Invasive weeds: Why should we care? | PostIndependent.com

Invasive weeds: Why should we care?

Hal Pearce
U.S. Forest Service
Musk thistle, an invasive plant of our area.
Hal Pearce / Provided |

mORE Information

For more information on speicific weed species, or ho w you can help efforts to contain this invasive tidal wave, contact your local forest service office:

Aspen/Sopris Ranger District, Carbondale 970-963-2266

Blanco Ranger District, Meeker 970-878-4039

Dillon Ranger District, Silverthorne 970-468-5400

Eagle/Holy Cross Ranger District, Minturn 970-827-5715

Rifle Ranger District, Rifle 970-625-2371

Imagine yourself hiking up a quiet mountain trail. Just as you round a corner into a lush meadow you are taken aback by a sea of musk thistle, with some plants reaching over six feet tall.

While their single red flower nodding in the summer breeze is undeniably pretty, just look at those thorns, some of them are nearly one inch long!

You may remember this same mountain meadow a few years ago. There were only a handful of these prickly giants scattered across the landscape, mostly undetected. Now there are hundreds of plants, if not thousands.

How did this happen so quickly?

Over time, each one of those few scattered plants produced up to 20,000 seeds, which lay dormant in the soil until the growing conditions were just right. Our cool, wet spring has been ideal for just such an explosion.

This scenario is taking place throughout Colorado, and the entire intermountain west. While many of the invasive weed infestations are still located in the lower valleys and on private land, they are quietly expanding to the higher elevations and onto our public lands.

Humans, wildlife and domestic animals all aid in this expansion. It can be as subtle as a few seeds stuck in a hiker’s shoelaces or droppings from birds and other animals, to carrying seeds and propogative plant parts with our vehicles and other mechanized equipment.

Non-native (noxious) weed populations have slowly increased throughout the Rocky Mountain Region over the past several decades. Nationally it is estimated that noxious weeds are increasing at a rate of 3 million acres per year. Some estimate that nearly six square miles of National Forest and Bureau of Land Management lands are infested every day.

These invasive weeds are exotic species to the United States. In their native environment, they may not pose a problem. They have evolved with natural enemies such as specialized insects or plant pathogens that keep their populations in check. When those weed species are introduced to the United States, in the absence of their natural enemies, they can become very aggressive, and their populations can expand out of control.

These invasive plants threaten the health and diversity of our forests and rangelands by overtaking native plant communities and altering the balance that makes the ecosystem function.

While the thistle species with their sharp thorns are easily accepted as a weed, there are a number of escaped ornamental species that can have devastating environmental consequences. Some of these ornamentals are very pretty such as yellow toadflax, sometimes referred to as butter and eggs. And of course there are the showy oxeye and chamomile daisies. These pretty invasives can negatively affect wildlife habitat, recreational opportunities, watershed function, and more.

The White River National Forest emphasizes the principles of Integrated Pest Management (IPM) and the National Strategic Framework for Invasive Species Management (2013) which identifies four key invasive species program elements:

Prevention

Detection

Control and Management

Restoration and Rehabilitation

Tools to control the spread of noxious weeds can include mechanical control (cutting, chopping, tilling), biological control (insects, plant pathogens), cultural control (grazing rotations, prescribed fire), or chemical control (herbicides).

So what can you do to help prevent the spread of these noxious weeds? Become familiar with the noxious weeds of Colorado at https://www.colorado.gov/pacific/agconservation/noxiousweeds.

Yes, they can be attractive, but don’t plant them in your yard — their seeds will spread to your neighbor’s yard and your public lands. Check your hiking boots and clothing before and after you go for a hike — are you carrying any seeds on your clothes that can be spread? Wash off your ATV or mountain bike before entering public lands; join local volunteer weed pull days, like the weed pull sponsored recently by Wilderness Workshop in Hunter Creek Valley: http://www.wildernessworkshop.org.

Prevention is the key.

Hal Pearce is the White River National Forest Range program manager & regional invasive species coordinator. Contact him at 970-878-6008


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