Impact of genomic diversity in river ecosystems

•We highlight the importance of genomic biodiversity in aquatic macrophytes.•We suggest that N and P availability selects for genetic variants in macrophytes.•We discuss how genetic variants differ in nutritional quality, influencing herbivores.•We propose that genomic biodiversity influences ecosystem functioning.

We propose that genomic diversity in aquatic macrophytes of rivers, driven by the underlying genomic processes of interspecific hybridization and polyploidy (whole-genome duplication), play a significant role in ecosystem functioning. These genomic processes generate individuals which might differ in their demands for nitrogen (N) and phosphorus (P). This is significant because (i) N and/or P are frequently limiting nutrients in freshwater ecosystems, and (ii) nucleic acids are demanding in N and P. We suggest that N and P availability will provide a selection pressure for genetic variants in macrophytes which will, in turn, influence the nutritional quality of plant biomass, and hence their consumption by herbivores and detritivores as well as the energy flux of their biomass through the food web.