Biodiversity of Angola pp Cite as. Angola is a large country of 1,, km 2 on the southwest coast of Africa. These range from the ultra-desert of the Namib, through arid savannas of the coastal plains to a biologically diverse transition up the steep western Angolan Escarpment.
Congolian rainforests are found in Cabinda and along the northern border with the Democratic Republic of Congo, with outliers penetrating southwards along the Angolan Escarpment, or up the tributaries of the Congo Basin. Above the escarpment, high mountains rise to m above sea level, with isolated remnants of Afromontane forests and grasslands.
Rainfall varies from lower than 20 mm per year in the southwest to over mm in the northwest and northeast. This chapter presents a general outline of the physical geography and biodiversity characteristics of Angola, as background to the chapters that follow.
Colonial records of climatic variables Silveira are used in the absence of recent time series. This outline also draws on the recent regional geographies of Angola by Mendelsohn and co-workers Mendelsohn et al. The chapter is also strengthened by material detailed in the specialist papers that form the core of this volume. It is bounded to the west by an arid km coastline along the Atlantic Ocean; to the north by the moist forest and savanna ecosystems of the Republic of Congo and the Democratic Republic of Congo DRC ; to the east by the moist savanna and woodland ecosystems of the DRC and Zambia; and by arid woodlands, savannas and desert along its km southern border with Namibia.
Topography of Angola, indicating provincial boundaries and capitals. The coastal lowlands, western escarpments, central highlands and plateaus, and the major drainage basins of the Cuanza, Congo and Zambezi rivers are clearly revealed. Geological profile from Luanda to Quisonde, scanned from the original manuscript produced by Friedrich Welwitsch during his expeditions between and He recognised five major erosional planation surfaces in western Angola at a time when geomorphology was evolving as a discipline, and he was recognised by King as one of the founders of peneplanation theory.
Geomorphological studies in Angola continued from the s to s by Portuguese researchers, including Marques , Feio and Amaral , whose work is summarised by Costa More recent research, in particular that on the evolution and of the major tectonic and erosional patterns across southern Africa Cotterill , ; Cotterill and De Wit and on the biogeography of the freshwater fishes of Angola Skelton provide a picture of a very dynamic landscape since the breakup of Gondwana in the late Cretaceous. These and other authors are providing an improved understanding of the processes of uplift, back-tilting, down-warping, deposition, erosion and river capture on the evolution of the Kalahari Basin.
The impacts of sea-level fluctuations and of the flow of the Congo River on coastal waters and on the erosional forces of the Congo Basin as it impacts on the Zambezi Basin are guiding our interpretation of the dramatic events shaping the faunal and floral patterns of today.
The interplay of geological and paleoclimatic drivers described by Cotterill , , through the pulsing of hot wet and cool dry episodes during the Plio-Pleistocene, was accompanied by the expansion and contraction of forest and savanna habitats responding to climatic and fire regimes. The role of fire in shaping the landscapes of Angola — and particularly of the dominant miombo moist savanna biome — has become a topic of discussion in recent years Zigelski et al.
Maurin et al. They suggest that moist savannas pre-date the emergence of anthropogenic fire and deforestation, becoming a prominent component of tropical vegetation from the late Miocene ca. The further interpretation of these key drivers of evolution processes is fundamental to an improved understanding of the biogeography of Angola. Coastal Belt Faixa litoranea sensu Diniz.
This is a mostly continuous platform at 10— m above sea level, broken occasionally by broad river valleys. In contrast to the situation on the east coast of Africa at similar latitudes, the Angolan coastline is notable for the absence of coral reefs and coastal dune forests. Long sandbars stretch northwards from rivers such as the Cunene and Cuanza. Mudflats and mangroves occur at most river mouths from Lobito northwards, increasing in dimension and diversity towards the Congo.
Much of the coast is uplifted, resulting in sharp sea-cliffs of 10— m. In places as narrow as 10 km, the coastal belt is mostly of about 40 km width, broadening to km northwards of Sumbe and up the lower Cuanza. The coastal plains are composed mostly of fossiliferous marine sediments of the Cabinda, Cuanza, Benguela and Namibe geological basins.
The northern coastal platforms are covered by deep red Pleistocene sands terras de musseque of former beaches. Lying below the sands, and exposed over large areas, are Cretaceous to Miocene clays, gypsipherous marls, dolomitic limestones and sandstones.
Important beds of Cretaceous fossils occur at Bentiaba and Iembe, the latter including the sauropod dinosaur Angolatitan adamastor Mateus et al. The southernmost segment of the Coastal Belt includes the mobile and mostly vegetation-less dunes of the Namib Desert.
