Table 2.

Comparison between the obtained parameters from 1983–1984 and 2006. For each parameter, an F-test was used to compare the regression-line slopes obtained from the 1983–1984- and 2006-datasets (table 1). Because these were not different (rows 1 and 2), the fitted model was altered to include only a single, shared slope for both datasets (rows 3–5; with 95% confidence intervals in parentheses). Per parameter, the y-intercepts from this model were compared (F-test; rows 6 and 7). Based on the difference in y-intercepts, the regression-line slope and the decrease in temperature with elevation (5.5°C km⁻¹) [15], an expected temperature change (ΔT; 2006 re. 1983–1984) was calculated (row 8).

row			co-note	qui-note	call duration	SVL
1 2	slope	F-test	F1,257 = 3.37	F1,261 = 0.09	F1,264 = 0.26	F1,194 = 2.99
		p-value	0.07	0.76	0.61	0.09
3 4 5	slope y-intercept		−0.49 (±0.03)	−0.97 (±0.06)	150 (±10)	14.0 (±1.4)
		1986	1.64 (±0.02)	2.79 (±0.03)	320 (±6)	30.1 (±0.8)
		2006	1.67 (±0.02)	2.87 (±0.04)	307 (±6)	29.4 (±1.0)
6 7	y-intercept	F-test	F1,258 = 6.87	F1,262 = 23.6	F1,265 = 19.96	F1,195 = 2.38
		p-value	0.01	<0.001	<0.001	0.12
8	ΔT (°C)		0.27	0.46	0.48	0.26