May Invasive Species Invade Municipal Ordinances?

Municipal Law Alert, March 2009

An influx of invasive species has caused considerable damage to local fauna, lakes and waterways in our area. This has resulted in an increased public concern about regulating the movement of invasive species. The most common concern is watercraft moving between lakes and waterways. Municipalities are responding to the concerns by enacting ordinances regulating the transport of invasive species. The ordinances typically require that watercraft be free of weeds and other forms of aquatic life before transport.

Prior to enacting ordinances that regulate invasive species, municipalities need to consider whether they have the authority to regulate transport of aquatic plants and invasive animals. The Federal Government and the State of Wisconsin, through the Department of Natural Resources (DNR), have adopted a series of rules and regulations addressingthe treatment of aquatic plants and invasive animals. The fact that both the federal and state governments have regulated in this area raised a question of whether they have exclusive authority to enact and enforce regulations concerning the transport of aquatic plants and invasive animals. If the state and federal government have exclusive authority, any ordinance enacted by a municipal governmental body would be pre-empted by the state and federal regulations and, as a consequence, would be null and void.

The Wisconsin Attorney General addressed the question in an opinion released on February 22, 2008. The attorney general’s opinion concluded that a county had authority to enact an invasive species ordinance. The attorney general cautioned that any invasive species ordinance must be narrowly drafted to avoid pre-emption by state and federal regulations. The attorney general relied on the broad home rule powers held by a county to

support his interpretation. See

Municipalities may rely on the attorney general’s opinion when deciding whether to enact an ordinance of this nature. However, the attorney general’s opinion relied on the fact that state and federal rules and regulations did not specifically limit the authority of local governmental bodies to regulate. The legislature and the DNR, through its rule making authority, may change those rules to specifically ban local regulation. If the federal or state rules change, the basis for the attorney general’s opinion would be undercut. Federal or state rule changes could mean that the federal or state laws would pre-empt local municipal attempts at regulation by ordinance.

Aside from concerns about pre-emption, as a practical matter, a municipality may desire to consult with state DNR officials prior to enacting an ordinance. The municipality should inquire if the DNR is in support of local legislation and if the DNR intends to pre-empt local regulation in this area. At this point, the DNR has generally not objected to local regulation.

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