Pollinator-centered burn and seed restorations are beneficial to floral resources within a year of treatment

Samuel R. Wilhelm, Sean R. Griffin and Shalene Jha, Integrative Biology, University of Texas at Austin, Austin, TX, Kristen A. Baum, Integrative Biology, Oklahoma State University, Stillwater, OK, Elinor M. Lichtenberg, Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ

Background/Question/Methods
The use of restoration techniques to bolster native pollinator populations and their resources is of the utmost importance as these species face habitat fragmentation and loss. It is unknown what effect controlled burn and seed restorations have on pollinator communities, especially amidst confounding factors such as seasonality, precipitation levels, and land use history. In the winter / early spring of 2018 we facilitated 5 acre burns, 50 acre burns, 5 acre burns with wildflower seeding at sites across the Cross Timbers ecoregion of Texas and Oklahoma. Following the treatment, we monitored the blooming activity of groups of prairie forbs (native, nonnative, seeded) for 8 seasons (intervals of spring, summer, fall) as a proxy for understanding how supportive the treated landscapes would be for different pollinator groups. We predicted that following a stark drop in abundance and richness immediately following treatment our plots would produce higher floral diversity and abundances over time, with communities becoming less similar as the species pool increases. Additionally, we predicted that the flower community in plots which received wildflower seed would display a higher percentage of these seeded species relative to other treatments.
Results/Conclusions
Following a significant decrease in floral abundance of native and seeded inflorescences in 2018, 2019 saw a significant rise in the proportional abundance of native species at all treatments. Burn and seed treatments significantly boosted the proportion of seeded species at seeded plots. The presence of invasive grasses negatively impacted the success of seeded species. Treatment by year had a significant effect on native and seeded floral abundances, and it is likely that floral communities in restored plots are still in the process of stabilizing. The full effects of restoration will take several more years to ascertain, but our results suggest that, albeit for the effects of precipitation and invasive grass prevalence, burn and seed treatments are viable options for landowners looking to restore degraded landscapes for pollinators.