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Albertine Rift (albertine + rift)
Selected AbstractsThe Eastern Congo,a beauty spot, rediscovered from a geological point of viewGEOLOGY TODAY, Issue 2 2010F.U. Bauer In East Africa, the feedback between tectonic uplift, erosional denudation and associated possible climate changes is being studied by a multidisciplinary research group, ,Riftlink'. The group's focus is the Albertine Rift, the northern part of the western branch of the East African Rift System, and in particular the rising Rwenzori Mountains that stretch along the border of the D.R. Congo and Uganda. Major questions relate to the timing of the formation of the Rwenzori Mountains, and whether the height of these mountains (> 5000 m) relates to rift movements in Neogene times, or represents an old basement block that formed a topographic high long before. Though, at first, research concentrated on the eastern (Ugandan) part of the Albertine Rift and Rwenzori Mountains, it has now moved further to the west to the D.R. Congo. A first field-campaign, covering the area from northern Lake Edward along the rift shoulder up to the Blue Mountains at Lake Albert, was conducted in summer 2009, in cooperation with the Ruwenzori State University of Butembo. Here, we present a brief overview of the field-campaign, with impressions gathered on the morphology and geology of the study area. [source] Pliocene forest dynamics as a primary driver of African bird speciationGLOBAL ECOLOGY, Issue 1 2010Gary Voelker ABSTRACT Aim, Montane tropics are areas of high endemism, and mechanisms driving this endemism have been receiving increasing attention at a global scale. A general trend is that climatic factors do not explain the species richness of species with small to medium-sized geographic ranges, suggesting that geological and evolutionary processes must be considered. On the African continent, several hypotheses including both refugial and geographic uplift models have been advanced to explain avian speciation and diversity in the lowland forest and montane regions of central and eastern Africa; montane regions in particular are recognized as hotspots of vertebrate endemism. Here, we examine the possible role of these models in driving speciation in a clade of African forest robins. Location, Africa. Methods, We constructed the first robustly supported molecular phylogenetic hypothesis of forest robins. On this phylogeny, we reconstructed habitat-based distributions and geographic distributions relative to the Albertine Rift. We also estimated the timing of lineage divergences via a molecular clock. Results, Robust estimates of phylogenetic relationships and clock-based divergences reject Miocene tectonic uplift and Pleistocene forest refugia as primary drivers of speciation in forest robins. Instead, our data suggest that most forest robin speciation took place in the Late Pliocene, from 3.2 to 2.2 Ma. Distributional patterns are complex, with the Albertine Rift region serving as a general east,west break across the group. Montane distributions are inferred to have evolved four times. Main conclusions, Phylogenetic divergence dates coincide with a single period of lowland forest retraction in the late Pliocene, suggesting that most montane speciation resulted from the rapid isolation of populations in montane areas, rather than montane areas themselves being drivers of speciation. This conclusion provides additional evidence that Pliocene climate change was a major driver of speciation in broadly distributed African animal lineages. We further show that lowland forest robins are no older than their montane relatives, suggesting that lowland areas are not museums which house ,ancient' taxa; rather, for forest robins, montane areas should be viewed as living museums of a late Pliocene diversification event. A forest refugial pattern is operating in Africa, but it is not constrained to the Pleistocene. [source] Observations on the breeding behaviour of the Stripe-breasted tit (Parus fasciiventer) in Bwindi Impenetrable National Park, UgandaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Jane Yatuha Abstract The motivation of this study was to investigate some hitherto unknown information on the breeding ecology of the Stripe-breasted Tit (Parus fasciiventer) in Bwindi Impenetrable National Park, south-western Uganda. Parus fasciiventer is one of the least studied and endemic bird species restricted to the montane forests of the Albertine Rift. Regionally, it is classified as near-threatened. The study was carried out around the Institute of Tropical Forest Conservation Ruhija camp and the period of study was from January to June 2003. Data were generated through direct observation at the nest box sites of three active nests. Each of the nest boxes was monitored from the time of nest building to the time the chicks fledged. Results and comparative assessments from this study demonstrate that P. fasciiventer, compared with its temperate congeners like Great Tits (Parus major), Marsh Tits (Parus palustris), Crested Tits (Parus cristatus), Coal Tits (Parus ater) and Blue Tits (Parus caeruleus), raised small broods and had longer nestling period. The findings further revealed that the species is capable of raising more than one brood in a single breeding season and provide further evidence that it is a cooperative breeder. Parents participated equally in raising the young, an indication of pure parenting in the species. Résumé La raison de cette étude était de rechercher certaines informations jusqu'alors inconnues sur l'écologie de la reproduction de la mésange à ventre strié, Parus fasciiventer, dans le Parc National de la Forêt impénétrable de Bwindi, dans le sud-ouest de l'Ouganda. Parus fasciiventer est une des espèces d'oiseaux endémiques les moins étudiées; elle se limite aux forêts de montagne du Rift Albertin. Au niveau régional, elle est classée comme quasi menacée. L'étude s'est réalisée autour du camp de Ruhija de l'Institute of Tropical Forest Conservation de janvier à juin 2003. Les données furent obtenues par des observations directes sur les sites de trois nichoirs actifs. Chaque nid a été suivi depuis sa construction jusqu'à la mue des oisillons. Les résultats