Table 2.

Multiple regressions on distance matrices (MRM) were employed to estimate the relatively explained variance of environmental factors on methanotrophic community structure (β-diversity).

Steppe regions or types	Variable	R2	p
All regions	MAT	0.179	0.0001
	pH	0.161	0.0001
	AI	0.161	0.0001
Loess	MAP	0.735	0.0001
	AI	0.727	0.0001
	PC	0.474	0.0001
Inner Mongolia	pH	0.326	0.0001
	AI	0.282	0.0001
	MAP	0.254	0.0001
Qinghai-Tibet	pH	0.496	0.0001
	NH4+-N	0.469	0.0001
	TOC	0.453	0.0001
Meadow	pH	0.561	0.0001
	MAT	0.524	0.0001
	TOC	0.418	0.0001
Typical	MAT	0.558	0.0001
	PC	0.371	0.0001
	MBC	0.245	0.0001
Desert	MAT	0.534	0.0001
	AI	0.358	0.0001
	TP	0.197	0.0001

MAT, Mean annual temperature; AI, Aridity index; MAP, Mean annual precipitation; PC, Plant coverage; TOC, Total organic carbon; MBC, Microbial biomass carbon; TP, Total phosphorus. In the table, for each region and grassland type, only the top three factors with the highest explanatory power, sorted in descending order of their explanatory degrees, are displayed.