Table 1 Results from multiple regressions testing for the effects of climatic factors (“PC temperature” and “PC precipitation”, z-scores from a Principal Components Analysis [PCA] of temperature- and precipitation-related variables, see Methods) and soil factors (“PC1 soil” and “PC2 soil”, z-scores from the first two PCs from a PCA using a set of soil variables, see Methods) on the concentration (mg g⁻¹ d.w.) of phosphorus, nitrogen, carbon, and their ratios in leaves of Ruellia nudiflora sampled across 30 populations spanning 5° latitude (from SE Mexico and Belize).

Predictor	Phosphorus		Nitrogen		Carbon		C:P		N:P		C:N
	Model R² = 0.229		Model R² = 0.267		Model R² = 0.197		Model R² = 0.144		Model R² = 0.114		Model R² = 0.262
	β	r ²	β	r ²	β	r ²	β	r ²	β	r ²	β	r ²
PC temperature	—	—	—	—	−4.723	0.078	—	—	—	—	—	—
PC precipitation	0.262	0.229**	—	—	6.271	0.110	−27.53	0.094	—	—	—	—
PC1 soil	—	—	−0.853	0.045	—	—	—	—	2.734	0.114	—	—
PC2 soil	—	—	−2.199	0.240*	8.409	0.180*	—	—	—	—	0.963	0.262**

R² = coefficient of determination, β = slope estimator, r² = partial correlation coefficient (in the case of models including only one predictor this is equivalent to model R²). Significant (*P < 0.05, **P < 0.01) and marginal (0.05 < P < 0.10) effects are in bold and italics, respectively. Results are presented only for predictors retained after AIC model selection (see section on statistical analyses in the Methods).

Quick links

Search