Phylogeography of Haplocarpha rueppelii (Asteraceae) suggests a potential geographic barrier for plant dispersal and gene flow in East Africa

Chen, Ling Yun; Muchuku, John K.; Xue, Yan; Hu, Guang; Wang, Qing Feng

doi:10.1007/s11434-015-0832-x

Cited by 9 publications

(7 citation statements)

References 32 publications

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“…In both species, populations from opposite sides of the narrow Rift Valley barrier in Ethiopia were genetically more distant than those from opposite sides of the vast Ethiopia-East Africa barrier. The surprising pattern of high genetic similarity between populations from the Bale Mts in Ethiopia and the distant East African mountains has also been identified in several other species (Ehrich et al 2007;Gizaw et al 2013Gizaw et al , 2016bMasao et al 2013;Chen et al 2015;Wondimu et al 2017). It is still a mystery why the vast Ethiopia-East Africa barrier seems to be more permeable-at least for some species-than the narrow Rift Valley barrier within Ethiopia, which is found to be a major biogeographic barrier for both animals (reviewed in Komarova et al 2021) and plants.…”

Section: Migration Corridors Among the Sky Islands: Do They Or Did They Exist?mentioning

confidence: 99%

History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg

et al. 2021

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The monumental work of Olov Hedberg provided deep insights into the spectacular and fragmented tropical alpine flora of the African sky islands. Here we review recent molecular and niche modelling studies and re-examine Hedberg’s hypotheses and conclusions. Colonisation started when mountain uplift established the harsh diurnal climate with nightly frosts, accelerated throughout the last 5 Myr (Plio-Pleistocene), and resulted in a flora rich in local endemics. Recruitment was dominated by long-distance dispersals (LDDs) from seasonally cold, remote areas, mainly in Eurasia. Colonisation was only rarely followed by substantial diversification. Instead, most of the larger genera and even species colonised the afroalpine habitat multiple times independently. Conspicuous parallel evolution occurred among mountains, e.g., of gigantism in Lobelia and Dendrosenecio and dwarf shrubs in Alchemilla. Although the alpine habitat was ~ 8 times larger and the treeline was ~ 1000 m lower than today during the Last Glacial Maximum, genetic data suggest that the flora was shaped by strong intermountain isolation interrupted by rare LDDs rather than ecological connectivity. The new evidence points to a much younger and more dynamic island scenario than envisioned by Hedberg: the afroalpine flora is unsaturated and fragile, it was repeatedly disrupted by the Pleistocene climate oscillations, and it harbours taxonomic and genetic diversity that is unique but severely depauperated by frequent bottlenecks and cycles of colonisation, extinction, and recolonisation. The level of intrapopulation genetic variation is alarmingly low, and many afroalpine species may be vulnerable to extinction because of climate warming and increasing human impact.

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Section: Migration Corridors Among the Sky Islands: Do They Or Did They Exist?mentioning

confidence: 99%

History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg

et al. 2021

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“…The major fault activity, structural growth, subsidence and associated uplift of East Africa occurred between 5 and 2 Ma (Sepulchre & al., 2006;Macgregor, 2015), and such uplift might have subsequently triggered the diversification of the afro-montane Delphinium group in the Pleistocene . Studies on other tropical African mountain taxa such as other flowering plants, frogs or birds have shown that their diversification mostly occurred before the Pleistocene and that long-distance dispersal, climatic fluctuations, habitat stability and mountain uplifts are important mechanisms possibly explaining the origin of African mountain biodiversity (Galley & Linder, 2006;Kebede & al., 2007;Fjeldså & Bowie, 2008;Gehrke & Linder, 2009;Lawson, 2010;Voelker & al., 2010;Chen & al., 2015). However, Pleistocene cooling events have also been proposed to have played an important role in promoting diversification in African mountain clades (Hedberg, 1969;Assefa & al., 2007;Dimitrov & al., 2012;Masao & al., 2013), and this might have been the case also for the afro-montane Delphinium clade.…”

Section: Delphinium Leroyimentioning

confidence: 99%

The evolution of afro‐montane Delphinium (Ranunculaceae): Morphospecies, phylogenetics and biogeography

