Multiple constraints cause positive and negative feedbacks limiting grassland soil CO2 efflux under CO2 enrichment

Authors

Philip A. Fay, USDA, Agricultural Research ServiceFollow
Dafeng Hui, Tennessee State UniversityFollow
Robert B. Jackson, Stanford University
Harold P. Collins, USDA, Agricultural Research Service
Lara G. Reichmann, University of Texas at Austin
Michael J. Aspinwall, Auburn University
Virginia L. Jin, University of Nebraska - LincolnFollow
Albina R. Khasanova, University of Texas at Austin
Robert W. Heckman, University of Texas at Austin
H. Wayne Polley, USDA, Agricultural Research Service

Document Type

Article

Publication Date

12-21-2020

Abstract

Understanding ecosystem carbon-cycling responses to atmospheric CO₂ enrichment is critical to preserve biodiversity and maintain vital ecosystem services in grasslands impacted by global change. We conducted an 8-y experiment enriching CO₂ concentrations from preindustrial to midtwenty-first century levels on grassland plant communities on upland, lowland, and alluvial soils. CO₂ enrichment increased the CO₂ efflux from soils to atmosphere in amounts depending on whether the dominant limitation was CO₂ or feedbacks (net positive or negative) from soil moisture and plant species turnover. These findings highlight how multiple concurrent limitations, not single limitations in sequence, regulate the impacts of global change drivers in diverse grasslands. Incorporating multiple limitations will improve forecasts of terrestrial carbon sequestration and ecosystem services.

Recommended Citation

Multiple constraints cause positive and negative feedbacks limiting grassland soil CO2 efflux under CO2 enrichment Philip A. Fay, Dafeng Hui, Robert B. Jackson, Harold P. Collins, Lara G. Reichmann, Michael J. Aspinwall, Virginia L. Jin, Albina R. Khasanova, Robert W. Heckman, H. Wayne Polley Proceedings of the National Academy of Sciences Jan 2021, 118 (2) e2008284117; DOI: 10.1073/pnas.2008284117