Effects of differing coverage of moss-dominated soil crusts on hydrological processes and implications for disturbance in the Mu Us Sandland, China

Abstract

Abstract:To study the effects of biological soil crusts (BSCs) on hydrological processes and their implications for disturbance in the Mu Us Sandland, the water infiltration, evaporation and soil moisture of high coverage (100% BSCs), middle coverage (40% BSCs) and low coverage (0% BSCs, bare sand) of moss-dominated crusts were conducted in this study, respectively. The conclusions are as follows: (1) the main effects of moss-dominated crusts in the Mu Us Sandland on the infiltration of rainwater were to reduce the infiltration depths and to retain the limited rainwater in shallow soil; (2) moss-dominated crusts have no significant effects on daily evaporation when the volumetric water content at 4 cm depth in 100% BSCs (VWC4) was over 24.7%, on enhanced daily evaporation when the VWC4 ranged from 6.5% to 24.7% and on reduced daily evaporation when the VWC4 was less than 6.5%; and (3) decreasing the coverage of moss-dominated crusts (from 100% to 40%) did not significantly change its effects on infiltration, evaporation and soil moisture. Our results demonstrated that for the growth and regeneration of shrubs, which were dominated by Artemisia ordosica in the Mu Us Sandland, high coverage of moss-dominated crusts has negative effects on hydrological processes, and these negative effects could not be significantly reduced by decreasing the coverage of moss-dominated crusts from 100% to 40%. Therefore, for the sustained and healthy development of shrub communities in the Mu Us Sandland, it is necessary to take appropriate measures for the well-developed BSCs in the sites with high vegetation coverage in the rainy season.

Characteristics of the surface–subsurface flow generation and sediment yield to the rainfall regime and land-cover by long-term in-situ observation in the red soil region, Southern China

“…The variability of the hydrological and erosion response with biological soil crusts depended on the crust composition, the underlying material properties and the stage of crust development (Kideon and Yair, 1997;Cantón et al, 2001;Rodríguez-Caballero et al, 2012). The biological crusts protected the topsoil directly exposed to the raindrops, and the lichen and moss growing on the topsoil improved the soil structure (Leys and Eldridge, 1998;Malam Issa et al, 2001;Jordán et al, 2010) and provided a certain strength that was useful in against concentrated flow scouring (Knapen et al, 2007;Yang et al, 2015). The development of surface crust encouraged runoff, but it also produced a soil surface that had a greater resistance to detachment (Janeau et al, 2003;Kinnell, 2005).…”

Monitoring the variations of evapotranspiration due to land use/cover change in a semiarid shrubland

“…Previous studies demonstrated that dry sand layers and BSCs could effectively restrict the soil evaporation rate (Z. Wang et al, 2006;Lv et al, 2006;Liu et al, 2006;Dong et al, 1999;Yang et al, 2015;Fu et al, 2010;Liu, 2012). However, the bulldozing of sand dunes at our experimental site made the elevation of the flat soil surface lower than the average elevation of the undisturbed soil surface (approximately 1.5 m lower, Fig.…”

“…The area covers only 40 000 km 2 (Dong and Zhang, 2001) and is ecologically fragile (Yang et al, 2007). In such an ecosystem, sand dunes and BSCs are commonly observed (Gao et al, 2014;Yang et al, 2015;Li and Li, 2000;Liu, 2012). Due to the existence of BSCs and dry sand layers (Z.…”

Impacts of alpine meadow degradation on the soil moisture and hydrological processes in the three river source region on the Qinghai Tibetan plateau

“…During the entire infiltration process, water temperature was monitored with mercurial thermometer. The infiltration rate and cumulative infiltration were calculated for the equation (Yang et al, 2015).…”