High rainfall frequency promotes the dominance of biocrust under low annual rainfall

• Published in: Plant and soil 2019-02, Vol.435 (1/2), p.257-275
• Main Authors: Jia, Rongliang, Chen, Ning, Yu, Kailiang, Zhao, Changming
• Format: Article
• Language: English
• Subjects: Annual rainfall; Arid zones; Biomedical and Life Sciences; Climate change; Desert environments; Deserts; Ecology; Ecosystems; Environmental aspects; Global climate; Global temperature changes; Life Sciences; Plant Physiology; Plant Sciences; Plants; Plants (botany); Rain; Rainfall; REGULAR ARTICLE; Restoration; Soil Science & Conservation; State variable; Structural stability
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-018-3880-6

Aims Global climate change may greatly alter the structure and stability of drylands, creating an urgent need to recover their functions and services. Biological soil crust (biocrust), an interface between the soil and atmosphere, plays a crucial role in ecohydrological processes, and thus in influencing the restoration dynamics of dryland ecosystems. Previous studies have generally investigated the influences of biocrust on ecohydrological processes as an exogenous factor. However, it remains unclear how biocrusts, as an integral part of many ecosystems (i.e., as a system state variable), will change under global climate change. Methods This study developed a new ecohydrological model with biocrust cover as a system state variable, and explored the response of dryland ecosystems to altered rainfall regimes. Results Biocrust cover responded with an inverted U-shaped curve relationship to increasing annual rainfall and linearly to increasing rainfall frequency. Vascular plant (grass and shrub) cover showed an increasing trend with increasing annual rainfall and a decreasing trend to increasing rainfall frequency. Therefore, biocrust usually dominated over vascular plants (i.e., high biocrust cover and low vascular plant cover) under low annual rainfall. Furthermore, an increasing rainfall frequency would amplify the range of environmental (rainfall) conditions dominated by biocrust from an annual rainfall 0–100 mm under a rainfall frequency of 0.025 day −1 to 0–500 mm under a rainfall frequency of 1 day −1 . Conclusions This study developed a model framework to predict dryland dynamics for surfaces covered by biocrust under global climate change. We suggest that restoration efforts could target at biocrust-dominated state in deserts, especially in a (future) drier climate.