Supplementary Table S1. Descriptive statistics and testing for significant differences of nitrogen content in litter mixtures. N percent concentration (mean ± s.e.m. and 95% confidence interval of 10 replicates) in cellulose, wood, Quercus ilex and Hedera helix litter of three different ages decomposed at two temperatures is reported, according to litter pairing with four different organic substrates. Different small letters indicate significant differences dependent on litter pairing within each combination of litter type, temperature, and litter age levels (table row). Within each block at fixed litter pair and temperature, age-dependent significantly highest and lowest values are reported in bold and italic, respectively (post-hoc Duncan test from GLMs in Table 1, p < 0.05).
Litter type/ Temperature (°C) / Litter age
(days) / Paired organic substrate
Cellulose strips / Woody sticks / Q. ilex leaves / H. helix leaves
Cellulose strips / 12 / 90 / 0.17 ± 0.02 a
(0.13 ÷ 0.21) / 0.15 ± 0.03 a
(0.08 ÷ 0.22) / 0.17 ± 0.01 a
(0.16 ÷ 0.18) / 0.17 ± 0.01 a
(0.15 ÷ 0.19)
180 / 0.24 ± 0.06 a
(0.11 ÷ 0.37) / 0.16 ± 0.04 a
(0.07 ÷ 0.25) / 0.24 ± 0.03 a
(0.17 ÷ 0.31) / 0.42 ± 0.08 b
(0.25 ÷ 0.59)
360 / 0.27 ± 0.05 a
(0.16 ÷ 0.38) / 0.25 ± 0.05 a
(0.14 ÷ 0.36) / 0.53 ± 0.08b
(0.35 ÷ 0.71) / 0.83 ± 0.12c
(0.57 ÷ 1.09)
24 / 90 / 0.09 ± 0.01 a
(0.07 ÷ 0.11) / 0.09 ± 0.01 a
(0.08 ÷ 0.10) / 0.32 ± 0.04 b
(0.23 ÷ 0.41) / 0.43 ± 0.12 b
(0.16 ÷ 0.70)
180 / 0.18 ± 0.01 a
(0.17 ÷ 0.19) / 0.19 ± 0.04 a
(0.10 ÷ 0.28) / 0.40 ± 0.06 b
(0.27 ÷ 0.53) / 0.87 ± 0.17 c
(0.49 ÷ 1.25)
360 / 0.18 ± 0.01 a
(0.16 ÷ 0.20) / 0.19 ± 0.03 a
(0.12 ÷ 0.26) / 1.37 ± 0.11 b
(1.13 ÷ 1.61) / 1.34 ± 0.15 b
(1.01 ÷ 1.67)
Woody sticks / 12 / 90 / 0.10 ± 0.02 a
(0.06 ÷ 0.14) / 0.11 ± 0.02 a
(0.07 ÷ 0.15) / 0.15 ± 0.03 a
(0.09 ÷ 0.21) / 0.13 ± 0.02 a
(0.09 ÷ 0.17)
180 / 0.14 ± 0.02 a
(0.10 ÷ 0.18) / 0.13 ± 0.03 a
(0.06 ÷ 0.20) / 0.32 ± 0.02 b
(0.28 ÷ 0.36) / 0.35 ± 0.07 b
(0.19 ÷ 0.51)
360 / 0.24 ± 0.04 a
