Get reliable science

The interacting effects of fire and grazing influence structure, composition and functioning across grasslands globally. Management focused on restoring the interaction of fire and grazing through patch-burn grazing is well-studied throughout the central and southern plains of North America. However, few studies examine this management strategy in drier climates, like that of the northern Great Plains, and minimal research exists on how sheep interact with fire. Furthermore, the westward expansion of the Corn Belt has diminished the rangeland available for sheep and grassland-dependent wildlife, making the adoption of a management strategy that can maintain economic stability while promoting biodiversity especially important in this region. We examined how different domestic herbivores (moderately-stocked sheep or cattle) affect biodiversity by assessing butterflies and the floral resources they depend upon in a landscape managed with patch-burn grazing (3, 65-ha pastures per grazer). We sampled butterflies three times per season using line-transect distance sampling and counted all flowering stems within 1 m of transects. Our first field season was conducted during a severe drought (21 cm below average), and showed notable differences in available floral resources between pastures grazed by different herbivores. Within cattle pastures we observed 35 total forb species with an average of 1.45 flowering stems/m2 (se = 0.17), while in sheep pastures we only observed 12 species of forbs with an average of 0.22 flowering stems/m2 (se = 0.03). Butterfly species richness followed a similar trend with 17 species detected in cattle pastures and 14 observed in sheep pastures. Despite these contrasts, butterfly abundances were similar between grazing treatments. Continued monitoring of how different herbivores in a patch-burn grazing framework affect butterflies and floral resources will provide important insights into how range management can better support pollinators, especially in areas where sheep are the dominant livestock.