UW releases new findings on the economic impacts of invasive weeds in Wyoming

Agricultural economists and invasive weed specialists at the University of Wyoming (UW) have released a new report on the economic impacts of 10 invasive weeds in Wyoming. 

The pilot study, which assesses both current and potential economic impacts, was developed in response to Gov. Mark Gordon’s 2020 Invasive Species Initiative Report.

Collaborators include all Wyoming weed and pest districts and the Wyoming Weed and Pest Council Guiding Principles Committee.

“This report represents an important step to better understanding the impacts of invasive weeds on Wyoming’s agricultural economy and gives some insight into how bad it could be if such weeds were left unchecked,” says coauthor Brian Mealor, director of the Sheridan Research and Extension Center and the Institute for Managing Annual Grasses Invading Natural Ecosystems.

Economic analysis

To estimate each weed’s statewide and county-level economic impacts on agriculture, the study examined current grazing and crop value losses due to infestation and losses if each species were permitted to spread, unmanaged, into all potentially suitable habitat.

The 10 species analyzed in the new report are cheatgrass, hoary cress, leafy spurge, medusahead, Palmer amaranth, perennial pepperweed, Russian knapweed, Russian olive, ventenata and yellow starthistle. 

For each weed, direct economic impacts were estimated as losses in cash rent for agricultural land currently or potentially infested. 

The authors found “while current estimated statewide grazing losses are in the tens of millions of dollars annually, county-level impacts vary widely.” 

Of the 10 weeds included in the study, cheatgrass poses the most economically-damaging current and future threat to Wyoming agriculture. The authors estimate the weed’s future impact may exceed $110 million annually if left unmanaged. 

While it may be tempting to focus on cheatgrass and other species currently of highest concern, the authors advise against this tactic. 

“Preventing further spread of species with very limited range in Wyoming is a higher-leverage approach than waiting for them to have broad-reaching impacts before implementing a strategic management approach,” the report states.

In addition to direct economic impacts, the pilot study also estimated the “ripple effects” of lost agricultural rent. 

“Each year, invasive plants reduce the value of both forage and crop values across Wyoming. Beyond this, part of every dollar lost by an agricultural producer to weeds would otherwise be spent at the local feed store, restaurant or doctor’s office,” says Amy Nagler, research scientist in the UW Department of Agricultural and Applied Economics and coauthor of the report. “Estimating these economic losses due to weed infestation is an important tool for prioritizing limited funds for control.”

Conclusion

The new report serves as a potential model for future studies, establishing methods for estimating the impacts of individual weeds on Wyoming’s agricultural economy. 

However, the authors acknowledge their estimates are likely quite conservative because they accounted only for economic losses due to grazing reduction. Key factors like ecosystem services, recreation, wildfire and wildlife habitat were not incorporated into the pilot study.

Opportunities for further research include consideration of these factors as well as analysis of impacts to specific crops, irrigated versus non-irrigated cropland, parcel-level land area and use and public versus private rangelands.

UW Extension serves Wyoming communities by helping residents apply university research and resources to practical problems. Since 1914, UW Extension has provided educational programs and tools to the state’s 23 counties and the Wind River Indian Reservation. To learn more, visit uwyo.edu/uwe or call 307-766-5124.