Vegetation–soil–microbial diversity influences ecosystem multifunctionality across different tropical coastal ecosystem types

An improved understanding of the vegetation and microbial diversity across different coastal landscape and it’s interlink with ecosystem multifunctionality are vital for sustaining the ecosystem services. In view of this, the present study was carried out in Andaman Island, India creating three representatives transects covering four major ecosystem types by subplot sampling and ecosystem multifunctionality was computed from eleven related soil properties after Z-score transformation. We have estimated the vegetation and soil microbial diversity, examined individual effects of edaphic factors on vegetation and soil microbial diversity, extracellular enzyme activities and also investigated the combined effects on ecosystem multiple functions as matrices by Mantel tests. The results suggested that above ground vegetation diversity (2.4–4.9) exhibited significant effect on soil microbial diversity (1.07–1.47) due to difference in species richness and organic matter addition. In turn microbial diversity played a critical role in enzyme activities and nutrient recycling, both constituted the vital coastal ecosystem functions. Amongst the different ecosystems, highest species richness and microbial diversity was found in littoral forest and moist deciduous forest, respectively whilst agro-ecosystem recorded the lowest values. Soil organic carbon, excluding agriculture, increased downward the topography from moist deciduous forest in the hill top to the mangroves in the coastal lowlands while soil enzymes, total N  and microbial biomass C and N followed the trend as in soil organic C. The study also observed large endemism and constraints to diversity in mangrove ecosystem due to specific environmental conditions. Our findings provided empirical evidence that above ground and below ground diversity conditioned by edaphic factors constituted the primary drivers for ecosystem multifunctionality in different coastal ecosystem types.