MANAGEMENT OF INVASIVE PLANTS IN THE WESTERN USA
  • Defining the Problem
    • What is a Weed? >
      • Federal Definitions of Noxious Weeds
    • Costs of invasive plants
    • Human Factor
    • Challenges of Invasive Plants
    • Wildfires in the Western USA >
      • Forest Fires: Structure
      • Bark Beetles & Forest Ecosystems
      • Rangeland Fires
    • Climate Change Impacts on Plants >
      • Climate Change: CO2, NO, UV, Ozone Impacts on Plants
      • Climate Change Impacts on Crops
      • Climate Change Impacts on C4 Plants
      • Climate Change Impacts on Rangelands
      • Climate Change Impacts on Forests
    • What are we doing?
  • Focus of this Project
    • Why Western States? >
      • Audience for these reports
    • History: Are we doomed to repeat it? >
      • Dust Bowl Re-visited >
        • China: Past & Present
        • UN Biodiversity Report
    • Policy vs. Practice
    • Ecosystems & Economics >
      • Reductionist Approach to science
      • Ecology & Feminism
      • Systems View of Life
      • Ecosystems Health
      • Economic Growth
      • Impact of the Petrochemical Industry
      • Interrelation of Economics & Ecology
    • Federal Agencies >
      • Federal Agencies and Invasive Species
      • History of Coordination with States
      • Challenges of Coordination between Federal Agencies
      • Collaboration or Confusion
    • Organizations to assist landowners
    • Federal Legislation on Invasive Species >
      • 1930s Federal Laws on Invasive Species
      • Federal Seed Act 1939
      • 1940s-1960s Federal Laws on Invasive Species
      • 1970s Federal Laws on Invasive Species
      • 1980s Federal Laws on Invasive Species
      • 1990s Federal Laws on Invasive Species
      • 2000-2010 Federal Laws on Invasive Species
      • 2011-2022 Federal Laws on Invasive Species
      • Federal Bills on Invasive Species not passed
      • Executive Orders on Invasive Species
      • Federal Excise Taxes
    • State Laws and Lists of Noxious Weeds
  • Why we need plants
    • Native Plants
    • Plant Resources
  • Invasive Success Hypotheses
    • Unified Framework
    • Role of Diversity >
      • How Ecosystems Maintain Diversity
      • Fluctuation Dependent Mechanisms
      • Competition-based coexistence mechanisms
      • Niche Differences
      • Species Richness
    • Enemy Release Hypothesis
    • Constitutive Defense Mechanisms
    • Evolution of Increased Competitive Ability
    • Role of Microbes
    • Indirect Defense Mechanisms
    • Novel weapons hypothesis
    • Evolutionary Shifts
    • Resource Allocation
    • Evolutionary Dynamics >
      • Pre-introduction evolutionary history
      • Sampling Effect
      • Founder Effect
      • Admixture, hybridization and polyploidization
      • Rapid Evolution
      • Epigenetics
      • Second Genomes
    • Role of Hybridization
    • Role of Native Plant Neighbors
    • Species Performance
    • Role of Herbivory
    • Evolutionary Reduced Competitive Ability
    • Summary Thoughts on Research
  • Historical Record
    • Regional Conferences
    • Timeline
  • Innovative Solutions
    • Grazing Solutions >
      • Sheep, Goat & Chicken Grazing
      • Cattle & Sheep Grazing
      • Cattle and Bison Grazing
      • Grazing and Revegetation
    • Agricultural Best Practices >
      • Ecologically based Successional Management >
        • Regenerative Agriculture
        • Sustainable Agriculture
      • Perennial Crops, Intercropping, beneficial insects
      • Soil Solarization
      • Natural Farming
      • Permaculture
      • Organic Farming
      • Embedding Natural Habitats
      • Conservation Tillage
      • Crop Rotation
      • Water Use Practices
      • Tree Planting: Pros & Cons
    • Rangeland Restoration >
      • Federal Goals for Rangelands
      • Novel Ecosystems
      • Prairie Restoration >
