A framework for cost‐effective scalable revegetation planning: Experimental evidence of early establishment using native grass species

Abstract To ensure the effective allocation of funding, revegetation projects require transparent and integrated evaluations of costs and benefits. Yet, these elements are commonly omitted or reported separately, leaving stakeholders with an incomplete picture of the resourcing required to plan effective interventions at scale. Here, we present findings from an experimental field trial establishing native grasses using three planting interventions (direct seeding, pelletized seeding, and tubestock seedlings) interpolated to three project scale scenarios (1, 10, and 100 ha). Our experiment was designed to simultaneously quantify key revegetation costs and early establishment benefits in grassland restoration. To guide our choice of empirical measures of costs and benefits, we developed theories of change (ToC) which explicitly link intervention activities to predicted outcomes and resource inputs. Our ToC allows for outcomes observed in the field to be mapped to predictions underpinning an intervention's success and guide adaptive management and planning. While the cost‐effectiveness of each planting intervention improved with increasing project scale scenario, costs and outcomes significantly differed between interventions. As expected, seed‐based interventions provided the most cost‐effective and scalable establishment outcomes compared to tubestock plantings. Tubestock, while more expensive to implement, yielded lower weed cover and more uniform establishment across target species—benefits that may justify higher costs depending on a project's early establishment goals. Our 7‐month early establishment monitoring period would benefit from complementary long‐term data to inform future decision‐making.