Aiming for phylogenetic diversity (PD) in restorations has a number of positive impacts. High PD may increase productivity, stability, and diversity in higher trophic levels. In addition, high PD could reduce invasion by non-native species, which could decrease the amount of time and money spent managing them. Increasing evolutionary lineages in a restoration may allow for better competition against invasion through niche complementarity or limiting similarity. In the case of limiting similarity, closely related native and invasive species may compete strongly given similar traits and strategies for acquiring resources. Alternatively, non-natives species may be ‘pre-adapted’ to microhabitats of closely related native species. These two outcomes are referred to as Darwin’s Naturalization Hypothesis. Here, we examine how aspects of plant communities such as species richness, PD, and invasive species relatedness impact invasions in restored prairies. We also compare PD in restored and remnant prairies. We surveyed 18 restored prairies in the Chicagoland region, looked at neighborhood and habitat scales, and compared results to 38 remnant prairies.
Results/Conclusions
For the restored prairies, we found that native species richness and phylogenetic distance to invasive species predicted invasion at the neighborhood scale. This supports the ‘pre-adaptation’ aspect of Darwin’s Naturalization Hypothesis. It also shows that evolutionary history provides additional information beyond species richness when studying invasion. At the habitat scale, site soil characteristics predicted invasion, which may reflect site history and management. Compared to remnant prairies, PD of native species is lower in restored prairies, with plant families missing from restored prairies. Encouragingly, seed mixes with high PD resulted in restorations with higher PD. Our findings show how PD can improve restorations and be incorporated into restoration planning.