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Extreme hydroclimate gradients within the western Cape Floristic region of South Africa since the Last Glacial Maximum

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journal contribution
posted on 21.08.2019, 10:23 by BM Chase, A Boom, A Carr, M Chevalier, LJ Quick, AG Verboom, P Reimer
The Cape Floristic Region (CFR) is one of the world's major biodiversity hotspots, and much work has gone into identifying the drivers of this diversity. Considered regionally in the context of Quaternary climate change, climate stability is generally accepted as being one of the major factors promoting the abundance of species now present in the CFR. However, little direct evidence is available from the region, and responses to changes in global boundary conditions have been difficult to assess. In this paper, we present new high-resolution stable isotope data from Pakhuis Pass, in the species-rich western CFR, and contextualise our findings through comparison with other records from the region. Combined, they indicate clear, coherent changes in regional hydroclimate, which we relate to broader forcing mechanisms. However, while these climate change events share similar timings (indicating shared macro-scale drivers), the responses are distinct between sites, in some cases expressing opposing trends over very short spatial gradients (<50 km). We describe the evolution of these trends, and propose that while long-term (105 yr) general climatic stability may have fostered high diversity in the region through low extinction rates, the strong, abrupt changes in hydroclimate gradients observed in our records may have driven a form of allopatric speciation pump, promoting the diversification of plant lineages through the periodic isolation and recombination of plant populations.


The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007–2013), ERC Starting Grant “HYRAX”, grant agreement no. 258657. We are very grateful to Louis Scott for providing a portion of the PK1173 midden for analysis. This contribution is number ISEM 2019-138.



Quaternary Science Reviews, 2019, 219, pp. 297-307

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/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/School of Geography, Geology and the Environment/Physical Geography


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Quaternary Science Reviews





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