et des évaluations comparatives de cette étude ont montré que P. fasciiventer, comparéà ses congénères des régions tempérées comme la mésange charbonnière Parus major, la mésange nonnette Parus palustris, la mésange huppée Parus cristatus, la mésange noire Parus ater et la mésange bleue Parus caeruleus, élevait de plus petites nichées et avait une plus longue durée de nidification. Les résultats ont aussi révélé que cette espèce est capable d'élever plus d'une nichée au cours d'une même saison de reproduction et apportent de nouvelles preuves du fait que c'est une espèce qui pratique la reproduction coopérative. Les parents participaient de façon équitable à l'élevage des jeunes, un signe de parenté directe chez cette espèce. [source] Revision of Afrotropical Monolepta species (Coleoptera, Chrysomelidae, Galerucinae) Part III: Species with red elytra and yellow prothorax, including descriptions of new species,MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE IN BERLIN-DEUTSCHE ENTOMOLOGISCHE ZEITSCHRIFT, Issue 1 2002Thomas Wagner Abstract Material of Afrotropical Monolepta Chevrolat, 1837 which are characterized by red elytra, metathorax and abdomen, and a yellow head, prothorax (including pronotum) and mesothorax, is revised. Six new species are described: Monolepta budongoensis sp. n. and Monolepta congoensis sp. n. distributed from Cameroon eastwards to the Albertine Rift in western Uganda; Monolepta decellei sp. n. distributed from Sierra Leone to Ghana; Monolepta alwineae sp. n. from Liberia and Cameroon, Monolepta tessmanni sp. n. from Nigeria and Cameroon, and Monolepta heinrichi from northern Tanzania. Material of Monolepta conradi Jacoby, 1899 from west Africa, Monolepta alluaudi Laboissière, 1920 (= Monolepta montana Bryant, 1953 syn. n.) from eastern Africa, and Monolepta umbrobasalis Laboissière, 1940 and Monolepta wittei Laboissiàre 1940 from the Albertine Rift, is revised. Lectotypes are designated for M. alluaudi, M. montana, M. wittei and M. umbrobasalis. Distribution maps and an identification key are given. [source] Chimpanzee seed dispersal quantity in a tropical montane forest of RwandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2009Nicole D. Gross-Camp Abstract We describe chimpanzee seed dispersal in the tropical montane forest of Nyungwe National Park (NNP), Rwanda, for a total of three years from January 1998 through May 2000 and May 2006 through March 2007. Relatively few studies have examined chimpanzee seed dispersal in montane communities where there are generally fewer fruiting tree species than in lowland forests. Such studies may reveal new insights into chimpanzee seed dispersal behaviors and the role that they play in forest regeneration processes. Chimpanzees are large-bodied, highly frugivorous, and tend to deposit the seeds of both large- and small-seeded fruits they consume in a viable state. We found that chimpanzees dispersed a total of 37 fruiting species (20 families) in their feces, 35% of which were large-seeded trees (,0.5,cm). A single large-seeded tree, Syzygium guineense, was the only species to be dispersed in both wadges and feces. Based on phenological patterns of the top five large-seeded tree species found in chimpanzee feces, our results indicate that chimpanzees do not choose fruits based on their availability. There was, however, a positive relationship between the presence of Ekebergia capensis seeds in chimpanzee feces and S. guineense seeds in chimpanzee wadges and their respective fruit availabilities. Our data reveal that proportionately fewer chimpanzee fecal samples at NNP contained seeds than that reported in two other communities in the Albertine Rift including one at mid-elevation and one in montane forest. As in other chimpanzee communities, seeds of Ficus spp. were the most common genus in NNP chimpanzee feces. Our data do not support previous studies that describe Ficus spp. as a fallback food for chimpanzees and highlights an intriguing relationship between chimpanzees and the large-seeded tree species, S. guineense. Am. J. Primatol. 71:901,911, 2009. © 2009 Wiley-Liss, Inc. [source] Speciation mirrors geomorphology and palaeoclimatic history in African laminate-toothed rats (Muridae: Otomyini) of the Otomys denti and Otomys lacustris species-complexes in the ,Montane Circle' of East AfricaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009PETER J. TAYLOR We adopted an integrated systematic approach to delimit evolutionary species and describe phylogeographic, morphometric and ecological relationships in Otomys denti (from the Albertine Rift, Southern Rift in Malawi and the northern Eastern Arc Mountains) and Otomys lacustris (from the Southern Rift in Tanzania and Zambia, and the southern Eastern Arc Mountains). Molecular [cytochrome (cyt) b sequences, 1143 bp, N = 18], craniometric (classical, N = 100 and geometric, N = 60) and ecological (Partial Least Squares regression of shape and ecogeographic variables) approaches show a profound, parallel disjunction between two groups: (1) Eastern Arc and Southern Rift (including the Malawi Rift) (O. lacustris and Otomys denti sungae) and (2) Albertine Rift (Otomys denti denti and Otomys denti kempi) taxa. Within both groups, cyt b sequences or craniometric analysis provided evidence for the differentiation of both southern and northern Eastern Arc from Southern Rift lineages (across the so-called Makambako Gap). Within the Albertine Rift (denti,kempi) lineage, populations from individual mountain ranges differed significantly in skull shape (but not size), but were similar genetically. Over-reliance in the past on very few morphological characters (e.g. number of molar laminae) and a polytypic species concept has obscured phylogenetic relationships and species discrimination in this group. We recognize at least three species in this group, and distinct lineages within two of these species. Each species or lineage was endemic to one of three regions: the Albertine Rift, the Malawi Rift or the Eastern Arc. Our result echo conclusions of recent studies of other mammalian and bird taxa and reflect the geomorphology and palaeoclimatic history of the region. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 913,941. [source] | ||||||||||