The effects of seed enhancements on plant establishment in native grasses: A meta‐analysis

Abstract

QuestionsNative grasses are widespread with high commercial value and demand across the restoration sector, though their uptake is often hampered by seed‐use challenges. Seed enhancement technologies (SETs) provide a valuable tool for improving plant establishment outcomes for species (such as native grasses) where seed‐based approaches are essential to achieve large‐scale targets. However, due to the increased investment in resources and time associated with application of SETs, their adoption is dependent on the ability of these treatments to consistently provide benefits to one or more demographic life stages, particularly under field conditions. This meta‐analysis addresses the following research question: what are the overall effects of SETs on plant establishment outcomes compared to untreated florets or seeds in native grasses globally?LocationGlobal.MethodsThe effects of six major SET categories (acid treatment, coating, pelleting, flash flaming, priming, and treatment combinations) on germination, emergence, and shoot and root length and biomass were explored. Furthermore, the consistency of the effects of SETs across study types (i.e., laboratory, glasshouse, and field) was investigated.ResultsThe overall effects of SETs on native grasses in this meta‐analysis were positive for germination (16% improvement), emergence (22% improvement), and growth (6.42–8.86 cm and 2.26–2.77 g increase in seedling length and biomass, respectively). However, effects ranged from neutral to positive when data were grouped by SET type, with coating, pelleting and priming delivering consistent benefits across multiple life stages, and acid treatments, flash flaming, and combination treatments having mixed effects. This analysis also provided evidence that benefits observed from SET application in laboratory and glasshouse studies are not translating to field environments.ConclusionsOverall, SETs generally had positive effects and can therefore provide a relatively low‐risk approach to improving seed‐based restoration outcomes in native grasses. Continued SET research focussed on long‐term plant establishment outcomes in field environments is needed to further advance SET uptake.