Linking genetic variation in plant functional traits to source climate in key native Southwest restoration species

Identifying intraspecific variation in plant functional traits in relation to source climate is the first step towards understanding local adaptation, an ecological concept that can be used to guide modern-day restoration decisions such as seed sourcing. Forbs are a historically understudied functional group of plants in this area. We implemented a common garden study to examine intraspecific variation in a series of plant traits across a group of Southwestern native forb species that are commonly used in restoration. The common garden was planted with 10 species, each species sourced from 8 populations collected from varying climatic locations. Plant functional traits related to performance in terms of growth, leaf characteristics, and reproductive output were measured over the 2020 growing season. We found that source climate predicted intraspecific variation in plant functional traits in some species and traits, but the degree and direction of the trait-climate relationship varied by species and by trait. Height showed patterns of climate adaptation across six of the nine species. In contrast, leaf N, specific leaf area, leaf dry matter content, and seed mass each showed climate adaptiveness for only a small subset of the species we examined. These results show that genetic variation of traits is related to climate in these species, which has implications for guiding species selection in restoration