Soil-mediated effects of global change on plant communities depend on plant growth form

Authors: HINES, J - Friedrick-Schiller University; PABST, S - Friedrick-Schiller University; Blumenthal, Dana; CESARZ, S - Friedrick-Schiller University; MUELLER, K - Cleveland State University; EISENHAUER, N - Friedrick-Schiller University

Submitted to: Ecosphere
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2017
Publication Date: 11/17/2017
Citation: Hines, J., Pabst, S., Blumenthal, D.M., Cesarz, S., Mueller, K.E., Eisenhauer, N. 2017. Soil-mediated effects of global change on plant communities depend on plant growth form. New Phytologist. 8(11):1-15. doi:10.1002/ecs2.1996.
DOI: https://doi.org/10.1002/ecs2.1996

Interpretive Summary: Understanding why species respond to climate change is critical for forecasting invasions, diversity, and productivity of plant communities. To test whether global change influences the outcome of plant competition via indirect feedbacks mediated by soil resources, mutualists, or antagonists, we grew plant communities in soils collected from a seven-year field manipulation of CO2, warming, and invasion. We evaluate mechanisms underlying competition by comparing species’ growth in equivalent soil histories with, and without, experimentally reduced soil biota and nutrient limitation. We show that grasses performed consistently across all soil history scenarios, and that soil biota limited grasses more than nutrients. In contrast, forbs were differentially sensitive to soil history scenarios, with the magnitude and direction of responses to soil biota and nutrients dependent upon plant species and global change scenario. The distinct responses of grasses and forbs are likely explained by differential allocation to growth and defense. We conclude that accounting for species’ competitive strategies will improve predictions of species sensitivity to altered soil feedbacks in future climates.

Technical Abstract: (1) Understanding why species respond to climate change is critical for forecasting invasions, diversity, and productivity of communities. Although researchers often predict species’ distributions and productivity based on direct physiological responses to environments, theory suggests that striking shifts in community composition could arise if global change alters indirect feedbacks mediated by resources, mutualists, or antagonists. (2) To test whether global change influences the outcome of competition via indirect soil-mediated feedbacks, we grew plant communities in soils collected from a seven-year field manipulation of CO2, warming, and invasion. We evaluate mechanisms underlying competition by comparing species’ growth in equivalent soil histories with, and without, experimentally reduced soil biota and nutrient limitation. (3) We show that grasses performed consistently across all soil history scenarios, and that soil biota limited grasses more than nutrients. In contrast, forbs were differentially sensitive to soil history scenarios, with the magnitude and direction of responses to soil biota and nutrients dependent upon plant species and global change scenario. (4) The asymmetry in importance of soil history for grasses and forbs is likely explained by differential allocation to growth and defense. We conclude that accounting for species’ competitive strategies will improve predictions of species sensitivity to altered soil feedbacks in future climates.