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ONLINE SUPPLEMENTARY MATERIAL (TABLES S1-S8)

Supplementary Table S1. Amounts of honeydew and N added to experimental units each month during the entire experimental period.

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Month Low honeydewa High honeydewb Nitrogenc

(g C/m2/month) (g C/m2/month) (g N/m2/month)

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January / 0.6 / 8.4 / 1.4
February / 0.0 / 7.1 / 1.2
March / 0.5 / 29.5 / 4.9
April / 1.6 / 31.8 / 5.3
May / 0.8 / 9.6 / 1.6
June / 5.4 / 5.4 / 0.9
July / 22.2 / 22.2 / 3.7
August / 34.7 / 34.7 / 5.8
September / 21.8 / 21.8 / 3.6
October / 22.8 / 22.8 / 3.8
November / 42.7 / 42.7 / 7.2
December / 11.5 / 11.5 / 1.9

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aAdded to low honeydew treatment (LC) only

bAdded to all treatments with full honeydew (HC and HC+N)

cAdded to all treatments with N added (N and HC+N)

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Supplementary Table S2. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on soil abiotic properties.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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Humus pH / 0.1 (0.783) / 0.7 (0.633) / 2.4 (0.060) / 98.2 (<0.001) / 0.9 (0.432) / 2.2 (0.053) / 1.8 (0.100)
Humus N conc. / 0.1 (0.822) / 1.6 (0.199) / 1.1 (0.393) / 26.8 (<0.001) / 0.3 (0.710) / 0.8 (0.621) / 1.2 (0.309)
Humus P conc. / 0.0 (0.837) / 1.0 (0.194) / 0.4 (0.831) / 0.8 (0.455) / 0.5 (0.432) / 1.6 (0.161) / 2.6 (0.013)
Humus Olsen P
conc. / 0.4 (0.549) / 0.2 (0.958) / 4.6 (0.004) / 95.9 (0.001) / 0.7 (0.521) / 1.5 (0.185) / 4.1 (<0.001)
Humus C to N
ratio / 2.5(0.120) / 0.7 (0.785) / 4.1 (0.007) / 29.7 (<0.001) / 0.7 (0.492) / 0.3 (0.927) / 1.6 (0.368)
Humus C to P
ratio / 1.2 (0.271) / 0.3 (0.878) / 3.6 (0.012) / 4.3 (0.018) / 0.3 (0.762) / 0.7 (0.674) / 0.6 (0.806)
Humus N to P
ratio / 0.6 (0.449) / 0.4 (0.837) / 2.2 (0.076) / 10.8 (<0.001) / 0.6 (0.568) / 1.0 (0.485) / 0.9 (0.842)
Litter mass per
unit area / 0.5 (0.476) / 0.8 (0.518) / 0.7 (0.583) / 29.0 (<0.001) / 0.6 (0.541) / 2.2 (0.053) / 1.4 (0.200)
Humus mass per
unit area / 2.4 (0.131) / 1.9 (0.121) / 1.4 (0.241) / 10.9 (<0.001) / 1.5 (0.224) / 2.6 (0.015) / 1.1 (0.400)
Humus C per
unit area / 0.4 (0.362) / 3.0 (0.283) / 2.7 (0.042) / 55.1 (<0.001) / 4.3 (0.016) / 4.7 (<0.001) / 2.1 (0.040)
Humus N per
unit area / 2.3 (0.131) / 3.4 (0.017) / 1.7 (0.174) / 54.9 (<0.001) / 4.5 (0.014) / 4.5 (<0.001) / 2.1 (0.049)
Humus P per
unit area / 2.9 (0.097) / 3.1 (0.025) / 1.8 (0.142) / 16.4 (<0.001) / 1.9 (0.151) / 2.3 (0.032) / 1.8 (0.101)

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Degrees of freedom are: R (1, 40), S (4, 40), R x S (4, 40), T (2, 77), R x T (2, 77), S x T (8, 77), R x S x T(8, 77)

Numbers in bold are statistically significant at P = 0.05.

