Wildlife and Ecosystems

Construction crews with the Washington State Department of Transportation are often called upon to execute unusual tasks within their road building and maintenance activities – and that can include “going fishing” as part of stream realignment efforts.

[Above photo by WSDOT]

The agency noted in a recent blog post that a good portion of its transportation infrastructure work involves streams and wetlands, especially in the Pacific Northwest, where roads, streams, and wetlands often intersect.

For example, WSDOT pointed to the SR 167 Completion Project in Pierce County – located in an area where I-5 crosses over Hylebos Creek at the Fife curve, with tributaries and wetlands on either side of the freeway. As a result, WSDOT construction crews made changes so the freeway, creek, and wetlands can co-exist in harmony – work that included a wetland and stream restoration project, revitalizing almost 150 acres of land on either side of I-5 near the Fife curve.

[Editor’s note: The Federal Highway Administration recently issued $196 million to 59 tribal, state, and local governments to help fix or remove 169 culvert barriers to improve fish passage. The agency said outdated culverts and other related infrastructure can cause roads to flood and severely restrict or altogether block fish passage.]

As part of that restoration effort, in mid-July, WSDOT crews removed fish from Hylebos Creek so they could rebuild and realign a 2,200-foot section of the stream by mid-September. Crews carefully removed fish from the stream’s work zone and relocated them another area of the creek where they won’t be affected by construction work – a process technically known as “de-fishing,” the agency explained.

WSDOT noted its crews are only allowed to step foot or put equipment into a stream during a designated “fish window,” which is often mid-summer to early fall, depending on the stream, when the fewest number of fish are generally present.

The agency stressed that its crews are not “fishing” in the traditional sense when conducting such “de-fishing” operations. They set up and secure fine-meshed netting, dragging it in the water to encourage fish to naturally swim downstream away from the construction area – basically “shooing” them out of the area – as it is less stressful for the fish if they can swim away on their own. The crews will then secure another fine-meshed net in the stream to block off the area they just waded through so the fish do not return to the just-cleared area.

WSDOT noted that any fish stragglers trapped between the two secured nets are removed first by “seining passes” followed by “electro-fishing,” whereby a very small electrical charge in the water temporarily stuns the remaining fish so they can be gently scooped up in nets by trained fish handlers. WSDOT noted that crews keep moving downstream, repeating this entire process, until all the fish are caught and relocated safely from the construction area.

A recent video posted by the Georgia Department of Transportation details how the agency is helping “rejuvenate” a rare species of vegetation commonly known as the “​Pitcher Plant” along State Route 177 on the way to Okefenokee Swamp Park by using “prescribed burns.”

[Above photo by Georgia DOT]

The closely monitored burn occurred in 2022 during the winter on roadside right-of-way and mimics nature’s own cycle of rejuvenation. It’s also the first time Georgia DOT has used a prescribed burn to manage vegetation in this way.

The agency noted that such prescribed burns are conducted under strict safety regulations and in partnership with the Georgia Forestry Commission and the Georgia Department of Natural Resources.

The Georgia DOT added in a blog post that the Okefenokee National Wildlife Refuge in Sou​theast Georgia is a vast, mysterious wilderness of bogs, forests and swampy prairies, home to wild species that evoke fauna and flora of primeval times. Rare carnivorous plants like the Sarracenia, or “Pitcher Plant,” entrap insects and use digestive enzymes to dissolve prey.

[Editor’s note: A 2021 episode of the Environmental Technical Assistance Program or ETAP Podcast featured Matthew Quirey – a  landscape design and research fellow with The Ray – discussing how roadside landscapes, more often termed the “right-of-way,” are now being viewed as “habitat assets” instead of maintenance burdens among state departments of transportation.]

Okefenokee – a 438,000-acre wetland that is the largest blackwater wetland in North America – draws around 100,000 visitors from around the globe each year.

To reach its entrance, visitors must travel along a four-mile stretch of SR 177 that is becoming a Georgia DOT living laboratory for innovative vegetative management practices designed to protect plants in the environmentally sensitive area while simultaneously ensuring public safety.

The agency has been involved in a number of plant and pollinator support efforts in recent years.

For example, in 2021, Georgia DOT the Georgia Association of Conservation Districts or GACD installed 15 pollinator habitat sites in designated locations as part of a joint effort to educate state residents about the important role “pollinators” such as bees, butterflies, and other insects play in Georgia’s agricultural sector.

A team of University of Minnesota researchers recently wrapped up a study that examined the effectiveness of “revegetation” efforts following the conclusion of infrastructure projects statewide. That study also compiled “best practice” recommendations to transportation departments and roadside management organizations regarding post-project efforts to create pollinator-friendly habitats.

