Official websites use. Share sensitive information only on official, secure websites. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Loss in intraspecific diversity can alter ecosystem functions, but the underlying mechanisms are still elusive, and intraspecific biodiversityโecosystem function iBEF relationships have been restrained to primary producers.
Here, we manipulated genetic and functional richness of a fish consumer Phoxinus phoxinus to test whether iBEF relationships exist in consumer species and whether they are more likely sustained by genetic or functional richness. We found that both genotypic and functional richness affected ecosystem functioning, either independently or interactively. Loss in genotypic richness reduced benthic invertebrate diversity consistently across functional richness treatments, whereas it reduced zooplankton diversity only when functional richness was high.
Finally, losses in genotypic and functional richness altered functions decomposition through trophic cascades. We concluded that iBEF relationships lead to substantial top-down effects on entire food chains. Global change is expected to generate a loss of intraspecific diversity worldwide. This mesocosm study explores whether loss of genetic and functional diversity in a predator species affects community and ecosystem functioning of lower trophic levels in pond ecosystems, revealing that diversity loss in a single consumer species can impact an entire ecosystem, reducing its functionality.
Human disturbances associated with global change are increasingly altering worldwide patterns of species diversity, as well as the functions and services provided by ecosystems [ 1 โ 3 ]. Nonetheless changes observed at the species and ecosystem levels are always preceded by changes in phenotypic and genotypic composition within plant and animal populations [ 4 โ 6 ].
Accordingly, extremely rapid changes in intraspecific diversity are currently occurring worldwide [ 7 โ 10 ]. Changes in intraspecific diversity can affect species turnover and composition [ 11 , 12 ], as well as ecosystem functioning [ 13 , 14 ]. For instance, the loss of genotypes within primary producers can reduce ecosystem process rates and species diversity [ 15 โ 17 ], suggesting the existence of biodiversityโecosystem functioning relationships at the intraspecific level iBEF [ 14 , 18 , 19 ], in addition to the more widely studied BEF relationships at the interspecific level.
