Table 2.

Comparison of geographical range characteristics for species with and without IBD.

variable	mean with IBD	mean without IBD	t-test p-value
area (km2)	6.24 × 106	3.50 × 106	1.93 × 10−7
minimum distance from equator	29.6712	32.1637	7.12 × 10−10
mid-point latitude of range	31.4947	34.1037	6.92 × 10−8
length of latitude°	14.5924	10.4653	2.20 × 10−16
mean elevation	113.9991	112.9753	0.4563
standard deviation elevation	63.5219	59.7870	3.92 × 10−7