Abstract
Numerous studies claim that rewetting interventions reduce CO 2 and increase CH 4 fluxes. To verify the claim, we conducted a systematic review and meta-analysis of the effects of rewetting on CO 2 and CH 4 fluxes and dissolved organic carbon (DOC). We identified 28 primary articles eligible for meta-analysis, from which we calculated 48 effect sizes for CO 2 emissions, 67 effect sizes for CH 4 emissions, and 5 effect sizes for DOC. We found that rewetting significantly decreased CO 2 fluxes, with temperate zones showing the highest Hedges’ g effect size (−0.798 ± 0.229), followed by tropical (−0.338 ± 0.269) and boreal (−0.209 ± 0.372) zones. Meanwhile, rewetting increased CH 4 fluxes, with the highest Hedges’ g effect size shown in temperate zones (1.108 ± 0.144), followed by boreal (0.805 ± 0.183) and tropical (0.096 ± 0.284) zones. In addition, based on yearly monitoring after rewetting, the CH 4 emissions effect size increased significantly over the first 4 years ( r 2 = 0.853). Overall, the rewetting intervention reduced CO 2 emissions by −1.43 ± 0.35 Mg CO 2 –C ha −1 year −1 , increased CH 4 emissions by 0.033 ± 0.003 Mg CH 4 –C ha −1 year −1 , and had no significant impact on DOC. To improve the precision and reduce the bias of rewetting effect size quantification, it is recommended to conduct more experimental studies with extended monitoring periods using larger sample sizes and apply the before-after control-impact study design, especially in boreal and tropical climate zones.