TABLE 1.

Descriptive statistics of environmental factors including means, stand deviations (SD), medians, and minimum and maximum values as well as the number of sites for which data were available (n).

Environmental factor	n	Mean	SD	Median	Min	Max
Organic carbon [%]a	225	5.6	5.2	3.9	0.1	35.9
Total nitrogen [%]a	231	0.4	0.3	0.3	0.02	2.6
Carbon-nitrogen ratioa	225	13.6	5.8	12.5	3.2	58
pHa	236	5.6	1.3	5.6	2.9	7.8
Bulk density [g dried fineb soil/cm3]a	238	0.7	0.3	0.7	0.1	1.4
Clay [%]a	194	20.6	10.6	18.4	0.5	58.2
silt [%]a	194	32.8	10.2	31.8	12.1	74
Sand [%]a	255	40.9	16.8	41.9	0	80.1
Soil water content [%]a	238	26.9	11.5	25.7	4.3	75.5
DNA content [ng/g dry weight of soil]a	238	21.5	20.8	15.5	2.3	169.6
Plant ind.c for moisture	255	3.0	0.2	3.1	2.3	4
Plant ind.c for variability of moisture	255	1.7	0.3	1.7	1	3
Plant ind.c for pH	255	3	0.5	3.1	1.5	4.4
Plant ind.c for nutrients	255	3	0.6	3	1.9	4.3
Elevation [m.a.s.l.]	255	1194.8	647.6	1074	267	2741
Slope [gradian]	255	18.2	12.9	17	0	49
Exposition [gradian]	224	204.8	119.5	189.5	3	400
Mean annual temperature [°C]d	255	6.1	3.3	6.7	−3	12.2
SD of inter-annual temperature [°C]de	255	1.8	0.1	1.8	1.3	2
Mean annual precipitation [mm/y]df	255	1386.2	371.3	1335.5	617.1	2565.6
SD of inter-annual precipitation [mm/mo]dg	255	62.9	22.1	56.2	34.9	148.2
Mean annual solar radiation [W/m2/y]df	255	1689.5	73.3	1668.4	1563.6	1899.9
SD of inter-annual solar radiation [W/m2/mo]dg	255	19.9	1.8	19.5	17.4	27.1

SD, standard deviation.

^aBased on means for each site.

^bDried and sieved soil (<2 mm).

^cPlant indicator.

^dBased on values from between 1981 and 2010.

^eMean of monthly standard deviations.

^fMean of yearly sums.

^gMean of standard deviation of monthly sums.