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Site Map / Index This page last modified: 7th January, 2008 ŠPaul Markwick 2000-2008 |
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Markwick, P.J. (2000) Biodiversity gradients as a palaeoclimate tool? Geosciences 2000 (Geological Society, London), Manchester, UK. Abstract A climate origin has been postulated to explain observed "latitudinal" diversity (richness) gradients in many Recent terrestrial organic groups. This study tests Ostrom's suggestion that such gradients may provide a tool for retrodicting palaeoclimate. A digital dataset of Recent North American, European and Australian non-avian tetrapod faunas is used. Results show that while ectotherm diversity varies monotonically with absolute latitude and mean annual temperature (MAT), the behaviour of endotherms (mammals) is more complex. A strong linear relationship is found between the proportion of each fauna represented by ectotherms and MAT. This relationship is used to retrodict the MAT for the middle Eocene Messel fauna. The good agreement between derived temperatures using this relationship and those from other climate proxies implies, but does not prove, that the current relationship is a more general phenomena and not simply an artifact of history. It therefore provides geologists with an additional tool for investigating past climates, given an understanding of fossil animal physiology and taphonomic effects. The relationship also implicitly predicts the potential response of terrestrial vertebrates to future climate change. |
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