Table 1. The collection sites of Festuca rubra plants and their attributes.

N = number of collected plants. Mean NDVI = mean normalized difference vegetation index estimated from year 2000 to 2012. Inf. % = percentage of endophyte infected plants (endophyte frequency) in population. 4x %, 6x % and 8x % = percentage of tetraploids, hexaploids and octoploids, respectively, in population.

Population code	Geographic site	Population	N	Geographic coordinates	Altitude (m a.s.l.)	Mean NDVI	Inf. %	4x %	6x %	8x %	Features of the site	Grazing
SP1	Spain	Cáceres	31	N 40°12'1'' W 5°45'11''	768	0,59	81	100	0	0	Xerophytic forest	High (cattle)
SP2	Spain	Salamanca 1	27	N 40°56'20'' W 6°7'6''	863	0,57	67	78	22	0	Meadow	High (cattle)
SP3	Spain	Salamanca 2	37	N 40°58'24'' W 5°57'33''	812	0,51	59	81	3	16	Meadow	High (cattle)
SW1	Switzerland	Andermatt	26	N 46°32'19'' E 8°40'31''	1500	0,42	23	0	96	4	Meadow with natural grassland vegetation, slope facing east	High (cattle)
SW2	Switzerland	Biez	25	N 46°37'42'' E 8°35'26''	1600	0,41	36	0	100	0	Meadow with natural grassland vegetation, slope facing north-west	High (cattle)
SW3	Switzerland	Piasca	23	N 46°53'56'' E 8°42'9''	1850	0,19	22	0	100	0	Meadow with natural grassland vegetation, sawed every second year, slope facing south	High (cattle)
FI1	Southern Finland	Hanko 1	42	N 59°50'23'' E 23°13'40''	0	0,55	0	2	98	0	Meadow along the coast	Low
FI2	Southern Finland	Hanko 2	44	N 59°50'27'' E 23°13'15''	0	0,53	0	0	93	7	Meadow along the coast	Low
FI3	Southern Finland	Hanko 3	40	N 59°53'0'' E 23°5'52''	0	0,43	0	5	95	0	Meadow along the coast	Low
FO1	Faroe	Sandoy	39	N 61°50'11'' W 6°51'21''	69	0,42	21	3	97	0	Meadow	High (sheep)
FO2	Faroe	Nolsoy	41	N 62°1'15'' W 6°41'8''	55	0,33	5	0	98	2	Meadow	High (sheep)
FO3	Faroe	Mykines	37	N 62°5'51'' W 7°40'56''	125	0,16	68	0	100	0	Meadow	High (sheep)
FO4	Faroe	Vagar	24	N 62°6'59'' W 7°26'43''	246	0,30	25	0	83	17	Meadow	High (sheep)
FO5	Faroe	Eysturoy	39	N 62°17'24'' W 7°2'10''	316	0,34	54	5	87	8	Meadow	High (sheep)
FO6	Faroe	Vidoy	32	N 62°22'3'' W 6°32'32''	148	0,31	44	9	91	0	Meadow	High (sheep)
IC1	Iceland	Iceland 1	44	N 64°47'34'' W 21°32'0''	390	0,28	32	2	98	0	Meadow	High (sheep)
IC2	Iceland	Iceland 2	34	N 64°48'52'' W 23°23'14''	10	0,34	32	0	97	3	Meadow	High (sheep)
IC3	Iceland	Iceland 3	42	N 66°1'21'' W 20°23'39''	38	0,30	26	5	95	2	Meadow	High (sheep)
GR1	Greenland	Greenland 1	70	N 69°14'59'' W 53°31'15''	0	0,16	3	0	100	0	Meadow along the coast	Low
GR2	Greenland	Greenland 2	10	N 69°15'27'' W 53°32'40''	0	0,19	0	0	100	0	Meadow along the coast	Low
FI4	Northern Finland 1	Halti 1	22	N 69°15'0'' E 21°24'36''	860	0,20	0	0	100	0	Meadows along rivulets above tree-line with patchy grass and sedge dominated vegetation	Moderate (reindeer)
FI5	Northern Finland 1	Halti 2	42	N 69°15'0'' E 21°19'12''	900	0,11	0	0	0	100		Moderate (reindeer)
FI6	Northern Finland 1	Halti 3	32	N 69°16'12'' E 21°19'12''	920	0,28	0	0	100	0		Moderate (reindeer)
FI7	Northern Finland 2	Kevo 1	34	N 69°38'6'' E 27°5'1''	91	0,31	56	3	97	0	Meadow	High (reindeer)
FI8	Northern Finland 2	Kevo 2	40	N 69°43'56'' E 27°12'0''	85	0,31	75	3	85	13	Meadow	High (reindeer)
FI9	Northern Finland 2	Kevo 3	34	N 69°45'32'' E 26°59'19''	107	0,31	50	0	94	6	Meadow	High (reindeer)
FI10	Northern Finland 2	Kevo 4	42	N 69°54'36'' E 27°1'48''	73	0,27	45	2	98	0	Riverbank	High (reindeer)
FI11	Northern Finland 2	Kevo 5	31	N 69°56'11'' E 26°27'45''	106	0,28	23	0	94	6	Riverbank	High (reindeer)
FI12	Northern Finland 2	Kevo 6	35	N 69°56'41'' E 26°43'22''	85	0,29	20	0	100	0	Riverbank	High (reindeer)