Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus
| dc.contributor.author | Bentley, Joanne | |
| dc.contributor.author | Verboom, G A | |
| dc.contributor.author | Bergh, Nicola G | |
| dc.date.accessioned | 2015-01-17T13:44:30Z | |
| dc.date.available | 2015-01-17T13:44:30Z | |
| dc.date.issued | 2014-02-13 | |
| dc.date.updated | 2015-01-15T17:52:08Z | |
| dc.description.abstract | Background: The role of tectonic uplift in stimulating speciation in South Africa’s only alpine zone, the Drakensberg, has not been explicitly examined. Tectonic processes may influence speciation both through the creation of novel habitats and by physically isolating plant populations. We use the Afrotemperate endemic daisy genus Macowania to explore the timing and mode (geographic versus adaptive) of speciation in this region. Between sister species pairs we expect high morphological divergence where speciation has happened in sympatry (adaptive) while with geographic (vicariant) speciation we may expect to find less morphological divergence and a greater degree of allopatry. A dated molecular phylogenetic hypothesis for Macowania elucidates species’ relationships and is used to address the potential impact of uplift on diversification. Morphological divergence of a small sample of reproductive and vegetative characters, used as a proxy for adaptive divergence, is measured against species’ range distributions to estimate mode of speciation across two subclades in the genus. Results: The Macowania crown age is consistent with the hypothesis of post-uplift diversification, and we find evidence for both vicariant and adaptive speciation between the two subclades within Macowania. Both subclades exhibit strong signals of range allopatry, suggesting that geographic isolation was important in speciation. One subclade, associated with dry, rocky environments at high altitudes, shows very little morphological and ecological differentiation but high range allopatry. The other subclade occupies a greater variety of habitats and exhibits far greater morphological differentiation, but contains species with overlapping distribution ranges. Conclusions: Species in Macowania are likely to have diversified in response to tectonic uplift, and we invoke uplift and uplift-mediated erosion as the main drivers of speciation. The greater relative morphological divergence in sympatric species of Macowania indicates that speciation in the non-sympatric taxa may not have required obvious adaptive differences, implying that simple geographic isolation was the driving force for speciation (‘neutral speciation’). | en_ZA |
| dc.identifier.apacitation | Bentley, J., Verboom, G. A., & Bergh, N. G. (2014). Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus. <i>BMC Evolutionary Biology</i>, http://hdl.handle.net/11427/12261 | en_ZA |
| dc.identifier.chicagocitation | Bentley, Joanne, G A Verboom, and Nicola G Bergh "Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus." <i>BMC Evolutionary Biology</i> (2014) http://hdl.handle.net/11427/12261 | en_ZA |
| dc.identifier.citation | Bentley, J., Verboom, G. A., & Bergh, N. G. (2014). Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus. BMC evolutionary biology, 14(1), 27. | en_ZA |
| dc.identifier.issn | 1471-2148 | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Bentley, Joanne AU - Verboom, G A AU - Bergh, Nicola G AB - Background: The role of tectonic uplift in stimulating speciation in South Africa’s only alpine zone, the Drakensberg, has not been explicitly examined. Tectonic processes may influence speciation both through the creation of novel habitats and by physically isolating plant populations. We use the Afrotemperate endemic daisy genus Macowania to explore the timing and mode (geographic versus adaptive) of speciation in this region. Between sister species pairs we expect high morphological divergence where speciation has happened in sympatry (adaptive) while with geographic (vicariant) speciation we may expect to find less morphological divergence and a greater degree of allopatry. A dated molecular phylogenetic hypothesis for Macowania elucidates species’ relationships and is used to address the potential impact of uplift on diversification. Morphological divergence of a small sample of reproductive and vegetative characters, used as a proxy for adaptive divergence, is measured against species’ range distributions to estimate mode of speciation across two subclades in the genus. Results: The Macowania crown age is consistent with the hypothesis of post-uplift diversification, and we find evidence for both vicariant and adaptive speciation between the two subclades within Macowania. Both subclades exhibit strong signals of range allopatry, suggesting that geographic isolation was important in speciation. One subclade, associated with dry, rocky environments at high altitudes, shows very little morphological and ecological differentiation but high range allopatry. The other subclade occupies a greater variety of habitats and exhibits far greater morphological differentiation, but contains species with overlapping distribution ranges. Conclusions: Species in Macowania are likely to have diversified in response to tectonic uplift, and we invoke uplift and uplift-mediated erosion as the main drivers of speciation. The greater relative morphological divergence in sympatric species of Macowania indicates that speciation in the non-sympatric taxa may not have required obvious adaptive differences, implying that simple geographic isolation was the driving force for speciation (‘neutral speciation’). DA - 2014-02-13 DB - OpenUCT DO - 10.1186/1471-2148-14-27 DP - University of Cape Town J1 - BMC Evolutionary Biology LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 SM - 1471-2148 T1 - Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus TI - Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus UR - http://hdl.handle.net/11427/12261 ER - | en_ZA |
| dc.identifier.uri | http://dx.doi.org/10.1186/1471-2148-14-27 | |
| dc.identifier.uri | http://hdl.handle.net/11427/12261 | |
| dc.identifier.vancouvercitation | Bentley J, Verboom GA, Bergh NG. Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus. BMC Evolutionary Biology. 2014; http://hdl.handle.net/11427/12261. | en_ZA |
| dc.language | eng | en_ZA |
| dc.language.rfc3066 | en | |
| dc.publisher | BioMed Central | en_ZA |
| dc.publisher.department | Department of Biological Sciences | en_ZA |
| dc.publisher.faculty | Faculty of Science | en_ZA |
| dc.publisher.institution | University of Cape Town | |
| dc.rights | This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. | * |
| dc.rights.holder | Bentley et al.; licensee BioMed Central Ltd. | |
| dc.rights.uri | http://creativecommons.org/licenses/by/2.0 | en_ZA |
| dc.source | BMC Evolutionary Biology | en_ZA |
| dc.source.uri | http://www.biomedcentral.com/1471-2148/ | |
| dc.subject.other | Afrotemperate | en_ZA |
| dc.subject.other | Drakensberg | en_ZA |
| dc.subject.other | Adaptive speciation | en_ZA |
| dc.subject.other | Vicariance | en_ZA |
| dc.subject.other | Gnaphalieae | en_ZA |
| dc.title | Erosive processes after tectonic uplift stimulate vicariant and adaptive speciation: evolution in an Afrotemperate-endemic paper daisy genus | en_ZA |
| dc.type | Journal Article | en_ZA |
| uct.type.filetype | ||
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Article | en_ZA |