Naturalist Spotlight: Non Native Species
By Rob Pudim and Kelly Prendergast
Non-Native Plants
People have told me a weed is any plant you do not want in your garden. The Colorado Weed Management Association says "weeds are more than plants out of place, they are non-native plants disrupting our native vegetation and ecosystems." They classify weeds in three categories:
List A: If you find it, eradicate it.
A newly arrived, uncommon, and potentially dangerous plant that requires mandatory eradication from all lands within the state to prevent it from becoming a larger problem. The management goal for List A species is their complete elimination to protect the economic and environmental health of Colorado.
List B: Help stop the spread.
Invasive plants with discrete, statewide distributions that must be managed to stop their continued spread, either through eradication, containment, or suppression, with the specific strategy varying by location and determined by the Colorado Commissioner in consultation with local governments. These are non-native plants already established in Colorado that have the potential to cause significant ecological damage, and their spread is a priority for the state.
List C: Widely distributed.
The species are widespread and well-established throughout the state, making statewide eradication impractical. The Colorado Department of Agriculture provides educational, research, and biological control resources to support local management efforts.
I prefer to think of them as noxious and obnoxious aliens. Noxious aliens threaten fresh water, agriculture and native plants and animals. Obnoxious aliens have some use as a resource and are marginally beneficial. I also extend the designation to include animals and birds.
An example of an obnoxious alien in the Wilderness is Cheat Grass (Bromus tectorum).
It is actually a collective term for several species of grass. It is called Cheat Grass because it "cheats" other vegetation out of moisture and cheated ranchers who imported it as an early spring forage for their cattle. By late June and early July, it dries out and its spine-like seeds stick to the cow's mouths and tongues. It is also tinder for wildfires. Ranchers have said they were "cheated" by this forage grass. Cheat grass looks like it is going to take over the West.
Other examples of obnoxious aliens are the Ox-eyed Daisy (Chrysanthemum leucanthemum) and the Common Mullein (Verbascum thapsus).
Ox-eye daisies have a white flower with a yellow disk which spreads by seed (>500 seeds/plant) and by rhizomes. European settlers brought the oxeye daisy to North America in the 1800s intentionally as an ornamental garden plant, though seeds also arrived accidentally as contaminants in cereal and crop seed shipments. Insects use it for pollen and nectar.
Mullein, originally from Africa, has soft, downy leaves and a stout stem 2 to 5 feet tall packed with seeds. Because it sticks out of the snow, many birds use it as a food source in winter. Native Americans and settlers adopted the plant, using its fuzzy leaves for cough teas, shoe linings for warmth, and crushed seeds as a traditional method to temporarily stun fish in slow waters.
As you can imagine, Weed Management is an interagency effort in Colorado that involves coordination between the USFS Boulder Ranger District, Boulder County Parks and Wildlife, and State level management entities such as the Colorado Park and Wildlife Division and the Colorado Department of Agriculture.
Managing noxious weeds in the James Peak and Indian Peaks Wilderness areas involves navigating strict federal wilderness regulations while combating aggressive non-native species. Because it is a designated wilderness area, management focuses heavily on prevention, minimal-impact hand removal, and strict rules regarding pack animals.
Non-Native Animals
An example of an obnoxious animal would be the Mountain Goat. Mountain goats were introduced to Mt. Blue Sky (formally known as Mt. Evans) by Colorado's Parks and Wildlife (previously Colorado Division of Wildlife), and occasionally make their way north to the park. Mountain goats are not native to Colorado and carry diseases that can infect native bighorn sheep, and they compete with the native sheep for food and habitat. Because mountain goats are a significant threat to the survival of native bighorn sheep, the National Park Service and Colorado Parks and Wildlife take active measures to reduce impacts to bighorn sheep and to remove mountain goats that enter the park.
Non-Native Birds
There are a number of common non-native/invasive birds that can also be found near the Wilderness (i.e. Nederland, Grand Lake). While true high-alpine and subalpine zones resist most invasive birds, lower elevations and adjacent Boulder County areas record species like the following:
House Sparrow (Passer domesticus): Frequently tied to human structures, ranches, and lower-elevation developed edges.
Photo source https://www.allaboutbirds.org/guide/House_Sparrow/overview
Rock Pigeon (Columba livia): Found around human habitation and lower foothills.
Photo source: https://www.allaboutbirds.org/guide/rock_pigeon
Eurasian Collared-Dove (Streptopelia decaocto): Their populations have surged across Colorado, primarily occupying lower-elevation towns and agricultural valleys rather than wilderness backcountry.
Photo source: https://www.allaboutbirds.org/guide/Eurasian_Collared-Dove
European Starling (Sturnus vulgaris): Common in lower developed valleys, though uncommon in high wilderness terrain.
Photo source: https://www.allaboutbirds.org/guide/European_Starling/photo-gallery/303928891
Naturalist column exploring high country flora, fauna and geography
IPWA volunteers are often asked by visitors not just about the trails, but about what they are seeing in the Indian Peaks and James Peak Wilderness Areas. This column will cover some of the plants, animals and geographic features that hikers, anglers and backpackers may come across in these areas.
About Rob Pudim
A long time Boulder resident, Rob describes himself as “a coal-miner's son from Pennsylvania, a "fallen" scientist (Chemistry, Rutgers University and Microbiology, Tulane University) an editorial cartoonist, an amateur lepidopterist, a Native Plant Master, and a long-time birder”. His affiliation with IPWA goes back to its founding in the 1980s.
About Kelly Prendergast
Longtime volunteer and former board chair: "My grandparents, who loved birds and plants, were a huge influence in my life growing up in the Hudson Valley and Catskill mountains of New York State. My siblings and I were encouraged to spend many hours exploring the nearby woods which fostered a lifelong curiosity and desire to learn more about the natural world. I'm continuously surprised by the abundance of things to discover and love hearing about and sharing new discoveries with others."
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