Ideas and perspectives: soil cracking should be given great attention in the collapse of Kobresia ecosystems on the Tibetan Plateau

Abstract. The Kobresia meadow in the Tibetan plateau is the world's largest and most unique pastoral alpine ecosystem, forming dense and closed ‘lawns’ mainly dominated by Kobresia species. Soil cracking induced by overstocking is an important feature of degraded alpine Kobresia meadows: it cuts the closed, intact rangeland and alters microtopography. However, soil cracks in alpine grasslands of the Tibetan plateau have rarely been reported and the importance of cracking in relation to livestock overgrazing for the degradation and collapse of alpine rangelands has not been taken seriously. In this Perspectives article, we explain the mechanisms of soil crack formation in Kobresia meadows under overgrazing; the ways in which the soil cracks affect the dynamics of hydrological processes and trigger the erosion of Kobresia turfs; and finally the effects on plant community composition and distribution. We outline the importance of recognizing soil cracks as visual indicators and early warning signs of degradation in order to recover alpine Kobresia meadows by reducing stocking rate. The purpose of this article is to emphasize that researchers and managers of alpine rangelands should pay more attention to crack phenomena in an effort to promote sustainable practices and restoration in Kobresia meadow-livestock systems.