Plant species use and presence among Great Plains United States Department of Agriculture Conservation Reserve Program grasslands

Introduction The United States Department of Agriculture (USDA) Conservation Reserve Program (CRP) supports grassland reconstruction practices that vary in what plants are seeded into enrolled sites. Although the program is federally administered, methods and species used in CRP plantings are locally determined. Objectives We assessed seeded species composition and subsequent presence in CRP grasslands enrolled under a suite of grassland practices. Methods We obtained seeding information for 109 sites distributed across the United States Great Plains and recorded plant species encountered along a 200 m transect at each site in summer 2022. We evaluated how seeding efforts contributed to site species pools using generalized linear models and used species turnover and Principal Component Analyses to summarize variation in seeded and site species composition. Results One hundred sixty‐three species were seeded throughout the region. Seeded species composition varied with an east–west environmental gradient. Seed mixtures varied with conservation practice, but these differences were weaker in the field. A third or more of the species at each site was derived from local species pools, and there was a stronger effect of location and site characteristics on site species pools due to this variation. Conclusions Despite efforts to introduce many species, only a handful consistently and successfully established across sites, and they did so in a way that was consistent with background environmental variation.