Planting diversity begets multifaceted tree diversity in oil palm landscapes

Optimizing restoration outcomes is crucial for enhancing multifaceted diversity, resilience, and ecosystem functioning in monoculture-dominated landscapes globally. Here, we experimentally tested the performance of passive and active restoration strategies to recover taxonomic, phylogenetic, and functional diversity by establishing 52 tree islands in an oil palm landscape. Tree diversity via natural regeneration was shaped by local rather than landscape properties, with the diversity of planted tree species and tree island size driving higher multifaceted diversity. We show that large tree islands with higher initial planted diversity catalyze the recovery of multifaceted diversity at both the local and landscape level, including forest-associated species. Our results demonstrate that planted diversity begets regenerating diversity, overcoming major limitations of natural regeneration in highly modified landscapes. By elucidating the contribution of experimental, local, and landscape drivers to natural regeneration, these findings provide practical insights to make oil palm landscapes more biodiversity-friendly by enhancing functional and phylogenetic diversity within plantations.