Aims – Soil respiration (R_s) is a major pathway for releasing fixed carbon back to the atmosphere. However, controls over R_s are poorly understood in arid and hyper-arid systems where microbial activity is frequently constrained by moisture. We addressed key uncertainties in R_s: 1) How do short-term rainfall pulses affect R_s at sites that differ in long-term precipitation inputs?, 2) how do R_s responses to short and long-term rainfall differ across soil surfaces?, and 3) how are R_s responses affected by local-scale attributes?

Methods – We measured R_s responses to rainfall pulses over a 48 h period. Working across a climate gradient, we compared R_s responses on two contrasting soil surfaces which both had two vegetation/soil morphology patch types that differed in organic matter inputs and accumulation.

Results – Rates of R_s were low, but highly responsive to rainfall pulses. Stimulation of R_s by rainfall was generally greater in areas with higher annual rainfall. However, patterns for R_s responses to rainfall differed greatly on the two soil surfaces and among patch types.

Conclusions – The strong role of patch type and soil surface in controlling R_s points to the need to carefully consider small-scale spatial and temporal variation when interpreting dryland biogeochemical fluxes.

See manuscript details.