Biogeographical Importance of the Livingstone Mountains in Southern Tanzania: Comparative Genetic Structure of Small Non-volant Mammals

Abstract

The Livingstone Mountains (LM; also known as the Kipengere Range) found in south-western Tanzania at the northern end of Lake Nyasa are an important region for understanding the biogeography of Eastern Africa. The two branches of the East African Rift Valley meet here and the mountains might represent stepping stones for colonization and migration between different parts of the Eastern Afromontane Biodiversity Hotspot (especially the link between the Eastern Arc Mountains, EAM, and the Southern Rift Mountains, SRM), as well as an efficient barrier to gene flow for taxa living in drier savannahs in lower elevations. Here we combine new mitochondrial sequence data from 610 recently sampled rodents and shrews with available georeferenced genetic data (3538 specimens) from southern Tanzania, northern Malawi/Zambia and northern Mozambique and compare the spatial genetic structure among different taxa. There is no universal phylogeographic pattern in taxa preferring humid montane habitats. For some of them, the Makambako Gap acts as a barrier between the SRM and the EAM, but other taxa can bridge this gap. Barriers within the EAM (frequently) and within the SRM (sometimes) appear more important. The Rukwa rift between the SRM and the ARM is an important barrier that perhaps can only be crossed by taxa that are not that strictly tied to humid montane environments. For mammals living in lower-elevation savannah-like habitats, the LM can act as a strict barrier to gene flow, and together with the Ufipa Plateau, Lake Nyasa and the EAM create a very similar phylogeographic pattern with three recognizable genetic groups in most savannah-dwellers. The Livingstone Mountains thus appear to be one of the most important biogeographic crossroads in Eastern Africa.

Influence of environmental factors on small mammal communities along an altitudinal gradient of Mount Rungwe in South Western Tanzania

“…The study conducted trapping for five nights in each location and season. The collected species identified based on morphometric measurements, recent distribution data and cytochrome b gene sequence (Cuypers et al, 2022; Happold, 2013; Sabuni et al, 2015; Verheyen et al, 2007; Voelker et al, 2021).…”

“…Table 1; URT, 2017). (Cuypers et al, 2022;Happold, 2013;Sabuni et al, 2015;Verheyen et al, 2007;Voelker et al, 2021).…”

Cryptic diversity of Crocidura shrews in the savannahs of Eastern and Southern Africa

“…These rift basins, either filled with water or extremely dry with halophytic vegetation (White, 1983), could prevent the dispersal of animals living in savannahs and woodlands (Trauth et al, 2010). There are an increasing number of phylogeographical studies of rodents in the Zambezian savannah (see Cuypers et al [2022] for a review), and they show numerous similarities with the hirta-flavescens shrews. First, the arid zone of central Tanzania (delimited by the Albertine rift on the west and south and Eastern Arc Mountains (EAM) in the east and inhabited by C. cf.…”

“…flavescens seem to have split about 2 Ma during the Pleistocene climatic oscillations. In open habitats of eastern and southern Africa (Zambezian bioregion), such detailed and comprehensive data are now available for several groups of rodents (summarized by Cuypers et al, 2022) but completely missing for shrews.…”

Diversity, distribution, and evolutionary history of the most studied African rodents, multimammate mice of the genusMastomys: An overview after a quarter of century of using DNA sequencing

“…Numerous savannah mammals in Africa diversified in the consequence of the intensified climate oscillations (for example in rodents see Bryja et al, 2014Bryja et al, , 2019Hánová et al, 2021;Mazoch et al, 2018). A generally accepted scenario predicts the survival of aridadapted taxa in spatially restricted refugia during interglacial periods (sometimes called "pluvials" in tropics), separated from each other by mountains (Cuypers et al, 2021) or large rivers and riverine forests (Brouat et al, 2009). The precise localization of such refugia is difficult to reconstruct, but very often the allopatric diversification produced spatially concordant patterns in widely distributed taxa, with main phylogeographic groups in western, eastern, and southern Africa (for ungulates reviewed by Lorenzen et al, 2012, for gerbils see Colangelo et al, 2007 andGranjon et al, 2012).…”