        • Prairie Restoration Workshop
        • Weed Prevention Areas
        • California grassland restoration
        • Selah: Bamberger Ranch Preserve
      • Sagebrush Steppe Restoration >
        • Low Nitrogen in Sagebrush Steppe
      • Revegetation with Native Plants
      • Dogs as detectors of noxious weeds
    • Habitat Conservation
    • Technology solutions
    • Nudges
  • Biological Control
    • Insects as Biocontrol >
      • Impacts of Biocontrol Agents on Non-Target Species
      • Indirect Impact of Biocontrol on Native Species
    • Challenges of Using Biocontrols >
      • DNA studies on Biocontrol Insects
      • Biocontrol takes time
    • Prioritization process for Biocontrol Programs
    • Evolutionary changes impact Biocontrol
    • Vertebrates as Biocontrol Agents
  • Herbicides: History and Impacts
    • Effectiveness of Herbicides in Agricultural Lands
    • Effectiveness of Herbicides in Rangelands
    • History of Use of Herbicides and Pesticides Prior to and During WWII
    • Herbicide use during and post-World War II >
      • 2,4-D Herbicide Use
      • 2,4-D and 2,4,5-T, post-World War II
    • Modern use of Herbicides >
      • Atrazine Herbicide
      • Dacthal, DCPA
      • Dicamba Herbicide
      • Glyphosate Herbicide
      • Paraquat Dichloride
      • Picolinic acid family of herbicides >
        • Picloram (Tordon 22K) Herbicide
        • Triclopyr Herbicide
    • Herbicide Resistance in Invasive Plants >
      • Herbicide Resistant Crops
      • Controlling herbicide-resistant weeds in herbicide-resistant crops
      • Best Management Practices
    • Myth of the Silver Bullet
    • Myth of Eradication
    • Merging of Agrochemical Companies
    • Funding for Research on Pesticides
    • Impacts of Pesticides on Environment and Human Health >
      • Pesticide Drift
      • Impacts of Pesticides on Biological Diversity
      • Impacts of Herbicides on Native Plants
      • Pesticide Impacts on Insects >
        • Butterflies: The Impacts of Herbicides
        • Monarch Butterflies: Impacts of Herbicides
      • Impacts of Pesticides on Wildlife >
        • Reptiles & Amphibians: Pesticide Impacts
      • Pesticide Residue in Foods
      • Commentary on Herbicide Use
  • Interviews
    • Interviews Biocontrol >
      • Biocontrol Wyoming
      • Montana Biocontrol Interview Maggio
      • Montana Biocontrol Interview Breitenfeldt
    • California Interviews >
      • Robert Price
      • Doug Johnson
    • Colorado Interviews >
      • George Beck Interview
      • Scott Nissen Interview
    • Idaho Interviews >
      • Purple Sage Organic Farms in Idaho
    • Montana Interviews >
      • Jasmine Reimer Interview Montana
      • Organic Farms Montana Interviews
    • Texas Interviews
    • Washington Interviews >
      • Ray Willard
    • Wyoming Interviews >
      • Slade Franklin Interview
      • John Samson Interview
    • Wyoming Weed and Pest Districts >
      • Josh Shorb Interview
      • Slade Franklin Interview 2
      • Lars Baker Interview
      • Steve Brill Interview
      • George Hittle Interview
      • Peter Illoway Interview
      • Robert Jenn Interview
      • Sharon Johnson Interview
      • Larry Justesen Interview
      • Gale Lamb Interview
      • Stephen McNamee Interview
      • Allen Mooney Interview
      • Rob Orchard Interview
      • Robert Parsons Interview
      • Dick Sackett Interview
      • Comments by Delena
    • NRCS Interviews: Wyoming
  • Western Weed Control Conference 1940s Minutes
    • 1942 Conference
    • 1945 Conference
    • 1946 Conference
  • Who am I?
    • My Work
    • My Inspirations
    • My Adventures
    • Contact Page
  • Road Logs
    • Colorado Road Logs
    • Idaho Road Logs
    • Montana Road Logs
    • New Mexico Road Logs
    • Texas Road Logs
    • Wyoming Road Logs
  • Bibliography

