Features on Fractal Dimension of Barren Patch and Mouse Hole among Different Degenerated Succession Stages on Alpine Meadow in the Source Region of the Yangtze and Yellow River,Qinghai-Tibetan Plateau,China Cellular automata simulation of barren patch connectivity effect in degradation sequence on alpine meadow in the source region of the Yangtze and Yellow rivers, Qinghai-Tibetan Plateau, China Features and application of a rangeland detection algorithm based on fractal dimensions to detect characteristics of barren patch