Table 1.

Mixed ANCOVA effects of soil moisture (covariate), mowing (factor) and species (factor) on the Relative Interaction Index (RII) and the I_imp index computed on the growth data

	d.f.	den d.f.	RII		Iimp
			F	P	F	P
Intercept	1	58	14·40	***	15·30	***
Moisture	1	13	2·42	n.s.	5·25	*
Mowing	1	13	9·14	**	6·14	*
Species	3	58	5·81	**	5·09	**
Moisture ×mowing	1	13	15·55	**	9·25	**
Moisture × species	3	58	1·45	n.s.	1·91	n.s.
Mowing × species	3	58	1·37	n.s.	0·76	n.s.
Moisture × mowing × species	3	58	6·17	***	2·28	†

d.f., numerator degrees of freedom; den d.f., denominator degrees of freedom; n.s., not significant; ^†P < 0·1; *P < 0·05; **P < 0·01; ***P < 0·001.