Specialization of Mutualistic Interaction Networks Decreases toward Tropical Latitudes

• DOI: 10.1016/j.cub.2012.08.015
• Publication Date: 2012-09-13T15:26:21Z
• Authors: Matthias Schleuning; Jochen Fründ; Alexandra-Maria K...; Stefan Abrahamczyk; Ruben Alarcón; Matthias Albrecht; Georg K.S. Andersson; Simone Bazarian; Katrin Böhning-Gaese; Riccardo Bommarco; Bo Dalsgaard; D. Matthias Dehling; Ariella Gotlieb; Melanie Hagen; Thomas Hickler; Andrea Holzschuh; Christopher N. Ka...; Holger Kreft; Rebecca J. Morris; Brody Sandel; William J. Suther...; Jens-Christian Sv...; Teja Tscharntke; Stella Watts; Christiane N. Weiner; Michael Werner; Neal M. Williams; Camilla Winqvist; Carsten F. Dormann; Nico Blüthgen
• Keywords: 0106 biological sciences; Tropical Climate; Agricultural and Biological Sciences(all); Biochemistry, Genetics and Molecular Biology(all); 577; Genetic Variation; 1100 General Agricultural and Biological Sciences; Biodiversity; 580 Plants (Botany); Plants; 15. Life on land; 01 natural sciences; 10121 Department of Systematic and Evolutionary Botany; 1300 General Biochemistry, Genetics and Molecular Biology; Seed Dispersal; Animals; Pollination; Symbiosis; Ecosystem

Species-rich tropical communities are expected to be more specialized than their temperate counterparts. Several studies have reported increasing biotic specialization toward the tropics, whereas others have not found latitudinal trends once accounting for sampling bias or differences in plant diversity. Thus, the direction of the latitudinal specialization gradient remains contentious. With an unprecedented global data set, we investigated how biotic specialization between plants and animal pollinators or seed dispersers is associated with latitude, past and contemporary climate, and plant diversity. We show that in contrast to expectation, biotic specialization of mutualistic networks is significantly lower at tropical than at temperate latitudes. Specialization was more closely related to contemporary climate than to past climate stability, suggesting that current conditions have a stronger effect on biotic specialization than historical community stability. Biotic specialization decreased with increasing local and regional plant diversity. This suggests that high specialization of mutualistic interactions is a response of pollinators and seed dispersers to low plant diversity. This could explain why the latitudinal specialization gradient is reversed relative to the latitudinal diversity gradient. Low mutualistic network specialization in the tropics suggests higher tolerance against extinctions in tropical than in temperate communities.