Fractional cover estimates of sweet clover derived from UAV, aerial, and Sentinel-2 imagery for central Montana and northwest South Dakota, 2019

Yellow sweet clover (Melilotus officinalis; clover hereafter) is a biennial legume native to Eurasia that is now present in all 50 states. Clover can grow 2 m tall and achieve high densities across large areas in the Northern Great Plains when conditions are conducive, such as in 2019. Clover is highly efficient at fixing nitrogen in soils which reduces the abundance of native grasses, while simultaneously facilitating invasion of non-native grasses, which may alter fire regimes. In contrast, clover provides considerable forage for ungulates, attracts a wide variety of insects that, along with clover seeds, are important to waterfowl, gamebirds, and songbirds, and supports numerous pollinators. Little is known about the extent of clover [...]