Melica przewalskyi population spatial pattern and response to soil moisture in degraded alpine grassland Fractal root system of Melica przewalskyi along different aspect in degraded grassland Relationship between leaf traits of Melica przewalskyi and slope aspects in alpine grassland of Qilian Mountains, China In the process of grassland degradation the spatial pattern and spatial association of dominant species Trade-off between root forks and link length of Melica przewalskyi on different aspects of slopes