Wildlife and Ecosystems

The key role birds, bees, and insects play in agricultural propagation is typically celebrated once a year during events such as Pollinator Week. But for many state departments of transportation, support for such “pollinators” is becoming a year-round endeavor.

Take Idaho, for one. Idaho has more than 11.8 million acres in agricultural production and many of the state’s leading crops rely on insect pollination. For that reason, the Idaho Transportation Department (ITD) is actively engaged in supporting ants, butterflies, beetles, and other wildlife responsible for helping pollinate flowering plants. 

For starters, the ITD follows the Idaho Pollinator Protection Plan – recently published by the Idaho State Department of Agriculture – and partners with both it and the Idaho Department of Fish and Wildlife to put that plan into action. 

One example of the ITD’s use of the plan’s guidelines can be found at the Interstate 84 Westbound Bliss Rest Area. A partnership between ITD, the Bureau of Land Management, the U.S. Fish and Wildlife Service, and Native Roots LLC resulted in the creation of a new “pollinator garden” located on the grounds of that rest area grounds. 

Cathy Ford, ITD’s roadside vegetation coordinator and program manager, explained that native flowering plants – such as the cordroot beardtongue and the firecracker penstemon – were added to the garden along with native plants to fit the arid environment and provide pollinator habitat. “We hope to do another one on the eastbound side in the future,” she noted.

[Editor’s note: ITD is also a part of the Candidate Conservation Agreement with Assurances or CCAA for the Monarch Butterfly – a national agreement established in April and supported by the American Association of State Highway and Transportation Officials that encourages transportation and energy firms to voluntarily participate in Monarch Butterfly conservation.]

In addition to the Bliss Rest Area, ITD has several other ongoing projects to promote pollination wellness. ITD’s District 5 is working to install pollinator plantings around its office in Pocatello, which will include small-stature flowering shrubs and perennial flowers as well as some milkweed plants – the only food source for Monarch caterpillars – salvaged in April from a state irrigation ditch construction project. The focus at the District Office is to provide blooming plants from early spring through fall to best support pollinators, Ford noted. 

Pollination “wellness” efforts also impact state DOT duties such as roadside and right-of-way moving practices. The Illinois Department of Transportation for one now uses “revised” mowing practices aimed at creating and maintaining habitat for pollinators, including the monarch butterfly. Last year, the Illinois DOT began following the Illinois Monarch Project Mowing Guidelines for Pollinators, establishing July 1 to August 15 as its “most extensive” roadside and highway right-of-way mowing period.

The agency said in a statement that by timing when mowing takes place and reducing the amount of land being mowed, the Illinois DOT is encouraging the growth of critical plant species, such as milkweed.

Back in Idaho, the ITD is also involved in the Operation Wildflower Program, where districts distribute native wildflowers to volunteer groups to seed in selected areas. Partnerships between ITD and Idaho Fish and Game led to the formation of “pollinator waystations,” created by seeding roadsides with native flowers and grasses. These efforts not only support more pollinators but also beautify Idaho’s roadways and reduce maintenance costs, Ford said.

“ITD uses a variety of native seed and pollinator plant species for re-vegetation activities on construction and maintenance projects around the state,” she added.

Photo credit: Idaho Transportation Department

State departments of transportation may soon be forced to adapt to changing rules surrounding the protection of migratory birds within transportation construction projects.

As noted in part one of this story, a notice of proposed rulemaking originally issued January 30 by the U.S. Fish and Wildlife Service (FWS) – with a comment period set to end on July 20 – would change key aspects of the Migratory Bird Treaty Act of 1918 or MBTA in terms of how state DOTs manage migratory bird populations during transportation construction activities and would prevent them from being fined for accidentally killing birds such as geese, herons, ducks, and other migratory species.

Under the proposed rule change, many requirements would be considered voluntary and could result in many protective undertakings to be abandoned. 

One example centers on the Virginia Department of Transportation Hampton Roads Bridge-Tunnel expansion project. An estimated 25,000 seabirds recently lost their nesting site of 40 years when the entire South Island of the Bridge-Tunnel project was paved over during the tunnel expansion project. In early 2020. state DOT officials began work with researchers and federal agencies to establish alternative nesting areas, but those efforts were abandoned when the proposed rule loosened repercussions for bird deaths during construction and when federal money to protect or relocate the habitats elsewhere was eliminated.

As a result, Virginia’s Department of Game and Inland Fisheries submitted a request to the Army Corps of Engineers to use dredged material to build a new bird island to mitigate the situation and Governor Ralph Northam (D) acted in February to make sure this mitigation effort would occur. The Department of Game and Inland Fisheries plans to create a new habitat for the birds by preparing the artificial island adjacent to the Hampton Roads Bridge-Tunnel and will also seek authorization to put barges in place to provide additional nesting habitat in advance of the upcoming nesting season.