(0.15 ÷ 0.33) / 0.23 ± 0.04 a
(0.14 ÷ 0.32) / 0.52 ± 0.05 b
(0.41 ÷ 0.63) / 0.64 ± 0.11 b
(0.41 ÷ 0.87)
24 / 90 / 0.09 ± 0.01 a
(0.08 ÷ 0.10) / 0.08 ± 0.01 a
(0.07 ÷ 0.09) / 0.14 ± 0.04 a
( 0.06 ÷ 0.23) / 0.15 ± 0.03 a
(0.08 ÷ 0.22)
180 / 0.08 ± 0.03 a
(0.01 ÷ 0.15) / 0.11 ± 0.01 a
(0.09 ÷ 0.13) / 0.31 ± 0.03 b
(0.24 ÷ 0.38) / 0.62 ± 0.10 c
(0.40 ÷ 0.84)
360 / 0.10 ± 0.01 a
(0.08 ÷ 0.12) / 0.11 ± 0.02 a
(0.07 ÷ 0.15) / 0.52 ± 0.07 b
(0.38 ÷ 0.66) / 0.67 ± 0.04 c
(0.58 ÷ 0.76)
Q. ilex leaves / 12 / 90 / 1.25 ± 0.22 a
(0.76 ÷ 1.74) / 1.27 ± 0.10 a
(1.05 ÷ 1.49) / 1.40 ± 0.05 a
(1.29 ÷ 1.51) / 1.17 ± 0.27 a
(0.57 ÷ 1.77)
180 / 1.40 ± 0.07 a
(1.24 ÷ 1.56) / 1.37 ± 0.07 a
(1.22 ÷ 1.52) / 1.65 ± 0.03 b
(1.58 ÷ 1.72) / 1.23 ± 0.08 a
(1.05 ÷ 1.41)
360 / 1.61 ± 0.12 a
(1.34 ÷ 1.88) / 1.58 ± 0.08 a
(1.41 ÷ 1.75) / 1.71 ± 0.06 a
(1.58 ÷ 1.84) / 1.82 ± 0.15 a
(1.49 ÷ 2.15)
24 / 90 / 1.46 ± 0.07 a
(1.30 ÷ 1.62) / 1.53 ± 0.06 a
(1.40 ÷ 1.66) / 1.59 ± 0.06 a
(1.46 ÷ 1.72) / 1.85 ± 0.11 b
(1.60 ÷ 2.10)
180 / 1.65 ± 0.12 a
(1.38 ÷ 1.92) / 1.72 ± 0.11 a
(1.47 ÷ 1.97) / 1.65 ± 0.08 a
(1.47 ÷ 1.83) / 1.98 ± 0.06 b
(1.85 ÷ 2.11)
360 / 1.78 ± 0.11 a
(1.53 ÷ 2.03) / 1.78 ± 0.04 a
(1.69 ÷ 1.87) / 2.10 ± 0.05 b
(1.99 ÷ 2.21) / 2.70 ± 0.06 c
(2.57 ÷ 2.83)
H. Helix leaves / 12 / 90 / 2.59 ± 0.09 a
(2.32 ÷ 2.76) / 1.87 ± 0.08 b
(1.69 ÷ 2.05) / 2.75 ± 0.10 a
(2.52 ÷ 2.98) / 2.74 ± 0.07 a
(2.58 ÷ 2.92)
180 / 3.30 ± 0.71 a
(1.72 ÷ 4.88) / 3.13 ± 0.14 a
(2.81 ÷ 3.55) / 3.44 ± 0.23 a
(2.95 ÷ 3.93) / 3.46 ± 0.90 a
(1.45 ÷ 5.47)
360 / 3.29 ± 0.31 a
(2.60 ÷ 3.98) / 3.06 ± 0.28 a
(2.46 ÷ 3.66) / 3.68 ± 0.38 a
(2.83 ÷ 4.53) / 3.53 ± 1.15 a
(0.97 ÷ 6.09)
24 / 90 / 3.55 ± 0.21 a
(3.07 ÷ 4.03) / 4.03 ± 0.42 a
(3.17 ÷ 4.89) / 3.78 ± 0.25 a
(3.20 ÷ 4.36) / 3.21 ± 0.36 a
(2.37 ÷ 4.04)
180 / 3.46 ± 0.17 a
(3.08 ÷ 3.84) / 3.11 ± 0.34 a
(2.35 ÷ 3.87) / 3.49 ± 0.58 a
(2.20 ÷ 4.78) / 3.31 ± 0.26 a
(2.73 ÷ 3.89)
360 / 3.82 ± 0.23 a
(3.31 ÷ 4.33) / 4.10 ± 0.29 a
(3.45 ÷ 4.75) / 3.53 ± 0.41 a
(2.66 ÷ 4.40) / 4.26 ± 0.37 a
(3.49 ÷ 5.03)