A review on biological soil crusts of grassland

Biological soil crusts are a complex covering integrities developing by combining cryptigams with bacteria,fungi and soil particles, and are widely distributed in each grassland type in the world, and play an active role in improving the ecological environment and prevention of grassland degradation. In recently years, many studies throughout the world have been conducted in this field, and these studies focus on the cognition of its function and effect. However, how biological soil crusts develop under global change and how they maintain the stability of the ecosystem are still not well documented. This paper reviewed the research achievements in this filed, and discussed the current shortage and future directions of the research, and these would encourage the biological soil crusts to further advance and helpful understand the soil evolution in grassland ecosystem.