Roadsides As Vital Habitat: An Old Idea Is Getting Its Due

By Tony Romano, OKNP botanist/Conservation Coordinator

Grasslands are an increasingly rare plant community type in Kentucky and the southeastern United States. Kentucky has often been depicted as a continuous forest, but we now understand that grasslands (defined broadly here to include prairie, savanna, barrens, and woodland communities) were once much more widespread throughout the state. Estimates of pre-settlement grassland communities in Kentucky range from 2.5 to 3 million acres. These grasslands are now nearly gone, with less than 1 percent of natural prairie and barrens remaining today in Kentucky (Abernathy et al. 2010). Much of this loss can be attributed to direct conversion of habitat through agricultural and urban development. The cessation of historical disturbances such as fire and grazing by large herds of animals has allowed the remaining grasslands to be degraded and slowly converted into forests by woody succession.

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Aldo Leopold, a name that looms large in ecology, recognized over 70 years ago that roadsides were some of the last bastions of the mid-west tallgrass prairie in Wisconsin and Illinois. Even in Leopold’s time, most of the tallgrass prairie in the mid-west was already lost to the same processes that have diminished Kentucky’s grasslands. A Sand County Almanac, a collection of Leopold’s essays published posthumously in 1949, is a seminal work of ecological and philosophical writing that continues to influence the thinking of ecologists and conservationists to this day. While re-reading Almanac this past winter, I was struck by two essays that had direct bearing on the topic of this article. In Prairie Birthday, Leopold describes a remnant prairie tucked in the corner of a cemetery which borders a highway. He describes a stand of compass plant (Silphium laciniatum), perhaps the last population in that county, that blooms each July in that cemetery. Sadly, the fence separating the prairie from the road is eventually removed and the Silphium is mowed. Leopold laments that “this is one little episode in the funeral of the native flora, which in turn is one episode in the funeral of the floras of the world.”

Recognizing that things don’t need to be this way, Leopold continues “…every highway is bordered by an idle strip as long as it is; keep cow, plow, and mower out of these idle spots, and the full native flora … could be part of the normal environment of every citizen.”

In a later essay, Illinois Bus Ride, Leopold describes the vestiges of native plants and animals that he observes out the window of a bus traveling through Illinois. He notes that “In the narrow thread of sod between the shaved banks and toppling fences grow the relics of what once was Illinois: the prairie.” The foresight of these essays, that roadside remnants would become vital for grassland conservation, is truly astounding.

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In recent years, roadsides and utility right-of-ways have been increasingly recognized by ecologists and land managers for their potential conservation value. Research has shown that roadsides can provide important habitat for many pollinating insects, including at-risk species like the monarch butterfly (Hopwood 2008). Because they are maintained in an open, grass dominated state, roadsides can also contain remnants of native grassland communities that support diverse and sometimes rare plant species. Importantly, research shows that intact, high-quality, grasslands provide some of the best habitat for pollinators due to the abundance and diversity of plant species that occur in these communities (Ries et al. 2001). In other words, if we can protect high-quality roadside grasslands, we will also be providing vital habitat to insect populations. Nationwide, approximately 10 million acres of roadside right-of-ways are managed by state transportation departments (Forman et al. 2003). If successfully managed for native plant species, ten million acres is a tremendous amount of potential pollinator and grassland habitat.

Fortunately, Leopold’s old idea has gained traction. At the federal level, an important 2014 Presidential Memorandum addressed concerns over the monarch butterfly and declining populations of important pollinating insects. The memo directed federal agencies to increase or improve pollinator habitat nationwide (White House 2014). The memo additionally directed the Federal Department of Transportation to work with state departments of transportation to promote pollinator friendly practices. In accordance with this memo, the Federal Highway Administration researched and published several documents outlining best management practices (BMPs) and restoration techniques for managing roadside right-of-ways for native plants and pollinating insects (U.S. Department of Transportation, 2016).

