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The predominant grazing-management practice of the Kansas Flint Hills involves annual prescribed burning in March or April with postfire grazing by yearling beef cattle at a high stocking density from April to August. There has been a dramatic increase in sericea lespedeza (Lespedeza cuneata [Dumont] G. Don) coincident with this temporally focused use of prescribed fire in the Flint Hills region. The species is an aggressive invader and a statewide noxious weed in Kansas. Control has generally been attempted using repeated herbicide applications. This approach has not limited proliferation of sericea lespedeza and resulted in collateral damage to nontarget flora and fauna. Alternative timing of prescribed fire has not been evaluated for its control. Our objectives for this 4-yr experiment were to (1) document the effects of prescribed burning during early April, early August, or early September on vigor of sericea lespedeza, standing forage biomass, and basal cover of native graminoids, forbs, and shrubs and (2) measure responses to fire regimes by grassland bird and butterfly communities. Whole-plant dry mass, basal cover, and seed production of sericea lespedeza were markedly less (P < 0.01) in areas treated with prescribed fire in August or September compared with April. Forage biomass did not differ (P ≥ 0.43) among treatments when measured during July; moreover, frequencies of bare soil, litter, and total basal plant cover were not different (P ≥ 0.29) among treatments. Combined basal covers of C4 grasses, C3 grasses, annual grasses, forbs, and shrubs also did not differ (P ≥ 0.11) between treatments. Densities of grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), and eastern meadowlark (Sturnella magna) were not negatively affected (P > 0.10) by midsummer or late-summer fires relative to early-spring fires. There were no differences (P > 0.10) in densities of grassland-specialist butterfly species across fire regimes. Under the conditions of our experiment, prescribed burning during summer produced no detrimental effects on forage production, desirable nontarget plant species, grassland birds, or butterfly communities but had strong suppressive effects on sericea lespedeza. Additional research is warranted to investigate how to best incorporate late-summer prescribed fire into common grazing-management practices in the Kansas Flint Hills.

Sericea lespedeza (Lespedeza cuneata) is a high-tannin, late-season invasive forb species that reduces biodiversity in tallgrass prairie ecosystems. The largest tallgrass prairie remnant exists in the Flint Hills of Kansas and Oklahoma, where the most common grazing management practice involves prescribed fire in early spring followed by intensive stocking with yearling beef cattle from April to July. Sericea has continued to spread under this management regime. From 2013 to 2016, in Kansas Flint Hills tallgrass prairie, we tested the effects of using spring burning with early-season steer grazing, followed by late-season sheep grazing (Steer+Sheep) compared to spring burning followed by steer grazing only (Steer) on sericea vigor, grassland birds, and pollinators. Density and nest success of Grasshopper Sparrows (Ammodramus savannarum) and Eastern Meadowlarks (Sturnella magna) were not negatively affected by Steer+Sheep relative to Steer treatments, whereas there was evidence of a negative effect in these same metrics for Dickcissels (Spiza americana). Abundance of butterflies and their nectar sources were similar between treatments but abundance of grassland specialist butterfly species was low, overall. Comprehensively, Steer+Sheep effectively controls the spread of sericea but may not create habitat for all tallgrass prairie wildlife species.