Predicting current and future suitable habitat and productivity for Atlantic populations of maritime pine (Pinus pinaster Aiton) in Spain

Table 4 Variables included in the SDM including their type and variable importance

Type	Variable	Normalized importance	Relative importance	Summarized values for suitable habitat
Type	Variable	Normalized importance	Relative importance	Mean	Max.	Min.	SD
Climate	BIO1	11.57	100.00	12.96	15.10	8.00	1.00
Climate	BIO03	11.22	93.49	3.94	4.40	3.60	0.14
Climate	BIO04	10.60	81.81	413.34	565.40	307.00	60.44
Climate	BIO16	9.44	59.84	447.94	662.00	241.00	77.91
Climate	BIO15	9.40	59.09	42.26	53.00	27.00	4.77
Soil	BD	9.28	56.85	1274.66	1506.00	1042.00	59.12
Soil	SILT	8.63	44.69	32.42	44.00	20.00	3.85
Soil	R	8.14	35.36	16.02	43.00	1.00	5.48
Terrain	TSI	7.96	31.95	0.00	0.32	− 0.26	0.03
Soil	WRB-LEV¹	7.51	23.52	–	–	–	–
Soil	DB200	6.26	0.00	199.82	200.00	161.00	1.37

To ensure values of variable importance were expressed on a comparable scale for each of the response variable, the scores of all the predictors selected were normalized so that they added up to a unitary value (normalized importance) or were expressed as relative values. Relative importance = (VIM−VIM_min)/(VIM_max−VIM_min)
¹Qualitative variable

ISSN: 1297-966X