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Soil respiration (Rs) is a major component of an ecosystem carbon cycle. To quantify soil CO2 efflux, field experiments were conducted in situ (2015-2017) with an LCi-SC soil CO2 flux system under three semi-arid ecosystems in the Mediterranean as one of the main identified climate change hotspot. Mean values of Rs rates showed that soil CO2 effluxes were significantly different among various terrestrial ecosystems with higher Rs in semi-natural ecosystems as under Steppe 1.739 +/- 0.717 mu mol CO2 m(-2) s(-1) (658.093 +/- 271.336 g C m(-2) yr(-1)) and under Forest 4.205 +/- 1.731 mu mol CO2 m(-2) s(-1) (1591.307 +/- 655.066 g C m(-2) yr(-1)) than under the natural ecosystem Garrigue 0.914 +/- 0.309 mu mol CO2 m(-2) s(-1) (345.887 +/- 116.935 g C m(-2) yr(-1)). It appears that soil CO2 efflux is highly ecosystem-specific, so it is required to be verified across ecosystem types. We recorded a very strong relationship between Ts and Ws, as documented by the correlation coefficient (r = -0.848), respectively R-squared (71.908%). Our results show that the natural ecosystem Garrigue under climate warming could release less CO2 efflux than semi-natural ecosystems and each semi-arid ecosystem can emit different amounts of CO2 emissions under the same environmental conditions.