Table 1.

Associations of climate variables and mean annual fitness of Columbian ground squirrels. For each of the years 1992–2012, the climate variable was averaged over the specified dates, except for date of snowmelt. “r with annual fitness” indicates the correlation of mean annual fitness on the mean daily value of the climate variable for the 21 years of the study

Variable	Dates	Days	r with annual fitness	r with year
Temperature	30 April–11 May	12	0.691***	−0.235
Temperature	22 Aug–1 September	11	−0.685***	0.323
Rainfall	28 June–12 July	15	0.559**	−0.525*
Rainfall	28 July–13 August	17	−0.498*	0.034
Snowmelt	Various Julian Dates		−0.471*	0.484*
Snow Accumulation	27 April–24 May	28	−0.517*	0.201
Snowfall beforea	14 Feb–8 March	23	−0.663**	0.177
Snowfall beforea	30 April–19 May	20	−0.442*	0.179
Snowfall afterb	19 Jan–17 February	30	−0.583**	0.248
Snowfall afterb	26 April–20 May	25	−0.514*	0.212

^aSnowfall before annual fitness was measured, reflects influence of snowfall on the timing of reproduction.

^bSnowfall after reproduction and in the year for which annual fitness was measured, reflects influence of snowfall on survival of mother and offspring.

*P ≤ 0.05, **P ≤ 0.01, ***P ≤ 0.001.