Table 2.

Principal components analysis (PCA) percentage of variance represented by the first axis, loadings on Axis 1 for the four PCA-summarized neighbor categories, and the correlation between Axis 1 and target shoot dry weights for treatments with drought or watered conditions and with severed or intact common mycorrhizal networks (CMNs). Axis 1 was rotated to be congruent with the third largest neighbor to create the strongest Pearson correlations between all neighbors with Axis 1. For all treatments, the first axis was the only significant axis in explaining the variance among neighboring plants

	Percentage of variance (P*)	Pearson's correlation coefficient with Axis 1†, r
Treatment	Principal Component Axis 1	Largest neighbor	2nd largest neighbor	3rd largest neighbor	4th largest neighbor	Targets
Watered, Intact CMNs	80.5% (0.001)	0.878	0.957	0.922	0.801	0.530
Watered, Severed CMNs	68.0% (0.011)	−0.780	−0.036	0.983	0.960	−0.01
Drought, Intact CMNs	92.9% (0.001)	0.951	0.986	0.987	0.904	0.567
Drought, Severed CMNs	76.6% (0.005)	0.564	0.714	0.945	0.949	0.144

*The probability is from a randomization test with 999 runs

†Axis 1 was rotated to maximize congruence with the largest, nearest neighbor for each PCA