Wisconsin Revises Invasive Species Rules to Take Effect
Changes to ch. NR 40 add 65 species, remove 22 and amend 46 current classifications starting Jan. 1, 2027.
Updated on Nov. 10, 2026 in Botany
The Wisconsin Department of Natural Resources has announced revisions to its invasive species regulations under chapter NR 40 of the Wisconsin Administrative Code, effective Jan. 1, 2027. The changes add 65 newly regulated species, remove 22 species and amend the classification of 46 currently regulated species.
Why it matters
Chapter NR 40 makes it unlawful to transport, transfer, introduce or in some cases possess regulated invasive species, so the revisions change what residents and businesses may move or keep statewide. The update reflects the state's effort to address nonnative organisms that harm Wisconsin's environment, economy and human health.
The revision adds 65 new regulated species, removes 22 and amends classifications for 46 currently regulated species under chapter NR 40. Under the rule, invasive species are classified as either prohibited, meaning not yet present or present only in small isolated populations, or restricted, meaning already widespread in the state.
The players
Wisconsin Department of Natural Resources
The state agency responsible for managing Wisconsin's natural resources, including the regulation of invasive species under chapter NR 40 of the Wisconsin Administrative Code.
The details
The DNR's revision clarifies key sections of the rule and updates the species classified under it. To help the public understand the changes, the agency published a summary of species regulation changes and a Rule Revision Guide.
Timeline
Nov. 10, 2026: Wisconsin DNR announces revisions to chapter NR 40 invasive species regulations.
Jan. 1, 2027: Revisions to chapter NR 40 take effect.
Legacy Framework
The revisions update Wisconsin's existing chapter NR 40 rule, which classifies invasive species as prohibited when not yet established and restricted when already widespread. The changes adjust that classification system rather than replacing it, keeping the same prohibition and restriction categories in place.
Residents who transport, transfer or keep plants and organisms will need to check whether newly added species are on the regulated list before Jan. 1, 2027. Businesses and property owners should review the Rule Revision Guide to understand how the updated classifications affect their activities.
The takeaway
Check the species lists before moving plants, organisms or materials across state lines or within Wisconsin, since the rule's new additions take effect Jan. 1, 2027. Reviewing the Rule Revision Guide now can help avoid unintentional violations once the changes are in force.
What happens next
The revisions to chapter NR 40 take effect Jan. 1, 2027, when the 65 new species additions, 22 removals and 46 reclassifications become enforceable.
Further reading
For more on how plant and organism science informs invasive species policy, explore the Botany section.
