Aboveground Biomass Removal by Burning and Raking Increases Diversity in a Reconstructed Prairie

Abstract

Abstract Prescribed spring burning often contributes to a predominance of C4 grasses and low forb abundance and is impractical at many sites, especially near development. We tested raking after mowing as an alternative to prescribed burning in a reconstructed Minnesota prairie. We also tested mowing without raking as a possible means of maintaining prairie communities. Frequency, flowering stem abundance, and cover were measured for all plant species and native functional groups (C4 grasses, C3 graminoids, forbs, legumes, and annual or biennial forbs). Mowing alone did not differ from the control in its effect on any functional groups of plants. Round‐headed bush clover (Lespedeza capitata), a legume, and Black‐eyed Susan (Rudbeckia hirta), a biennial, increased in frequency with treatments that removed biomass (i.e., fire or raking), but they did not have significantly more flowering stems. Thus, new plants established well from seed, whereas the vitality of mature plants did not change. Raking had similar effects to burning on most functional groups, although flowering stems of C4 grasses were significantly more abundant after fire than after raking. Burning reduced some C3 forbs and grasses and favored the dominance of C4 grasses. Therefore, raking after mowing in the spring provides an alternative to prescribed burning that has many of the same positive aspects as fire but does not promote aggressive C4 grasses to the same extent.