MSU Graduate Investigates Presence of Monarch Butterflies and Other Pollinators in Roadside Habitats

Monarch butterfly on orange flower
Source: MS Word Image Library

Monarch butterflies (Danaus plexippus), the striking and iconic orange and black insects of postcards and motivational posters, have been in population decline since the 1980s and Thomas Meinzen, a master’s student in Montana State University’s Ecology Department, turned to a largely overlooked environment to save them. His thesis, Bees and Butterflies in Roadside Habitats: Identifying Patterns, Protecting Monarchs, and Informing Management, investigated the value of highway rights-of-way (ROWs) for pollinator, especially monarch, conservation. Supported by the Idaho Transportation Department (ITD), the project evaluated undeveloped land that parallels many roads for its potential to sustain western US monarch migrations and determined the variety of other pollinator species that used its native and non-native plants.

Thomas was advised by MSU Ecology Department Head, Dr. Diane Debinski, a butterfly specialist, in partnership with fellow ecology professor Dr. Laura Burkle, a bee specialist, and WTI’s Road Ecology Program Manager, Rob Ament. He surveyed 910 miles of southeast Idaho highways for the presence of monarchs and identified the number and location of showy milkweed patches (Asclepias speciosa – the obligate host plant of monarch larva). Thomas also noted the abundance and variety of other butterflies, bees, and native and non-native plants found in the roadside habitats.

The researchers were surprised to find that showy milkweed was quite common along SE Idaho highways, while monarch butterfly numbers had decreased alarmingly in 2021 and 2022. They were also surprised that bee variety and quantity was higher in secondary highway roadsides compared to primary and interstate ROWs, as well as areas dominated by native plants.

“Our study found that areas with diverse native flora and sagebrush steppe, in particular,” said Dr. Debinski, “had significantly higher bee richness and abundance than other sites.” At the same time, the abundance of butterflies depended almost entirely on the number of flowering plants, native or not.

The field study also developed roadside management recommendations to help insects overcome the downside of living and breeding in the ROWs. “Collisions with vehicles, pollutants, herbicides, insecticides, and disturbance caused by management practices were all hazards associated with bee and butterfly use of roadsides,” explained Dr. Debinski. “One of the goals of this research was to understand the best way to manage those areas for pollinators.” This is particularly true for monarchs, which are experiencing critically low population numbers, cannot afford to lay eggs or have their larva feed on plants that will be cut or sprayed in the middle of their lifecycle.

“Bees and Butterflies in Roadside Habitats” expressed concern that roadside habitats could become traps, luring pollinators in with healthy ecosystems and then collapsing population numbers through highway management practices or pollution. To avoid creating a population sink, the report recommended a suite of good practices, from protecting all roadside milkweed patches from herbicides and mowing, mowing smaller portions of the ROW with less frequency and never after flowering, and using pollinator-safe mowers, to spot treating weeds rather than applying herbicides to the entire roadside.

Overall, the research revealed that land along southeast Idaho highways, particularly those with lower traffic levels, was supporting a wide variety of pollinators and could provide an important role in pollinator conservation. “This is one of those areas in road ecology that is finally receiving the attention it is due, particularly given 85% of all agricultural crops require pollinators,” commented Rob Ament.

However, further research is required. “We need to figure out if roadsides are contributing to pollinator population growth or decline overall,” noted Dr. Debinski. “Future research should also determine whether roadside habitats act as corridors for pollinator dispersal; a catchy idea, but one that needs support from more data.”

IN THE NEWS: Reducing Wildlife-Vehicle Collisions in Appalachia

Marcel Huijser

Public Policy magazine In These Times recently interviewed WTI Road Ecologist Marcel Huijser for an in-depth article on wildlife crossings.  “Toward a World Without Roadkill” highlights efforts by residents and local organizations near Great Smoky Mountains National Park to reduce the rising number of bears, deer, and elk being hit by vehicles on Interstate 40.  Marcel discusses how mitigation efforts such as wildlife crossings can have significant conservation, safety, and economic benefits.

