Data: Population and species neighbor identity impact trait-trait relationships and plant performance

To understand how mixtures of multiple populations (intraspecific mixtures) influence plant performance and trait outcomes in comparison to single population monocultures and interspecific mixtures, we assessed trait variation among multiple populations following plant interactions in a greenhouse common environment. We used three populations each of two forb species native to the western US in all combinations and found that four of six population pairings led to more positive interaction outcomes in intraspecific mixtures compared to monocultures.

Neighbor trait differences in shoot height and root length had the largest impact on plant growth following interactions, while increasing neighbor trait differences in plant height, leaf count, and root length resulted in positive growth outcomes for both interspecific and intraspecific mixtures, and root mass fraction showed the opposite pattern. These findings show nuance in the outcomes of intraspecific interactions and that they depend on population identity and varying importance of evaluated traits.