Table 2 Summary of the methods employed in the analysis of emissions and environmental variables.
From: Predominantly positive XCO2 anomalies in the Caatinga biome highlight carbon vulnerability
Reference | Location | Method/Variable | Reported value | Conclusion |
|---|---|---|---|---|
Mendes et al.53 | ESEC-Seridó (RN), Brazil | Eddy covariance – NEE, GPP, Rₑco (2014–2015) | NEE: −1.69 and − 1.45 Mg C ha−1 yr−1 | The Caatinga acted as a carbon sink during the studied years. |
Schulz et al.44 | Caatinga regions | Soil sampling – SOC stocks by depth | SOC ≈ 16.9 Mg C ha−1 (varies with depth and management) | Grazing reduces soil carbon stocks, especially near the surface. |
Silva et al.54 | Brazilian semiarid (Caatinga) | SOC change under natural regeneration | Increased SOC, N and P in abandoned pastures after regeneration | Natural regeneration helps recover soil carbon and nutrients. |
Freitas et al.55 | Transition zone between Caatinga and Cerrado | Soil carbon and nitrogen stocks in agrosilvopastoral systems | ASP systems maintain or improve SOC and N stocks | Sustainable land-use systems can mitigate soil carbon losses. |
Viana-Lima et al.56 | Caatinga degraded areas | Soil health indicators and SOC under overgrazing vs. restoration | Loss of ~ 14.7 Mg C ha−1 in topsoil under overgrazing | Overgrazing strongly degrades soil carbon and ecosystem health. |
This study | Caatinga biome (Brazil) | OCO-2 L2 v10 bias-corrected Lite Files; ACOS algorithm; bands at 0.76, 1.6, 2.06–2.10 μm; Nadir/Glint/Target modes; quality_flag = 0 and 1; period 2015–2023 | Predominantly positive XCO2 anomalies; heterogeneous patterns; emission hotspots; instability in some phytophysiognomies | XCO2 anomalies reveal high sensitivity to climate and anthropogenic pressure; sink potential compromised; emission hotspots indicate rising vulnerability; urgent monitoring, protection and restoration needed in the Caatinga |
