Repeated annual seeding and higher seeding rates show potential to improve recruitment outcomes in a post-fire dryland ecosystem

Introduction Seeding is a widely used tool to restore drylands after wildfire, yet success is often limited by interannual climate variability. Combining repeated seeding over multiple years with higher seeding rates may increase the likelihood of successful establishment in the face of interannual climate variability while also addressing competitive dominance of invasive, non-native species.Objective This study investigates how repeated seeding over multiple years and higher seeding rates interact to influence post-fire restoration outcomes, focusing on sagebrush steppe in the Great Basin (U.S.A).Methods Using a fully factorial experimental design, we broadcast seeded a native seed mix (perennial forbs, grasses, and shrubs) at a low or high seeding rate. Seeding occurred either 1 year after a fire, 2 years after, or in both years. Treatments were applied across an elevational gradient to account for local-scale environmental variability.Results In the first year, precipitation was below the long-term median and temperatures were above the long-term median. The second year experienced above-median precipitation and below-median temperatures. Perennial forb recruitment was highest in plots seeded during the second year with the high seeding rate. No recruitment was observed for the perennial grasses and shrubs.Conclusions Our results show potential for the combined use of repeated annual seeding and higher seeding rates to increase the establishment of perennial forbs by simultaneously increasing the likelihood that seeding occurs during a favorable year and overcoming potential establishment barriers from lower seeding rates when climate conditions are favorable.