Economic & Ecological
​Costs of Invasive Plants

Photo: Salt Cedar & Giant Cane along the Rio Grande. © 2017 Delena Norris-Tull
Economic and Ecological Costs of Invasive Plants

Research summary and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, July 2020, updated November 2024.

The Invasive Species Specialist Group (Lowe, et al., 2009) reports that, “Today, alien invasion is second only to habitat loss as a cause of species endangerment and extinction. Safeguarding the earth’s diversity is the best way to maintain our life support system. There is evidence to suggest that the biosphere acts as a self-regulating whole and that diverse systems may be more resilient. Island ecosystems, which have evolved in isolation often have relatively fewer plants, herbivores, carnivores and decomposers to maintain essential processes and are more vulnerable to invasion. On islands around the world species extinction is increasing at an unprecedented rate.”
 
Rural areas in the Western United States have some similarities with island populations. Like islands, many ecosystems in the West are isolated from each other. Mountain ranges and desert basins create many localized climatic systems that have resulted in ecosystems isolated from distinct ecosystems just a few miles away. High altitude locations in the West, with very short growing seasons and often desert-like conditions, are isolated from other such locations. And Western deserts create unique ecosystems unlike those found in the eastern United States.
 
Invasive plants have had a significant negative economic impact on agriculture and ecological systems. For example, Leistritz, Bangsund, & Hodur, 2004, point out that, “Leafy spurge has become a serious problem for ranchers and land managers in the northern Great Plains region. A bioeconomic model was developed to estimate the economic impacts of leafy spurge on grazing land and wildland in a four-state region (Montana, North Dakota, South Dakota, and Wyoming). Leafy spurge infestations on grazing land were estimated to result in a loss in regional grazing capacity sufficient to support a herd of 90,000 cows. Direct economic impacts on stock growers, landowners, and agribusiness firms were estimated to exceed $37 million annually, whereas secondary impacts throughout the regional economy totaled almost $83 million. Impacts on wildland were smaller but still substantial.”

Invasive plant species are estimated to have an economic cost to agriculture of approximately two billion dollars annually in the United States. In the 2017 report on Washington State, Economic Impact of Invasive Species, the authors conclude that, “The direct impact of invasive species [both invasive plants and animals] on crops grown in Washington is estimated to be $239.5 million per year…. The direct economic impact of invasive [plant] species on the livestock industry is estimated to be $120.1 million annually…. The direct economic impact of invasive [plant and insect] species on the timber industry is estimated to be $124.8 million…. The direct economic impact to recreational activities [including hunting, fishing, and boating] from invasive species is estimated to be $20.5 million per year.” The report includes the estimated economic costs for each of twelve noxious weed species.

As another example of the damages caused by invasive plant species, Herron, et al., 2001, point out that in the northwestern US and Canada, spotted knapweed (Centaurea maculosa) has “altered plant community composition and reduced forage value, wildlife habitat, and species diversity. [It] displaces perennial grasses and increases bare ground, surface water run-off, and stream sedimentation.”

The following data comes from the Montana Department of Transportation, Statewide Integrated Roadside Vegetation Management Plan: 2018-2024:

“The impact of weeds on biological communities, ecosystem processes, and the agricultural economy is well documented in Montana. Studies have shown that replacement of native bunchgrasses with taproot weeds such as spotted knapweed can increase surface water runoff and soil erosion by 56% and 192% respectively… Weeds have been shown to influence wildlife by reducing forage, modifying habitat structure—such as changing grassland to a forb-dominated community—or changing species interactions within the ecosystem… Non-native plants also threaten biological diversity of native plant communities by displacing native species… and can threaten the survival of rare and sensitive plants….

“The cost of spotted knapweed and leafy spurge to Montana’s economy is substantial…Total impact from spotted knapweed infestations were estimated at $42 million per year…The impact of leafy spurge to Montana’s economy was estimated at $18.6 million per year.”
​
The total of all invasive species (including plants, arthropods, and vertebrates) has an estimated annual cost to the United States of $120 billion annually (Pimentel, Zuniga, & Morrison, 2004). The cost to the US economy of invasive plants alone is in the billions. Worldwide the cost of all invasive species has been in the trillions of dollars.
 
In 2011, the U.S. Department of the Interior spent $120 million on invasive species management (US Fish & Wildlife, January 2012). In 2015, Montana-based Federal Agencies jointly spent nearly $9 million on invasive species management (including both plants and animals), and disbursed an additional $2 million to various Montana State entities. Montana State Agencies spent $7.5 million in 2015, and disbursed $3.4 million to other entities, primarily local and county governments (Creative Resource Strategies, 2016).

References:
  • ​CAI. (Jan., 2017). Economic impact of invasive species: Direct cost estimates and economic impacts for Washington State. Seattle: Community Attributes, Inc (CAI).
  • Creative Resource Strategies. (March, 2016). Montana Management Assessment of Invasive Species. Montana Invasive Species Advisory Council.
  • Herron, G.J., Sheley, R.L., Maxwell, B.D., & Jacobsen, J.S. (Sept, 2001). Influence of nutrient availability on the interaction between spotted knapweed and bluebunch wheatgrass. Restoration Ecology, 9 (3): 326-331.
  • Leistritz, F.L., Bangsund, D.A., Nancy M. Hodur, N.M. (2009).Assessing the Economic Impact of Invasive Weeds: The Case of Leafy Spurge (Euphorbia esula).  Weed Technology, 18, Invasive Weed Symposium: 1392-1395.
  • Lowe, S., Browne, M., Boudjelas, S., & De Poorter, M. (2000). 100 of the World’s Worst Invasive Alien Species: A Selection From The Global Invasive Species Database. Published by the Invasive Species Specialist Group, a specialist group of the Species Survival Commission of the World Conservation Union. University of Auckland, Auckland, New Zealand.
  • Montana Department of Transportation. (2019). Statewide integrated roadside vegetation management plan: 2018-2024. Helena, MT: Montana Department of Transportation.
  • Pimental, D., Zuniga, R. & Morrison, D. (December, 2004). Update on the environmental and economic costs associated with alien-invasive species in the United States. Ecological Economics: 52 (2005), 273– 288.
  • US Fish & Wildlife Service. (January, 2012). Fact sheet: The Cost of Invasive Species. US Fish & Wildlife Service.

