Soils of the lowland forests of West and Central Africa

1996 ◽  
Vol 104 ◽  
pp. 15-29 ◽  
Author(s):  
A. S. R. Juo ◽  
L. P. Wilding
Keyword(s):  
East Africa ◽  
Central Africa ◽  
Congo Basin ◽  
The West ◽  
Forest Zone ◽  
Lower Elevation ◽  
Lowland Forests ◽  
West And Central Africa ◽  
Hydrological Cycles ◽  
Great Rift Valley

The forest zone of West and Central Africa comprises the coastal and adjacent inland regions bounded the semi-deciduous forests in the west and the equatorial forests in central Africa and the Congo basin. Sedimentary plains, developed mostly on weathered sandy materials, lie along the coastal stretches and cover vast areas of the Congo basin. Behind the coast the plain rises gradually to hills and plateaus of much lower elevation than those of the highlands of East Africa. Two great rivers, the Niger and the Congo, which discharge huge volumes of fresh water to the Atlantic Ocean, are major contributors to the hydrological cycles of the rain forests ecosystems of the Guinea–Congo Region. The Niger originates from the forested highlands of Guinea and discharges its waters into the Bight of Benin by way of a large delta in southern Nigeria. The Congo basin occupies an immense area of 750 000 km2, surrounded by Pre-Cambrian uplands. The alluvial floor of the saucer-shaped basin is flat, and marshes and swamps comprise a large proportion of the total area. The highlands and plateaus along the rim are low to the west and north and higher to the south. To the east, they merge with the mountains of the Great Rift Valley of East Africa (Gann & Duignan 1972; Hance 1975; Grove 1978; Hamilton 1989).

scholarly journals Response of African humid tropical forests to recent rainfall anomalies

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120306 ◽  
Author(s):  
Salvi Asefi-Najafabady ◽  
Sassan Saatchi
Keyword(s):  
West Africa ◽  
Tropical Forests ◽  
Large Scale ◽  
Forest Canopy ◽  
Central Africa ◽  
Extreme Rainfall ◽  
Research Unit ◽  
Congo Basin ◽  
West And Central Africa ◽  
Rainfall Anomalies

During the last decade, strong negative rainfall anomalies resulting from increased sea surface temperature in the tropical Atlantic have caused extensive droughts in rainforests of western Amazonia, exerting persistent effects on the forest canopy. In contrast, there have been no significant impacts on rainforests of West and Central Africa during the same period, despite large-scale droughts and rainfall anomalies during the same period. Using a combination of rainfall observations from meteorological stations from the Climate Research Unit (CRU; 1950–2009) and satellite observations of the Tropical Rainfall Measuring Mission (TRMM; 1998–2010), we show that West and Central Africa experienced strong negative water deficit (WD) anomalies over the last decade, particularly in 2005, 2006 and 2007. These anomalies were a continuation of an increasing drying trend in the region that started in the 1970s. We monitored the response of forests to extreme rainfall anomalies of the past decade by analysing the microwave scatterometer data from QuickSCAT (1999–2009) sensitive to variations in canopy water content and structure. Unlike in Amazonia, we found no significant impacts of extreme WD events on forests of Central Africa, suggesting potential adaptability of these forests to short-term severe droughts. Only forests near the savanna boundary in West Africa and in fragmented landscapes of the northern Congo Basin responded to extreme droughts with widespread canopy disturbance that lasted only during the period of WD. Time-series analyses of CRU and TRMM data show most regions in Central and West Africa experience seasonal or decadal extreme WDs (less than −600 mm). We hypothesize that the long-term historical extreme WDs with gradual drying trends in the 1970s have increased the adaptability of humid tropical forests in Africa to droughts.

Contributions to the Petrology of British East Africa

1903 ◽  
Vol 13 (61) ◽  
pp. 228-263 ◽  
Author(s):  
G. T. Prior
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Volcanic Rocks ◽  
Central Africa ◽  
British Museum ◽  
Basaltic Rocks ◽  
Basement Rocks ◽  
Great Rift Valley ◽  
Rock Specimens

The following notes on the petrology of British East Africa are the result of an examination of rock-specimens collected by Professor J. W. Gregory on his well-known expedition from Mombasa to Mt. Kenya and Lake Baringo in 1892-3, and of rock-collections from the Uganda Protectorate which have been recently presented to the British Museum by Sir Harry Johnston.The collections include examples of the Archaean gneisses, schists, and granites which constitute the prevailing basement rocks of Central Africa; of ferruginotls schists, coarse sandstones, and quartzites belonging to the Palaeozoic Karagwe series ; and of an interesting series of Tertiary volcanic rocks comprising phonolites, phonolltic traehytes, riebeckite-rhyolites, kenytes, and basalts from the volcanoes of the Great Rift Valley, as well as of nephelinites and basaltic rocks containing melilite and perofskite from Mr. Elgon.

scholarly journals Promising High-Yielding Tetraploid Plantain-Bred Hybrids in West Africa

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Abdou Tenkouano ◽  
Niéyidouba Lamien ◽  
Josephine Agogbua ◽  
Delphine Amah ◽  
Rony Swennen ◽  
...  
Keyword(s):  
West Africa ◽  
Research And Development ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Central Africa ◽  
International Institute ◽  
The West ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
West And Central Africa

