Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 116; no. 33; pp. 16442 - 16447
• Main Authors: Sirami, Clélia, Gross, Nicolas, Baillod, Aliette Bosem, Bertrand, Colette, Carrié, Romain, Hass, Annika, Henckel, Laura, Miguet, Paul, Vuillot, Carole, Alignier, Audrey, Girard, Jude, Batáry, Péter, Clough, Yann, Violle, Cyrille, Giralt, David, Bota, Gerard, Badenhausser, Isabelle, Lefebvre, Gaëtan, Gauffre, Bertrand, Vialatte, Aude, Calatayud, François, Gil-Tena, Assu, Tischendorf, Lutz, Mitchell, Scott, Lindsay, Kathryn, Georges, Romain, Hilaire, Samuel, Recasens, Jordi, Solé-Senan, Xavier Oriol, Roblen˜o, Irene, Bosch, Jordi, Barrientos, Jose Antonio, Ricarte, Antonio, Marcos-Garcia, Maria Ángeles, Min˜ano, Jesús, Mathevet, Raphaël, Gibon, Annick, Baudry, Jacques, Balent, Gérard, Poulin, Brigitte, Burel, Françoise, Tscharntke, Teja, Bretagnolle, Vincent, Siriwardena, Gavin, Ouin, Annie, Brotons, Lluis, Martin, Jean-Louis, Fahrig, Lenore
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 13-08-2019
• Subjects: Agricultural ecosystems; Agricultural land; Agricultural management; Agricultural production; Agricultural Science; Agricultural Science, Forestry and Fisheries; Agricultural Sciences; Agriculture; Animals; Bees; Biodiversity; Biodiversity loss; Biological Sciences; Birds; Butterflies; Butterflies & moths; Complementation; Crop mosaic; Crops; Crops, Agricultural; Ecology; Ecosystem; Ecosystem services; Ekologi; Environmental Sciences; Environmental Sciences related to Agriculture and Land-use; Europe; Farmland; Heterogeneity; Humans; Jordbruksvetenskap; Landscape; Lantbruksvetenskap och veterinärmedicin; Lantbruksvetenskap, skogsbruk och fiske; Miljö- och naturvårdsvetenskap; Multitaxa; North America; Spiders; North America; Europe; multitaxa; biodiversity; crop mosaic; farmland; landscape complementation; farmland landscape complementation
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.1906419116

Agricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter “crop heterogeneity”) can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production.