P-values of less than 0.004 remain as statistically significant at P = 0.05 following Bonferroni correction.


Supplementary Table S3. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on microbial respiration and activity variables.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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Litter
Basal respiration
(BR) / 1.3 (0.268) / 1.2 (0.345) / 1.4 (0.238) / 90.5 (<0.001) / 1.8 (0.069) / 0.3 (0.980) / 1.3 (0.242)
SIRa / 2.7 (0.110) / 3.1 (0.027) / 2.3 (0.078) / 108.2 (<0.001) / 1.6 (0.080) / 1.7 (0.103) / 1.9 (0.079)
BR:SIR / 0.1 (0.902) / 1.1 (0.388) / 0.8 (0.572) / 2.8 (0.065) / 0.2 (0.796) / 0.9 (0.572) / 0.3 (0.950)
Humus
Basal respiration
(BR) / 0.8 (0.388) / 0.4 (0.420) / 0.7 (0.583) / 36.4 (<0.001) / 0.5 (0.562) / 0.5 (0.856) / 0.5 (0.847)
SIR / 0.3 (0.576) / 6.4 (<0.001) / 0.1 (0.969) / 75.9 (<0.001) / 1.6 (0.208) / 1.5 (0.184) / 0.8 (0.575)
BR:SIR / 1.1 (0.292) / 1.1 (0.391) / 0.9 (0.497) / 1.6 (0.200) / 0.4 (0.600) / 0.9 (0.559) / 0.7 (0.772)
SIR/(total C) / 0.7 (0.397) / 4.8 (0.003) / 1.9 (0.121) / 62.1 (<0.001) / 1.0 (0.390) / 1.6 (0.150) / 1.1 (0.401)

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aSIR = substrate induced respiration.

Degrees of freedom are: R (1, 40), S (4, 40), R x S (4, 40), T (2, 77), R x T (2, 77), S x T (8, 77), R x S x T(8, 77)

Numbers in bold are statistically significant at P = 0.05.

P-values of less than 0.008 remain as statistically significant at P = 0.05 following Bonferroni correction.

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Supplementary Table S4. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on phospholipid fatty acid (PLFA) and substrate utilization (SUP) data in humus samples.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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PLFA data
Total PLFAs / 0.1 (0.746) / 2.1 (0.609) / 1.4 (0.238) / 14.4 (<0.001) / 0.8 (0.450) / 1.0 (0.456) / 2.2 (0.038)
Bacterial PLFAs / 0.2 (0.628) / 5.3 (<0.001) / 1.0 (0.444) / 51.4 (<0.001) / 1.9 (0.156) / 1.5 (0.172) / 1.1 (0.396)
Fungal PLFAs / 0.1 (0.739) / 8.1 (<0.001) / 1.4 (0.246) / 89.4 (<0.001) / 0.1 (0.958) / 1.9 (0.680) / 0.4 (0.928)
Bacterial:fungal
PLFAs / 0.0 (0.982) / 8.8 (<0.001) / 0.9 (0.499) / 81.9 (<0.001) / 0.2 (0.788) / 3.1 (0.004) / 0.4 (0.897)
PLFA diversitya / 0.1 (0.914) / 2.3 (0.071) / 0.2 (0.928) / 12.4 (<0.001) / 1.4 (0.248) / 1.6 (0.129) / 2.6 (0.015)
PCIb (23.6 %) / 0.0 (0.954) / 0.7 (0.644) / 0.2 (0.912) / 25.5 (<0.001) / 0.5 (0.626) / 1.4 (0.191) / 0.8 (0.591)
PC2 (19.7%) / 1.5 (0.235) / 10.9 (<0.001) / 0.2 (0.932) / 37.7 (<0.001) / 1.0 (0.390) / 1.6 (0.150) / 1.1 (0.401)
PC3 (13.8%) / 0.5(0.450) / 4.3 (0.006) / 4.3 (0.006) / 10.5 (<0.001) / 0.5 (0.563) / 0.3 (0.578) / 2.8 (0.009)
SUP data
Total SUPsc / 5.9 (0.019) / 4.5 (0.005) / 0.6 (0.657) / 21.0 (<0.001) / 3.5 (0.033) / 1.0 (0.432) / 1.6 (0.151)
Total amino
acidsd / 2.0 (0.168) / 4.0 (0.008) / 0.2 (0.543) / 37.9 (<0.001) / 0.2 (0.802) / 1.0 (0.451) / 1.5 (0.159)
Total COOHe / 6.3 (0.016) / 4.6 (0.004) / 0.7 (0.594) / 37.0 (<0.001) / 4.7 (0.012) / 1.1 (0.350) / 1.4 (0.216)
Diversitya / 1.6 (0.218) / 1.6 (0.194) / 1.0 (0.409) / 10.0 (<0.001) / 0.5 (0.538) / 1.6 (0.151) / 0.8 (0.594)
PCIb (30.5%) / 0.3 (0.575) / 1.5 (0.209) / 1.0 (0.432) / 98.5 (<0.001) / 1.0 (0.354) / 1.5 (0.178) / 1.1 (0.331)
PC2 (12.2%) / 2.7 (0.105) / 1.0 (0.407) / 3.3 (0.031) / 3.6 (0.031) / 0.4 (0.678) / 0.4 (0.881) / 1.5 (0.168)

