Table 2.

Variation in three functional traits in relation to GT and precipitation. For each trait, only significant fixed effects were incorporated (based on the results of an AIC model comparison (see Supporting Information—Tables S4 and S5)), which included species identity (S), GT, TAP and associated interaction terms (denotes by ‘*’). In these models, Zea mays was coded as a dummy variable in order to evaluate differences among species (S). Therefore, any parameters that include ‘S’ are associated with Z. mays only. Significant model parameters (where P ≤ 0.05) are highlighted in bold. Random effects were also included in these models based on preliminary analysis (as per Equation 1 and Supporting Information—Table S3). Specifically, across the three different models random effects included (i) the number of days since planting for A_max, (ii) nitrogen fertilization only for leaf N and (iii) the number of days since planting, irrigation and type of study for SLA.

Trait	Parameter	Estimate	SE	d.f.	t-value	P-value
A max (n = 197)	Intercept	−13.41	6.49	161	−2.07	0.0404
	S	48.89	11.26	161	4.34	<0.001
	GT	0.93	0.38	161	2.43	0.0162
	TAP	0.02423	0.003	161	7.93	<0.001
	S * GT	−1.82035	0.7	161	−2.61	0.01
	S * TAP	−0.01	0.01	161	−2.298	0.023
	Model marg. r2	0.394
	Model cond. r2	0.73
Leaf N (n = 206)	Intercept	41.7	5.8	201	7.16	<0.001
	GT	−0.9	0.2	201	−3.97	0.0001
	TAP	0.01	0.003	201	2.33	0.021
	S * GT	−0.04	0.1	201	−0.47	0.642
	Model marg. r2	0.054
	Model cond. r2	0.355
SLA (n = 34)	Intercept	46.63	8.48	21	5.5	<0.001
	GT	−1.33	0.42	21	−3.19	0.004
	TAP	−0.014	0.003	21	−4.36	0.0003
	Model marg. r2	0.437
	Model cond. r2	0.966