Table 2.

Statistics for GAMs whereby a binary dataset of the distribution of phototrophy in 439 springs in YNP served as the response variable.

GAM	ΔAIC	Df	adj R2
Temp + pH + sulfide	0.0	14.7	0.666
Temp + sulfide	39.3	8.2	0.534
Temp + pH	51.3	11.1	0.529
Temp	92.4	6.2	0.388
pH + sulfide	151.6	9.7	0.289
Sulfide	192.1	3.9	0.196
pH	244.2	8.6	0.112

GAM, generalized additive model; Df, degrees of freedom; adj R², sample size adjusted R² or the fraction percent of variance explained.