Seeding in single species aggregations promotes evenness of diverse shrub species in Banksia woodlands in the first year of growth

Authors: Svejcar, Lauren; MILLER, BEN - University Of Western Australia; STEVENS, JASON - University Of Western Australia; STANDISH, RACHEL - Murdoch University

Submitted to: Restoration Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2025
Publication Date: 2/2/2026
Citation: Svejcar, L.N., Miller, B.P., Stevens, J.C., Standish, R.J. 2026. Seeding in single species aggregations promotes evenness of diverse shrub species in Banksia woodlands in the first year of growth. Restoration Ecology. Online pages 1-10. https://doi.org/10.1111/rec.70320.
DOI: https://doi.org/10.1111/rec.70320

Interpretive Summary: Restoring plant species in post-mining landscapes is important to the maintenance of plant diversity on the Swan Coastal Plain of Western Australia. In this experiment, we tested whether six commonly seeded species have higher survival in single species aggregated, mixed species aggregated and mixed species dispersed plantings. We found that overall species evenness was greatest in single species aggregated plantings.

Technical Abstract: 1. Species interactions are an overlooked yet important determinant of plant community assembly in ecological restoration. Specifically, they may determine species that are helped or hindered by neighbouring plants during community assembly. Evidence suggests manipulating plant species’ spatial arrangements to create intraspecific aggregations (compositional segregation) might lead to species coexistence and so improved diversity outcomes in restoration. Equally, physical segregation of plants can determine species coexistence as it determines both the likelihood of plant-plant interactions and the influence of abiotic processes on species persistence. 2. To quantify the effect of plant aggregations in banksia woodland restoration, we planted seeds of six common woody shrub species in three spatial patterns: single species aggregated, mixed species aggregated and mixed species dispersed plantings. Seedling emergence was monitored, and survival was measured monthly through seedling establishment. These data were used to infer strength and direction of intraspecific and interspecific interactions in relation to spatial patterns of planting. 3. Four of the six species demonstrated higher survival in single-species aggregated plantings relative to mixed-species dispersed plantings (P < 0.05), while survival of a fifth was higher in mixed species dispersed plantings than either aggregated planting arrangements (P < 0.01). Survival of the last species was higher in mixed-species dispersed plantings than single-species aggregated plantings (P < 0.01), but similar to aggregated plantings. At the plot level (1 m2), single-species aggregated plantings had greater community evenness than either mixed-species aggregated (P = 0.02) or mixed-species dispersed (P < 0.01) planting treatments. 4. Synthesis and applications. Our results support the notion of intraspecific aggregation and interspecific segregation promoting species coexistence in restoration of a high plant diversity ecosystem. Results of this study suggest merit in the development of alternative seeding practices, such as seed enhancement or deployment technologies that can impose species-specific aggregated plantings to improve diversity of restoration plantings.