Global drivers, such as altered precipitation regimes due to climate change, are extensively altering different types of grassland communities (e.g., microbial, plant, herbivore, etc.,), with implications for ecosystem functioning and services at regional to global scales. Climatic extreme events, such as drought, are predicted to become more intense and frequent in the future. Drought has been shown to have varied responses, making understanding these responses highly important. This study specifically aimed to understand microbial functional recovery (i.e. resilience) to drought. To gain understanding of this resilience we sought to answer if belowground processes such as carbon, nitrogen, and phosphorus cycling through microbial activity return to pre-drought rates after cessation of drought. We studied the two-year post-drought recovery of a mesic grassland in the flint hills of Kansas. We conducted extracellular enzyme assays for carbon, nitrogen, and phosphorus limitation; inorganic nitrogen concentrations and mineralization; and microbial carbon mineralization.
Results/Conclusions
Overall, our study found that the carbon cycling was unable to fully recover from drought two-years post drought. Microbial carbon mineralization showed increased mineralization levels of 45% compared to the non-droughted plots. Although, carbon extracellular enzyme activities showed no difference from non-droughted conditions. On the other hand, our study found that belowground nitrogen cycling (inorganic nitrogen concentrations, nitrogen mineralization, and nitrogen extracellular enzymatic activity) showed no difference from non-droughted conditions. Belowground phosphorus cycling also seemed to recover after drought (no change in extracellular enzyme activity). In conclusion, belowground carbon cycling seems to be more sensitive to drought than nitrogen or phosphorus.