In the Commonwealth, the Office of Kentucky Nature Preserves (OKNP) and the Kentucky Transportation Cabinet (KYTC) have partnered on a 5-year project to survey all of the state maintained roads for high-quality pollinator and grassland habitat. KYTC maintains approximately 31,000 miles of roadside right-of-way which includes the interstates, US highways, and all state highways. Surveys began in 2020, and so far our botanists have surveyed over 13,000 miles of road in over 40 counties. We have evaluated over 200 sites for pollinator habitat and have identified over 30 high-quality grasslands. We also identified over 20 additional sites that do not necessarily meet high-quality grassland criteria, but still provide important habitat for certain rare plant species like the Appalachian Rosinweed (Silphium wasiotense). This Silphium is a globally rare species (G3/S3), endemic to Kentucky and Tennessee, that thrives on forest edges along roads in eastern Kentucky. In line with the goals of the Kentucky Pollinator Protection Plan (Kentucky Department of Agriculture 2019), once important sites are identified, we are working with KYTC to modify existing management to support and benefit these grassland communities and rare plant habitats. We believe this work will help preserve the full native flora of Kentucky.

Now, there is a second old idea in Leopold’s essays that I would like to briefly touch on if the reader will permit it. In addition to his concern over the retreating prairie, Leopold was once again ahead of his time when he observed what we would now call “plant blindness” in his contemporaries. In Illinois Bus Ride he comments that “No one in the bus sees these relics. A worried farmer … looks blankly at the lupines, lespedezas, or Baptisias … He does not distinguish them from the parvenu [exotic] quackgrass in which they grow.” Leopold continues “Were I to ask him the name of that white spike of pea-like flowers hugging the fence, he would shake his head. A weed, likely.” In Prairie Birthday he states the issue directly “We grieve only for what we know. The erasure of Silphium from western Dane County is no cause for grief if one knows it only as a name in a botany book.”

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Coined in 1998 by botanists Elisabeth Schussler and James Wandersee the term “plant blindness” refers to “the inability to see or notice the plants in one’s own environment” (Allen 2003). Plant blindness among the general public diminishes peoples understanding, interest, and connection to nature. Left untreated, plant blindness can result in declines in funding for plant biology education, research, and conservation initiatives. One of the primary missions of KNPS is to educate the public about plants and alleviate plant blindness. It is my hope that OKNP’s roadside habitat project will contribute to the visibility of native plants and spark interest in learning about and conserving our native flora.

One way that readers could help our efforts is to take a look at your local backroads. OKNP’s roadside survey project is limited to state maintained roads and generally excludes county and local roads. Please join our inaturalist project and help us document important habitat by adding your observations of roadside native plants to the project at https://www.inaturalist.org/projects/kentucky-roadside-native-plants.

References:

              Abernathy, G., D. White, E. L. Laudermilk, and M. Evans, editors. 2010. Kentucky’s Natural Heritage: An Illustrated Guide to Biodiversity. University Press of Kentucky, Lexington, KY., USA.

              Allen, W. 2003. Plant Blindness. BioScience. 53(10).

              Forman, R. T. T., D. Sperling, J.A. Bissonette, A. P. Clevenger, C.D. Cutshall, V.H. Dale, L. Fahrig, R. France, C. R. Goldman, K. Heanue, J.A. Jones, F.J. Swanson, T. Turrentine, and T.C. Winter. 2003. Road Ecology: Science and Solutions. Washington, D.C.: Island Press.

              Hopwood, J. 2008. The contribution of roadside grassland restorations to native bee conservation. Biological Conservation. 141.

              Kentucky Department of Agriculture. 2019. Kentucky Pollinator Protection Plan. Available at: https://www.kyagr.com/statevet/documents/OSV_Bee_KY-Pollinator-Pro-Plan.pdf. Accessed: October 2021.

              Ries, L., Debinski, D.M., and M.L. Wieland. 2001. Conservation value of roadside prairie restoration to butterfly communities. Conservation Biology. 15(2).

U.S. Department of Transportation, Federal Highway Administration. 2016. Pollinators and Roadsides: Best Management Practices for Managers and Decision Makers. Available: https://www.environment.fhwa.dot.gov/env_topics/ecosystems/Pollinators_Roadsides/BMPs_pollinators_roadsides.pdf. Accessed: October 2021.

White House Office of Press Secretary. 2014. “2014 Pollinator Presidential Memo.” Available: https://www.nps.gov/subjects/pollinators/presidential-memo.htm. Accessed: October 2021.