This week is National Invasive Species Awareness Week. The goal of the week is to promote public education of noxious weeds and their vast and detrimental effects on our landscapes, recreational opportunities, wildfire risks and climate change.
Noxious weeds are plants that have been designated by the Colorado Department of Agriculture as being injurious to agriculture, natural habitats and ecosystems, human beings and crops. In Colorado noxious weeds are plants that didn’t originate in this state and came to be in the state either by intentional or unintentional releases.
Many noxious weeds have origins in Asia and Europe, and all are not part of successional cycles in Colorado. Noxious weeds know no boundaries and have no natural predators allowing them to spread without restraints. These weeds influence the hydrologic cycle by consuming more water than their native counterparts and reducing water flows in streams. A good example is Tamarisk, which was introduced into the United States for stream bank stabilization. This species has spread rapidly throughout Colorado waterways and has become a persistent problem to eradicate, and additionally it has caused harm to other species such as the Southwestern Willow Flycatcher by reducing the native vegetation which the bird favors. In the western United States Tamarisk is detrimental to our area which is already struggling with drought. An invasive annual grass known as Cheatgrass has invaded rangelands and made them more susceptible to more frequent wildfires. Several noxious weeds are detrimental (or toxic) to livestock, and contribute to reduced productivity on agricultural lands.
Noxious weeds can be terrestrial or aquatic weeds. Aquatic weeds can make boating impossible and choke waterways for fish species. A large infestation can change water temperatures and dissolved oxygen content of the waterway. Terrestrial weeds can impair access to trails and contribute to reduced recreational opportunities.
Noxious weeds reduce habitat for the wildlife species which bring a great deal of tourism dollars to the state of Colorado. Oxeye Daisy, which has become prevalent in several Colorado counties, reduces forage for big game and is not consumed by wildlife. Large infestations of Oxeye Daisy will encourage those iconic big game species we love to photograph and hunt to leave an area.
Noxious weeds in and of themselves are also very detrimental to Colorado’s agriculture. A single infestation of a weed such as Leafy Spurge, or Russian Knapweed can render that land unusable. Weeds like Russian Knapweed also emit chemicals which make growth of many other species impossible. Noxious weed species contribute to increased management efforts, and can contribute to pollinator declines. Some species may forage on the noxious weeds, but not all pollinators will. Each time a pollinator species forages on noxious weeds, one less native plant species enjoys pollinator services.
Noxious weeds are detrimental to Colorado’s natural and agricultural lands, regardless of their sometimes beautiful appearance. The more beautiful the weed the less citizens are moved to take care of the infestation. Noxious weeds are a growing environmental problem and require persistent and rapid elimination. Please report noxious weeds to your county weed manager, and remember that ridding Colorado of noxious weeds is a community effort! Please do your part and contact Julie Kolb, Manager, San Miguel County Vegetation Control & Management at (970)327-0399 or juliek@sanmiguelcountyco.gov with any questions.