Furthermore, the Department of Game and Inland Fisheries has started developing a state regulation dealing with the “incidental take” of migratory birds; a step only California has emulated to date.

That illustrates the decisions state governments and state DOTs alike across the country may face in terms of protecting migratory birds during construction and inspection activities under the new FWS regulatory initiative.

The Migratory Bird Treaty Act of 1918 or MBTA – which guides the evaluation of bird nesting areas and flight paths in order to avoid “taking” of the creature’s lives unnecessarily – may change due to a notice of proposed rulemaking originally issued January 30 by the U.S. Fish and Wildlife Service (FWS), with its comment period set to end on July 20.

That proposed rulemaking would codify the Department of the Interior’s existing interpretation that MBTA only applies to actions “directed at” migratory birds, their nests, or their eggs and would not apply to any incidental killing of birds due to commercial activity.

This action may also change the way state of departments or transportation have traditionally dealt with migratory bird regulations and would also prevent them from being fined for accidentally killing birds such as geese, herons, ducks, and other migratory species.

Migratory birds are frequently killed by industrial construction activities and accidents such as oil spills or collisions with aircraft, such as the 2009 commercial jetliner crash-landing on the Hudson River after the plane collided with geese and lost all engine power.

Migratory birds also often make their homes in highway structures or nest in areas where construction is planned and as a result, over the past decade, the MBTA’s prohibitions have been an increasing target of litigation. In enforcing the MBTA, the federal government has typically relied on its discretion and FWS guidelines that recommend best practices for certain industries. State DOTs use those recommendations along with state-specific regulations to develop their own bird mitigation efforts where transportation construction is concerned. 

However, under the current proposed rule, those efforts will become largely voluntary and could result in mitigation efforts being decreased in order to save on overall construction costs.

The move toward this proposed rule started on January 10, 2017 when a legal opinion – M-37041, Incidental Take Prohibited Under the Migratory Bird Treaty Act – interpreted the MBTA’s prohibitions and penalties as applying regardless of a violator’s intention. Under that interpretation, any act that takes or kills a migratory bird is within the scope of the MBTA prohibitions so long as the act resulted in the death of a bird. 

Yet on February 6, 2017, the M-37041 ruling was suspended for further review and then withdrawn and replaced on December 22, 2017, by the issuance of M-37050, The Migratory Bird Treaty Act Does Not Prohibit Incidental Take.

That ruling’s conclusion is an otherwise lawful activity that results in an incidental take of a protected bird does not violate the MBTA. And it is that 2017 legal ruling that the FWS’s current proposed rule would codify as a way to provide state agencies and construction companies with “legal certainty” so that they would not be fined for incidental taking of migratory birds.

Conservationists have proposed a different direction, describing instead a migratory bird incidental take permitting system in the Migratory Bird Protection Act (H.R. 5552), or MBPA, introduced on January 8, 2020, with agreed-upon best management practices providing the basis for a permit.

The Federal Highway Administration uses a similar permit system in order to work with swallow populations in construction and inspection. The Section 1439  of the Fixing America’s Surface Transportation or FAST Act authorizes the temporary take of nesting swallows that is otherwise prohibited under the MBTA.

Under the FHWA’s permitting system, the entity undertaking a bridge construction project must submit a document that contains the practicable measures to minimize significant adverse effects on nesting swallows. But those measures can often be time consuming, costly, and include timing bridge construction activities to avoid bird nesting season as well as moving and restoring nesting areas that are near the work area or constructing temporary alternative nesting areas in the vicinity of the bridge.

How are state DOTs responding to such changes in migratory bird protection rules? We’ll examine that in part 2 of this story next week.

As the Texas Department of Transportation works its way through a three-year study to determine why bats make their homes in certain types roadway bridges and culverts, other states are engaging in similar bat-preservation endeavors as well – especially in terms of mitigating the impact of bridge demolition and construction activity on bat populations.

For example, the southern region of New Mexico is home to year-round bat activity and Jim Hirsch, District 4 environmental analyst with the New Mexico Department of Transportation, said bats commonly hang out under bridges that span perennial waterways, such as the Rio Grande and Pecos rivers. 

“However, they also [hang out] under bridges that span ephemeral waterways, especially those near irrigated agricultural fields,” he added. “Most bat species are not protected by federal or state law, but the New Mexico DOT recognizes their importance in the ecosystem and the benefits they provide to the agricultural industry.” 

In addition, he said, New Mexico DOT “would rather manage bats with flexibility and adaptability, rather than by strict protocols and measures. It is in New Mexico DOT’s best interest to avoid listing of a bat species under the Endangered Species Act.”