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aShannon-Weiner diversity index

bPC = Axis scores from principal components analysis, with percentage of total variation explained by axes in brackets.

cTotal sum of respiration for all added compounds in SUP test.

dTotal sum of respiration for all added amino acids in SUP test.

eTotal sum of respiration for all added carbohydrates in SUP test.

Degrees of freedom are: R (1, 40), S (4, 40), R x S (4, 40), T (2, 77), R x T (2, 77), S x T (8, 77), R x S x T(8, 77)

Numbers in bold are statistically significant at P = 0.05.

P-values of less than 0.004 remain as statistically significant at P = 0.05 following Bonferroni correction.

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Supplementary Table S5. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on microfaunal communities in the litter layer.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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Total
nematodesa / 0.1 (0.784) / 3.3 (0.020) / 0.4 (0.828) / 94.4 (<0.001) / 0.4 (0.650) / 2.2 (0.041) / 1.2 (0.288)
Microbe feeding
nematodesa / 0.2 (0.649) / 4.0 (0.008) / 0.2 (0.917) / 98.4 (<0.001) / 0.4 (0.469) / 2.5 (0.016) / 1.3 (0.270)
Predatory
nematodesa / 1.0 (0.317) / 3.2 (0.023) / 0.6 (0.650) / 9.6 (<0.001) / 0.3 (0.718) / 0.9 (0.519) / 0.9 (0.510)
BF to FF
Ratiob / 0.5 (0.477) / 9.6 (<0.001) / 1.1 (0.378) / 48.7 (<0.001) / 2.6 (0.077) / 2.6 (0.015) / 0.3 (0.945)
Richness of
genera / 0.1 (0.797) / 6.6 (<0.001) / 2.0 (0.120) / 4.1 (0.019) / 0.1 (0.875) / 1.0 (0.428) / 1.4 (0.192)
Nematode
Diversityc / 0.0 (0.969) / 6.2 (<0.001) / 1.4 (0.268) / 3.9 (<0.001) / 0.1 (0.894) / 1.2 (0.304) / 1.2 (0.298)
Nematode
PC1 (21.4%)d / 2.1 (0.154) / 2.5 (0.050) / 1.3 (0.306) / 30.6 (<0.001) / 1.8 (0.178) / 0.5 (0.887) / 0.9 (0.561)
Nematode
PC2 (18.0%) / 0.7 (0.786) / 8.1 (0.001) / 1.0 (0.446) / 8.0 (0.007) / 0.5 (0.588) / 1.9 (0.072) / 0.9 (0.488)
Tardigradesa / 0.2 (0.886) / 13.0 (<0.001) / 0.6 (0.679) / 43.8 (<0.001) / 0.4 (0.653) / 5.8 (<0.001) / 0.6 (0.678)
Enchytraeidsa / 0.3 (0.613) / 2.4 (0.066) / 0.8 (0.507) / 11.5 (<0.001) / 0.2 (0.822) / 0.5 (0.849) / 0.6 (0.732)

