Habitat distribution and suggested management units of the giant panda. Habitat distribution of the giant panda, with each filled circle representing a sampling location. Population abbreviations are as follows: QLI, Qinling; MSH, Minshan; QLA, Qionglai; DXL, Daxiangling; XXL, Xiaoxiangling; and LSH, Liangshan. Numbers indicate sampling sites as shown in Additional file 4: Table S3. Different levels of grey in the habitat distribution represent the 3 management units as suggested by this study (light grey, QLI; grey, MSH-QLA; dark grey, DXL-XXL-LSH).