Analysis of soil respiration and influencing factors in a semiarid dune–meadow cascade ecosystem

Highlights: • Soil respiration shows obvious spatiotemporal variations. • The intensity of soil respiration in meadows is twice stronger than that in dunes. • Soil bacteria, moisture and temperature are the main factors driving soil respiration. • Field capacity is a demarcation point for the interaction of soil respiration and moisture. The characteristics of soil respiration (R_s) in semiarid regions are important with regard to the carbon cycle of complex underlying surfaces and estimation of carbon emissions from regional ecosystems. During the growing season (May–September 2016), in situ observations of R_s were obtained concurrently with measurements of soil bacteria (B_s), soil moisture (M_s), and soil temperature (T_s) at depths of 0–10 cm, in a dune–meadow cascade ecosystem. Results showed that R_s differences among the various ecosystems were significant (P < 0.01), the intensity of R_s in meadows was twice stronger than that in dunes. The average values of R_s presenting a declined trend follows MPA (11.19 μmol m⁻² s⁻¹) > MAF (7.75) > SSG (6.78) > SMAH (5.02) > SFAH (4.8) > FLC (4.28) > SBG (3.09). An extremely significant (p < 0.01) positive correlated power relationship can be found between R_s and B_s, which could explain 62.41%–86.56% of the variation in R_s in the various ecosystems. Field capacity and the saturated water content were the key demarcation points for the interactive relationship between R_s and M_s, which showing a significant (P < 0.05) positive correlated power relationship in dunes, in contrast, it presenting a significant (P < 0.05) negative correlated exponential relationship in meadows. R_s was positively exponentially correlated with T_s, significant (P < 0.05) in meadows and nonsignificant (P > 0.05) in dunes. Future research should be strengthened to consider multiple growing seasons experiencing various climatic conditions for accurate estimation of terrestrial carbon emissions in arid and semiarid ecosystems.