Shaping of modern southern African biomes: Neogene vegetation and climate changes

Neumann, Frank; Bamford, Marion K.

doi:10.1080/0035919x.2015.1072859

Cited by 61 publications

(67 citation statements)

References 113 publications

(167 reference statements)

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“…This was also the case for R. ferrumequinum (Jiang et al, 2015) in Asia and for R. capensis in southern Africa. Similar to R. damarensis, R. capensis has a distribution that extends into the more arid western and northwestern regions of South Africa (Neumann & Bamford, 2015;Odendaal et al, 2014) and its RF was also not correlated with RH (Odendaal et al, 2014).…”

Section: Discussionmentioning

confidence: 95%

“…Nevertheless, the two regions have different climates. The northern part of Namibia is a more mesic region and characterized by woodland vegetation (Hoetzel, Dupont, & Wefer, 2015;Simmons, Griffin, Griffin, Marais, & Kolberg, 1998;White, 1983), while central Namibia and the Karoo ecoregions (Succulent and Nama) of South Africa are semi-arid (Neumann & Bamford, 2015;Okitsu, 2005;Thuiller et al, 2006; Figure 2). The importance of region as a predictor of RF variation may be indicative of these environmental discontinuities.…”

Section: Discussionmentioning

confidence: 99%

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Environmental correlates of geographic divergence in a phenotypic trait: A case study using bat echolocation

Maluleke

Jacobs

Winker

2017

Ecology and Evolution

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Divergence in phenotypic traits may arise from the interaction of different evolutionary forces, including different kinds of selection (e.g., ecological), genetic drift, and phenotypic plasticity. Sensory systems play an important role in survival and reproduction, and divergent selection on such systems may result in lineage diversification. Such diversification could be largely influenced by selection in different environments as a result of isolation by environment (IbE). We investigated this process using geographic variation in the resting echolocation frequency of the horseshoe bat species, Rhinolophus damarensis, as a test case. Bats were sampled along a latitudinal gradient ranging from 16°S to 32°S in the arid western half of southern Africa. We measured body size and peak resting frequencies (RF) from handheld individual bats. Three hypotheses for the divergence in RF were tested: (1) James’ Rule, (2) IbE, and (3) genetic drift through isolation by distance (IbD) to isolate the effects of body size, local climatic conditions, and geographic distance, respectively, on the resting frequency of R. damarensis. Our results did not support genetic drift because there was no correlation between RF variation and geographic distance. Our results also did not support James' Rule because there was no significant relationship between (1) geographic distances and RF, (2) body size and RF, or (3) body size and climatic variables. Instead, we found support for IbE in the form of a correlation between RF and both region and annual mean temperature, suggesting that RF variation may be the result of environmental discontinuities. The environmental discontinuities coincided with previously reported genetic divergence. Climatic gradients in conjunction with environmental discontinuities could lead to local adaptation in sensory signals and directed dispersal such that gene flow is restricted, allowing lineages to diverge. However, our study cannot exclude the role of processes like phenotypic plasticity in phenotypic variation.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Environmental correlates of geographic divergence in a phenotypic trait: A case study using bat echolocation

Maluleke

Jacobs

Winker

2017

Ecology and Evolution

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“…Uplift was greater in the east than west, causing the subcontinent to slope towards the west. The raised eastern escarpment acted as a rain shadow to reduce rainfall in the interior (Neumann & Bamford ) and contributed to grassland expansion by the Miocene (McCarthy & Rubidge ). Overall, the Oligocene is considered an epoch of global aridity (Cachel ).…”

