Despite being a non-native species, bermudagrass is certainly no stranger to Oklahoma. In fact, data from Oklahoma’s ecological system mapping project revealed that bermudagrass was the most commonly encountered plant species across the state. Unfortunately, the presence of bermudagrass across the landscape creates many challenges to landowners trying to manage for bobwhite quail. Realizing the negatives of bermudagrass for bobwhites and considering management options can be helpful for controlling this aggressive species.
Bermudagrass Negative 1: Poor Growth Form
Bobwhite quail require a substantial amount of bare ground for easy travel and for finding seeds and insects. The sod-grass growth form of bermudagrass, however, essentially eliminates bare ground, especially over time. The bunchgrass habit of several native warm-season grasses such as little bluestem, big bluestem, sideoats grama and Indiangrass are generally prevalent within good to excellent bobwhite habitat because they provide the open space that quail require. In addition, the open space between grass clumps allows a diversity of other grasses and forbs to establish, which elevates the attractiveness and value of the habitat for quail. Although research has shown that adult and sub-adult quail can maneuver through stands of bermudagrass to some extent, their movements are greatly slowed because of the lack of bare ground.
Bermudagrass Negative 2: Aggressive Competition for Space
Plant diversity is one of the key components within good bobwhite habitat. Simply put, bobwhites require a large variety of plants throughout the year to provide for their everyday needs, including food and cover. Unfortunately, bermudagrass is an aggressive competitor for nutrients, water and sunlight. It aggressively spreads by above-ground and below-ground runners. Over time, bermudagrass can form extensive stands and all but eliminate other plant species from establishing. In addition, bermudagrass has allelopathic properties that can further inhibit the growth of nearby plants. Overall, monoculture bermudagrass areas fragment the landscape for bobwhites.
Bermudagrass Negative 3: Poor Nesting Cover
Bobwhites are generalists when it comes to nesting. However, even generalists have their limits, and bermudagrass simply doesn’t provide optimal nesting cover for quail. Instead, bobwhites often select the dead growth of warm-season bunchgrasses such as little bluestem, broomsedge bluestem, sideoats grama and switchgrass for nesting cover, especially those clumps that are about 10 inches in diameter and at least 8 inches in height. While bermudagrass can grow to heights of 10 inches or more, its sod-like growth rarely produces enough aboveground structure to effectively hide bobwhite nests, especially in areas where it is grazed by livestock.
Bermudagrass Negative 4: Poor Brooding Cover
Adult quail lead young broods to forb-rich habitats almost immediately after hatching as these weed-dominated areas usually provide an abundance of bare ground and nutrient-rich insects under a dense canopy of leaves. While many forbs and grasses can provide suitable brood cover, a diverse mix of plants is best to maximize insect diversity and abundance. Unfortunately, because of its sod-like growth form and competitive nature, large stands of bermudagrass rarely offer suitable brood habitat and can actually trap very young chicks within the thick growth, exposing them to predators and weather extremes. In addition, the sod-like growth limits maneuverability of young chicks and impedes their ability to catch insects.
Bermudagrass Negative 5: Poor Food Value
Bobwhites are known to consume the seeds and/or vegetative stems/leaves from more than 1,000 plants across the bobwhites range. Included in that list of plants is bermudagrass. However, the importance of bermudagrass as a dietary item for quail as well as its selection by quail as a food item should not be overlooked. Of the more than 40 bobwhite food habit investigations that were searched, only one investigation reported bermudagrass seed in the diet of bobwhites, and its use was less than 0.1 percent overall. Bermudagrass does attract some insect species that are readily eaten by quail, but these insects are largely unavailable in dense bermudagrass stands as these sites provide such poor maneuverability. Overall, the very limited food value of bermudagrass is further diminished by its poor cover value. Therefore, bermudagrass is considered a poor to worthless dietary item for bobwhites.
Eradicating bermudagrass is improbable at best. Therefore, the key is simply control. That is, controlling its spread into and within quail habitat as well as controlling its dominance within unsuitable habitat to enhance the site for quail. Unfortunately, controlling bermudagrass is difficult without the use of herbicides and is generally short-lived without multiple herbicide treatments over a period of two years or more.
When planning an herbicide treatment, it is important to remember that bermudagrass is immune to nearly every herbicide when it is applied during the dormant period including the winter and early spring months and during periods of extreme heat and drought. Therefore, it is important to spray only during an active growth period which, in Oklahoma, is optimum during June. Although the specific herbicide options are many, both grass-selective herbicides and non-selective herbicides have proven effective in the control of bermudagrass (see table).
Grass-selective herbicides are formulated to control specific weeds but are much less toxic to other plants. Non-selective herbicides are formulated to control both broadleaf and grass weeds. Prior to spraying, however, it is highly recommended to burn the stand of bermudagrass during March or heavily graze the stand during April and May to stimulate new, fresh growth. While mowing is another option to stimulate new growth, the heavy thatch can blanket growing plants and prevent the herbicide from coming into contact with growing stems and leaves. Monitoring the areas that were sprayed and spot spraying problem areas is a must for at least 12 months and can go a long way in maximizing control of bermudagrass. Over time, native annual and perennial plants will establish and, with a little luck, quail will follow.
For questions about improving habitat for quail, including free habitat evaluations, contact Kyle Johnson, quail habitat biologist, at (405) 684-1929 or check out the “Oklahoma Quail Habitat Guide” on the Oklahoma Department of Wildlife Conservation website,www.wildlifedepartment.com.