A weed is defined as any plant that interferes with the management objectives for a piece of land or body of water at a given point in time. 

An invasive weed is defined as any plant that is non-native (exotic) to an ecosystem that threatens, or has the potential to threaten, environmental health, human health, and agriculture. 

A noxious weed is any weed that has been designated by the State of Montana and/or the United States of America as noxious due to its potential to directly or indirectly injure agriculture, navigation, fish, wildlife, or public health. All noxious weeds are non-native (exotic) and invasive species. By law, you are required to manage your noxious weed species on your property. It is illegal to transport, sell, or grow noxious weed species. Every state has their own noxious weed list pertaining to their unique environments and agriculture. The United States of America also has a 'federal noxious weed list' applicable to all states. 

Invasive and noxious weed species have the potential to negatively impact the ecological integrity and economic productivity of landscapes. Invasive and noxious weed infestations:

• harm land values and wildlife habitat

• increase the potential for surface runoff, soil erosion, and sedimentation in above-ground water sources

• reduce plant diversity and forage available for livestock

• displace native plants and plant communities

Invasive and noxious weed species threaten and have the ability to reduce and eliminate our ecosystem's biological diversity. 

Biodiversity is what is responsible for ecosystem productivity. The greater the biodiversity, the greater the productivity. Biodiversity also provides natural defense mechanisms to the environment that help sustain our wildlife habitat, ability to recover from disruption events, food and medicine resources, and natural resources such as: freshwater, forests, soil fertility, and minerals. By protecting our biodiversity, we can ensure out ecosystem's productivity for years to come. 

Landowners in Montana are required by law to control noxious weeds on their property. Although control of invasive species is not legally mandated, it is highly encouraged. By making an effort to control these invasive and noxious weeds, and by managing your property in a sustainable manner, you can help protect and maintain our ecosystem's biodiversity, natural resources, and the scenic beauty of the vast landscapes of Park County, Montana.