Controlling invasive plants while preserving habitats
When right-of-way (ROW) and natural resource managers return to school to learn how to control unwanted vegetation on public lands, many of them will work with Zach Lowe, a doctoral student in restoration ecology who restores native plant and animal habitats in Indiana and the Upper Midwest. For the past several years, Lowe and his colleagues at the Purdue University Department of Forestry and Natural Resources have been an important resource for state and county DOTs that are seeking to control invasive species on their properties. “Exotic and invasive plants have an extremely negative ecological impact on native ecosystems,” Lowe says. “They are rated as the No. 2 cause of biodiversity loss around the world, second only to man-made habitat destruction.”
Since 2002, when he began restoring 256 acres of wetland and prairie habitat on the school's property, Lowe's research team has hosted a vegetation management open house every September, drawing more than 400 visitors from at least 21 states. During the open house, Lowe presents research results addressing a variety of land management scenarios, including right-of-way invasive weed and brush control, prairie and native grass establishment and wetland rehabilitation. The United States Fish and Wildlife Services (USFWS), Natural Resources Conservation Service (NRCS), departments of natural resources (DNR), DOTs and parks departments from several Midwestern states are using the Purdue program to meet a variety of conservation and land management goals. The USFWS, for example, used Lowe's research as a framework to write a woody vegetation management plan for a local wildlife refuge, where efforts are under way to protect native grassland habitats. “Any type of vegetation manager can come take a look at our plots and create management plans based on our results,” Lowe says. “The Purdue project has expanded so much that the individual needs of each agency can be met.”
Since the project's inception, the Purdue team has developed methods to eliminate invasive plant species, established 38 desirable native grassland species including wildflowers and restoredto the depleted marsh. By raising the bar in vegetation management and showing land managers tangible results, Lowe's research fosters a conservation ethic among vegetation management professionals who look to Purdue as an invasive plant species management resource. “Students and professionals for the next 20 years and beyond will look at the progress of this restoration project to aid them in making land-management decisions,” Lowe says.
Minnesota emphasizes wildlife
Not far from the Indiana prairies, the Minnesota Department of Transportation (Mn/DOT) operates under a principle similar to that of Lowe's research team: form partnerships to protect native habitats and wildlife. The sweltering summers, icy winters and construction season consistently stress the state'sas well as the Mn/DOT highway maintenance personnel who must maintain them. In addition to roadway maintenance, Mn/DOT is responsible for vegetation management, including controlling invasive weed species and developing wildlife habitats.
Mn/DOT and the Minnesota DNR use their Roadsides for Wildlife Program, which gives money to counties and cities that implement native plant restoration programs, to increase vegetation and habitats for birds and small mammals while minimizing the number of deer along roadsides. Minnesota deer populations pose a significant hazard to drivers when non-native species of alfalfa and clover are in roadside areas. Fortunately, Mn/DOT plants native species that are less attractive to the deer in roadside right-of-way zones. Additionally, native birds and small mammals use native grasses found in managed roadsides for nesting and foraging.
Roadsides for Wildlife Coordinator Tom Keefe, a 25-year veteran of the DNR, works with Dan Gullickson, Mn/DOT Living Snow Fence Program coordinator, and Dwayne Stenlund, Mn/DOT erosion and sediment control professional, to ensure that vegetation management practices meet residents' needs. “More than 40 species of birds and animals nest on the ground or in low vegetation,” Keefe says. “We need to protect the areas essential to ringneck pheasant, bobolink, cottontail rabbits and waterfowl, and keep the deer out so drivers are safe.”
Stressing limited disturbance of the vegetative cover during the nesting season from spring to Aug. 1, Roadsides for Wildlife also recognizes that spot mowing and careful spot herbicide applications are needed to control weed species and invasive vegetation. “We work closely with the DNR to get recommendations when we set our maintenance calendars,” Gullickson says. “They not only help us avoid disturbing the nesting birds and animals, but make great recommendations about native plants we can plant to keep deer out and reduce the amount of maintenance over a period of years.”
The combination of DNR expertise and cost share money has restored more than 1,000 acres in the state over the past 10 years. “It's great to work with the excellent botanists and foresters at Mn/DOT on their maintenance program,” Keefe says. “We can restore habitat for birds and animals, and expand the reach of viable native plant stands in Minnesota roadsides, while still keeping safety and maintenance at the forefront.”
A southern exposure
With the nation's densest concentration of federally protected natural areas, Calhoun County, Ala., faced a similar challenge of balancing the needs of civilization with those of nature. Surrounded by the Talladega National Forest, Mountain Longleaf National Wildlife Refuge, Nocalula Falls, Lookout Mountain, the Appalachians and the Coosa River, the county is a wellspring of valuable native species worth protecting from invasive plant monocultures.
However, snaking through the abundant scenic outposts are the county's public roads. Calhoun County Highway Department Project Manager Brian Conary, a 12-year veteran of the CCHD vegetation management program, and his team have developed an innovative strategy to maintain county roadsides by eliminating unwanted vegetation on a limited budget. Controlling Johnsongrass is his biggest challenge.
Johnsongrass is a resilient and prolific seed producer, which makes it difficult for bermudagrass to maintain a foothold in roadside ROWs. Because the plant can grow more than eight feet tall, it poses a significant safety hazard for drivers by blocking sight lines. Its height also prevents wildlife species from foraging or nesting in its stands.
A mowing program was used initially to maintain Johnsongrass height, but it was found to be too expensive and time-consuming and did not protect the native grass species or wildlife living in the roadside areas. The mowing program also released yellow foxtail, giant foxtail and marestail — all unwanted weed species. Yellow and giant foxtail are annual grasses that thrive in disturbed areas, such as roadsides, and out-compete bermudagrass. While foxtail grows to only about three feet, marestail can grow as tall as 10 feet, sometimes surpassing Johnsongrass.
In response, Conary tested herbicides to control Johnsongrass, foxtail and marestail in the roadsides, finding that he could meet all the county's vegetation management goals without causing harm to native species. “Before implementing chemical control methods into our program, we mowed twice per season, but now we mow only once, with minor touch-ups and spot work when needed,” Conary says. “Although herbicides are an up-front cost, they actually save the county money over the course of the season by reducing annual mowing expenses.”
Conary only uses state-certified applicators and ensures that his team attends all available training offered by the state. “In addition to the training, we gather as much current information about invasive plants from the Alabama Vegetation Management Association and the Alabama Department of Transportation (DOT), so we can prepare for new weeds coming our way,” Conary says.
Staff from other counties, the Alabama DOT and the Agriculture Department visited Conary's roadside demonstration plots in summer 2005. “These folks wanted to see where we've been and where we're going,” Conary says. “They could see parallels to their own situations, and work out how to get their own programs going.”
Conary says he is proud of what CCHD has accomplished in recent years. “I'd like to see good stands of bermudagrass, and we're getting there, slowly but surely,” he says. “We're keeping resistance in mind and preparing for any new invasive weed. The cost savings we've achieved with our program allows us the flexibility to adapt our treatment to whatever comes next.”
Dan Beran is a market development specialist for Research Triangle Park, N.C.-based BASF Professional Vegetation management.