Epsilon Archive for Student Projects

Abstract

Tropical forest restoration initiatives increasingly aim to enhance biodiversity recovery, yet long-term data remains scarce, particularly on how different enrichment strategies influence naturally regenerating communities. This study assesses the biodiversity outcomes of line planting and gap-cluster planting 27 years after implementation in the INIKEA Sow-a-Seed project in Sabah, Malaysian Borneo. Focusing exclusively on naturally regenerated trees, I evaluated tree species richness, composition, and successional status across 38 plots, including enriched and control sites, while accounting for a degradation gradient based on remnant tree structure.

Generalized linear models revealed that both enrichment treatments significantly increased species richness compared to control plots, regardless of initial degradation level. NMDS and PERMANOVA analyses confirmed distinct community compositions between treatments, showing that enrichment planting not only increases the number of species but also steers regeneration toward compositionally different forest communities. In contrast, Shannon and Simpson indices showed no significant differences between treatments, indicating similar species evenness. Likewise, the proportion of late-successional species among naturally regenerated individuals did not differ significantly, likely reflecting the slow functional recovery typical of these species.
These findings suggest that enrichment planting can effectively steer regeneration toward more diverse and compositionally distinct communities, but that full ecological recovery remains a long-term process shaped by both intervention and initial site conditions.