[Above photo by the Minnesota DOT]

The study – sponsored by the Minnesota Department of Transportation and the Minnesota Local Road Research Board – examined how transportation agencies “revegetate” roadsides after construction projects to provide road stability, storm water filtration, and visual appeal. Revegetation is also a good opportunity to create pollinator-friendly habitat. However, planting and maintaining ditches can be expensive, funds for such projects are usually limited, and there isn’t much data on which methods actually work, the researchers found.

“This project will help agencies across the state refine the seed mixes they use with substantial benefits to pollinator habitat,” noted Dan MacSwain, natural resource coordinator for Washington County Public Works and the technical liaison for this project, in a blog post. “It will also produce cost savings.”   

A key part of the study measured the presence of bumblebees and flowers in roadside ditches and generally found a positive link between the two – suggesting that greater flower diversity promotes stronger pollinator populations. That portion of the study also found that bumblebees are more prolific in roadside ditches where the surrounding landscape is also pollinator-friendly; suggesting that ditches alone cannot fully meet the habitat needs of insects, Snell-Rood emphasized, meaning roadside restoration efforts can generally perform better if they’re located near already-established pollinator habitat.

The insects that the survey studied – bumblebees and butterflies – showed a ready willingness to use non-native flowers for food. However, the study also points out that these insect groups are “generalists” and this amenable to feeding on a wide variety of flowering plants. That means revegetating ditches with non-native plants will not support more specialized pollinators – ones that need specific, native flowers to survive, the researchers found.

“Our results suggest that roadsides could be managed with a ‘more flowers everywhere’ strategy without raising costs,” added Emilie Snell-Rood, associate professor with the University of Minnesota’s Department of Ecology, Evolution, and Behavior and the principal investigator for the project. “[However] the ‘set it and forget it’ approach to native roadside revegetation efforts is insufficient if long-term establishment of native plants is the goal.”

For generalized, pollinator-friendly revegetation practices, the researchers recommended using an inexpensive, non-native seed mix – such as alfalfa, red clover, or white clover – mixed in with a handful of native species proven to be good at establishing themselves, such as wild bergamot, field thistle, goldenrod, and common milkweed. However, if the goal is to conserve a particular species, the roadside will need to be tailored to that species’ plant food needs.

“Our results overall suggest roadside management for natives and pollinators requires some discussions within agencies and management organizations about primary goals,” Snell-Rood said.

State departments of transportation across the country have been heavily involved in a wide array of pollinator specie preservation and growth efforts over the years.

For example, in 2021, the Georgia Department of Transportation and the Georgia Association of Conservation Districts installed 15 pollinator habitat sites in designated locations as part of a joint effort to educate state residents about the important role “pollinators” such as bees, butterflies, and other insects play in Georgia’s agricultural sector.

Out west, the Texas Department of Transportation has been working for several years to make the state’s bridges and related infrastructure more hospital to bats, especially as the nocturnal flying rodents help to naturally suppress the insect population without the use of pesticides while acting as pollinators to assist in flowering plant reproduction.

Meanwhile, the Tennessee Department of Transportation, along with the Tennessee Department of Environment & Conservation and Tennessee Department of Agriculture, formed a partnership in 2019 to support 64 acres of “pollinator meadows” at eight state parks. Each blooming meadow contains a mix of nectar-bearing plants and milkweed, which sustain pollinators such as bees, moths, butterflies, birds, and small mammals such as bats.

And in in March 2020, the American Association of State Highway and Transportation Officials sent a two-page letter to the U.S. Department of the Interior supporting “expedited approval” of the voluntary national Candidate Conservation Agreement with Assurances or CCAA to further encourage the creation of pollinator habitats in highway rights-of-way.

The CCAA – eventually finalized in April 2020 – provides a “huge boost” for the conservation of Monarch butterflies and other pollinators on a landscape scale, the U.S. Fish & Wildlife Service noted at the time.

The Arizona Department of Transportation recently highlighted the benefits of its collaboration with the Arizona Game & Fish Department (AZGFD) to reduce elk-vehicle crashes on northbound I-17 south of Flagstaff in a blog post.

[Above photo by Arizona DOT]

In 2011, AZGFD noted a high number of elk-vehicle crashes occurred along a stretch of I-17 near Munds Park.  Because a full-grown bull elk can weigh upwards of 700 pounds, crashing into something that large can destroy a vehicle and cause serious injury or death to vehicle occupants, as well as the animal. 

