Hydrological Interaction Between Leaf Litters and Moss Crusts: Combined Effects on Soil Evaporation in a Karst Region

ABSTRACT

Karst ecosystems are highly vulnerable to water stress because of their shallow soils and distinctive hydrological characteristics, and soil evaporation, as a key pathway of water loss, can constrain vegetation recovery. However, the effects of combined surface cover formed by leaf litters and moss crusts on soil evaporation during vegetation restoration remain poorly understood. In this study, a controlled experiment was conducted to evaluate the effects of needle litters, broadleaf litters and moss crusts, applied alone or in combination at four litter biomass levels of 0.16, 0.32, 0.64 and 1.00 kg/m ² with bare soil as the CK, on soil evaporation, surface temperature and near‐surface microenvironmental conditions. Treatment effects, temporal dynamics and factor relationships were evaluated using full‐factorial modelling, repeated‐measures ANOVA with LSD post hoc tests, Spearman correlation analysis and partial correlation analysis. Surface temperature was strongly associated with atmospheric temperature, litter biomass and moss crusts cover, and broadleaf litters showed a stronger warming effect than needle litters. Relative to the uncovered control (CK), cumulative evaporation under single cover of needle litters, broadleaf litters and moss crusts decreased by 30.1%–46.5%, 44.0%–68.9% and 32.3%, respectively. Under combined cover, cumulative evaporation was further reduced relative to CK: needle litters with moss crusts decreased evaporation by 41.3%–55.7%, while broadleaf litters with moss crusts produced an even larger reduction of 59.3%–71.9%. Overall, combined cover suppressed evaporation more strongly than the corresponding single‐cover treatments. These findings indicate that surface organic cover, especially broadleaf litters and their combination with moss crusts, can effectively reduce soil water loss and support soil moisture conservation during ecological restoration in karst regions.