Who is the Invader? Alien Species, Property Rights and Police Power

This paper argues that the occurrence of a non-native species, such as purple loosestrife, on one's property does not constitute a nuisance in the context of background principles of common law. No one is injured by it. The control of non-native species, such as purple loosestrife, does not constitute a compelling public interest, moreover, but represents primarily the concern of an epistemic community of conservation biologists and ecologists. This paper describes a history of cases in agricultural law that establish that a public authority may enter private property to destroy a tree or other species but only to protect a compelling public interest, such as the apple industry in Virginia or the citrus industry in Florida, and only if it pays all the costs including just compensation. The paper argues a fortiori that if a public authority enters private property to control non-native or “invasive” species it must pay all the costs and indemnify the owner—contrary to what many state laws contemplate and the Environmental Law Institute recommends.

Mark Sagoff
Published in: Social Philosophy and Policy
2009 26 (2) Pages 26-52