| 水分梯度 | 藓类结皮 | 藻类结皮 | 混生结皮 | 流沙 |
| 1 | a | a | a | a |
| 2 | a | b | b | b |
| 3 | a | b | b | c |
| 4 | a | b | ab | c |
| 5 | a | b | b | c |
| 6 | a | a | a | b |
| 7 | a | b | b | c |