Going deeper into the belowground ecology of Southeast Asian tropical forests: a case study in Singapore

Abstract

Roots and the rhizosphere drive many biogeochemical processes underlying phosphorus (P)-limited pantropical forests. Yet, knowledge on plant P acquisition strategies remains elusive in Southeast Asian (SEA) tropical forests. Using Bukit Timah Nature Reserve, Singapore, as a case study, I examined root trait syndromes underlying tree species in SEA tropical forests to identify 1) trade-offs in P acquisition strategies among species, 2) how root traits relate to local-scale edaphic variation; and 3) whether root traits effectively predict species’ net uptake rates of simple and complex P forms. My findings revealed multiple dimensions of root trait variation, reflecting independent strategies for root construction and P acquisition. Root traits were weakly constrained by local-scale variation in soil nutrients and poorly explained species’ net uptake rates of multiple P forms. These findings contrast hypothesised relationships between root traits, soil nutrients and P uptake rates, highlighting the complexity of root-soil interactions underlying tropical forest species.