The latitudinal diversity gradient (LDG) is one of the most widely studied patterns in ecology, yet no consensus has been reached about its underlying causes. We argue that the reasons for this are the verbal nature of existing hypotheses, the failure to mechanistically link interacting ecological and evolutionary processes to the LDG, and the fact that empirical patterns are often consistent with multiple explanations. To address this issue, we synthesize current LDG hypotheses, uncovering their eco-evolutionary mechanisms, hidden assumptions, and commonalities. Furthermore, we propose mechanistic eco-evolutionary modeling and an inferential approach that makes use of geographic, phylogenetic, and trait-based patterns to assess the relative importance of different processes for generating the LDG.

Biological and Environmental Sciences University of Stirling Stirling FK9 4LA Scotland

Center for Theoretical Study Charles University and Czech Academy of Sciences Jilská 1 110 00 Praha 1 Czech Republic; Department of Ecology Faculty of Science Charles University Viničná 7 128 44 Praha 2 Czech Republic

Department of Biology and Curriculum in Environment and Ecology University of North Carolina Chapel Hill NC 27599 USA

Department of Ecological Modeling Helmholtz Centre for Environmental Research UFZ Permoserstrasse 15 04318 Leipzig Germany; German Centre for Integrative Biodiversity Research Halle Jena Leipzig Leipzig Germany

Department of Ecology and Environmental Science Umeå University 901 87 Umeå Sweden

Department of Ecology Federal University of Goiás Campus Samambaia Goiânia GO 74690 900 Brazil

Department of Evolutionary Biology and Environmental Studies University of Zürich Winterthurerstrasse 190 8057 Zürich Switzerland

Ecosystem Modeling Center for Computational and Theoretical Biology University of Würzburg Emil Fischer Str 32 97074 Würzburg Germany

Environmental Science 130 Mulford Hall University of California Berkeley CA 94720 USA

Groningen Institute for Evolutionary Life Sciences University of Groningen Box 11103 9700 CC Groningen The Netherlands

Institut de Biologie de l'Ecole Normale Supérieure Ecole Normale Supérieure CNRS INSERM PSL Research University 75005 Paris France

Senckenberg Biodiversity and Climate Centre Senckenberg Gesellschaft für Naturforschung D 60325 Frankfurt Germany; Institute of Ecology Evolution and Diversity Goethe University D 60438 Frankfurt Germany

Senckenberg Biodiversity Research Centre Senckenberganlage 25 60327 Frankfurt am Main Germany

Swiss Federal Research Institute WSL CH 8903 Birmensdorf Switzerland

Swiss Federal Research Institute WSL CH 8903 Birmensdorf Switzerland; Landscape Ecology Institute of Terrestrial Ecosystems ETH Zürich CH 8092 Zürich Switzerland

Theoretical Ecology University of Regensburg Universitätsstraße 31 93053 Regensburg Germany

Univ Grenoble Alpes CNRS Univ Savoie Mont Blanc CNRS LECA Laboratoire d'ÉcologieAlpine F 38000 Grenoble France

References provided by Crossref.org

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