Landscapes adjacent to highways provide the opportunity for increasing biodiversity. Ecological systems are more robust and are able to rebound from stresses if they are more diverse. Recent research, especially that of Doug Tallamy (2007) at the University of Delaware, is showing that landscapes designed with attention to plant selection that includes regional natives can have a dramatic positive effect on the biodiversity of that area.
Lack of Biodiversity
Most areas adjacent to highways are not now designed with an eye toward increasing biodiversity. As the plant palette that we use in landscapes adjacent to highways narrows, we unwittingly also determine the fate of many species of butterflies and birds that have relied on the native plant communities for their survival. Tallamy has compiled the research that connects plant selection with the wildlife communities that rely on these plants.
Highway development has reduced habitat for many species, but by careful attention to plant selection in the design of adjacent landscapes, we can restore the ecological balance that once existed in these places. The result can be highway landscapes that provide aesthetic value to the traveler as well as environmental value to the butterflies and birds.
Better Use of Adjacent Land
We can achieve the environmental benefits outlined above by more creative and thoughtful use of highway rights-of-way, including road sides, interchange infields and median strips. The land that is a part of our highways is a public resource that is greatly underutilized to provide cleaner air, cleaner water and to reduce net carbon emissions. In the United States, we have an estimated 4 million miles of roads with 60 million acres of right of way, which now is largely managed by mowing and spraying with herbicides as an afterthought and nuisance (Thompson, 2006). Federal transportation policy should incorporate a component that incorporates better use of this resource in new projects and converts existing rights-of-way to improve the ecological services they provide.T
In urban areas and along corridors where the right-of–way does not permit development of robust ecological services, projects can be planned in the adjoining neighborhoods, parks and other public spaces to accomplish similar objectives.
Delaware Leads In Green Highway Design
he State of Delaware is a leader in improving the ecological services provided by its highway rights-of-way. Through its "Livable Delaware” initiative, DelDOT has developed standards for roadside plantings and maintenance that consider the ecological services that these areas could provide if planted and maintained properly.