AUTHOR=Yaffar Daniela , Defrenne Camille E. , Cabugao Kristine G. , Kivlin Stephanie N. , Childs Joanne , Carvajal Niko , Norby Richard J. TITLE=Trade-Offs in Phosphorus Acquisition Strategies of Five Common Tree Species in a Tropical Forest of Puerto Rico JOURNAL=Frontiers in Forests and Global Change VOLUME=4 YEAR=2021 URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2021.698191 DOI=10.3389/ffgc.2021.698191 ISSN=2624-893X ABSTRACT=

Tree species that are successful in tropical lowlands have different acquisition strategies to overcome soil phosphorus (P) limitations. Some of these strategies belowground include adjustments in fine-root traits, such as morphology, architecture, association with arbuscular mycorrhizal fungi, and phosphatase activity. Trade-offs among P-acquisition strategies are expected because of their respective carbon cost. However, empirical evidence remains scarce which hinders our understanding of soil P-acquisition processes in tropical forests. Here, we measured seven fine-root functional traits related to P acquisition of five common tree species in three sites of the Luquillo Experimental Forest in Puerto Rico. We then described species-specific P-acquisition strategies and explored the changes in fine-root trait expression from 6 months before to 6 months after two consecutive hurricanes, Irma and MarĂ­a, passed over the island. We found that variations in root trait expression were driven mainly by the large interspecific differences across the three selected sites. In addition, we revealed a trade-off between highly colonized fine roots with high phosphatase activity and fine roots that have a high degree of branching. Furthermore, the former strategy was adopted by pioneer species (Spathodea campanulata and Cecropia schreberiana), whereas the latter was adopted by non-pioneer species (mostly Dacryodes excelsa and Prestoea montana). Additionally, we found that root trait expression did not change comparing 6 months before and after the hurricanes, with the exception of root phosphatase activity. Altogether, our results suggest a combination of structural and physiological root traits for soil P acquisition in P-poor tropical soils by common tropical tree species, and show stability on most of the root trait expression after hurricane disturbances.