Moss-dominated biological soil crusts significantly influence soil moisture and temperature regimes in semiarid ecosystems

- Soil moisture was increased at 5 cm and decreased at 15-50 cm by moss crust.
- Soil temperature was decreased by up to 11.8 °C by moss crust in summer.
- Soil temperature was increased by up to 8.0 °C by moss crust in winter.
- Effects of crust on soil moisture and temperature were correlated with each other.
- Effects of crust on soil moisture and temperature depended on seasons and soil depths.

Biological soil crusts (BSCs) have been recognized as a vital influence factor to desert terrestrial ecosystems under semiarid climate. However, their effects on soil moisture and temperature, which play very important roles in many ecological and hydrological processes, have not yet been well understood. To provide more insight into this issue, we conducted a five-year monitoring experiment for moisture (0-150 cm) and temperature (0-30 cm) of soil with or without moss-dominated BSCs in a semiarid ecosystem on the Loess Plateau of China. The results showed that: (1) the BSCs significantly increased soil moisture by up to 7.6% at 5 cm depth, and significantly decreased soil moisture by up to 3.1%, 6.1%, and 8.1% at 15, 30, and 50 cm depths, respectively; while they had nearly no influence on soil moisture at 70-150 cm depths; (2) the BSCs significantly decreased soil temperature by up to 11.8, 7.5, 5.4, and 3.2 °C at 0, 5, 15, 30 cm depths, respectively, under wet and hot conditions in summer; whereas they significantly increased soil temperature by up to 8.0, 3.7, 2.9, and 1.9 °C, respectively, under dry and cold conditions in winter; and (3) the effects of the BSCs on soil moisture and temperature were significantly correlated with each other, and both of them were significantly driven by solar radiation and precipitation. We concluded that soil moisture and temperature regimes were significantly changed by moss-dominated BSCs in semiarid ecosystems, however, their effects mostly depended on seasons and soil depths.