Stage-specific microbial dynamics underpin ecosystem restoration on tropical coral islands

Abstract

Soil properties and biodiversity in artificial vegetation on tropical coastal islands did not reach levels comparable to native forests over short-term restoration. Bacteria were key drivers in later restoration stages, whereas fungi acted as keystone taxa during early restoration of tropical coral islands. Soil microbial communities in both native forests and plantations on tropical coral islands were co-limited by carbon (C) and phosphorus (P). Despite the recognized benefits of diverse vegetation for terrestrial biodiversity and ecosystem services, its role in island ecosystem restoration remains poorly understood. We established five artificial vegetation types (grassland, windbreak and sand fixation, shelterbelt, public green space, roadside trees) on tropical coralislands and compared their soil properties and microbial communities with those of native forests. Artificial vegetation showed different levels of soil properties (except total potassium), microbial biomass (excluding fungi), enzyme activities, diversity indices (excluding fungi). Additionally, the community composition and network structure of soil microbes in artificial vegetation were distinct from those in native forests. Both ecosystems exhibited co-limitation by carbon and phosphorus. Fungi dominated in early restoration stages, while bacteria emerged as keystone drivers in later phases. Initial fungal inoculation accelerated vegetation establishment, and late-stage labile carbon inputs enhanced bacterial-mediated ecosystem stability. Phosphorus supplementation is recommended to alleviate nutrient co-limitation given that phosphorus is indispensable for microbial growth. Future research should focus on long-term dynamics to better assess restoration sustainability. (Figure presented.)