Latitudinal phytoplankton distribution and the neutral theory of biodiversity
Aim: Recent studies have suggested that global diatom distributions are not limited by dispersal, in the case of both extant species and fossil species, but rather that environmental filtering explains their spatial patterns. Hubbell's neutral theory of biodiversity provides a framework in whic...
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Published in | Global ecology and biogeography Vol. 22; no. 5; pp. 531 - 543 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Blackwell Publishing Ltd
01.05.2013
John Wiley & Sons Ltd Blackwell Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Aim: Recent studies have suggested that global diatom distributions are not limited by dispersal, in the case of both extant species and fossil species, but rather that environmental filtering explains their spatial patterns. Hubbell's neutral theory of biodiversity provides a framework in which to test these alternatives. Our aim is to test whether the structure of marine phytoplankton (diatoms, dinoflagellates and coccolithophores) assemblages across the Atlantic agrees with neutral theory predictions. We asked: (1) whether intersite variance in phytoplankton diversity is explained predominantly by dispersal limitation or by environmental conditions; and (2) whether species abundance distributions are consistent with those expected by the neutral model. Location: Meridional transect of the Atlantic (50° N-50° S). Methods: We estimated the relative contributions of environmental factors and geographic distance to phytoplankton composition using similarity matrices, Mantel tests and variation partitioning of the species composition based upon canonical ordination methods. We compared the species abundance distribution of phytoplankton with the neutral model using Etienne's maximum-likelihood inference method. Results: Phytoplankton communities are slightly more determined by niche segregation (24%), than by dispersal limitation and ecological drift (17%). In 60% of communities, the assumption of neutrality in species' abundance distributions could not be rejected. In tropical zones, where oceanic gyres enclose large stable water masses, most communities showed low species immigration rates; in contrast, we infer that communities in temperate areas, out of oligotrophic gyres, have higher rates of species immigration. Conclusions: Phytoplankton community structure is consistent with partial niche assembly and partial dispersal and drift assembly (neutral processes). The role of dispersal limitation is almost as important as habitat filtering, a fact that has been largely overlooked in previous studies. Furthermore, the polewards increase in immigration rates of species that we have discovered is probably caused by water mixing conditions and productivity. |
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Bibliography: | European Commission - No. 264933 istex:29BC4170C190563988EE1F4431D6BA1B3D522D5D ArticleID:GEB12016 UK Natural Environment Research Council ark:/67375/WNG-BRKP0HT9-4 Malaspina - No. CSD2008-00077 Appendix S1 Test of fitting phytoplankton species abundance distributions to the neutral model for the each sampling station.Appendix S2 Latitudinal patterns of sea surface temperature, salinity and species richness of diatoms, dinoflagellates and coccolithophores.Appendix S3 Unimodal relation of phytoplankton species richness across biomass and abundance. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1466-822X 1466-8238 1466-822X |
DOI: | 10.1111/geb.12016 |