@article{2430f752cafd418a8d56f7296939ed9c,
title = "Climatic stability recorded in speleothems may contribute to higher biodiversity in the Cape Floristic Region",
abstract = "Aim: The geography and genesis of diversity remain an enduring topic in ecology and evolution. Mediterranean Climate Ecosystems (MCEs), with their high plant diversities in winter rainfall climates, pose a challenge to popular hypotheses evoking high water availability and temperature as necessary for the evolution of high diversity. We test the hypothesis of environmental stability as a driver for the evolution of regional-scale floristic diversity using speleothem oxygen (δ18O) and carbon (δ13C) isotopic values as proxies for past climatic variability in the Cape Floristic Region (CFR) and other MCEs. Location: south-western Africa, California, Mediterranean Basin. Taxon: Plantae. Methods: We present new speleothem δ18O and δ13C records from a cave near Robertson in the western CFR. Stable isotope samples included in the analyses cover the time intervals between 240 and 670 ka BP with hiatuses at 630–500 ka and 360–310 ka. The dispersion of these stable isotope records is used as a measure for climatic variability. We compare our new analyses to speleothem records that cover full glacial and interglacial conditions in other MCEs (California and the Mediterranean Basin) as well as in eastern regions of the CFR. All sites used in this comparison have lower vascular plant biodiversity than the western CFR. Results: Analyses of the dispersion of the δ18O and δ13C datasets suggest that the highly diverse western CFR experienced climatic stability across several glacial–interglacial cycles, compared with the less diverse regions within and outside of the CFR. Main Conclusion: This result provides support for the hypothesis that lower extinction rates associated with Pleistocene biome stability may explain the higher diversity in the CFR relative to other MCEs.",
keywords = "California, Cape Floristic Region, Mediterranean Basin, Mediterranean climate ecosystems, South Africa, carbon isotopes, oxygen isotopes, palaeoclimate, plant diversity, speleothem, stable isotopes",
author = "Kerstin Braun and Cowling, {Richard M.} and Miryam Bar-Matthews and Alan Matthews and Avner Ayalon and Tami Zilberman and Mark Difford and Edwards, {R. Lawrence} and Xianglei Li and Marean, {Curtis W.}",
note = "Funding Information: We would like to thank three anonymous reviewers for the comments. We thank the Institute of Human Origins and School of Human Evolution and Social Change staff at Arizona State University (ASU) and the Mossel Bay Archaeology Project (MAPCRM) staff for their assistance, the Dias Museum for field facilities, Cape Lime (Pty) Ltd for permitting sampling in their quarry, the Cape Peninsula Spelaeological Society for bringing the cave to our attention, Andy Herries, Panagiotis Karkanas and Lizelle Bezuidenhout for assistance with sampling, and the Geological Survey of Israel for research support. We acknowledge funding from the European Commission 7th Framework Marie Curie People programme FP7/2007–2013 through funding of the Initial Training Network {\textquoteleft}GATEWAYS{\textquoteright} ( www.gatewaysitn.eu ) under the grant number 238512. This research was further funded by grants from the National Science Foundation (to Marean BCS‐0524087 and BCS‐1138073, Braun 2002486 and Edwards 2002474), the Hyde Family Foundations, the Institute of Human Origins at ASU, the ASU Strategic Initiatives Fund and a grant by the John Templeton Foundation to the Institute of Human Origins at ASU (grant ID 48952). Funding Information: We would like to thank three anonymous reviewers for the comments. We thank the Institute of Human Origins and School of Human Evolution and Social Change staff at Arizona State University (ASU) and the Mossel Bay Archaeology Project (MAPCRM) staff for their assistance, the Dias Museum for field facilities, Cape Lime (Pty) Ltd for permitting sampling in their quarry, the Cape Peninsula Spelaeological Society for bringing the cave to our attention, Andy Herries, Panagiotis Karkanas and Lizelle Bezuidenhout for assistance with sampling, and the Geological Survey of Israel for research support. We acknowledge funding from the European Commission 7th Framework Marie Curie People programme FP7/2007–2013 through funding of the Initial Training Network {\textquoteleft}GATEWAYS{\textquoteright} (www.gatewaysitn.eu) under the grant number 238512. This research was further funded by grants from the National Science Foundation (to Marean BCS-0524087 and BCS-1138073, Braun 2002486 and Edwards 2002474), the Hyde Family Foundations, the Institute of Human Origins at ASU, the ASU Strategic Initiatives Fund and a grant by the John Templeton Foundation to the Institute of Human Origins at ASU (grant ID 48952). Publisher Copyright: {\textcopyright} 2023 The Authors. Journal of Biogeography published by John Wiley & Sons Ltd.",
year = "2023",
month = jun,
doi = "10.1111/jbi.14592",
language = "English (US)",
volume = "50",
pages = "1077--1089",
journal = "Journal of Biogeography",
issn = "0305-0270",
publisher = "Wiley-Blackwell",
number = "6",
}