The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera

The Cenozoic planktonic foraminifera (calcareous zooplankton) have arguably the most detailed fossil record of any group. The quality of this record allows models of environmental controls on macroecology, developed for Recent assemblages, to be tested on intervals with profoundly different climatic...

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Bibliographic Details
Published in:Philosophical Transactions of the Royal Society B: Biological Sciences
Main Authors: Fenton, Isabel, Pearson, PN, Dunkley Jones, Tom, Farnsworth, Alexander J, Lunt, Dan J, Markwick, Paul, Purvis, A
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:https://hdl.handle.net/1983/2de27bdf-b497-4a9a-bec9-a07e3d2a64a8
https://research-information.bris.ac.uk/en/publications/2de27bdf-b497-4a9a-bec9-a07e3d2a64a8
https://doi.org/10.1098/rstb.2015.0224
https://research-information.bris.ac.uk/ws/files/59807078/Fenton_et_al_revision_submitted_1_.pdf
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Summary:The Cenozoic planktonic foraminifera (calcareous zooplankton) have arguably the most detailed fossil record of any group. The quality of this record allows models of environmental controls on macroecology, developed for Recent assemblages, to be tested on intervals with profoundly different climatic conditions. These analyses shed light on the role of long-term global cooling in establishing the modern latitudinal diversity gradient – one of the most powerful generalizations in biogeography and macroecology. Here we test the transferability of environment-diversity models developed for modern planktonic foraminiferal assemblages to the Eocene epoch (~56 to 34 Mya), a time of pronounced global warmth. Environmental variables from global climate models are combined with Recent environment-diversity models to predict Eocene richness gradients, which are then compared with observed patterns. The results indicate the modern latitudinal diversity gradient – lower richness towards the poles – developed through the Eocene. Three possible causes are suggested for the mismatch between statistical model predictions and data in the early Eocene: the environmental estimates are inaccurate, the statistical model misses a relevant variable, or the intercorrelations among facets of diversity – e.g. richness, evenness, functional diversity – have changed over geological time. By the late Eocene environment-diversity relationships were much more similar to those found today.