Generally, Hirsch explained that the New Mexico DOT will install bat boxes under new bridges if the previous bridge supported daytime bat roosting activity. His agency will also perform bat exclusion measures if a bridge is scheduled for demolition or major rehabilitation during the “active season” for bat colonies.

“The active bat season usually coincides with the migratory bird nesting season in northern New Mexico,” he noted. “Therefore, avoidance and exclusion efforts usually protect both migratory birds and bats.”

A recent challenge faced by the agency is the cost of undertaking bat exclusion measure, as funds for such measures usually come from the limited resources of the New Mexico DOT’s environmental bureau budget. To change that, he said the department is evaluating cost effective partnerships with universities as well as with other state and federal agencies.

Research by the Texas DOT is creating a clearer picture of what specific types of bridge and culvert structures best buoy bat populations. The agency surveyed hundreds of bridges and culverts in West Texas over the last two years and found that state highway type pre-stressed concrete girder bridge designs situated near evergreen forests, deciduous forests, and standing water had a positive correlation to bat presence. Texas DOT also found that interstate highway and square box girder variables had a negative correlation on bat presence. 

“These results corroborate and refine anecdotal observations from decades of Texas DOT work to attract and maintain healthy bat populations on bridges, including the placement of artificial roosts on bridges that are not the right type, but are in the right ecological setting,” noted Dr. Stirling Robertson, the biology team lead in Texas DOT’s natural resources management section.

He added that those variables differed between species of bats, which is allowing Texas DOT to target species-specific bridge design solutions.

With a better understanding of the variables attracting bats to bridges and culverts, as well as the demonstrable success of artificial roost design and placement, Texas DOT is looking for future success by applying this knowledge where appropriate across the state.

“Bridges that are in the appropriate ecological setting and that are being replaced or rehabilitated give us ideal opportunities to enhance or preserve bat colonies,” Robertson pointed out. “We can also retrofit existing structures with artificial roosts if the existing design is not bat friendly.”

There may be a new mammal vying for the title of man’s best friend – and a new study is looking into how Texas Department of Transportation bridges may be key to this profitable mammal-human connection.  

Dr. Stirling Robertson, the biology team lead within Texas DOT’s natural resources management section, explained that bats help preserve the health of natural ecosystems and also provide substantial economic impacts by pollinating plants, spreading seeds and eating pests such as moths, beetles, mosquitoes, stinkbugs and termites. Some have been documented to consume as much as 85 percent of their body weight in insects every night – and bats can weigh anywhere from an ounce and a half to north of two pounds.

“Such voracious foraging on insects has definite economic impacts, especially for agricultural production,” he explained. “More than 100 million Brazilian free-tailed bats can fly nightly from caves and highway structures, like bridges and culverts, eating up all kinds of crop pests.”

In Texas’ Winter Garden Region southwest of San Antonio, a single Brazilian free-tailed bat will eat 20 insects a night. That translates to two cents per bat, per night, of ecosystem services as farmers do not need to apply additional pesticides to achieve the same yield of cotton. When extrapolated across that region, it translates to an annual “agro-economic value” on cotton ranging from $121,000 to more than $1.72 million. That’s compared to the total value of the crop in this region of $4.6 million to $6.4 million per year.

To obtain firm numbers on the economic benefits bats provide Texas and how bridge structures contribute to that benefit, the Texas DOT and Texas A&M University are in the midst of a three-year field study expected to last through May 2021 – though, due to the COVID-19 pandemic, that study may need to be extended as stay-at-home orders has shelved the agency’s field research for two months.

“Finding places to hang during the day can be a critical limiting factor for many of these temperate bat species,” Robertson pointed out. “This is why learning more about how and why bats interact with our bridges is important to the distribution and abundance of these important species.”

He said that, of the 33 species of bats that live in Texas, 18 have been documented and six potentially use Texas DOT highway structures as day roosts.

Based on several scattered records, a number of different bat species use bridges and culverts statewide in summer and winter, with studies of sites and species combinations indicating that many highway structures house more than 1,000 bats. 

“This sample is undoubtedly an underestimate of highway structure roost use in the state, but currently the frequency of this bat-highway structure interaction is unknown,” Robertson noted. That’s why Texas DOT began this study in partnership with Texas A&M; conducting a systematic inventory of bridges and culverts in the state to compare sites that have bats and those that don’t so experts can find what attracts bats to these structures.

Current research indicates that culverts that cross divided highways usually range about 200 to 400 feet long and are about 5 to 10 feet underground; creating “thermal qualities” that simulate the thermal qualities of caves, which could be a factor in the bat’s preference. By contrast, bridges provide numerous nooks, crannies and expansion grooves that offer tight spaces for bats to roost in.

A previous study by researchers at Boston University compared the development of Brazilian free-tailed pups raised in a cave to those raised under a bridge and found that the increased temperature of those bridges during the spring and summer resulted in pups that developed faster, weaned quicker, and had larger body sizes than those in a cave.