In 2012, after a series of studies, AZGFD and the Arizona DOT installed ungulate – “ungulate” means “hoofed mammal” – fencing in four locations near Munds Park on I-17. In most instances, Arizona DOT works crews modified existing right-of-way fences with bolts and barbed wire, eliminating the need for completely new fencing and poles.

This project produced almost immediate results, both agencies said. From the 20 documented elk-vehicle crashes that occurred along this strip of I-17 from 2007 to 2010, only one occurred between 2010 and 2014.

Arizona DOT said this is but one example of the state mitigating wildlife issues through partnerships among multiple agencies. The agency noted it also collaborated with AZGFD to construct wildlife underpasses and elk crossings along State Route 260 east of Payson and desert bighorn sheep overpasses near historic Hoover Dam on US 93.

The wildlife protection efforts undertaken by Arizona DOT are reflective of similar initiatives spearheaded by state departments of transportation nationwide.

For example, in July and August every year, the North Carolina Department of Transportation temporarily lowers speed limits from 55 mph to 20 mph on the William B. Umstead Bridge – locally known as the old Manns Harbor Bridge – at dusk and dawn during the roosting period of purple martin bird flocks.

NCDOT noted in a statement that it has collaborated with the Coastal Carolina Purple Martin Society since 2007 to educate the public about the purple martin flocks, to protect both the birds and motorists.

Meanwhile, the Colorado Department of Transportation recently completed the state’s newest wildlife overpass and underpass on U.S. Highway 160 in the southwestern part of the state, celebrating the accomplishment with a ribbon-cutting event.

To date, Colorado DOT said it has built more than 60 wildlife mitigation structures crossing above or under highways throughout the state. Additionally, it has installed 400 miles of high big game fencing along state and U.S. highways or next to the interstates.

On the research front, a report released by an international pool funded study led by the Nevada Department of Transportation in July provides an “authoritative review” of the most effective measures to reduce animal-vehicle collisions, improve motorist safety, and build safer wildlife crossings.

With as many as two million collisions with large mammals in the United States leading to approximately 200 human deaths every year, the review compiled, evaluated, and synthesized studies, scientific reports, journal articles, technical papers, and other publications from within the United States and beyond to determine effectiveness of 30 different mitigation measures.

Ultimately, the report provides best management practices to reduce animal-vehicle collisions, increase habitat connectivity, and implement cost-effective solutions, Nevada DOT said.

As the Arizona Department of Transportation starts work on the  I-17 Improvement Project from Anthem Way to Sunset Point, it is taking steps protect the natural landscape along this stretch of scenic highway corridor as well. 

[Above photo by the Arizona DOT]

The agency said its work crews are removing native vegetation – including saguaros, palo verde trees and ocotillos – from the 23-mile project corridor to temporary nurseries, before eventually replanting them alongside an improved and wider highway. 

Drivers who regularly travel I-17 between Anthem Way and Sunset Point may see some of what the Arizona DOT describes as “plant salvage” work during the next several months. Plant salvage crews from the Kiewit-Fann Joint Venture developer team will collect hundreds of viable native trees, “accents” (such as ocotillos and yuccas), saguaros and other cacti from the construction area. Altogether, roughly two-thirds of the right-of-way along the 23-mile project area will remain undisturbed, meaning no plant salvaging will be necessary.

“October is usually the prime time for salvaging the plant material, just because our temperature is not too hot and not too cold,” said David Casselbury, a landscape architect with Arizona DOT, in a statement. “We’re hoping the general public will enjoy driving along the highway and seeing this plant material back in its natural environment once the project is complete.” 

The salvaged trees and cacti are not the only plants returning to the natural landscape once the improvement project is finished, the agency added, as it plans to add native seed mixes and nursery-grown plants to the highway construction area. Those efforts help to achieve the long-term goal of successfully revegetating areas within the construction area considered “landscape-able” with a mix of plants that will thrive and restore the natural environment for years to come. 

Restoring native plants has been an integral part of many Arizona DOT projects for more than 35 years, according to the agency.

For example, Arizona DOT spent the last four years relocating a rare and endangered species of cactus growing near the Pinto Creek bridge replacement project along U.S. 60 near Globe-Miami. Initiated in 2018, this relocation effort is the latest step in a long-term partnership between the Arizona DOT and the Desert Botanical Garden in Phoenix to protect hedgehog cactuses that only grow in one tiny area of the state.

The agency also relies on ‘biomonitor’ teams from Northern Arizona University or NAU to help its work crews find and relocate endangered species – including snakes, birds and fish – from construction sites.

Specifically, those biomonitor teams train construction workers and other involved in transportation projects to identify any endangered species and what to do if they come across one. The teams also monitor construction activity and help safely remove any endangered species out of harm’s way.