New Project: Conserving Monarch Butterfly Habitats Along Idaho Highways

Monarch butterfly on orange flower
Source: MS Word Image Library

Researchers from the Montana State University Ecology Department and WTI’s Road Ecology program will investigate the roadside habitats of monarch butterflies in Idaho, as part of a new project for the Idaho Transportation Department (ITD).

The monarch butterfly population has declined drastically in western states since the 1980s, largely due to habitat loss and fragmentation. In Idaho, the Snake River Plain is a target location for conservation and restoration activities. ITD manages a large number of highway miles and adjacent right of way (ROW) acreage in this region, but there is little data on the amount of land or the specific locations that support butterfly populations, migration routes, and breeding habitat.

For this project, researchers will conduct a field study to identify the amount and location of existing monarch butterfly habitat within ITD ROW land, as well as additional locations that could be easily restored to suitable habitat.  Monarchs and their host plants, milkweeds, are a key focus of the project, and it will also evaluate several other native butterflies and bee species that are of high conservation concern. From the findings, the research team will develop recommendations for ITD on how to manage roadsides that connect natural areas and conserve butterfly and bee populations. The research will be led by Dr. Diane Debiniski (MSU Ecology), in partnership with Rob Ament (WTI) and Dr. Laura Burkle (MSU Ecology).

As the project progresses, updates will be available on the project webpage.

Why did the bear cross the road? Because he had it all to himself

rural two-lane road with no vehicles in mountainous region

Discover Magazine Interviews WTI Researcher about Wildlife Behavior during Pandemic

Humans are staying home more and traveling less during the current COVID-19 restrictions.  What does that mean for wildlife?  Discovery Magazine recently talked to WTI Research Scientist Tony Clevenger for an online article called “National Parks Are Empty During the Pandemic — and Wildlife Are Loving It,” about what happens when there are fewer vehicles, people, and noise on public lands. Tony discusses how large species, like bears, notice and take advantage of the empty travel corridors: “As you get people off trails and reduce the amount of human activity and movement in some of these rural-urban areas, wildlife really seem to key into that.” He also discusses how parks may have opportunities to enhance their habitat conservation efforts based on what they learn about wildlife during these unique conditions.

Road Ecologist Helps Launch Wednesday Webinars

Marcel Huijser

The Society for Ecological Restoration has started a “Wednesday Webinar” series to promote information sharing and professional development in response to conference cancellations.  One of the first invited speakers was WTI Research Scientist Marcel Huijser, who led a webinar on March 25 on “Open Access: Where Road Ecology and Ecological Restoration Converge.” The presentation focused on new approaches designed to shift from providing safe crossing opportunities for large mammals to restoring habitat connectivity for a wide range of species groups.  The webinar is available on the ECR Webinar webpage.

The following day, Marcel also presented via webinar at the University of Montana, which has transitioned its courses to online delivery.  He gave a remote lecture on road ecology to the students of WILD 370, Wildlife Biology, a course taught by Professor Mark Hebblewhite, who leads the UM Ungulate Ecology Lab.

New Publications from Road Ecology

two deer crossing a two-lane highway through a forestInterested in Road Ecology research? Check out these recent and upcoming publications.

WOLVERINE TRAPPING: The Journal of Wildlife Management has published “The Sustainability of Wolverine Trapping Mortality in Southern Canada,” by Garth Mowat, Tony Clevenger, and their research team. It summarizes the team’s research study, in which they observed wolverines over a large area of southern British Columbia and Alberta, Canada, used spatial capture‐recapture models to estimate density, and calculated trapping kill rates using provincial fur harvest data. The study was also highlighted in a December feature story by the Wildlife Society: “Are southwest Canada wolverines being overharvested?

Citation: Mowat, G., Clevenger, A.P., Kortello, A.D., Hausleitner, D., Barrueto, M., Smit, L., Lamb, C., DorsEy, B. and Ott, P.K. (2019), The Sustainability of Wolverine Trapping Mortality in Southern Canada. Jour. Wild. Mgmt.. doi:10.1002/jwmg.21787

EFFECTS OF ROADS IN LATIN AMERICA. In 2020, the Environmental Impact Assessment Review will publish “Effects of Roads on Terrestrial Vertebrate Species in Latin America,” co-authored by Tony Clevenger.  It summarizes a review to qualitatively and quantitatively assess scientific research papers addressing road impacts on vertebrate species in Latin America. The paper also summarizes research gaps and recommends an approach for future research.

