Phylogenetic diversity reveals hidden patterns related to population source and species pools during restoration

A phylogenetic perspective of community assembly can reveal new insights into how variation within dominant species interacts with the local species pool to influence the structure of restored plant communities. Many studies have examined the effect of dominant species in structuring plant communities, but few have investigated their effect on phylogenetic diversity (PD).
We established grassland in a post-agricultural field using two population sources (cultivars and local ecotypes) of three dominant grasses (Sorghastrum nutans, Andropogon gerardii and Schizachyrium scoparium) with three unique pools of subordinate species that varied in PD but not taxonomic or life-form diversity. We tested the effect of the population source treatment on two metrics of community PD (net relatedness index [NRI] and nearest taxon index [NTI]) during the first 4 years of restoration. The NRI measures the overall pairwise phylogenetic distance between all pairs of taxa in a community. By contrast, NTI m...