Undoubtedly, not all bridges or culverts are used by bats, thus Robertson hopes that Texas DOT’s ongoing study will help better illuminate the factors that attract bats to nest in them. “Better information on which bridges serve as important roosts for bats will also be extremely useful for the planning and timing of maintenance and construction of highway infrastructure,” he said.

Part 2 of this story will examine the work New Mexico DOT is doing to make its bridge structures more “bat friendly.”

The charismatic and familiar Monarch Butterfly serves as a “flagship species” for pollinator conservation – and a new report from the Transportation Research Board examines how transportation industry stakeholders can evaluate whether certain roadway corridors provide suitable habitats to aid in their preservation.

That report – NCHRP Research Report 942 Pre-Pub: Evaluating the Suitability of Roadway Corridors for Use by Monarch Butterflies – examines the potential for roadway corridors to provide habitat for monarch butterflies and provides tools for roadside managers to optimize potential habitat for monarch butterflies in their road rights-of-way.

This NCHRP report follows on the heels of a “historic agreement” finalized between the U.S. Fish and Wildlife Service and the University of Illinois-Chicago on April 8 that encourages transportation and energy firms to voluntarily participate in Monarch Butterfly conservation by providing and maintaining habitat on potentially millions of acres of rights-of-way corridors on both public and private lands.

The American Association of State Highway and Transportation Officials supported this effort in a two-page letter to the U.S. Department of the Interior on March 12; seeking “expedited approval” of voluntary national CCAAs to further encourage the creation of pollinator habitats in highway rights-of-way – especially the Monarch Butterfly.

“This decision gives state DOTs the ability to meet their highest priority to provide safe roads for the traveling public while simultaneously safeguarding the health of habitat for essential pollinators like the Monarch Butterfly,” noted Jim Tymon, AASHTO’s executive director.

A “historic agreement” finalized between the U.S. Fish and Wildlife Service and the University of Illinois-Chicago on April 8 will encourage transportation and energy firms to voluntarily participate in monarch conservation by providing and maintaining habitat on potentially millions of acres of rights-of-way corridors on both public and private lands.

Both signed an integrated, nationwide Candidate Conservation Agreement (CCA) and Candidate Conservation Agreement with Assurances (CCAA) for the monarch butterfly on energy and transportation lands throughout the lower 48 states.

The USFW noted in a statement that those are formal yet voluntary agreements between the agency and both public and private landowners to conserve habitats that benefit at-risk species and that it integrated both CCA and CCAA programs so energy and transportation partners and private landowners can provide conservation seamlessly throughout their properties, where there may be a mix of non-federal and federal lands.

A CCAA is for non-federal partners only and provides assurances to participants in the form of an “enhancement of survival permit” that no additional conservation measures will be required of them if the covered species later becomes listed under the Endangered Species Act (ESA).

The American Association of State Highway and Transportation Officials supported this effort in a two-page letter to the U.S. Department of the Interior on March 12; seeking “expedited approval” of voluntary national CCAAs to further encourage the creation of pollinator habitats in highway rights-of-way – especially the Monarch butterfly.

“AASHTO salutes the U.S. Fish & Wildlife Service for approving this essential agreement,” said AASHTO’s executive director Jim Tymon. “This decision gives state DOTs the ability to meet their highest priority to provide safe roads for the traveling public while simultaneously safeguarding the health of habitat for essential pollinators like the Monarch Butterfly.” 

“The regulatory protections provided by this CCAA allow transportation agencies to continue vegetation management practices with less concern that these actions will lead to an increase in the costs of regulatory compliance if the monarch is listed under the ESA,” the organization said in its letter.

The USFW said that agreement participants will carry out conservation measures to reduce or remove threats to the species and create and maintain habitat annually. And although this agreement specifically focuses on monarch habitat, the conservation measures will also benefit several other species – especially pollinating insects.

“Completing this agreement is a huge boost for the conservation of monarch butterflies and other pollinators on a landscape scale,” noted Aurelia Skipwith, USFW director, in a statement. “This is a great example of how … working proactively with our partners in the energy, transportation and agriculture industries to provide regulatory certainty for industry while addressing the conservation needs of our most at-risk species.”

“By engaging early in voluntary conservation, utilities and departments of transportation can avoid increased costs and operational delays as a result of a potential listing. This provides tremendous value to industry and will also yield big benefits to the monarch butterfly,” added Iris Caldwell, program manager of the University of Illinois-Chicago’s Energy Resources Center, which will administer the agreement.

“Not only is this the largest CCAA in history and completed on one of the fastest timelines thanks to our incredible partners, but it also represents an extraordinary collaboration between industry leaders and the U.S. Fish and Wildlife Service that can serve as a model for addressing challenges to other at-risk species,” Caldwell said.