Table 2. Analyses of covariance to test for differences in litter mass loss of the six study species.

Litter species	Source of variance	df	Mean square	F value	P value
Fagus sylvatica	Covariable (C/N ratio)	1	12.56	1.30	0.26
	Block	2	4.07	0.42	0.66
	Litter diversity (D)	3	60.54	6.27	0.0008
	Macrofauna (M)	3	80.55	2.16	0.16
	D × M	9	37.32	3.86	0.0005
	Error	71	9.65
Quercus robur	Covariable (lignin/N ratio)	1	11.28	0.87	0.36
	Block	2	9.50	0.73	0.49
	Litter diversity (D)	3	46.81	3.60	0.026
	Macrofauna (M)	3	264.95	4.67	0.031
	D × M	9	56.73	4.36	0.0013
	Error	28	13.00
Acer campestre	Covariable (lignin/N ratio)	1	15.27	0.41	0.53
	Block	2	59.41	1.58	0.22
	Litter diversity (D)	3	171.79	4.58	0.0099
	Macrofauna (M)	3	342.89	2.62	0.12
	D × M	9	130.87	3.49	0.0053
	Error	28	37.53
Carpinus betulus	Covariable (C/N ratio)	1	67.00	0.61	0.45
	Block	2	313.81	2.88	0.067
	Litter diversity (D)	2	263.53	2.42	0.10
	Macrofauna (M)	3	606.60	9.44	0.011
	D × M	6	64.24	0.59	0.74
	Error	45	109.06
Prunus avium	Covariable (N concentration)	1	54.56	1.40	0.25
	Block	2	19.82	0.97	0.40
	Litter diversity (D)	2	43.90	1.13	0.34
	Macrofauna (M)	3	971.47	5.93	0.032
	D × M	6	163.75	4.20	0.0062
	Error	21	38.96
Tilia platyphyllos	Covariable (lignin/N ratio)	1	36.80	0.78	0.38
	Block	2	16.72	0.35	0.70
	Litter diversity (D)	3	45.64	0.96	0.42
	Macrofauna (M)	3	240.12	7.39	0.0084
	D × M	9	32.47	0.69	0.72
	Error	50	47.36

Analysis of covariance was used to test for effects of litter quality (covariable), blocking (random block factor), litter diversity (random factor), macrofauna presence (fixed factor), and the interaction of litter diversity and macrofauna presence on species-specific litter mass loss. The litter quality parameter explaining the largest portion of variance was used as covariable in the model. According to the mixed model used, the effect of macrofauna was tested against the mean square of D × M as the error term.