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Table 7 Test results for random effects meta-analyses for five intervention/exposure categories with sufficient data

From: Evaluating effects of land management on greenhouse gas fluxes and carbon balances in boreo-temperate lowland peatland systems

Intervention/exposure-vs-comparator Measured outcome No. studies SEE1 SE Lower 95% CI Upper 95% CI Description p-value* T2(±SE) Test for Heterogeneity; Q(df), p-value
Drained-vs-undrained NEE 3 116 161 −200 431 Greater in drained 0.473 7.40x103 (±77.8x103) 85.3(2), <0.001
Reco 10 125 60.2 6.71 243 Greater in drained 0.038* 31.1x103 (±16.9x103) 150(9), <0.001
CH4 9 −0.126 0.066 −0.254 0.003 Greater in undrained 0.055 0.000 (±0.016) 12.8(8), 0.119
N2O 5 0.008 0.004 0.001 0.016 Greater in drained 0.033* 0.000 (±0.0001) 2.33(4), 0.676
DOC 5 27.3 14.0 −0.099 54.7 Greater in drained 0.051 839 (±677) 134(4), <0.001
Dry-vs-wet N2O 3 0.221 0.103 0.019 0.424 Greater in dry 0.032* 0.018 (±0.032) 5.46(2), 0.065
Grazed-vs-mown CH4 3 −5.39 4.40 −14.0 3.23 Greater in grazed 0.220 44.4 (±58.8) 8.71(2), 0.013
Restored-vs-unrestored Reco 3 48.7 104 −155 253 Greater in restored 0.640 20.0x103 (±33.7x103) 5.89(2), 0.053
CH4 4 0.248 0.101 0.052 0.446 Greater in restored 0.014* 0.000 (±0.053) 1.18(3), 0.759
DOC 6 15.6 11.6 −7.20 38.3 Greater in restored 0.180 622 (±497) 26.1(5), <0.001
High intensity farmed-vs-low intensity farmed CH4 4 −0.004 0.004 −0.011 0.004 Greater in low intensity farmed 0.349 0.000 (±0.0003) 3.51(3), 0.314
N2O 5 0.143 0.100 −0.053 0.340 Greater in high intensity farmed 0.153 0.043 (±0.035) 18.0(4), 0.001
  1. 1Units: CH4=mg CH4 m-2 h-1, DOC=mg l-1, N2O=mg N2O m-2 h-1, NEE and Reco=mg CO2 m-2 h-1.
  2. Negative ‘summary effect estimates’ indicate a greater value for the control than the intervention and vice versa. SEE=summary effect estimate. SE=standard error, CI=confidence interval, T2=estimate of tau-squared, inter-study variability. ‘*’ indicates significance at α=0.05, ‘.’ indicates marginal significance. NEE=net ecosystem exchange CO2, Reco=ecosystem respiration CO2, DOC=dissolved organic carbon.