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aAnalyses performed on ln (x + 1) transformed data.

bRatio of bacterial feeding to fungal feeding nematodes

cShannon-Weiner diversity index

dPC = Axis scores from principal components analysis, with percentage of total variation explained by axes in brackets.

Degrees of freedom are: R (1, 40), S (4, 40), R x S (4, 40), T (2, 77), R x T (2, 77), S x T (8, 77), R x S x T(8, 77)

Numbers in bold are statistically significant at P = 0.05.

P-values of less than 0.005 remain as statistically significant at P = 0.05 following Bonferroni correction.


Supplementary Table S6. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on microfaunal communities in the humus layer.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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Total
nematodesa / 0.4 (0.525) / 1.2 (0.312) / 1.5 (0.197) / 15.5 (<0.001) / 0.8 (0.454) / 1.6 (0.142) / 0.2 (0.982)
Microbe feeding
nematodesa / 0.3 (0.607) / 0.9 (0.460) / 1.6 (0.203) / 14.1 (<0.001) / 0.2 (0.783) / 1.5 (0.183) / 0.5 (0.877)
Predatory
nematodesa / 10.8 (<0.001) / 4.4 (0.005) / 6.3 (<0.001) / 41.4 (<0.001) / 1.6 (0.203) / 1.6 (0.142) / 1.5 (0.157)
BF to FF
Ratiob / 0.9 (0.919) / 1.3 (0.323) / 1.0 (0.452) / 48.9 (<0.001) / 1.2 (0.294) / 2.9 (0.007) / 1.6 (0.153)
Richness of
genera / 1.6 (0.208) / 2.3 (0.072) / 2.1 (0.093) / 51.2 (<0.001) / 0.6 (0.535) / 0.9 (0.456) / 1.2 (0.297)
Nematode
Diversityc / 1.7 (0.194) / 3.4 (0.016) / 2.1 (0.093) / 47.9 (<0.001) / 0.8 (0.438) / 1.0 (0.457) / 1.1 (0.361)
Nematode
PC1 (27.1%)d / 2.4 (0.126) / 1.7 (0.163) / 1.4 (0.269) / 78.8 (<0.001) / 0.2 (0.806) / 0.5 (0.825) / 1.2 (0.294)
Nematode
PC2 (19.0%) / 1.3 (0.264) / 0.8 (0.549) / 1.1 (0.330) / 0.04 (0.962) / 0.4 (0.648) / 1.1 (0.376) / 1.3 (0.265)
Tardigradesa / 0.3 (0.561) / 2.9 (0.033) / 0.4 (0.858) / 23.6 (<0.001) / 1.6 (0.206) / 1.6 (0.137) / 1.4 (0.207)
Enchytraeidsa / 5.6 (0.022) / 5.3 (0.002) / 6.8 (<0.001) / 21.5 (<0.001) / 3.0 (0.054) / 1.0 (0.461) / 0.6 (0.818)

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aAnalyses performed on ln (x + 1) transformed data.

bRatio of bacterial feeding to fungal feeding nematodes

cShannon-Weiner diversity index

dPC = Axis scores from principal components analysis, with percentage of total variation explained by axes in brackets.

