Why you should care about noxious weeds
Have you ever heard of the term “noxious weed?” Whenever I bring it up to people that aren’t familiar with the term, I get a quizzical look, and then a funny comment. People might say something like, “Oh, are those weeds like my uncle Joe?” Noxious weeds have nothing to do with your Uncle Joe; they are plant species that are not native to New Mexico, and have negative economic and environmental impacts throughout our state. In order to be considered a noxious weed in the state they must be listed on the State Noxious Weed List, which can be found on the New Mexico Department of Agriculture’s website, bit.ly/3uBQklq.
Noxious weeds have the ability to outcompete native plant species. If they are not controlled, over time they can completely replace diverse native plant communities and form monotypic stands. They do this using three key attributes:
PROLIFIC SEED PRODUCTION:
Noxious weeds can produce massive amounts of seed. Musk thistle (Carduus nutans) can produce up to 20,000 seeds per plant. Common teasel (Dipsacus fullonum) can produce up to 3,000 seeds per plant.
EXTENSIVE ROOT SYSTEMS: One Canada thistle (Cirsium arvense) plant can spread 3 to 6 feet in diameter in 2 growing seasons. Horizontal roots can extend up to 15 feet, and vertical roots extend 6 to 15 feet deep.
LACK OF COMPETITION FROM
NATIVE PLANTS:
Since noxious weeds are not native, and have not evolved within New Mexico’s ecosystems, no native plants have developed the ability to directly compete with them. As a result, noxious weeds have the competitive edge on any site where they are established.
This all amounts to the destruction of native plant communities, negative impacts to ecosystem function, an increase in soil erosion and a decrease in the productivity of agricultural and wild lands. Several studies have also shown that sites dominated by noxious weeds have a decreased rate of use, and presence of wildlife — including elk and deer, upland birds such as quail and
Sage grouse, and a wide variety of migratory birds.
Taos County contains many riparian habitats along rivers, streams, acequias and ponds, as well as moist soil meadows and wetlands, where the ground water table is quite high, providing subsurface moisture to diverse plant communities. These are some of the most important habitats in the state for migratory birds, native wildlife, and plant biodiversity. These habitat types are also the rarest in the southwest composing less than 4 percent of total habitat. Using the advantages discussed above, noxious weeds are taking over these habitat types in Taos County.
Over the last 15 years I have noticed a dramatic increase in these kinds of sites being infested with noxious weeds. We are slowly losing these sites — and the biodiversity they provide. Once these sites are dominated by noxious weeds, and a monoculture is established, we begin to see more bare soil, higher soil compaction, lower soil moisture levels and as a result more soil erosion from both wind and the overland flow of water. This is because the noxious weeds that invade these sites have deep root systems that extend far below the top 8 inches of soil that hold the organic matter, fungi, and nutrients that our native plants need to grow. Once this top layer of soil is either lost through erosion, or severely degraded through prolonged loss of a living root, it is very difficult and costly to rehabilitate.
This same scenario occurs all over Taos County, and in every type of ecosystem and habitat type. From forested lands in the high country all the way out across the rangelands on both sides of the gorge, and the highly productive irrigated agricultural lands throughout the county.
There is a way for you to address this growing problem, and that is through early detection and a rapid response. Your ability to identify noxious weeds on your property and then quickly remove them can help to stop their spread. If you have a large infestation the response may take more time to implement, but if you allow the noxious weeds to hang around, one thing is for sure, they will continue to expand.
For help with identifying noxious weeds please visit the Taos Soil and water Conservation Districts website, tswcd.org/. They have a list of noxious weeds that occur in Taos County with pictures and descriptions of each. New Mexico State University has a publication entitled Noxious and Troublesome Weeds of New Mexico, ces.nmsu.edu/pubs/_ circulars/CR698.pdf. This is a great resource for identification. If you would like to join the effort to combat noxious weeds in Taos County, the Taos County Cooperative Weed Management Area meets the first Wednesday of each month, and are always looking for help. For details call the Taos Soil and water Conservation District at 575-7510584.