The influence of Pleistocene dynamics on the South African salt marsh species Sarcocornia pillansii (Moss) A. J. Scott (Amaranthaceae): Inferences from phylogeography and species distribution modelling
- Published
- Accepted
- Subject Areas
- Conservation Biology, Marine Biology, Molecular Biology, Plant Science
- Keywords
- cold-water dispersal; habitat suitability; sea level; ancestral haplotypes, population bottlenecks
- Copyright
- © 2018 Veldkornet et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2018. The influence of Pleistocene dynamics on the South African salt marsh species Sarcocornia pillansii (Moss) A. J. Scott (Amaranthaceae): Inferences from phylogeography and species distribution modelling. PeerJ Preprints 6:e26927v1 https://doi.org/10.7287/peerj.preprints.26927v1
Abstract
Glacial–interglacial climate oscillations during the Pleistocene played a significant role in shifting species distributions. During this period (26 500 - 19 000 years ago) the sea level was 120 m lower than it is currently with large areas of the Southern African continental shelf being exposed. This formed a barrier to cold-water dispersal of various aquatic organisms between the west and east coast. This study explores the influence of past climatic conditions on the salt marsh species Sarcocornia pillansii (Moss) A. J. Scott using species distribution modelling and multi-locus phylogeography. The area under curve (AUC) values were considered ‘good’ (> 0.80), indicating that the models had high specificity and sensitivity. The AUC was greater for the Maxent model (AUC = 0.881) compared to the Bioclim model (AUC = 0.837) under current conditions. Climate simulation of the Last Glacial Maximum (LGM) indicated greatest habitat suitability in estuaries along the west (Orange River Estuary to Langebaan) and east (Algoa Bay to Keiskamma) coast of South Africa. This pattern is reflected in the phylogeographic analysis where a greater number of haplotypes were found in estuaries west and east of the greater continental shelf. The nuclear DNA dataset that included 97 sequences eight ribotypes whereas the chloroplast DNA for 94 sequences that were resolved into four haplotypes. The results suggest that species survived in these estuaries (as refugia) during Pleistocene climate cycles. Post-LGM increases in sea level along the south coast allowed confluence between isolated river systems, offering opportunities for dispersal among populations.
Author Comment
This is a submission to PeerJ for review.