Trait-Based Filtering of the Regional Species Pool to Guide Understory Plant Reintroductions in Midwestern Oak Savannas, U.S.A

A common first step during ecological restoration is reestablishing the local species pool through active reintroduction of individual plant species. Unfortunately, the regional species pool is often far too large to be of practical use during restoration. Methods are needed to produce manageable lists of key species for directed reintroduction. We used life history traits to target species from the regional species pool (n 1⁄4 900) for reintroduction to degraded Midwestern oak savanna remnants (n 1⁄4 8) in central Iowa, U.S.A. Beginning with the full regional species pool, we first used a priori filters to remove exotic species, species that live in permanently wet habitats, and species already present at the degraded remnant savannas. Next, we created a set of filters to target species with high priority for reintroduction, based on comparisons between the degraded and regional species pools. By this process, we identified perennial forbs and grasses that may be dispersal limited (ant, passive, or heavy wind-dispersed seeds) and are conservative in habitat requirement or have affinities for high-light environments. By applying these filters, we were able to winnow down the regional species pool to a manageable number of species (n 1⁄4 111) that we recommend for initial reintroduction efforts to the degraded savanna remnants. Furthermore, we specifically targeted members of the regional species pool that could fill under-represented ecological niches at the degraded savanna remnants and discuss potential benefits of adding these species for restoring ecosystem function.