Section: Discussionmentioning

confidence: 99%

Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

et al. 2016

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Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present. -Zoologica Scripta, 46, 389-400. Africa, inclusive of the West Indian Ocean islands, harbours 11 of the world's 16 extant testudinid genera. Fossil records indicate that testudinids originated in Asia and dispersed first to North America and Europe (Early Eocene) and later to Africa (Late Eocene). We used mitochondrial (1870 bp) and nuclear (1416 bp) DNA sequence data to assess whether molecular data support the late cladogenesis of Southern African testudinid lineages. Our results revealed strong support for the monophyly of a clade consisting of Kinixys, the two Malagasy genera and four Southern African genera (Psammobates, Stigmochelys, Homopus and Chersina). Kinixys diverged from this clade in the Late Palaeocene, suggesting that testudinids occupied Africa at an earlier date than indicated by fossil records. The Southern African tortoises consist of three, strongly supported clades: Psammobates + Stigmochelys; the five-toed Homopus + Chersina; and the four-toed Homopus. Due to the paraphyly of Homopus, we propose the taxonomic resurrection of Chersobius for the five-toed Homopus species (boulengeri, signatus and solus). Cladogenesis at the genus level occurred mainly in the Eocene, with Chersina and Chersobius diverging in the Oligocene. The latter divergence coincided with species-level radiations within Homopus (areolatus and femoralis) and Psammobates (oculifer, geometricus and tentorius). Our phylogeny could not resolve relationships within Psammobates, indicating rapid speciation between the Late Oligocene and Early Miocene. The Chersobius species were the last to diverge in the Early to Mid-Miocene. By the Mid-Miocene, P. tentorius started to differentiate into four lineages instead of the three recognized subspecies: P. t. tentorius, P. t. trimeni and two P. t. verroxii subclades occurring north and south of the Orange River, respectively. Terminal radiations in several taxa suggest the existence of cryptic species and a more diverse tortoise fauna than currently recognized. Factors contributing to this diversity may include the early origin of African testudinids and climatic fluctuations over a heterogeneous landscape.

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“…Diversification of the predominantly alpine J. breviflora-J. stricta clade (3.05 [1.66, 4.70] Mya), for example, would almost certainly have been linked to uplift, as it is this event which most likely produced the modern Drakensberg alpine zone (Linder, 2014;Linder & Verboom, 2015;Neumann & Bamford, 2015). Similarly, marine regression following a sea-level highstand around 5 Mya (Miller et al, 2005) was probably instrumental in exposing the coastal limestone/ calcretic substrata (Hoffmann et al, 2015) that have served as an arena for radiation of the J. stellata Hilliard-J.…”

Section: Discussionmentioning

confidence: 99%

“…The roots of the modern flora of southern Africa are ancient, but much of its contemporary species richness is the product of recent radiation, possibly *Corresponding author. E-mail: tony.verboom@uct.ac.za prompted by geomorphic and associated climatic events since the late Miocene epoch (Linder & Verboom, 2015;Neumann & Bamford, 2015). Of principal importance is an episode of significant tectonic uplift along the south-eastern margin of the subcontinent around the Miocene-Pliocene boundary (3-5 Mya: Partridge & Maud, 2000).…”

Section: Introductionmentioning

confidence: 99%

Maintenance of species integrity in the context of a recent radiation: the case ofJamesbrittenia(Scrophulariaceae: Limoselleae) in southern Africa

et al. 2016

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Incomplete post‐zygotic isolation poses challenges for the maintenance of species integrity in recently radiated lineages. An example is Jamesbrittenia, a southern African‐centred genus, the species of which cross readily to produce viable offspring. We develop a dated phylogenetic hypothesis for Jamesbrittenia and used this to assess the evidence for recent radiation and to evaluate the roles of geography, relatedness and floral divergence in determining the incidence of wild hybridization. Phylogenetic inference is based on nuclear (GScp) and plastid (rps16, psb–trnH) loci, but uses morphological evidence to resolve instances of supported incongruence. Our data reveal four ecologically and biogeographically differentiated lineages in Jamesbrittenia. One of these, a widespread and predominantly shrubby lineage, reflects accelerated diversification, potentially triggered by environmental change, starting in the late Miocene epoch. In the widespread clade, strong range exclusivity indicates an important role for geography in maintaining species identity. Among species with overlapping ranges, however, differentiation in floral form is a powerful predictor of wild hybridization. The apparent importance of geography in maintaining species integrity in recently diverged lineages, like the widespread clade of Jamesbrittenia, needs to be considered when species are translocated, whether such translocation is horticulturally motivated or forms part of an ‘assisted migration’ exercise.

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Shaping of modern southern African biomes: Neogene vegetation and climate changes

Cited by 61 publications

References 113 publications

Environmental correlates of geographic divergence in a phenotypic trait: A case study using bat echolocation

Environmental correlates of geographic divergence in a phenotypic trait: A case study using bat echolocation

Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present

Maintenance of species integrity in the context of a recent radiation: the case ofJamesbrittenia(Scrophulariaceae: Limoselleae) in southern Africa

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