Tree diversity reduces pest damage in mature forests across Europe.
Forest pest damage is expected to increase with global change. Tree diversity could mitigate this impact, but unambiguous demonstration of the diversity-resistance relationship is lacking in semi-natural mature forests. We used a network of 208 forest plots sampled along two orthogonal gradients of increasing tree species richness and latitudes to assess total tree defoliation in Europe. We found a positive relationship between tree species richness and resistance to insect herbivores: overall damage to broadleaved species significantly decreased with the number of tree species in mature forests. This pattern of associational resistance was frequently observed across tree species and countries, irrespective of their climate. These findings confirm the greater potential of mixed forests to face future biotic disturbances in a changing world.
INRA, DYNAFOR, UMR 1201, 31326 Castanet-Tolosan, France INRA, BIOGECO, Université de Bordeaux, 33610 Cestas, France virginie.guyot@ensat.fr.
Virginie
http://orcid.org/0000-0003-1766-1465
V
Guyot
INRA, BIOGECO, Université de Bordeaux, 33610 Cestas, France.
Bastien
B
Castagneyrol
INRA, DYNAFOR, UMR 1201, 31326 Castanet-Tolosan, France INPT-ENSAT, DYNAFOR, Université de Toulouse, UMR 1201, 31326 Castanet-Tolosan, France.
Aude
A
Vialatte
INRA, DYNAFOR, UMR 1201, 31326 Castanet-Tolosan, France.
Marc
M
Deconchat
INRA, BIOGECO, Université de Bordeaux, 33610 Cestas, France.
Hervé
H
Jactel
D000818:Animals; D044822:Biodiversity; D002980:Climate; D005060:Europe; D065928:Forests; D060434:Herbivory; D007313:Insecta; D014197:Trees
associational resistance; biodiversity; ecosystem functioning