Species will be categorized based on the severity of their impact, and the threat they pose to our native plant communities. The results of the survey and the database that catalogues the properties of the invasive species will be made available this spring on GLIFWC’s web site, which can be accessed through a link on the IPAW website (ipaw.org).

If you can volunteer to complete the survey, a printable survey form can be downloaded from the IPAW website (ipaw.org). You will need the Acrobat Reader, which can be downloaded for free, to print out the survey. Printed and completed surveys should be mailed directly to GLIFWC at an address printed on the survey form. IPAW hopes to receive all completed surveys by 30 March 2002. If you would like more information about the survey, after reading the information on the website, contact:

Miles Falck at (715) 682-6619 or miles@glifwc.org.

SURVEY QUESTIONS:

Summary of the questions you will be asked when you complete the IPAW/GLIFWC survey.

Ecoregion -

Record the ecoregions of occurrence from the map provided.

Habitat -

Community (s) most often invaded:

A - aquatic

B - barrens

G - grasslands

F - forests

W - wetlands

D - disturbed ground

Disturbance -

0 - only in sites disturbed within the last 3 years

5 - in sites disturbed within the last 10 years

10 - in mid-successional sites disturbed 11-50 years ago

15 - in late-successional sites disturbed 51-100 years ago

20 - in high-quality natural areas with no known major disturbance in the last 100 years

Abundance -

The species occurs in what percentage of vulnerable sites:

0 - <10%

5 - 10-25%

10 - 25-50%

15 - >50% of vulnerable sites

Impact -

At sites where it occurs, the species:

0 - has little or no ecological impact

5 - modifies native communities

10 - replaces native communities

Competition -

Observed competitive ability:

0 - poor competitor

5 - moderate competitor

10 - highly competitive

Rate of Spread -

Within the last 5 years, abundance has:

0 - decreased

5 - remained the same

10 - increased slightly

15 - more than doubled

Control -

Feasibility of effective long term control:

0 - None required, plant looses vigor as succession proceeds

5 - Only one time management required

10 - Periodic management required (every 5-10 years)

15 - Requires annual management

20 - No feasible control option