The devastating threat of black leaf streak disease caused by Pseudocercospora fijiensis on plantain production in West Africa spurred the development of resistant hybrids. The goal of this research and development (R&D) undertaken was assessing the development and dissemination of two plantain hybrids PITA 3 and FHIA 21 bred in the 1980s by the International Institute of Tropical Agriculture (IITA, Nigeria) and the Fundación Hondureña de Investigación Agrícola (FHIA, Honduras), respectively. In Côte d’Ivoire, plantain growers selected PITA 3 and FHIA 21 based on their improved agronomic characteristics and, between 2012 and 2016, they were massively propagated and distributed to farmers in Benin, Burkina Faso, Côte d’Ivoire, and Togo under the West Africa Agricultural Productivity Program (WAAAP) coordinated by the West and Central Africa Council for Agricultural Research and Development (CORAF). In 2016, the Centre National de Recherche Agronomique in Côte d’Ivoire included the hybrids in the improved cultivar directory. This R&D activity illustrates how three decades of crossbreeding, selection, and distribution led to local acceptance. It also highlights how a CORAF-led partnership harnessed CGIAR research for development. The dissemination and acceptance of these plantain hybrids will enhance the sustainable intensification in plantain-based farming systems across the humid lowlands of West and Central Africa.

scholarly journals African Music and Human Experience in the 21st Century with Particular Reference to Nigeria

2019 ◽  
Vol 5 (02) ◽  
Author(s):  
Dr Sunday Nnamani
Keyword(s):  
21St Century ◽  
Central Africa ◽  
Traditional Music ◽  
Human Experience ◽  
The Other ◽  
Musical Experience ◽  
African Music ◽  
The West ◽  
Education Politics ◽  
West And Central Africa

Music in Africa portrays the totality of its cultural product. It cannot be separated from culture because in culture there is music and in music there is culture. This paper titled “African Music and Human experience in the 21st century with particular reference to Nigeria” examined the traditional music of the continent as it is passed down orally from one generation to the other, it looked at it on the basis of regions and later zeroed down to the West and Central Africa where Nigeria is located. The problems of development of musical experience which include, socio-economic and technological problems, disunity, lack of recognition, education, politics, etc were examined. Also the relevance of music to human experiences presently were looked into with a view to salvaging the dilapidating image of the study/ and research into pure African music highlighted. A list of crusaders and scholars of African music were also enumerated in order to encourage others to join

scholarly journals Phylogeographic analysis reveals an ancient East African origin of the human herpes simplexvirus 2 dispersal out-of-Africa.

2022 ◽  
Author(s):  
Jennifer L. Havens ◽  
Sebastien Calvignac-Spencer ◽  
Kevin Merkel ◽  
Sonia Burrel ◽  
David Boutolleau ◽  
...  
Keyword(s):  
East Africa ◽  
Molecular Clock ◽  
Central Africa ◽  
Human Migration ◽  
Evolutionary Rates ◽  
Human Herpes ◽  
Phylogeographic Analysis ◽  
West And Central Africa ◽  
Out Of Africa ◽  
Competing Hypotheses

Human herpes simplex virus 2 (HSV-2) is a globally ubiquitous, slow evolving DNA virus. HSV-2 genomic diversity can be divided into two main groups: an African lineage and worldwide lineage. Competing hypotheses have been put forth to explain the history of HSV-2. HSV-2 may have originated in Africa and then followed the first wave of human migration out of Africa between 50-100 kya. Alternatively, HSV-2 may have migrated out of Africa via the trans-Atlantic slave trade within the last 150-500 years. The lack of HSV-2 genomes from West and Central Africa, combined with a lack of molecular clock signal in HSV-2 has precluded robust testing of these competing hypotheses. Here, we expand the geographic sampling of HSV-2 genomes in order to resolve the geography and timing of divergence events within HSV-2. We analyze 65 newly sequenced HSV-2 genomes collected from primarily West and Central Africa along with 330 previously published genomes sampled over a 47-year period. Evolutionary simulations confirm that the molecular clock in HSV-2 is too slow to be detected using available data. However, phylogeographic analysis indicates that all biologically plausible evolutionary rates would place the ancestor of the worldwide lineage in East Africa, arguing against the trans-Atlantic slave trade as the source of worldwide diversity. The best supported evolutionary rates between 4.2x10-8 and 5.6x10-8 substitutions/site/year suggest a most recent common ancestor for HSV-2 around 90-120 kya and initial dispersal around 21.9-29.3 kya. These dates suggest HSV-2 left Africa during subsequent waves of human migration out of East Africa.

scholarly journals The bushmeat boom and bust in West and Central Africa

Oryx ◽  
2002 ◽  
Vol 36 (3) ◽  
pp. 236-242 ◽  
Author(s):  
Richard F. W. Barnes
Keyword(s):  
Central Africa ◽  
Forest Resources ◽  
Human Populations ◽  
Forest Zone ◽  
Hunting Pressure ◽  
High Productivity ◽  
National Statistics ◽  
Boom And Bust ◽  
West And Central Africa ◽  
Non Linear Systems

Poor soils and high rainfall mean that the high productivity of the forests, an assumption that drives the development of the forest zone, is an illusion. The potential of the forests to produce meat, from wild or domestic herbivores, is limited. Growing human populations and shrinking forests accelerate pressures on forest resources faster than national statistics indicate. A simulation model demonstrates the effects of growing hunting pressure on one monkey and two duiker species. A version of this model that includes random variation shows that large harvests can be obtained for many years, but that a population collapse can happen suddenly; there is no period of gradually declining harvests. The accelerating hunting pressure in a zone of low productivity, shrinking habitat for monkeys and antelopes, the dynamics of non-linear systems, and natural environmental variation that affects reproduction and survival will lead to a collapse of hunted populations across the forest zone. We are now seeing the bushmeat boom and soon we will see the bushmeat bust.

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