Table 1. Pairwise comparisons of different plant species and treatment δD (‰) for 2009 and 2010.

28-Jun-2009	28-Jul-2009	23-Aug-2009
LEPU vs. POSA **	KOPY vs ANTA *	KOPY vs. POFR *
	KOPY vs. OXST **	LEPU vs. POFR *
	KOPY vs. POFR **
	LEPU vs. POFR *
	LEPU vs. OXST *
8 -Jun-2010	9-Jul-2010	3-Aug-2010	25-Aug-2010
KOPY vs. POSA **	KOPY vs. POFR **	KOPY vs. ASRI *	POSA vs. POFR *
KOPY vs. POFR **	KOPY vs. ASRI **	LEPU vs. POSA **
KOPY vs. ASRI **	LEPU vs. POSA **	LEPU vs. ASRI **
LEPU vs. POFR **	LEPU vs. POFR *
LEPU vs. ASRI **	LEPU vs. ASRI **	S vs. W *
POSA vs. ASRI **		S vs. WS *
POSA vs. POFR **
C vs WS *

There were no treatments in 2009. Non-statistically significant comparisons were not included. Rooting depths from shallow to deep are as follows (5–35 cm): Kobresia pygmaea (KOPY), Leontopodium pusillum (LEPU), Potentilla saundersiana (POSA), Potentilla fruticosa (POFR), Oxygropis stracheyana (OXST), Astragalus rigidulus (ASRI). The four treatments were: C = control, W = warming, S = snow addition, WS = warming×snow addition. * signifies P<0.05, ** signifies P<0.005.