[1] Univ Edinburgh, Sch Geosci, Kings Bldg, Edinburgh EH9 3FF, Scotland
[2] Scotlands Rural Coll SRUC, Agr Hort & Engn Sci, Kings Bldg, Edinburgh EH9 3JG, Scotland
[3] Scotlands Rural Coll SRUC, Integrated Land Management, Auchincru Estate, Ayr KA6 5HW, Scotland