Effects of Different Ecological Restoration Paradigms on Soil Microbial Metabolic Limitation in a Tropical Coral Island

ABSTRACT Soil microbial metabolism reflects the balance between microbial resource demands and nutrient availability. In tropical coral islands, nutrient status is important for selecting restoration paradigms. However, soil microbial metabolic limitations in nutrient‐poor coral island ecosystems remain unclear. In this study, we investigated soil microbial metabolic limitations in different ecological restoration strategies, using six planting patterns from controls (CK) without plants to monoculture and mixed patterns. The results showed that tropical coral island exhibited low soil organic carbon (SOC) and nitrogen (N) content, along with low activities of β‐1,4‐glucosidase (BG), β‐1,4‐N‐acetylglucosaminidase (NAG), and L ‐leucine aminopeptidase (LAP) enzymes. The Monoculture Pisonia grandis ( P. grandis ) exhibited a lower microbial investment in C and N acquisition enzymes compared to the mixed planting, indicating lower demand for C and N in the monoculture. Enzymatic vector analysis revealed predominant C and N limitations in soil microbial metabolism, with the monoculture (notably P. grandis ) showing lower limitation than the mixed plantings. For phosphorus (P) acquisition enzymes, however, there was no significant difference between CK and planted plots, and the vector angle was less than 55°, indicating P is not a limiting factor in the coral islands. The partial least squares (PLS) path model explained 57% of N and 61% of C limitation in microbial metabolism, which were mainly regulated predominantly by soil nutrients. We suggest that monoculture paradigms seem more effective to establish pioneer vegetation than species‐rich plantings during early restoration stage. Nevertheless, once soil nutrient accumulation satisfies microbial demands, mixed‐species strategies could be selected to enhance biodiversity recovery in coral islands.