Degrees of freedom are: R (1, 40), S (4, 40), R x S (4, 40), T (2, 77), R x T (2, 77), S x T (8, 77), R x S x T(8, 77)

Numbers in bold are statistically significant at P = 0.05.

P-values of less than 0.005 remain as statistically significant at P = 0.05 following Bonferroni correction.


Supplementary Table S7. Results of Repeated Measures ANOVA (F-values with P values in brackets) for effects of rodent exclusion and substrate addition treatments on meso- and macrofaunal communities in the litter layer.

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Response variable Rodents (R) Substrate (S) R x S Time (T) R x T S x T R x S x T

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Diplopoda / 0.1 (0.858) / 2.9 (0.033) / 1.5 (0.196) / 2.3 (0.107) / 0.5 (0.631) / 1.4 (0.205) / 0.5 (0.842)
Hemipteraa / 0.2 (0.655) / 4.6 (0.004) / 1.9 (0.127) / 30.1 (<0.001) / 0.0 (0.985) / 0.5 (0.832) / 0.7 (0.694)
Psocopteraa / 0.1 (0.927) / 1.8 (0.148) / 0.9 (0.477) / 34.8 (<0.001) / 1.2 (0.297) / 0.8 (0.637) / 0.1 (0.998)
Coleopteraa / 0.8 (0.477) / 3.1 (0.023) / 1.0 (0.439) / 32.2 (<0.001) / 9.1 (<0.001) / 0.5 (0.887) / 1.2 (0.280)
Diptera (larvae)a / 0.4 (0.530) / 3.1 (0.025) / 0.2 (0.911) / 1.5 (0.247) / 0.8 (0.448) / 1.4 (0.198) / 0.6 (0.764)
Lepidoptera
(larvae)a / 0.1 (0.767) / 0.5 (0.768) / 2.4 (0.066) / 9.5 (<0.001) / 0.3 (0.732) / 0.6 (0.816) / 0.7 (0.737)
Hymenopteraa / 0.3 (0.595) / 0.1 (0.985) / 1.0 (0.462) / 4.8 (0.011) / 1.1 (0.359) / 1.2 (0.292) / 1.5 (0.161)
Pseudo-
scorpionidaea / 0.3 (0.567) / 0.2 (0.959) / 2.2 (0.081) / 15.5 (<0.001) / 1.1 (0.205) / 1.2 (0.317) / 0.2 (0.861)
Araenidaea / 0.8 (0.399) / 0.7 (0.607) / 0.3 (0.921) / 10.8 (<0.001) / 0.0 (0.992) / 1.5 (0.768) / 0.5 (0.828)
Collembolaa / 0.2 (0.658) / 0.4 (0.826) / 1.5 (0.227) / 8.2 (<0.001) / 0.5 (0.589) / 0.8 (0.556) / 0.5 (0.888)
Acaria / 2.6 (0.114) / 1.0 (0.219) / 1.9 (0.135) / 54.3 (<0.001) / 1.0 (0.360) / 1.2 (0.312) / 0.9 (0.489)
Richness of
ordersb / 1.2 (0.282) / 6.1 (<0.001) / 0.1 (0.986) / 27.7 (<0.001) / 3.4 (0.037) / 1.3 (0.244) / 1.2 (0.236)
Macrofaunal
diversityb,c / 0.1 (0.948) / 3.5 (0.016) / 0.4 (0.797) / 6.7 (0.002) / 1.4 (0.260) / 0.9 (0.517) / 0.9 (0.495)
Macrofaunal
PC1 (18.2%)b,d / 1.0 (0.329) / 0.7 (0.612) / 2.4 (0.066) / 40.3 (<0.001) / 1.4 (0.258) / 0.4 (0.915) / 1.3 (0.255)
Macrofaunal
PC2 (17.7%)b,d / 0.1 (0.794) / 0.5 (0.727) / 0.3 (0.807) / 0.8 (0.438) / 0.5 (0.604) / 1.0 (0.474) / 0.6 (0.800)

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