Wildflowers in Working Landscapes: Establishment Methods and Impacts on Pollinators and Cattle

Abstract

Insect pollinator populations are in decline globally due to habitat loss and degradation, climate change, pesticide use, and other stressors. These declines have severe implications for the ecosystem services provided by pollinators. Prior research has shown that creating wildflower plots in agricultural contexts is a promising avenue to provide pollinators with habitat. However, several questions remain regarding how these plots interact with grazing systems in particular, and how best to establish native wildflowers in the first place. This thesis explores strategies to provide pollinator habitat in agricultural landscapes, focusing on the establishment of native wildflower plots in cattle pastures over two experiments. The first study investigates wildflower set-aside plots established in pastures at a farm in western Virginia, finding that plots sown with native wildflowers saw pollinator populations more than three times greater than in control pastures (p<0.0001), and far higher floral abundance and diversity than un-enhanced pastures (p=0.013). Cattle stocked in wildflower-enhanced pastures performed similarly to those in control pastures across when all years were analyzed together (p=0.211), though in 2024 when supplemental feeding was delayed, cattle in wildflower paddocks gained less weight (p=0.04). The second experiment explored repeated tillage as a chemical-free site preparation method to reduce weed pressure and facilitate native wildflower establishment. Eight treatments were compared, ranging from minimal tillage to three rounds of seasonal tillage across the growing season, varying frequency and timing of tillage application. Following a year of site preparation, plots were winter seeded with a native wildflower mix. All treatments showed moderate wildflower establishment (>5 wildflowers/m²) though emergence rates were highly variable, and there was no strong evidence for differences between treatments. There were also no differences in the overall plant community attributable to the tillage treatments. These results suggest that tillage frequency and timing alone do not substantially influence wildflower establishment success, and site-specific factors like weed seed bank composition and other management decisions may play a more key role.