Abstract
Aim: Inverse latitudinal diversity gradients (i-LDGs), whereby regional richness peaks outside the tropics, have rarely been investigated, and their causes remain unclear. Here, we investigate three prominent explanations, postulating that species-rich regions have had: (1) longer time to accumulate species; (2) faster diversification; and (3) more energy to support species-rich communities. These mechanisms have been shown to explain the tropical megadiversity, and we examine whether they can also explain i-LDG. Location: Global. Time period: Contemporary. Major taxa studied: Amphibians, birds and mammals. Methods: We estimated the time for species accumulation, regional diversification rates and regional energy for six tetrapod taxa (c. 800 species). We quantified the relative effects and interactions among these three classes of variables, using variance partitioning, and confirmed the results across alternative metrics for time (community phylometrics and BioGeoBEARS), diversification rates (BAMM and DR) and regional energy (past and current temperature, and productivity). Results: Although regional richness across each of the six taxa peaked in the temperate region, it varied markedly across hemispheres and continents. The effects of time, diversification rates and regional energy varied greatly from one taxon to another, but high diversification rates generally emerged as the best predictor of high regional richness. The effects of time and regional energy were limited, with the exception of salamanders and cetaceans. Main conclusions: Together, our results indicate that the causes of i-LDG are highly taxon specific. Consequently, large-scale richness gradients might not have a universal explanation, and different causal pathways might converge on similar gradients. Moreover, regional diversification rates might vary dramatically between similar environments and, depending on the taxon, regional richness might or might not depend on the time for species accumulation. Collectively, these results underscore the complexity behind the formation of richness gradients, which might involve a symphony of variations on the interplay of time, diversification rates and regional energy.
Originalsprog | Engelsk |
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Tidsskrift | Global Ecology and Biogeography |
Vol/bind | 31 |
Udgave nummer | 9 |
Sider (fra-til) | 1794-1809 |
Antal sider | 16 |
ISSN | 1466-822X |
DOI | |
Status | Udgivet - 2022 |
Bibliografisk note
Funding Information:We are grateful to Fabricio Villalobos, Marcelo Weber, Mariana Bender and Renan Maestri for their relevant comments on the manuscript. This study was financed, in part, by the Coordenação de Aperfeiçoamento de Pessoa de Nível Superior – Brasil (CAPES) – Finance Code 001. This paper is developed in the context of National Institutes for Science and Technology (INCT) in Ecology, Evolution and Biodiversity Conservation, supported by MCTIC/CNPq (proc. 465610/2014‐5) and FAPEG (proc. 201810267000023). A.M. was funded by the Charles University Research Centre programme (no. 204069); EXPRO 20‐29554X Czech Science Foundation; European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska‐Curie Grant (agreement no. 785799); the Danish National Research Foundation (DNRF); and the Villum Foundation (Center for Global Mountain Biodiversity). Open access funding provided by ETH‐Bereich Forschungsanstalten.
Funding Information:
We are grateful to Fabricio Villalobos, Marcelo Weber, Mariana Bender and Renan Maestri for their relevant comments on the manuscript. This study was financed, in part, by the Coordenação de Aperfeiçoamento de Pessoa de Nível Superior – Brasil (CAPES) – Finance Code 001. This paper is developed in the context of National Institutes for Science and Technology (INCT) in Ecology, Evolution and Biodiversity Conservation, supported by MCTIC/CNPq (proc. 465610/2014-5) and FAPEG (proc. 201810267000023). A.M. was funded by the Charles University Research Centre programme (no. 204069); EXPRO 20-29554X Czech Science Foundation; European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant (agreement no. 785799); the Danish National Research Foundation (DNRF); and the Villum Foundation (Center for Global Mountain Biodiversity). Open access funding provided by ETH-Bereich Forschungsanstalten.
Publisher Copyright:
© 2022 The Authors. Global Ecology and Biogeography published by John Wiley & Sons Ltd.