Citation: Pinto, F., Clevenger, A., and Grilo, C. (2020). Effects of Roads on Terrestrial Vertebrate Species in Latin America. Environmental Impact Assessment Review 81 (2020) 106337.

NIGHT-TIME SPEED LIMITS: The National Transportation Research Database (TRID) has posted the final report for the project “Effectiveness of Night-time Speed Limit Reduction in Reducing Wildlife-Vehicle Collisions.” For this project, Research Scientist Marcel Huijser and his partners investigated the effects of speed limit reductions at mule deer collision hotspots in Wyoming. The researchers studied the effects of the speed limits on vehicle speeds, on the interactions between wildlife and vehicles, and on the number of observed collisions.

Citation:  Riginos, C., Fairbank, E. Hansen, J. Kolek & M. Huijser. 2019. Effectiveness of night-time speed limit reduction in reducing wildlife-vehicle collisions. Report No. FHWA-WY-1904F. Northern Rockies Conservation Cooperative, Jackson / The Nature Conservancy, Lander, Wyoming, USA. https://trid.trb.org/view/1659707

Wolverine Research Featured on MSU Website

Black and white image of a wolverine walking through snowy forestMontana State University News Service published a feature story last week on Tony Clevenger’s wolverine research and also highlighted the story on the MSU website homepage.

“MSU research shows impact of major transportation corridor on wolverine movement” summarizes the findings from a multi-year study by Clevenger and his colleagues in Banff, Yoho and Kootenay National Parks.  Their research showed that interstate highways in the area limit the movements of female wolverines, causing isolation that can negatively impact the rare species’ population stability and growth.

The results from this research, which used noninvasive genetic sampling methods to collect wolverine DNA samples, were published in the journal Biological Conservation this summer.

The final report for the Mapping the Wolverine Way project is available on the WTI website.

MSU News Highlights Fish Passage Research on Yellowstone River

Haley Tupen and Katey Plymesser with monitoring equipment next to Yellowstone River
Haley Tupen talks with assistant professor of civil engineering Katey Plymesser, right. MSU Photo by Adrian Sanchez-Gonzalez

Graduate students at Montana State University had a great opportunity to participate in aquatics field research this summer, which was captured in feature article by the Montana State University (MSU) News Service.  “MSU engineers, ecologists seek to improve fish passage on Yellowstone River” profiles grad students Haley Tupin and Ian Anderson, who gathered data at the Huntley Irrigation project on the Yellowstone River.  The article includes numerous photos of the pair at work on the river and with the fish they studied.

The research project, conducted for Montana Fish, Wildlife and Parks, is investigating the effectiveness of a fish bypass channel that was constructed for the Huntley Irrigation Project.  The data collected this summer will help determine if fish are using the bypass to navigate around the dam.  WTI Research Scientist Matt Blank is a co-PI on the research project and serves on Haley Tupin’s graduate committee.

USFWS Sponsors New Phase of Fish Passage Research

WTI, the MSU College of Engineering, and the Bozeman Fish Technology Center (BFTC) will continue their partnership with the U.S. Fish and Wildlife Service to study fish passage and the barriers that limit fish movements.  Under a 5-year cooperative agreement, USFWS will sponsor a new phase of fish passage research projects, using the open channel flumes and swim chambers at BFTC as well as the hydraulics lab and computational/modeling facilities at MSU’s Department of Civil Engineering.  The purpose of the research program is to characterize fish swimming performance and behavior, to enhance the design and operation of fish passages, and to develop new methods that improve landscape connectivity for fish and other aquatic organisms.  The program also offers many hands-on research opportunities – in both labs and field sites – for undergraduate and graduate students.  Read more about this partnership program on the Fish Passage and Ecohydraulics Research Group webpage.

Ongoing information about this project will be posted to the Fish Passage Research (phase 2) project page.