Miocene–Pliocene vegetation change in south-western Africa (ODP Site 1081, offshore Namibia)

Hoetzel, Sebastian; Dupont, Lydie M; Wefer, Gerold

doi:10.1016/j.palaeo.2015.02.002

Cited by 28 publications

(25 citation statements)

References 45 publications

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“…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%

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: 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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“…The Plucheinae is most likely of southern African, specifically in the Namib region, origin (Figs b & ). The origin correlates in time with the start of the Miocene aridification of the general Namib area (Senut et al ., ; Hoetzel et al ., ) in connection with the formation of the Benguela Upwelling, following the formation of the ACC. Connections between the formation of the Benguela upwelling and radiation of species with presumed Namib origin have been previously hypothesized (e.g.…”

Section: Discussionmentioning

confidence: 99%

From the Namib around the world: biogeography of the Inuleae–Plucheinae (Asteraceae)

Nylinder

Razafimandimbison

Anderberg

2016

Journal of Biogeography

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Aim We investigated the historical biogeography of the Inuleae-Plucheinae (Asteraceae), a group of arid-adapted plants with partly unresolved generic circumscriptions, in order to understand its origin and spatiotemporal evolutionary history in relation to the Cenozoic climate shifts.Location Global, with highest species diversity in the Southern Hemisphere.Methods The spatiotemporal biogeography of the Plucheinae was estimated by both a discrete method using a set of general distribution areas, and a relaxed random walk based on extant species distributions. The topology was time calibrated using a combination of secondary node ages and secondary derived rates for included loci.Results Our results indicate the median age of the Plucheinae to be approximately 15.4 Ma. The biogeographical analyses infer an ancestral origin in southern Africa, with the relaxed random walk analysis narrowing the uncertainty down to an area reaching from coastal Namibia to the western Kalahari. Africa was colonized in a (south)western-(north)eastern direction following the spread of arid habitats. Ancestral representatives of the Plucheinae colonized South America on at least three separate occasions (13.0-4.0, 4.3-3.1 and 4.1-3.7 Ma), with one subsequent spread to North America. Australia was colonized three times between 3.6 and 0.4 Ma. Madagascar and the Mascarenes were colonized at least seven times.Main conclusions The origin of the Plucheinae is estimated to the Namib region, with early speciations and radiations concurring with the timing of aridification of southern Africa, following the increase in strength of the Antarctic Circumpolar Current and subsequent formation of the Benguela Upwelling at c. 11.8 Ma. The current biogeographical distribution of the Plucheinae is best explained by several Neogene long-distance dispersal events from tropical Africa.

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“…30, Figure 1) off the coast of Namibia, involving pollen, microscopic charcoal and the stable isotopic composition of plant waxes, draws the picture of a late Miocene-Pliocene (c. 9-3 Myr) spread of C 4 grasses, probably more pronounced in the central than in the southern Namib (Ségalen et al, 2006;Senut & Ségalen, 2014), in an environment of shrinking grasslands and expanding deserts (Hoetzel et al, 2013). Hoetzel et al (2015) distinguish three vegetation phases utilising ODP 1081: a wet phase during the Tortonian, a transitional Messinian period with a pronounced spread of grasses and a rather dry Pliocene period with desert plants. Another marine core close by (ODP 1082, no. 30, Figure 1) shows major vegetation changes 3,4-1,8 Myr but they also show developments in the eastern hinterland of the desert (Dupont, 2006).…”

Section: Desert Biomementioning

confidence: 89%

“…The scarcity of terrestrial Neogene sites in southern Africa makes the study of marine records invaluable as this allows, at least to a limited degree, an indication of the vegetation onshore (e.g. van Zinderen Bakker, 1984;Dupont et al, 2005;Udeze & Oboh-Ikuenobe, 2005;Hoetzel et al, 2015). Although direct palaeobotanical evidence in Neogene terrestrial sites is often lacking, geochemical approaches (e.g.…”

Section: Introductionmentioning

confidence: 99%

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

Neumann

Bamford

2015

Transactions of the Royal Society of South Africa

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Miocene–Pliocene vegetation change in south-western Africa (ODP Site 1081, offshore Namibia)

Cited by 28 publications

References 45 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

From the Namib around the world: biogeography of the Inuleae–Plucheinae (Asteraceae)

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

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