This patterning is caused by wind and frost weakening and removing vegetation, leaving granite gravel patches. The vegetation is mostly crowberry (mat-forming), three-leaved rush (turning brown as it's past summer) and the light green racomitrium moss round the stones on the right. It's all easily damaged by further trampling, grazing,etc, but the prognosis is fair. This used to be a Munro summit, but must receive fewer visits now it's been relieved of that responsibility.
Uploaded to Geograph by Nic Bullivant on 14 August 2011
Photo © Nic Bullivant, 14 August 2011. Licensed for reuse under this Creative Commons licence