Table 2.

Influence of Variance in Relative Fitness and Other Time Changes on the Annual Variation in the Intensity of Linear Selection

Fitness Component	Proportion of Variation in Annual Linear Selection Coefficients Explained (R2)
	By Variance in Fitness Components Alone	By Years Alone	By Variance in Fitness Components Controlling for Years	By Years Controlling for Variance in Fitness Components	By Variance in Fitness Components and Years
Height
Total	0.03	0.06	0.02	0.04	0.10
Early survival	0.18	0.05	0.09	0.02	0.20
Fertility	0.03	0.08	0.02	0.06	0.10
BMI
Total	0.16	0.14	0.03	0.02	0.19
Early survival	0.24	0.03	0.17	0.06	0.32
Fertility	0.02	0.11	0.03	0.10	0.14

Values correspond to R² and partial R² obtained from linear models where selection coefficients for a given trait and for a given fitness component are regressed against two covariates: one describing the corresponding amount of fitness variation, and another representing the years allowing to capture other changes across time affecting selection. Computations were performed on bootstrapped data in order to capture uncertainty caused by sampling and measurement errors (see the Supplemental Experimental Procedures).