Supplementary information–Monocultural sowing in mesocosmsdecreases weed and invertebrate species richness and strongly reduces the fitness of the endangered European hamster.

Family / # of species / Counting / Occurrences (per type of mesocosms) / Hamsters presence / Occurrences / Consumption by hamsters
Amaranthaceae / 1 / #1 / 4 (3 Wheat > 1 Mix) / Yes / 1 / Possible
No / 3
#2 / 7 (4 Mix > 2 Wheat > 1 Corn) / Yes / 0
No / 7
Araliaceae / 1 / #2 / 3 (2 Corn > 1 Wheat) / Yes / 0 / NA
No / 3
Asteraceae / 7 / #1 / 75 (47 Mix > 21 Corn > 8 Wheat) / Yes / 22 / Yes (high)
No / 54
#2 / 114 (53 Mix > 47 Corn > 14 Wheat) / Yes / 7
No / 107
Betulaceae / 1 / #1 / 5 (Wheat) / Yes / 1 / Probable
No / 4
#2 / 7 (Wheat) / Yes / 0
No / 7
Brassicaceae / 1 / #1 / 44 (16 Wheat > 14 Corn – 14 Mix) / Yes / 11 / Probable
No / 33
Caryophyllaceae / 3 / #1 / 25 (13 Wheat > 11 Mix > 1 Corn) / Yes / 3 / Yes
No / 22
#2 / 24 (9 Mix – 9 Wheat > 6 Corn) / Yes / 0
No / 24
Convolvulaceae / 1 / #2 / 2 (1 Corn – 1 Wheat) / No / 2 / NA
Fabaceae / 4 / #1 / 43 (20 Corn > 12 Mix > 11 Wheat) / Yes / 10 / Yes (high)
No / 33
#2 / 48 (24 Mix > 13 Corn > 11 Wheat) / Yes / 4
No / 44
Fagaceae / 1 / #2 / 1 (Wheat) / No / 1 / NA
Geraniaceae / 2 / #1 / 8 (6 Wheat > 2 Mix) / Yes / 1 / Probable
No / 7
#2 / 10 (5 Mix > 3 Wheat > 2 Corn) / Yes / 2
No / 8
Juncaceae / 3 / #1 / 5 (Mix) / Yes / 2 / NA
No / 3
#2 / 9 (6 Mix > 2 Corn > 1 Wheat) / Yes / 3
No / 6
Galeopsis / 1 / #1 / 37 (18 Wheat > 14 Mix > 5 Corn) / Yes / 8 / Yes (low)
No / 29
#2 / 34 (13 Mix > 12 Wheat > 10 Corn) / Yes / 9
No / 25
Oenotheraceae / 2 / #1 / 13 (5 Mix – 5 Corn > 3 Wheat) / Yes / 4 / Yes (high)
No / 9
#2 / 53 (26 Mix > 16 Wheat > 11 Corn) / Yes / 5
No / 48
Oleaceae / 1 / #1 / 54 (21 Corn > 17 Mix > 16 Wheat) / Yes / 15 / Yes
No / 39
#2 / 34 (13 Corn – 13 Mix – 8 Wheat) / Yes / 1
No / 33
Onagraceae / 1 / #1 / 29 (16 Wheat > 12 Mix > 1 Corn) / Yes / 12 / Yes
No / 17
#2 / 34 (13 Mix – 13 Wheat > 8 Corn) / Yes / 5
No / 29
Oxalidaceae / 1 / #1 / 1 (Mix) / Yes / 1 / NA
No / 0
#2 / 4 (3 Mix > 1 Corn) / Yes / 0
No / 4
Papaveraceae / 1 / #1 / 1 (Mix) / Yes / 0 / Yes
No / 1
#2 / 3 (Mix) / Yes / 0
No / 3
Plantaginaceae / 4 / #1 / 25 (17 Wheat > 7 Mix > 1 Corn) / Yes / 8 / Yes
No / 17
#2 / 16 (8 Mix > 5 Wheat > 3 Corn) / Yes / 0
No / 16
Poaceae / 8 / #1 / 93 (33 Corn > 31 Mix > 29 Wheat) / Yes / 16 / Yes (selection)
No / 77
#2 / 178 (73 Corn – 73 Mix > 32 Wheat) / Yes / 40
No / 138
Polygonaceae / 3 / #1 / 4 (3 Mix > 1 Corn) / Yes / 1 / Probable
No / 3
#2 / 12 (5 Wheat > 4 Mix > 3 Corn) / Yes / 0
No / 12
Primulaceae / 1 / #2 / 1 (Mix) / No / 1 / NA
Ranunculaceae / 2 / #1 / 43 (19 Mix > 18 Wheat > 6 Corn) / Yes / 12 / Possible
No / 31
#2 / 11 (6 Mix > 3 Corn > 2 Wheat) / Yes / 2
No / 9
Rosaceae / 5+ / #1 / 66 (30 Wheat > 26 Mix > 10 Corn) / Yes / 21 / Yes (selection)
No / 45
#2 / 82 (33 Mix > 28 Wheat > 21 Corn) / Yes / 11
No / 71
Rubiaceae / 1 / #1 / 21 (11 Wheat > 5 Corn – 5 Mix) / Yes / 5 / Yes
No / 16
#2 / 7 (5 Mix – 2 Corn) / Yes / 0
No / 7
Salicaceae / 1 / #1 / 1 (Wheat) / Yes / 0 / NA
No / 1
#2 / 2 (1 Corn – 1 Mix) / Yes / 0
No / 2
Sapindaceae / 1 / #1 / 26 (11 Wheat > 10 Mix > 3 Corn) / Yes / 4 / Yes
No / 22
#2 / 15 (8 Mix > 5 Wheat > 2 Corn) / Yes / 0
No / 15
Scrophulariaceae / 3 / #1 / 3 (Wheat) / Yes / 1 / Yes
No / 2
#2 / 36 (22 Mix > 9 Wheat > 5 Corn) / Yes / 9
No / 27
Solanaceae / 1 / #1 / 2 (1 Mix – 1 Wheat) / Yes / 0 / Yes
No / 2
#2 / 24 (12 Corn – 7 Mix – 5 Wheat) / Yes / 1
No / 23
Urticaceae / 1 / #1 / 43 (17 Corn > 14 Mix > 12 Wheat) / Yes / 13 / No
No / 30
#2 / 51 (21 Corn > 19 Mix > 11 Wheat) / Yes / 16
No / 35

