The Combined Effects of Moss-Dominated Biocrusts and Vegetation on Erosion and Soil Moisture and Implications for Disturbance on the Loess Plateau, China

Abstract

Biological soil crusts (BSCs, or biocrusts) have important positive ecological functions such as erosion control and soil fertility improvement, and they may also have negative effects on soil moisture in some cases. Simultaneous discussions of the two-sided impacts of BSCs are key to the rational use of this resource. This study focused on the contribution of BSCs while combining with specific types of vegetation to erosion reduction and their effects on soil moisture, and it addressed the feasibility of removal or raking disturbance. Twelve plots measuring 4 m × 2 m and six treatments (two plots for each) were established on a 15° slope in a small watershed in the Loess Plateau using BSCs, bare land (as a control, BL), Stipa bungeana Trin. (STBU), Caragana korshinskii Kom. (CAKO), STBU planted with BSCs (STBU+BSCs) and CAKO planted with BSCs (CAKO+BSCs). The runoff, soil loss and soil moisture to a depth of 3 m were measured throughout the rainy season (from June to September) of 2010. The results showed that BSCs significantly reduced runoff by 37.3% and soil loss by 81.0% and increased infiltration by 12.4% in comparison with BL. However, when combined with STBU or CAKO, BSCs only made negligible contributions to erosion control (a runoff reduction of 7.4% and 5.7% and a soil loss reduction of 0.7% and 0.3%). Generally, the soil moisture of the vegetation plots was lower in the upper layer than that of the BL plots, although when accompanied with a higher amount of infiltration, this soil moisture consumption phenomenon was much clearer when combining vegetation with BSCs. Because of the trivial contributions from BSCs to erosion control and the remaining exacerbated consumption of soil water, moderate disturbance by BSCs should be considered in plots with adequate vegetation cover to improve soil moisture levels without a significant erosion increase, which was implied to be necessary and feasible.

Spatial distribution of biological soil crusts on the slope of the Chinese Loess Plateau based on canonical correspondence analysis

“…BSCs form a ground cover and are frequently found in arid and semiarid regions (Belnap, 2003), where they have important ecological functions (Bowker et al, 2010;Bu et al, 2015a;Viles, 2008;Yu et al, 2012;) and positively affect soil and water conservation (Bu et al, 2015b). The ecological functions of BSCs and their potential effects on desertification are also attracting more attention, as any change in their cover or biomass may impact the entire ecosystem .…”

Linking biological soil crust attributes to the multifunctionality of vegetated patches and interspaces in a semiarid shrubland

“…This is a major knowledge gap, since BSCs have complementary functions to those of plants, and might largely contribute to modulate different ecosystem processes in the vegetated patches. Indeed, a major challenge of ecological research in drylands is the study of the relative contributions and the combined effects of different biological components of the system (Berdugo et al., ; Bu et al., ; Chaudhary et al., ; Eldridge et al., ). For example, Wang et al.…”

“…cyanobacteria-, lichen-or moss-dominated communities) have been also extensively studied (e.g. Bowker, Eldridge, Val, & Soliveres, 2013;Bu, Wu, Han, Yang, & Meng, 2015;Chamizo, Canton, Rodriguez-Caballero, & Domingo, 2016). However, it has become evident that these approaches constitute a serious limitation to understand the relevance of BSCs upon particular functions, given that community structure can be an important determinant of BSC ecological role (Concostrina-Zubiri, Huber-Sannwald, Martínez, Flores Flores, & Escudero Alcántara, 2013;Eldridge et al, 2010).…”

“…Probably due to the assumed preponderant role of vascular plants regulating the dynamics of vegetated patches, most studies on BSC functioning have been performed in open spaces between vegetation patches, and little is known about the relative importance of BSCs growing underneath the canopies of perennial plants (but see Bu et al, 2015;Eldridge et al, 2010;Kidron, 2016;Maestre, Huesca, Zaady, Bautista, & Cortina, 2002;Xiao & Hu, 2017;Yang, Bu, Mu, Shao, & Zhang, 2014;Zhao & Xu, 2013). This is a major knowledge gap, since BSCs have complementary functions to those of plants, and might largely contribute to modulate different ecosystem processes in the vegetated patches.…”

Use of quantitative PCR with the chloroplast gene rps4 to determine moss abundance in the early succession stage of biological soil crusts

“…Moss cover and biomass, as well as their ecological role in some mature, well-developed moss BSCs, have been studied (Weber et al 2012;Smith and Stark 2014;Ball and Guevara 2015;Bu et al 2015;Fang et al 2015). However, in the early stage of BSC succession or, particularly, at the cyanobacterial-and lichenstages, the mosses are nearly invisible and their biomass is low, especially under dry conditions or in sporophytedominant crusts.…”