Ant and plant diversity respond differently to seed-based prairie restoration

Recovering biodiversity is a common goal of restoration, yet outcomes for animal communities are highly variable. A major reason for this variability may be that active restoration efforts typically target plant communities, with the assumption that animal communities will passively recover in turn. However, this assumption remains largely unvalidated experimentally making it unclear how plant-focused restoration strategies influence animal communities. We evaluated how the diversity of seed mixes used to restore tallgrass prairies (a common plant-focused technique) influenced the recovery of ant community diversity and composition. Our study took place within a large-scale restoration experiment in southwest Michigan, where 12 former agricultural fields are being restored to tallgrass prairie by sowing seeds of prairie plant species native to our region. Half of each field was seeded with 12 prairie species and the other half with 72 prairie species. Sites restored with high diversity seed mixes increased plant species richness, but did not consistently influence ant richness or community composition. Instead, ant species richness and composition were related to an interaction between realized plant species richness (which was only partly structured by seeding treatments) and environmental structure. Specifically, ant richness increased more with higher realized plant richness when vegetation cover was lower and soil-surface temperatures were higher. Our findings illustrate how plant and animal communities can respond differently to plant-focused restoration efforts. Despite this, plant community restoration can structure animal community responses, in concert with environmental factors. Layering additional restoration strategies onto existing plant-focused approaches may further benefit biodiversity across taxa.

Automated summary

Recovering biodiversity is a common goal of restoration, but the outcomes for animal communities can vary greatly. This study focused on the influence of seed mix diversity on ant community recovery in tallgrass prairies. The results showed that high diversity seed mixes for plant-focused restoration increased plant species richness, but did not consistently impact ant richness or composition. The interactions between realized plant richness, environmental structure, and ant community responses highlight the need for additional restoration strategies to benefit biodiversity.