Table 1. Main and Interaction Effects from Linear Models of Decay Parameters and Environmental Variables^a,b.

		labile OM (green tea)			recalcitrant OM (rooibos tea)
model	explanatory variables	A	ka	ks	A	ka	ks
ecosystem & climate	ecosystem:precipitation
	ecosystem:temperature	8.49***		8.57***
	ecosystem:temperature variation
	ecosystem	170.99***	319.6***	2404.6***	273.15***	449.65***	5444.0***
	precipitation
	temperature mean	18.45***		18.34***	15.84***		37.34***
	temperature variation	0.47		0.908
	days of incubation	2.64			7.21**	7.10**	12.48***
macroclimate	macroclimate	6.51***	3.21**	7.30***	4.02***	1.46	13.03***
	days of incubation	3.30*	2.51	3.05*	5.25**	8.32***	18.0***
freshwater wetland	IUCN Typologies 2.0	4.91***	0.48	5.06***	2.45*	1.02	8.16***
	days of incubation	0.291	2.26	1.31	3.01	2.42	0.77

^aEach model is run independently for the six OM type and decay parameter combinations. For the ecosystem and climate model, the starting model included all eight variables. We used the Bayesian information criterion (BIC) to identify the best-fitting model, for which we report F-values and significance for each variable. Missing F-values in the table indicate variables selected against by BIC model selection. The macroclimate categories are presented in Figure 1. The freshwater wetland model uses the IUCN Typologies 2.0 that incorporate climate, inundation, and vegetation characteristics. Temperature variation represents the mean monthly variation during the timeframe of incubation. Two decay equations were applied to site-level time series to provide information on different stages of decay. An asymptotic exponential model (eq 1) provides A (proportion of stable mass remaining) and k_a (rate constant of early decay, i.e., leaching). A single exponential decay model (eq 2) provides k_s values that represent the overall decay rate constant. Values represent F-values, and significant p-values are in bold. Precipitation is in mm units.

^bp-values: *** < 0.001, ** 0.001 ≤ to ≤ 0.01, * 0.01 < to ≤ 0.05.