Eagle River Watershed Council: There’s a weed in my watershed
It’s spring, which means gorgeous wildflowers are beginning to bloom and the world is becoming a little bit greener. It’s easy to imagine it now, walking along a trail beside a rushing river — being lured by a beautiful purple blossom, three feet in the air. It is attracting a hum of pollinators and commandeers the riparian zone.
You get a little bit closer and notice there’s not just one, but five. No, there are 30! As you reach to examine the leaves, you snap your hand away from the spikes. This isn’t the normal columbine or lupine or willow — what is this imposter? It’s no wildflower at all. In fact, it’s an invasive species, a noxious weed. It’s bull thistle!
Here in Eagle County, there are more than 35 different noxious weeds you might encounter while exploring the watershed or simply working in your own backyard. Each invasive species poses a risk to our beautiful and fragile mountain ecosystem, out-competing native vegetation and reducing biodiversity as they become more prolific. Without any native threats of their own, they can quickly change the landscape and lead to lasting impacts.
An invasive weed is one that has established, persisted and spread within an ecosystem outside of its native range. These plants often have migrated from Europe and Asia, either by accident or on purpose. Some of the more persistent and concerning weeds in North America were brought over as ornamental plants to be used in landscaping, as structural plantings for riverbank stabilization or creation of wind-row breaks in the open plains.
When an invasive weed is deemed as a threat to agriculture, recreation, wildlife, property or public health, it can be classified as a noxious weed. Once classified, more aggressive action can be prioritized and then taken to curb its spread within an area. Some of the most notable noxious weeds that have rooted, pun intended, in the High Country are a variety of thistles, knapweeds, tamarisk (saltcedar), Russian olive and hoary cress (whitetop).
Tamarisk is a great example of a plant that was human-introduced to stabilize banks and create wind-row breaks, thanks to its robust root system and dense foliage. However, these plants quickly took over riparian areas, pushing out cottonwoods and willows along with the wildlife that relied on them.
They also pose a complicated threat to water quantity in the West, as an acre of tamarisk is thought to use nearly 2.8 million gallons of water annually — that’s more than eight football fields covered by a foot of water consumed each year. With an already limited water supply that 40 million people rely on, it is critical that the Colorado River and its headwaters have as much water flowing through them as possible.
Tamarisk is tough to remove, often requiring repeated efforts, large equipment and chemical applications. Not all weeds are as difficult to remove as tamarisk, and some are more frequently found in backyards.
As you are diving into yard work and getting your space ready for summer, think about our watershed. What you plant and grow in your backyard is a part of the local ecosystem, so it is important to responsibly remove all invasive and noxious weeds.
In fact, according to the Colorado Noxious Weed Act, property owners must act if there are noxious weeds found on the property. There are numerous resources available to help identify these invasive species, as well as provide support for successful eradication, and some to help you learn about plants native to the High Rockies. Cultivating robust local vegetation will help contribute to the natural ecosystem, add beauty and help keep our watershed healthy. Visit erwc.org/weeds for more information and tips!
James Dilzell is the Education & Outreach Coordinator for Eagle River Watershed Council. The Watershed Council has a mission to advocate for the health and conservation of the Upper Colorado and Eagle River basins through research, education and projects. Contact the Watershed Council at (970) 827-5406 or visit erwc.org.
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