Effects of Soil Nutrient Availability on Ectomycorrhizal Communities’ Distribution in Two Dipterocarps Species Under Normal and Elevated Atmospheric Carbon Dioxide

Abstract

Abstract This study explores the impact of increasing atmospheric carbon dioxide (CO2) levels on belowground communities in tropical rainforests, focusing on the relationship between soil nutrient availability and the distribution of ectomycorrhizal (ECM) fungi on two dipterocarps seedlings, Shorea leprosula and S.lepidota in Tekam Forest Reserves, Pahang. Using the Free Air Carbon Dioxide Enrichment (FACE) hexagon plot, the research compared two different CO2 levels at normal (control plot) and elevated (FACE plot) concentrations. In the elevated CO2 plot, only four ECM species were found compared to five in the control plot. Notably, Geastrum sp. was exclusive to the control plot, while Lactarius sp., Russula sp., Tomentella sp., and Cenococcum sp. were present in both plots, indicating adaptability to varying soil nutrient and CO2 conditions. Statistical analyses (DCA, PCA, CCA) revealed associations between ECM fungi and plant hosts, soil nutrient composition, and a combination of parameters. For instance, S. lepidota exhibited a preference for phosphorus in the control plot, while S. leprosula preferred higher carbon contents. Tomentella sp. and Cenococcum sp. showed strong associations with nitrogen and potassium, respectively, while Lactarius sp. and Russula sp. correlated with the C:N ratio. In conclusion, this study underscores the importance of understanding the intricate relationship among soil nutrient availability, ECM distributions, and elevated atmospheric CO2 in tropical rainforest ecosystems.