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Prevalence of multimodal species abundance distributions is linked to spatial and taxonomic breadth
Author(s) -
Antão Laura H.,
Connolly Sean R.,
Magurran Anne E.,
Soares Amadeu,
Dornelas Maria
Publication year - 2017
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.12532
Subject(s) - multimodality , akaike information criterion , range (aeronautics) , abundance (ecology) , taxon , ecology , taxonomic rank , macroecology , habitat , spatial ecology , biology , biodiversity , relative abundance distribution , sample size determination , relative species abundance , statistics , mathematics , philosophy , linguistics , materials science , composite material
Aim Species abundance distributions (SADs) are a synthetic measure of biodiversity and community structure. Although typically described by unimodal logseries or lognormal distributions, empirical SADs can also exhibit multiple modes. However, we do not know how prevalent multimodality is, nor do we have an understanding of the factors leading to this pattern. Here we quantify the prevalence of multimodality in SADs across a wide range of taxa, habitats and spatial extents. Location Global. Methods We used the second‐order Akaike information criterion for small sample sizes (AIC c ) and likelihood ratio tests (LRTs) to test whether models with more than one mode accurately describe the empirical abundance frequency distributions of the underlying communities. We analysed 117 empirical datasets from intensely sampled communities, including taxa ranging from birds, plants, fish and invertebrates, from terrestrial, marine and freshwater habitats. Results We find evidence for multimodality in 14.5% of the SADs when using AIC c and LRT. This is a conservative estimate, as AIC c alone estimates a prevalence of multimodality of 22%. We additionally show that the pattern is more common in data encompassing broader spatial scales and greater taxonomic breadth, suggesting that multimodality increases with ecological heterogeneity. Main conclusions We suggest that higher levels of ecological heterogeneity, underpinned by larger spatial extent and higher taxonomic breadth, can yield multimodal SADs. Our analysis shows that multimodality occurs with a prevalence that warrants its systematic consideration when assessing SAD shape and emphasizes the need for macroecological theories to include multimodality in the range of SADs they predict.