Monitoring and Modelling Soil Respiration in Deciduous and Broadleaf Evergreen Oak-Dominated Ecosystems in Greece

Climate change alters rainfall patterns and increases temperatures, which disrupt soil processes, enhance CO2 emissions, and reduce the capacity of soils to store carbon. Soil respiration, the CO2 released into the atmosphere from the soil, is a vital process in the terrestrial carbon cycle. We performed a two-year study investigating the seasonal variation of soil CO2 efflux in two typical oak-dominated Mediterranean ecosystems, a deciduous and a broadleaf evergreen one, as we lack sufficient information on this topic. To understand the drivers of soil respiration, we also monitored soil water content and temperature, as well as organic matter input by sampling litterfall and fine roots and by applying in parallel a litter and root exclusion approach. We found a 30\%–54\% higher soil CO2 efflux in broadleaf evergreens vs. deciduous oaks, depending on the season. We also identified significant effects of all tested drivers on soil respiration. Soil water content controlled the dependency of soil respiration on temperature and resulted in the highest CO2 emissions in spring, when these conditions were optimal. The high litterfall input and turnover rate in spring further supported the peak of CO2 respired by broadleaf evergreens' soil in this period. On the contrary, low water availability limited soil respiration during summer in both ecosystems. The litter and fine root exclusion resulted in a 69.9\% and 38.7\% reduction in CO2 efflux in spring, for deciduous and evergreen oaks, respectively, verifying the important contribution of these organic inputs to soil respiration. However, it led to overestimation of soil respiration in summer and in the second year of the study, probably due to water retention. We developed a polynomial regression model that predicts CO2 efflux with soil temperature and water content as multipliers, and it is novel in including carbon fluxes of litterfall and fine root production as explanatory variables. The model predictions are good for broadleaf evergreen oaks (R2 = 0.64) and lower, but fair, for deciduous oaks (R2 = 0.48) and can efficiently illustrate how microclimate in combination with organic input and affects soil respiration. Our findings can improve our knowledge of soil CO2 effluxes and their drivers in typical oak-dominated Mediterranean ecosystems and support their climate-adapted management.

ZACHAROUDI Stavroula;  FENDRICH Arthur;  CESCATTI Alessandro;  SPYROGLOU Gavriil;  FOTELLI Mariangela;  RADOGLOU Kalliopi;  PANAGOS Panos; 

2025-12-23

WILEY

JRC141848

1365-2389 (online),   

https://bsssjournals.onlinelibrary.wiley.com/doi/10.1111/ejss.70254,    https://publications.jrc.ec.europa.eu/repository/handle/JRC141848,   

10.1111/ejss.70254 (online),