Effect of Livestock Species on Floral Resources and Pollinators in Low-Diversity Grasslands

Abstract

Livestock management influences the extent to which grazing lands provide resources for native species. We compared how livestock species – sheep or cattle – affected floral resources and bee and butterfly communities in low-diversity, post-Conservation Reserve Program (CRP) pastures managed with patch-burning. We sampled bees and butterflies three times per season 2017-2019 and counted flowering stems within 1 m of transects. Pastures grazed by sheep had significantly fewer flowers and significantly lower floral richness than cattle pastures. Native bees were three to sixteen times more abundant in cattle pastures compared to sheep. Butterfly communities were similar between grazing treatments, because agricultural-tolerant, habitat generalists comprised the majority of the butterfly community. Grassland-obligate butterflies comprised only 2% of observations. The dearth of grassland-obligate butterfly species and low native bee abundances suggest that post-CRP fields, especially those grazed by sheep, do not provide abundant and diverse floral resources for native bees and imperiled butterfly species.