Average cumulative fluxes and CO2 equivalents (g m−2, ±SD) of greenhouse gases in the different experimental treatments.

aCumulative fluxes were calculated separately for each chamber as areas under the temporal gas flux curve (Fig. 2; see also Appendix A). For CH4, N2O and CO2 equivalents, measurements from day 1 and 3 were based on a separate experiment conducted in 2012 (see Appendix A), whereas all CO2 measurements were based on data collected in 2011.bCompound-specific multipliers suggested by the IPCC (2007) were used to weigh together the contribution of individual compounds into the general currency of “CO2 equivalents”, at a 100-year time horizon. Thus, fluxes of CH4 were converted to CO2 equivalents through multiplication by a factor of 25, and fluxes of N2O through multiplication by a factor of 298. As the net warming impact of carbon first tied by plants, then released from the dung as CO2 will differ from that of CH4 or N2O fluxes from dung (see Discussion), we derive separate subtotals for the cumulative emission of CO2 equivalents of CH4, N2O, and their sum, as well as summing their total (equaling the warming impact of CO2, CH4, and N2O combined).cRow FBversus FN shows the results of a compound-specific t-test of treatments FB (presence of dung beetles) versus FN (absence of dung beetles). The last row of the table shows the ratio between fluxes in the presence (FB) versus absence (FN) of dung beetles as the percentage ((FB-FN)/FN).Variation in degrees of freedom reflects differences between tests based on equal versus unequal variances. (Where not otherwise specified, the test was based on the assumption of equal variances, as supported by a non-significant Levene’s test.).dTest based on unequal variances (cf. Fig. 2c); test of equality of variances, F9,9 = 3.81 P = 0.03.