Methane
Mean soil CH4 fluxes (µg CH4-C
m-2 h-1) for the reference, buffer,
and no buffer sites for the entire sampling period (June to September)
were -26.3 ± 17.7, -19.7 ± 21.6, and -9.1 ± 22.2, respectively (Figure
4B). Therefore, on average, all of the treatments were a net
CH4 sink over the study period. Based on the LME model,
CH4 uptake was significantly different between
treatments (R - NB: p < 0.01, Table 2); CH4uptake was on average 1.26 times lower at the buffer sites than the
reference sites, and 3.71 times lower at the no buffer sites than the
reference sites. CH4 fluxes were significantly (p
< 0.001) different between local groundwater conditions, with
CH4 uptake being significantly lower in the DIS areas
(Figure 5). CH4 gas flux was -11.2 ± 22.5 µg
CH4 m-2 h-1 at the
DIS areas while -24.4 ± 19.2 µg CH4m-2 h-1 at the ND sites, on average,
for the entire study period. Soil moisture and depth to groundwater were
significant predictors of CH4 fluxes according to the
LME models, with a marginal r2 of 0.37 and 0.46,
respectively. For every percent increase in soil moisture, mean
CH4 flux rate increased by 0.50 µg. For every cm
increase in depth to the groundwater table, mean CH4flux rate decreased by 0.67 µg.