Table 2 Data sources and description of variables used in MaxEnt to model the habitat use of Snow Partridge (Lerwa lerwa) at Balangshan mountains on the eastern Qinghai-Tibetan Plateau, Sichuan Province, China

Land cover type

Classified based on 30 m resolution Global Land Cover (Globeland30-2010) from National Geomatics Center of China (http://www.globallandcover.com/) and include cultivated land, forests, grassland, shrubland, wetland, waterbodies, tundra, artificial surfaces and permanent snow and ice

Terrain

Elevation

Elevation above sea level, obtained from http://www.gscloud.cn/

Slope

Extracted from a 30 m × 30 m digital elevation map (DEM), downloaded from http://www.gscloud.cn/

Aspect

Extracted from a 30 m × 30 m digital elevation map (DEM), downloaded from http://www.gscloud.cn/ and reclassified into 8 direction codes: North 1, Northeast 2, East 3, Southeast 4, South 5, Southwest 6, West 7 and Northwest 8, by 45° from 0° to 360° clockwise, with 0° and 360° both indicating due north. Aspect as a categorical environmental layer with 8 categories, used in MaxEnt

Distance

Distance to ridge

Ridge map drawn based on ridgelines extracted from a 30 × 30 m digital elevation model (DEM) following the method of hydrological analysis (Tang and Yang 2006). Distance to ridge is the distance from the locations to the nearest ridge