Table S1: number of plant species recorded (# of species) and species occurrences (total and per crop type) for each counting session (#1 and #2), according to hamster presence in the mesocosm (Yes/No). The total occurrence, in bold print, represents the sum of the occurrence of all plant species of a family in all the mesocosms. The occurrence per crop type represents the number of mesocosms of each crop type containing a species from each family. The last column provides information on whether hamsters eat plants of each family, according to our data and observations.

Class / Order / N / Occurrences (per type of mesocosms)
Insecta / Hymenoptera / 11 / 93 (32 Mix - 32 Corn > 29 Wheat)
Diptera / 10 / 71 (31 Mix > 22 Corn > 18 Wheat)
Hemiptera / 9 / 44 (16 Mix - 16 Wheat > 12 Corn)
Coleoptera / 9 / 110 (48 Mix > 44 Corn > 18 Wheat)
Orthoptera / 2 / 19 (10 Mix > 6 Corn > 3 Wheat)
Lepidoptera / 3 / 6 (3 Corn > 2 Mix > 1 Wheat)
Raphidioptera / 1 / 1 (Corn)
Neuroptera / 1 / 2 (Corn)
Malacostraca / Isopoda / 2 / 60 (23 Mix > 22 Corn > 15 Wheat)
Arachnida / Araneae / 10 / 82 (36 Corn > 26 Mix > 20 Wheat)
Opiliones / 1 / 11 (9 Corn > 2 Mix)
Chilopoda / Lithobiomorpha / 2 / 2 (1 Corn - 1 Mix)
Diplopoda / 1 / 5 (Corn)
Gastropoda / Pulmonata / 3 / 26 (19 Mix > 6 Wheat > 1 Corn)

Table S2: Number of invertebrate species recorded (N) andspecies occurrences for each order(total and per crop type). The total occurrence, in bold print, represents the sum of the occurrence of allinvertebrate species of an order in all the mesocosms. The occurrence per crop type represents the number of mesocosms of each crop type containing a species from each order.


Table S3: total number of pups emerging from the burrow, adult mortality and adult emigration/death according to the crop type (N = 6 breeding pair per crop type). The two asterisks indicate a statistical difference between the Mix group and both the Corn and Wheat groups. See the Results section of the manuscript for further details. ‘Adult mortality’shows the number and the percentage of adults that were found dead in the mesocosm. ‘Adult emigration/death’indicatesanimals that disappeared from their respective mesocosmsbut for which no corpse was found.Data do not include observations after August 23; see the methodology section of the manuscript for further details.