Plant community recovery following Sericea lespedeza (Lespedeza cuneata) removal: testing for a soil legacy effect

Abstract

Restoration of plant communities can be hindered by the legacy of previously established invaders, despite their physical removal from the community. Current evidence, mainly built on short‐term greenhouse experiments, suggests that Sericea lespedeza (Lespedeza cuneata) invasion not only suppresses native plant species, but also alters soil conditions in host communities. As a result, L. cuneata may create a soil legacy that impedes plant community restoration. We examined the response of a Kansas grassland following L. cuneata removal to determine if historical L. cuneata abundance affected (1) plant community composition and (2) the establishment of additional native species. To address these questions, L. cuneata seeds were sown into 300 plots at a wide range of densities under different combinations of simulated disturbance and soil fertilization. After a three‐year establishment period, L. cuneata was removed from the community, and 13 native forb species were sown into all plots. Over 4 years, we found little evidence for a soil legacy effect that influenced community response post‐removal. Although there was a detectable relationship between community composition and L. cuneata, the variation explained by this relationship was very low. Similarly, the establishment of sown native species was unrelated to the historical abundance of L. cuneata. These results indicate that, regardless of initial density, L. cuneata does not impede plant community recovery in this system if effectively controlled within the first 3 years of invasion, and legacy effects inferred from greenhouse experiments may not translate to impacts on the plant community in the field.