Water availability mediates the effectiveness of precision and bet‐hedging seeding strategies in wetland restoration
Hailey M. Machnikowski, Karin M. KettenringAbstract
Introduction
Hydrologic extremes such as drought are projected to intensify with climate change, challenging wetland revegetation. Seed‐based restoration is widely used because it is cost‐effective and scalable, but establishment often fails under unsuitable moisture conditions. Two frameworks may improve outcomes under uncertainty: precision restoration, which matches treatments to site conditions, and bet‐hedging, which diversifies strategies to spread risk. These approaches remain largely untested in wetlands.
Objective
To compare the effects of precision and bet‐hedging seeding strategies on plant community recovery in wetland restoration.
Methods
We evaluated one precision treatment (5‐species mix) and three bet‐hedging treatments: a diverse species mix, delayed germination, and multi‐year sowing at two hydrologically distinct sites in Great Salt Lake wetlands, Utah, United States. We measured native and invasive plant cover, community composition, and labor and seed costs.
Results
Hydrology dominated restoration outcomes. At Farmington Bay, rapid drying suppressed establishment across all treatments, indicating that neither strategy can overcome severe moisture limitation. At Howard Slough, where soils remained saturated, the precision treatment produced the highest seeded cover in year one. By year 2, seeded cover converged across treatments, but multi‐year sowing reduced invasive cover relative to the unseeded control. Precision and diverse mix treatments required the least labor, whereas multi‐year sowing required approximately 3× more effort but provided the strongest ecological benefits over time.
Conclusion
Water availability strongly constrains seed‐based wetland revegetation. Precision approaches promote rapid establishment under favorable conditions, whereas repeated sowing can improve longer‐term outcomes by reducing invasive cover, albeit with greater labor demands.