Chartier

Dreßler

Schönenberger

et al. 2016

TAXON

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The genus Delphinium (Ranunculaceae) consists of ca. 300 species and has a mainly holarctic distribution. Few species have been described from high‐altitude areas in West and East Tropical Africa, where the environmental conditions are mostly temperate‐like. We aim to clarify the taxonomy of these afro‐montane Delphinium species and to understand their evolutionary history in terms of their floral morphology and their phylogenetic and biogeographic relationships. Based on herbarium specimens, we analyze flower shape variation, map the geographic distribution of the morphologically defined taxa and reconstruct the molecular phylogeny of the group. Our quantitative analyses of flower shapes indicate that three species can be defined based on floral morphological traits, hence confirming the latest taxonomic treatment of the group where D. dasycaulon, D. leroyi and D. macrocentrum were described. The examination of herbarium specimens indicates that these three species are almost parapatric. However, their respective monophyly is not supported by molecular data. Considering their relatively young age, the non‐monophyly of each of the three morphospecies could be due to incomplete lineage sorting and/or hybridization events. Alternatively, the transition to the D. leroyi floral morph could be the result of evolutionary convergence in the two main groups of afro‐montane Delphinium driven by similar pollinators in different sky islands of the East African Rift System. We hypothesize that the main branches of the East African Rift System, as physical barriers to dispersal, may have prevented genetic exchange among geographic clusters.

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“…Kenya, while the lowest habitat was inhabited by herbaceous species, such as L. fervens and L. erinus . The altitudinal distribution of lobelias could have been shaped by their habitat preferences and by the adaptive evolution ( Hedberg 1964 ; Chen et al 2015 ). For example, L. telekii was confined to the afro-alpine belt characterised by an extreme climate with “summer every day and winter every night” ( Hedberg 1964 ).…”

Section: Discussionmentioning

confidence: 99%

Distribution pattern and habitat preference for Lobelia species (Campanulaceae) in five countries of East Africa

Muchuku¹,

Gichira²,

Zhao³

et al. 2020

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East Africa is one of the centres of distribution and diversity for Lobelia L. (Campanulaceae, sub-family Lobelioideae). Lobelia habitats in East Africa have been facing habitat fragmentation and loss, which are recognised as a major threat to biodiversity. However, previous plant conservation studies in East Africa only focused on protected areas and ignored unprotected areas. Future conservation strategies of plants, such as Lobelia, will depend on knowledge of their distribution patterns and habitat preference in East Africa. To understand the distribution pattern and the habitat preference of Lobelia in five countries (Kenya, Uganda, Tanzania, Rwanda and Burundi) of East Africa, we conducted a literature review in the seven major vegetation regions (afro-alpine, afro-montane forest, drier savannah, grasslands, wetter savannah, Zambezian woodland and semi-desert and desert). We also employed meander and patterned searches, which allowed greater opportunities for recording Lobelia species. Our results showed that the genus is distributed in all of the seven regions of the five countries with 54 taxa. The afro-montane forest region, with 41 taxa, is the richest in species diversity, followed by the Zambezian woodland region with 18 taxa. The semi-desert and desert region has the lowest number with only four taxa. The afro-alpine region has 15 taxa, although the region is the smallest by area. The herbaceous type was found in all regions, while the giant type has a clear preference for the afro-alpine and afro-montane forest regions. Future conservation for Lobelia should consider its habitat preference by, for example, focusing on the afro-alpine and afro-montane forest regions. This study will facilitate the setting of future conservation strategies for Lobelia.

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Phylogeography of Haplocarpha rueppelii (Asteraceae) suggests a potential geographic barrier for plant dispersal and gene flow in East Africa

Cited by 9 publications

References 32 publications

History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg

History and evolution of the afroalpine flora: in the footsteps of Olov Hedberg

The evolution of afro‐montane Delphinium (Ranunculaceae): Morphospecies, phylogenetics and biogeography

Distribution pattern and habitat preference for Lobelia species (Campanulaceae) in five countries of East Africa

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