Belowground advantages in construction cost facilitate a cryptic plant invasion

The energetic cost of plant organ construction is a functional trait that is useful in understanding carbon investment during growth (e.g., the resource acquisition vs. tissue longevity tradeoff), as well as in response to global change factors like elevated CO₂ and N. Despite the enormous importance of roots and rhizomes in acquiring soil resources and responding to global change, construction costs have been studied almost exclusively in leaves. In a new study in AoB PLANTS, the energetic costs of tissue construction were compared in two subspecies of Phragmites australis, the common reed – namely the primary native and introduced lineages in North America. Caplan et al. report that the introduced lineage has lower construction costs than the native under all environmental conditions assessed, driven mainly by its lower cost rhizomes. These results highlight the fact that belowground energetics, which are seldom investigated, can influence the performance advantages that drive many plant invasions. The authors also demonstrate that tissue construction costs in organs not typically assessed can shift with global change, suggesting that they may have increasingly important implications into the future.