Table 3.

Competing LMMs of the effects of plant phenology on calving date of a semidomesticated reindeer population in Kaamanen, northern Finland

Rank	Models	AIC	df	AIC weights	ΔAIC
	1970–2015
1	zDENSt−1 + zPMt−1 + dBCIWintert × zThermalEndt−1 + dThermalStartt−1	4373.78	9	0.71	0.00
2	zDENSt−1 + zPMt−1 + dBCIWintert × zThermalEndt−1 + dBCIWintert × dThermalStartt−1	4375.56	10	0.29	1.78
	1997–2015
1	dDENSt−1 + zPMt−1 + dBCISpringt × zVegOnsett−1 + zVegEndt−1	1658.53	9	0.62	0.00
2	dDENSt−1 + zPMt−1 + dBCISpringt × zVegOnsett−1 + dBCISpringt × zVegEndt−1	1659.50	10	0.38	0.98

The analyses were repeated over the 2 study periods: the whole study period (1970–2015) and the last part of the study period (1997–2015). All models included the female identity as a random factor on the intercept, as well as the population density (DENS) and the proportion of males in the herd (PM) as fixed effects. A lowercase “d” in front of the variable indicated that the variable was used “detrended,” whereas a lowercase “z” indicated that the variable was used standardized. ThermalStart and ThermalEnd represented, respectively, the start and end of the thermal growing season. The onset and end of the vegetative growing season were depicted by VegOnset and VegEnd, respectively. BCIWinter was the BCI of females averaged over the winter (from December to March), whereas BCISpring was the BCI of females, averaged in spring (April–May). A cross “×” indicated an interaction term between the 2 variables. The models presented in the table are the competing models retained in explaining calving date, that is, with ΔAIC < 2 (see text for details).