Interpreting the effects of plant species diversity and genotypic diversity within a dominant species on above- and belowground overyielding

A direct comparison of the effects and mechanisms between species richness and genotype richness in a dominant species on multiple ecosystem functions

“…Similar to species richness, the genotype richness in S. grandis showed a significant positive effect on the soil P cycle. Our recent studies have found the similar ecological effects of species richness and genotype richness in S. grandis on biomass production and litter decomposition (Yang, Qu, et al., 2019 ; Yang et al., 2021 ), and indicated that greater genotype richness in S. grandis could drive facilitative plant‐plant interaction by trait‐dependent complementarity effect (Yang et al., 2021 ). All these findings have confirmed that the effects of genotype richness in S. grandis on ecosystem functioning are as important as species richness in the semi‐arid temperate steppe of northern China.…”

“…These findings might result from the low degree of niche differentiation within species and less utilization of resources in marginal niches (Wang et al., 2019 ). Recently, some studies have shown unimodal relationships but not linear relationships between plant richness and ecosystem functions such as biomass production on the worldwide scale (Fraser et al., 2014 ; Yang et al., 2021 ). In a treeless community, the species richness–pH relationship has been found unimodal in the Western Sayan Mountains, southern Siberia (Chytrý et al., 2007 ).…”

“…The present study shows that the direct effects of species richness or genotype richness in the dominant species S. grandis on the soil P cycle are similar, which could be explained from the point of view of evolution, insurance hypothesis, and facilitative effects between plant and plant, considering the P deficiency in the semi‐arid temperate steppe of northern China. However, there are significant differences of the effects of community functional structure on ecosystem functions between the two richness experiments, which is related to the different resources utilization and biodiversity effects between inter‐ and intraspecific richness levels (Yang et al., 2021 ). These findings demonstrate the undeniably important effects of S. grandis genotype diversity on ecosystem functions in the semi‐arid steppe region and suggest the limitation of community functional structure in explaining the BEF relationships.…”