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 Rangeland
    • 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
    • My Inspirations
  • 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
    • Agricultural Best Practices >
      • Ecologically based Successional Management
      • 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
    • Grazing Solutions >
      • Sheep and Goat Grazing
      • Cattle & Sheep Grazing
      • Cattle and Bison Grazing
      • Grazing and Revegetation
    • 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
    • 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
      • 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
    • 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
    • Funding for Research on Pesticides
    • 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 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

The Impacts of Herbicides on Butterflies and
Their Host Plants

Photo: Broom snakeweed, NE New Mexico. © 2017 Delena Norris-Tull

Impacts of Herbicides on Butterflies and Their Host plants
 
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, October 2020.
​

Schultz & Ferguson, 2020, analyzed the impacts of herbicide-based restoration on habitat for the endangered Fender’s blue butterfly (Icaricia icarioides fenderi) and the threatened Kincaid’s lupine (Lupinus oreganus), the host plant for the butterfly larvae. These two species persist in highly degraded prairie remnants in western Oregon. They commented that, while there are a number of studies on the impact of herbicides on native plants, very few studies investigate the impacts of herbicides on animals (including insects).
 
Oregon has placed a priority on restoration of prairie remnants, as most of the habitats have been lost, and remaining habitats have been greatly degraded by invasive plants. Controlled fires and mowing have been useful in reducing invasive woody plants, but these have had limited success at reducing invasive grasses. In the Willamette Valley prairies, the main grass-specific herbicide in use is fluazifop-p-butyl, which has been shown to be effective at reducing invasive grasses, while having limited impacts on native forbs, native bunchgrass fescue, and butterflies.
 
Schultz & Ferguson, 2020, conducted field experiments in two remnant prairies west of Eugene, Oregon. Some plots received a chemical-free strategy of annual fall mowing plus seeding with native species in 2013, 2014, and 2015. The other plots were treated with the same strategy of annual fall mowing and seeding, and supplemented with an annual herbicide application in late March, 2014, 2015, and 2016.
 
Each June, butterfly eggs, lupine leaves, racemes, and seedpods were counted in five randomly selected lupine plots that had at least 30% lupine cover. The following April, larvae were counted, and larval feeding damage was assessed. Due to low counts of larvae in one site, in 2014 the plot sizes were increased. The counts were completed each year 2013-2016.
 
Schultz & Ferguson, 2020, results: “Herbicide treatment was associated with increases in [butterfly] reproduction, as measured by egg abundance and eggs per leaf, but only in some sites and some years… Density of eggs per leaf and overall egg abundance was much lower at Willow Creek than Fern Ridge and there were no years [at Willow Creek] in which higher egg abundance was associated with herbicide treatments….The effect of the herbicide treatment at [Fern Ridge] was not sustained and fecundity was significantly higher in the [chemical-free] plots in the following year. At Willow Creek, overall fecundity was much lower in 2015 than 2016. Here fecundity was higher in the [chemical-free] plots in 2015 and there were no notable effects of herbicide treatments in 2016.”
 
“Annual [butterfly] population growth rate was higher in herbicide-treated plots at Fern Ridge in 2014, but this effect was not sustained. There were no notable differences in estimated annual population growth rate in 2015 or 2016 at Fern Ridge or Willow Creek.”
 
“Overall, the abundance of Kincaid’s lupine leaves did not change in response to treatments… We did, however, see a response in Kincaid’s lupine seedpods. At Fern Ridge in 2016, there were more than twice as many pods in herbicide-treated plots than [chemical-free] plots…,and at Willow Creek, there were twice as many seedpods in herbicide-treated plots as [chemical-free] plots in both 2014 and 2016… There were more seedpods in herbicide-treated plots than [chemical-free] plots at Fern Ridge in 2016 and at Willow Creek in 2014 and 2016.” They also documented that “secondary invasion by non-native forb species increased over time in these plots.”
 
Schultz & Ferguson, 2020, “We conclude that grass-specific herbicide application can be included as a restoration tool in Fender’s blue butterfly habitat, but only if it results in reaching restoration goals unrelated to butterfly population enhancement….For the butterflies, and other nontarget invertebrates, there are no prior studies assessing effects on survival and fecundity in a field setting.”
 
Bennion, Ferguson, New, & Schultz, 2020, expanded on the study by Schultz & Ferguson, 2020, using the same data on treatments. They examined additional plant community dynamics, for one year prior to the treatments and for three years during treatment. They reported the following results: herbicide treatment did have the intended impact on invasive grasses, by reducing height of the grasses relative to the lupines. Surprisingly, lupine cover increased in the control plots but not in the herbicide plots. “Nectar production declined in 2015 but increased back to 2014 levels in 2016… We found control plots in Fern Ridge to have more nectar resources than herbicide plots... At Willow Creek in 2014–2015, there was no notable difference in nectar production between control and herbicide plots. However, in 2016 we noted a substantial increase in the herbicide plot relative to the control plot…. Annual sampling along transects detected 94 species of plants in the two conservation areas... We observed a general trend of exotic forbs (and one native fern) increasing in frequency relative to native forbs... We identified 10 exotic and one native forb species as well as one native fern that showed substantial increases in frequency in at least one plot following [herbicide] treatment.”
 
Bennion, et al., 2020, conclusions: “The application of grass‐specific herbicide met the management objective of altering the structure of Fender's blue habitat by reducing the height of invasive grasses and increasing the apparency of Kincaid's lupine, but resulted in unexpected costs…. Many restoration studies that focus on invasive species fail to monitor the response of native community…. We found 11 species, including false dandelion, each of which substantially increased in frequency as a result of herbicide treatment. Three of these species are native: coast tarweed, bracken fern, and wild strawberry… There are seven other exotic forbs that have increased substantially… We cannot predict the combined effect of all nine prominent invaders. Their interactions have the potential to result in a net gain for invaders relative to native species…. To promote establishment of nectar species we seeded native forbs throughout the experiment. Some species (e.g. Allium amplectans and Iris tenax var. tenax) gained in frequency while others declined or never established (e.g. Sidalcea malviflora ssp. virgata or Camassia leichtlinii) following seeding, but this change did not result in a net increase in nectar production in herbicide plots…. The treatment of invasive species with taxa‐specific herbicides can facilitate the establishment of species from other functional groups and thus begin the invasion treadmill.”

References:
  • Bennion, L.D., Ferguson, J.A., New, L.F, & Schultz, C.B. (Jan. 9, 2020). Community-level effects of herbicide-based restoration treatments: Structural benefits but at what cost? Restoration Ecology, 28(3). https://doi.org/10.1111/rec.13118
  • Schultz, C.B., & Ferguson, J.A. (May, 2020). Demographic costs and benefits of herbicide-based restoration to enhance habitat for an endangered butterfly and a threatened plant. Restoration Ecology, 28(3): 564-572.

Next Section on impact of pesticides on insects:
  • Monarch Butterflies: Impacts of Herbicides

Next Sections on impacts of pesticides:​
  • Wildlife: Impacts of Pesticides
  • Pesticide Residue in Foods
  • Funding for Research on Pesticides
  • Commentary on Herbicide Use
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 Rangeland
    • 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
    • My Inspirations
  • 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
    • Agricultural Best Practices >
      • Ecologically based Successional Management
      • 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
    • Grazing Solutions >
      • Sheep and Goat Grazing
      • Cattle & Sheep Grazing
      • Cattle and Bison Grazing
      • Grazing and Revegetation
    • 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
    • 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
      • 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
    • 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
    • Funding for Research on Pesticides
    • 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 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