TABLE 3.

Associations of OTUs to environmental factors, biogeographic regions, land-use types and bacterial community types (BCTs).

Environmental factorsa	Totalb		Non-redundantc				Maximum of rPBg
	Associated OTUs [N]d	Rel. abund. [%]e	Associated OTUs [N]d	Rel. abund. [%]e	Cumul.f [N]	Cumul.f [%]
pH	1,788	45.6	1,788	45.6	1,788	45.6	0.78
Plant ind.h for pH	1,406	30.9	535	3.4	2,323	49.0	0.79
Plant ind.h for nutrients	589	7.0	454	1.5	2,777	50.5	0.78
SD of monthly precipitationi	148	3.8	39	0.1	2,816	50.7	0.68
Bulk density	70	1.3	31	0.5	2,847	51.1	0.62
Elevation	47	3.1	10	0.2	2,857	51.3	0.60
Soil water content	33	0.7	10	0.1	2,867	51.4	0.57
Biogeographic region	86	4.4	16	0.3	2,883	51.7	0.63
Land-use type	287	6.4	66	0.9	2,933	52.6	0.74
Bacterial community types	2,931	58.7	1,049	11.8	3,998	64.4	0.81

^aEnvironmental factors were ordered according to the number of associated OTUs, followed by biogeographic region, land-use type and bacterial community types.

^bAssociated OTUs to each factor individually and their relative abundance.

^cAssociated OTUs to pH and number of associated OTUs to each factor in addition along the column in the table, thereby excluding redundant OTUs.

^dSelection of OTUs with a Benjamini and Hochberg adjusted p-value below 0.05 and r_PB larger than 0.5 based on all sites which were available for each factor.

^eRelative sequence abundance.

^fCumulative.

^gr_PB, point biserial correlation coefficient, which is used in case one of the variables is dichotomous.

^hPlant indicator.

ⁱInter-annual standard deviation of monthly precipitation sums between 1981 and 2010.