Larger islands enhance ecological restoration potential for Neolitsea Sericea: Evidence from China’s Biggest Archipelago

• Validated the classical theory of island biogeography under increased human disturbance. • The significant positive correlation between the ISI and the HPI of the Neolitsea sericea in Zhoushan Archipelago. • A critical threshold for the habitat quality surge of Neolitsea sericea was identified in Zhoushan Archipelago. • Quantify highly suitable habitats of Neolitsea sericea within Zhoushan Archipelago. • Provided a framework for island-endemic relict plant conservation. Neolitsea sericea , a nationally (China) protected relict plant species endemic to East Asian islands, requires targeted cultivation and landscape management as key conservation strategies. Effective protection necessitates precise identification and optimization of suitable habitat distribution patterns. Building on island biogeography theory—particularly the “area effect” hypothesis positing greater restoration potential in larger islands—this study develops a novel framework combining the Habitat Potential Index (HPI) and Island Size Index (ISI) to analyze size-dependent habitat restoration potential under increasing anthropogenic pressures. Using Maximum Entropy (MaxEnt) modeling with GIS spatial analysis, we quantified habitat suitability (HPI) and island carrying capacity (ISI) across the Zhoushan Archipelago, China. Key findings reveal: (1) elevation, vegetation cover, and soil conductivity as primary environmental determinants of N. sericea distribution; (2) 77.72 km 2 of high-suitability habitat (HPI > 0.64), predominantly concentrated in medium and large islands; and (3) a robust exponential correlation between ISI and HPI (R 2 = 0.656, p < 0.001). Crucially, we identified a 3.95 km 2 ecological threshold (ISI = 0.26), beyond which habitat potential increases non-linearly with island size. These results demonstrate the enduring relevance of classical island ecology theory in modern disturbance regimes while establishing quantitative thresholds for conservation prioritization. Our approach provides both: (i) a science-based framework for N. sericea habitat restoration and translocation in Zhoushan, and (ii) a transferable paradigm for spatial optimization in island plant conservation, offering critical insights for balancing regional development and biodiversity protection.