Table 1. Relative performance of integrated single- and two-predictor models of bioregion species richness.

Predictor Variables	Endemic				Resident
	Endotherms		Ectotherms		Endotherms		Ectotherms
	ΔAIC	r2	ΔAIC	r2	ΔAIC	r2	ΔAIC	r2
TimeAreaProductivity+Temperature	0	0.67	0	0.82	20	0.70	1	0.86
TimeArea+Temperature	0	0.68	0	0.82	14	0.75	0	0.87
AreaProductivity+Temperature	10	0.56	13	0.73	0	0.84	3	0.85
TimeAreaProductivity	20	0.36	46	0.22	31	0.56	55	0.20
TimeArea	23	0.29	49	0.14	32	0.54	58	0.13
AreaProductivity	26	0.22	50	0.10	22	0.66	57	0.16
Productivity	26	0.23	42	0.29	52	0.12	52	0.29
Area	31	0.09	53	0.02	35	0.49	61	0.04
Temperature	22	0.31	24	0.60	52	0.14	29	0.65

Endemic species are those restricted to a single bioregion and Resident counts species with the largest portion of their range in a given bioregion. Endotherms combine mammals and birds, ectotherms combine reptiles and amphibians. Best models (ΔAIC<2) are highlighted in bold, and r ² refers to pseudo-r ² values based on fitting model-predicted versus observed. Note that the results for both richness values are unaffected by the pseudo-replication that hampers the results of typical gridded analyses of species richness. Predictor variables: Temperature, average temperature of bioregion; Area, current-day extent of a bioregion; Productivity, average bioregion productivity; AreaProductivity, total bioregion productivity, that is, the product of Productivity and bioregion Area. TimeArea, time-integrated area, that is, the integrated areal extent of a bioregion over 55 million years; TimeAreaProductivity, time-integrated productivity, that is, the product of Productivity and TimeArea. For further details and results by taxon, see Methods and Tables S1, S2, S3, S4, S6, S7, S8, S9, S10.