Table 2.

Mean and variance of niche overlap along three environmental gradients, and the coefficient of heterogeneity (η) in 1979–1985 and 1999–2006. P-values are from randomization test based on 9999 permutations.

	Mean		P	Variance		P	η
	1979–1985	1999–2006		1979–1985	1999–2006		1979–1985	1999–2006
Habitat	0.578	0.543	***	0.180	0.178	**	0.739	0.716
Topography	0.584	0.589	**	0.044	0.044	NS	0.181	0.182
Altitude	0.402	0.387	***	0.068	0.066	***	0.285	0.279

NS, not significant

^**, significance at P < 0.01;

^***, P < 0.001.