Mitochondrial phylogeography of baboons (Papio spp.) – Indication for introgressive hybridization?

<p>Abstract</p> <p>Background</p> <p>Baboons of the genus <it>Papio </it>are distributed over wide ranges of Africa and even colonized parts of the Arabian Peninsula. Traditionally, five phenotypically distinct species are recognized, but recent molecular studies were not able to resolve their phylogenetic relationships. Moreover, these studies revealed para- and polyphyletic (hereafter paraphyletic) mitochondrial clades for baboons from eastern Africa, and it was hypothesized that introgressive hybridization might have contributed substantially to their evolutionary history. To further elucidate the phylogenetic relationships among baboons, we extended earlier studies by analysing the complete mitochondrial cytochrome <it>b </it>gene and the 'Brown region' from 67 specimens collected at 53 sites, which represent all species and which cover most of the baboons' range.</p> <p>Results</p> <p>Based on phylogenetic tree reconstructions seven well supported major haplogroups were detected, which reflect geographic populations and discordance between mitochondrial phylogeny and baboon morphology. Our divergence age estimates indicate an initial separation into southern and northern baboon clades 2.09 (1.54–2.71) million years ago (mya). We found deep divergences between haplogroups within several species (~2 mya, northern and southern yellow baboons, western and eastern olive baboons and northern and southern chacma baboons), but also recent divergence ages among species (< 0.7 mya, yellow, olive and hamadryas baboons in eastern Africa).</p> <p>Conclusion</p> <p>Our study confirms earlier findings for eastern Africa, but shows that baboon species from other parts of the continent are also mitochondrially paraphyletic. The phylogenetic patterns suggest a complex evolutionary history with multiple phases of isolation and reconnection of populations. Most likely all these biogeographic events were triggered by multiple cycles of expansion and retreat of savannah biomes during Pleistocene glacial and inter-glacial periods. During contact phases of populations reticulate events (i.e. introgressive hybridization) were highly likely, similar to ongoing hybridization, which is observed between East African baboon populations. Defining the extent of the introgressive hybridization will require further molecular studies that incorporate additional sampling sites and nuclear loci.</p

The forgotten ‘coastal forests’ of Mtwara, Tanzania: a biologically impoverished and yet important ecosystem.

Biodiversity surveys and the compilation of indigenous knowledge were conducted in eight previously unstudied proposed and already gazetted Forest Reserves of Mtwara Region, south-eastern Tanzania, from April to August of 2005. The results indicate relatively low biodiversity and endemism values in these forests, and high levels of forest disturbance. In most areas the original vegetation has been converted by clearance for cultivation and by fire, and has regenerated into degraded forms of Swahilian/Coastal Mixed Dry Forest, Swahilian/Coastal Brachystegia Forest and floristically impoverished Zambezian-Swahilian Brachystegia Woodland. Some Coastal Forest endemic and threatened species, however, occur in the degraded forest patches, such as east coast akalat Sheppardia gunningi, Reichenow’s batis Batis mixta reichenowi, spotted flat-lizard Platysaurus maculatus, woodland toad Mertensophryne micranotis and the shrub Gardenia transvenulosa. The low proportion of endemic and threatened species recorded implies that these forests are of modest biological importance within the context of the Eastern Arc Mountains and Coastal Forests Biodiversity Hotspot. Nevertheless, local inhabitants depend heavily on the long-term availability of timber and  non-timber resources and water and soil regulation services from these forests. The development and implementation of effective natural resourcemanagement is therefore urgently needed in this area.Keywords: coastal forest mosaic, biodiversity hotspot, biodiversity survey, forestdisturbance, species checklist, East Afric

Genetic testing of dung identification for antelope surveys in the Udzungwa Mountains, Tanzania.

Dung counts are frequently employed to infer abundance of antelope species in African forests, but the accuracy of dung identification has rarely been tested. We used non-invasive genetic methods to test the accuracy of both field identification and morphometrics for identifying dung samples collected in the Udzungwa Mountains, Tanzania. Species identity was established by sequencing part of the mitochondrial control region from faecal DNA. Field identification was found to be correct in only 58–76% of cases depending on the observer. Discriminant analysis of dung pellet length correctly classified 80% of samples but a larger reference sample size is needed before using this method to classify dung of unknown origin. The results of this study illustrate the potential inaccuracy of dung counts as a monitoring tool for sympatric forest antelope species when the probability of correct identification is unknown. We recommend molecular testing of species identity during forest antelope surveys before conclusions are drawn on the basis of other identification method