| dc.description.abstract | Mixed-grass prairies of the northern Great Plains evolved following frequent disturbances such as drought, fire, and extensive grazing by ungulates. As a result of periodic natural disturbances, native grass reproductive mechanisms have adapted to withstand frequent disturbance. Ninety-nine percent of native perennial grasses reproduction occurs through well-protected and densely structured axillary buds. Since vegetative buds are the primary driver of aboveground growth, bud response to differing seasons and fire return intervals may reveal strategies to enhance bud dynamics. The timing of fire may transition dormant buds into active buds elucidating the mechanism responsible for aboveground growth following fire. My objectives were to: 1) reveal belowground bud characteristics of Bouteloua gracilis (Willd ex. Kunth) Lag. ex Griffiths) (C4 species), Pascopyrum smithii (Rydb.) A. Löve) (C3 species), and Hesperostipa comata (Trin. & Rupr.) Barkworth) (C3 species), 2) examine immediate fire effects on belowground bud activity, dormancy, and mortality following seasonal fire and fire return interval treatments, 3) quantify short-term belowground bud dormancy, activity, and mortality trajectories following fire, and 4) determine the effects of soil moisture and soil temperature on bud growth and maintenance. Belowground bud characteristics differed among species, where B. gracilis produced the most buds (6 ± 4 buds tiller-1), P. smithii produced an intermediate amount (4 ± 2 buds tiller-1), and H. comata contained the least amount of buds (3 ± 3 buds tiller-1). Fire treatments did not result in immediate, direct mortality of B. gracilis, P. smithii, or H. comata buds. However, fire treatments enhanced bud activity and reduced dormancy for B. gracilis and P. smithii. Season of fire and fire return interval directly manipulated bud activity, dormancy, and mortality for these species throughout two or more growing and dormant seasons following fire. Soil moisture was found to be a good predictor for bud growth of cool-season species and soil temperature was a reliable predictor for warm-season species bud growth. Prescribed burning can be used to manipulate bud bank dynamics as a management tool and belowground bud dynamics can also be used to improve post-fire management strategies in wildfire situations. | en_US |