Next Sections on "Defining the Problem":
the human factor
CHAllenges of invasive plants
Climate Change
Wildfires
do we know what we are doing?
Copyright: Dr. Delena Norris-Tull, July 2020. Management of Invasive Plants in the Western USA.

These webpages are always under construction. I welcome corrections and additions to any page.
​Send me an email, and I can send you the original Word format version of any page you wish to correct.
contact Dr. Norris-Tull
Bibliography
who am i?
My work
my inspirations
my adventures
  • Defining the Problem
    • What is a Weed? >
      • Federal Definitions of Noxious Weeds
    • Costs of invasive plants
    • Human Factor
    • Challenges of Invasive Plants
    • Wildfires in the Western USA >
      • Forest Fires: Structure
      • Bark Beetles & Forest Ecosystems
      • Rangeland Fires
    • Climate Change Impacts on Plants >
      • Climate Change: CO2, NO, UV, Ozone Impacts on Plants
      • Climate Change Impacts on Crops
      • Climate Change Impacts on C4 Plants
      • Climate Change Impacts on Rangelands
      • Climate Change Impacts on Forests
    • What are we doing?
  • Focus of this Project
    • Why Western States? >
      • Audience for these reports
    • History: Are we doomed to repeat it? >
      • Dust Bowl Re-visited >
        • China: Past & Present
        • UN Biodiversity Report
    • Policy vs. Practice
    • Ecosystems & Economics >
      • Reductionist Approach to science
      • Ecology & Feminism
      • Systems View of Life
      • Ecosystems Health
      • Economic Growth
      • Impact of the Petrochemical Industry
      • Interrelation of Economics & Ecology
    • Federal Agencies >
      • Federal Agencies and Invasive Species
      • History of Coordination with States
      • Challenges of Coordination between Federal Agencies
      • Collaboration or Confusion
    • Organizations to assist landowners
    • Federal Legislation on Invasive Species >
      • 1930s Federal Laws on Invasive Species
      • Federal Seed Act 1939
      • 1940s-1960s Federal Laws on Invasive Species
      • 1970s Federal Laws on Invasive Species
      • 1980s Federal Laws on Invasive Species
      • 1990s Federal Laws on Invasive Species
      • 2000-2010 Federal Laws on Invasive Species
      • 2011-2022 Federal Laws on Invasive Species
      • Federal Bills on Invasive Species not passed
      • Executive Orders on Invasive Species
      • Federal Excise Taxes
    • State Laws and Lists of Noxious Weeds
  • Why we need plants
    • Native Plants
    • Plant Resources
  • Invasive Success Hypotheses
    • Unified Framework
    • Role of Diversity >
      • How Ecosystems Maintain Diversity
      • Fluctuation Dependent Mechanisms
      • Competition-based coexistence mechanisms
      • Niche Differences
      • Species Richness
    • Enemy Release Hypothesis
    • Constitutive Defense Mechanisms
    • Evolution of Increased Competitive Ability
    • Role of Microbes
    • Indirect Defense Mechanisms
    • Novel weapons hypothesis
    • Evolutionary Shifts
    • Resource Allocation
    • Evolutionary Dynamics >
      • Pre-introduction evolutionary history
      • Sampling Effect
      • Founder Effect
      • Admixture, hybridization and polyploidization
      • Rapid Evolution
      • Epigenetics
      • Second Genomes
    • Role of Hybridization
    • Role of Native Plant Neighbors
    • Species Performance
    • Role of Herbivory
    • Evolutionary Reduced Competitive Ability
    • Summary Thoughts on Research
  • Historical Record
    • Regional Conferences
    • Timeline
  • Innovative Solutions
    • Grazing Solutions >
      • Sheep, Goat & Chicken Grazing
      • Cattle & Sheep Grazing
      • Cattle and Bison Grazing
      • Grazing and Revegetation
    • Agricultural Best Practices >
      • Ecologically based Successional Management >
        • Regenerative Agriculture
        • Sustainable Agriculture
      • Perennial Crops, Intercropping, beneficial insects
      • Soil Solarization
      • Natural Farming
      • Permaculture
      • Organic Farming
      • Embedding Natural Habitats
