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Data from: Mowing effects on woody stem density and woody and herbaceous vegetation heights along Mississippi highway right-of-ways

Citation

Entsminger, Edward et al. (2019), Data from: Mowing effects on woody stem density and woody and herbaceous vegetation heights along Mississippi highway right-of-ways, Dryad, Dataset, https://doi.org/10.5061/dryad.55vk20v

Abstract

Roadside right-of-ways (ROWs) undergo regular disturbances such as mowing, maintenance, wrecks, and road developments, which affect soils, groundwater, surface hydrology, and the composition of vegetation. Roadsides can provide and support an environment for diverse plant communities, but management practices have reduced native grasses, wildflowers, and woody plants. Woody plants are not desirable for traffic safety, maintenance, and visibility along road ROWs. Therefore, the objectives of this study were to investigate effects of roadside mowing frequency on native and nonnative herbaceous and woody plant vertical height coverage, and native and nonnative woody stem density within plant communities along highway ROWs. Ten research plots, systematically situated along Highway 25 in Oktibbeha and Winston counties, Mississippi, were subdivided to receive (a) four or more mowings annually, (b) one mowing during fall, and (c) one mowing during fall with supplemental native wildflower seeding. Upland plots were differentiated based on soil drainage in upward hills. Riparian (lowland) areas were influenced by overbank inundations from streams and drainages, and were typically spanned by bridges or box culverts. Line transects were used to sample vegetation. Two hundred seventy-seven plant species were detected, which included native and nonnative forbs, legumes, grasses, rushes, sedges, and woody perennials (vines, shrubs, and trees). Nonnative grasses exhibited the greatest percent coverage ({greater than or equal to} 90%) in all treatments. Woody plants, including vines, trees, and shrubs, comprised {less than or equal to} 8% coverage throughout the study. Percent coverage of all vegetation in different height categories differed between upland and riparian elevations (F1, 59 {greater than or equal to} 4.65, P {less than or equal to} 0.04), seasons (F1, 59 {greater than or equal to} 12.78, P {less than or equal to} 0.01), and between years (F1, 59 {greater than or equal to} 4.91, P {less than or equal to} 0.03), but did not differ in height categories among treatments. Of the {less than or equal to}8% coverage of woody plants, woody vines comprised most ({greater than or equal to}68%) of the stem counts, whereas 24% were trees and <8% were shrubs. Woody stem density did not differ among treatments nor seasons, but between elevations (F1, 59 = 3.34, P = 0.07) and during the two-year study (F1, 59 = 3.21, P = 0.08) trend was in the predicted direction (α = 0.05). Thickets of woody vines, and low-lying trees and shrubs along the roadside ROWs did not compromise height requirements needed for roadside visibility and safety. At least one mowing per year would be needed to control tree and shrub species for visibility along roadside ROWs. We concluded that a 2-year study mowing regimen found no difference between once annual and greater than three times annual mowing in the plant communities in east central Mississippi. However, one mowing per year retained agronomic plant coverage, which is useful for erosion control and soil stabilization during roadside maintenance. Proactive management implementations can include native plantings, selective herbicide use to decrease nonnatives, continual mowing from roadside edge to 10 meters (m), and only one mowing in late fall with an extension of the boundary to reach beyond 10 m from the roadside edge to suppress invasion of woody plants. Adopting this less frequent mowing regimen could reduce long-term maintenance costs for Mississippi highways.

Usage Notes

Location

East Central Mississippi
east central Mississippi