      • Conservation Tillage
      • Crop Rotation
      • Water Use Practices
      • Tree Planting: Pros & Cons
    • Rangeland Restoration >
      • Federal Goals for Rangelands
      • Novel Ecosystems
      • Prairie Restoration >
        • Prairie Restoration Workshop
        • Weed Prevention Areas
        • California grassland restoration
        • Selah: Bamberger Ranch Preserve
      • Sagebrush Steppe Restoration >
        • Low Nitrogen in Sagebrush Steppe
      • Revegetation with Native Plants
      • Dogs as detectors of noxious weeds
    • Habitat Conservation
    • Technology solutions
    • Nudges
  • Biological Control
    • Insects as Biocontrol >
      • Impacts of Biocontrol Agents on Non-Target Species
      • Indirect Impact of Biocontrol on Native Species
    • Challenges of Using Biocontrols >
      • DNA studies on Biocontrol Insects
      • Biocontrol takes time
    • Prioritization process for Biocontrol Programs
    • Evolutionary changes impact Biocontrol
    • Vertebrates as Biocontrol Agents
  • Herbicides: History and Impacts
    • Effectiveness of Herbicides in Agricultural Lands
    • Effectiveness of Herbicides in Rangelands
    • History of Use of Herbicides and Pesticides Prior to and During WWII
    • Herbicide use during and post-World War II >
      • 2,4-D Herbicide Use
      • 2,4-D and 2,4,5-T, post-World War II
    • Modern use of Herbicides >
      • Atrazine Herbicide
      • Dacthal, DCPA
      • Dicamba Herbicide
      • Glyphosate Herbicide
      • Paraquat Dichloride
      • Picolinic acid family of herbicides >
        • Picloram (Tordon 22K) Herbicide
        • Triclopyr Herbicide
    • Herbicide Resistance in Invasive Plants >
      • Herbicide Resistant Crops
      • Controlling herbicide-resistant weeds in herbicide-resistant crops
      • Best Management Practices
    • Myth of the Silver Bullet
    • Myth of Eradication
    • Merging of Agrochemical Companies
    • Funding for Research on Pesticides
    • Impacts of Pesticides on Environment and Human Health >
      • Pesticide Drift
      • Impacts of Pesticides on Biological Diversity
      • Impacts of Herbicides on Native Plants
      • Pesticide Impacts on Insects >
        • Butterflies: The Impacts of Herbicides
        • Monarch Butterflies: Impacts of Herbicides
      • Impacts of Pesticides on Wildlife >
        • Reptiles & Amphibians: Pesticide Impacts
      • Pesticide Residue in Foods
      • Commentary on Herbicide Use
  • Interviews
    • Interviews Biocontrol >
      • Biocontrol Wyoming
      • Montana Biocontrol Interview Maggio
      • Montana Biocontrol Interview Breitenfeldt
    • California Interviews >
      • Robert Price
      • Doug Johnson
    • Colorado Interviews >
      • George Beck Interview
      • Scott Nissen Interview
    • Idaho Interviews >
      • Purple Sage Organic Farms in Idaho
    • Montana Interviews >
      • Jasmine Reimer Interview Montana
      • Organic Farms Montana Interviews
    • Texas Interviews
    • Washington Interviews >
      • Ray Willard
    • Wyoming Interviews >
      • Slade Franklin Interview
      • John Samson Interview
    • Wyoming Weed and Pest Districts >
      • Josh Shorb Interview
      • Slade Franklin Interview 2
      • Lars Baker Interview
      • Steve Brill Interview
      • George Hittle Interview
      • Peter Illoway Interview
      • Robert Jenn Interview
      • Sharon Johnson Interview
      • Larry Justesen Interview
      • Gale Lamb Interview
      • Stephen McNamee Interview
      • Allen Mooney Interview
      • Rob Orchard Interview
      • Robert Parsons Interview
      • Dick Sackett Interview
      • Comments by Delena
    • NRCS Interviews: Wyoming
  • Western Weed Control Conference 1940s Minutes
    • 1942 Conference
    • 1945 Conference
    • 1946 Conference
  • Who am I?
    • My Work
    • My Inspirations
    • My Adventures
    • Contact Page
  • Road Logs
    • Colorado Road Logs
    • Idaho Road Logs
    • Montana Road Logs
    • New Mexico Road Logs
    • Texas Road Logs
    • Wyoming Road Logs
  • Bibliography