A broad transition belt lies between the coastal plains and the interior plateaus — variable in breadth and gradient. Over much of the zone, the transition advances up several steep steps of between and m. The geology of the Escarpment Zone is complex, comprising crystalline rocks of the Precambrian: granites, gneisses, schists, quartzites and amphibolites.
The Escarpment Zone also referred to as the Western Angolan Scarp includes very hilly country, with mountainous belts in the north, and some major inselbergs in the south, the most important of which is Serra de Neve, which rises to m from the surrounding plains and low hills. The mountains are of biogeographic importance for their montane grasslands, with some elements of the Cape flora, and relict patches of Afromontane forests and endemic bird assemblages Humbert ; Hall b ; Hall and Moreau ; Huntley and Matos ; Dean ; Mills et al.
Ancient Plateau Planalto Antigo. This extensive plateau drops eastwards from below the Marginal Mountain Chain and encompasses the headwaters of the Cunene, Cubango, Queve and Cutato rivers, comprising rolling landscapes with wetlands and low ridges with scattered granitic inselbergs. It drops from m in the west to m in central Angola. Lower Cunene Baixo Cunene. The gentle gradient of the eastern half forms the very clearly defined Cuvelai Basin, which drains as an ephemeral catchment into the Etosha Pan.
West of the Cunene the landscape is more broken, with pockets of Kalahari sands between low rocky hills. Upper Cuanza Alto Cuanza. The upper catchments of the Cuanza and its tributary the Luando, at altitudes between and m, form a distinct basin of slow drainage feeding extensive wetlands during the rain season. Malange Plateau Planalto de Malange.
A gently undulating plateau at — m, dropping abruptly, on its northeastern margin, some several hundred metres to the Baixa de Cassange and the Cuango drainage. The escarpment ravines hold important moist forest outliers such as at Tala Mungongo that deserve investigation. These gently dipping plains, mostly at — m, are being aggressively dissected by the many northward flowing, parallel tributaries of the Congo Basin.
The southern boundary of this Congo Peneplain is defined imperceptibly by the watershed between the Zambezi and Congo basins, lying at ca. Cassange Basin Baixa de Cassange. A wide depression, several hundred metres below the surrounding plateaus, is demarcated by abrupt escarpments to the west and the densely dendritic catchment of the Cuango to the northeast. The geological substrate comprises Triassic Karoo Supergroup sediments of limestone, sandstone and conglomerates. Within the Basin, several large tablelands — remnants of the old planation surface — rise above the depression as extensive plateaus flanked by sheer, m escarpments, exemplified by Serra Mbango, which awaits biological survey.
This is the vast peneplain draining deep Kalahari sands, with slow-flowing rivers that meander across the gently dipping plateau from m at the watershed with the Congo Basin to m at the frontier with Namibia.
Within this extensive peneplain, the Bulozi Floodplain occupies an area in excess of , km 2 in Angola and Zambia. The Calunda Mountains of eastern Moxico, composed of Precambrian schists and norites, dolorites, sandstones and limestones, rise to m above the Zambezi peneplain which lies at m.
The mountains form a striking contrast to the almost featureless landscape that stretches some km eastwards from Huambo to Calunda. Main geomorphological and landscape units of Angola. After Diniz Angolan river systems fall into two categories. First, coastal rivers drain the central and western highlands and flow rapidly westwards where they have penetrated the steep escarpment to the Atlantic Ocean.
Most of these coastal rivers are relatively short, are highly erosive and carry high sediment loads. Backward erosion by some of these has produced minor basins, such as the amphitheatres of the upper Queve and Catumbela. The biogeographic importance of the river captures associated with these systems, especially the Congo, Cuanza, and Cunene, have been profound, as described by Skelton Most of the coastal rivers south of Benguela are ephemeral.
The second major category of river systems is that of the vast interior plateaus. Many of these rivers arise in close proximity on either side of the gently undulating watershed between the Cuanza, Cassai Congo , Lungue-Bungo Zambezi , Cunene, and endorheic Cubango Okavango basins.
These rivers drain the vast and deep Kalahari sands, are slow moving and due to the filtering action of the sands, are crystal clear and nutrient poor. A separate ephemeral, endorheic system, the Cuvelai Basin, drains southwards into the Etosha Pan. The conservation importance of the Angolan river systems is of great significance, feeding as they do two wetlands Okavango and Etosha of global importance, and the still under-researched Bulozi Floodplain of Moxico.
Outline of the main soil types of Angola from Jones et al. The Kalahari Basin, extending across km from the Cape in the south to the Congo Basin in the north, and up to km in breadth, is reputedly the largest body of sand in the world. The sands have been deposited by wind and water over the past 65 million years. Composed of quartz grains that hold no mineral nutrients, and with very little accumulated organic matter, they are thus of very low fertility and water-holding capacity.
Waters passing through the vast catchments of the Congo, Cubango and Zambezi basins that drain the Kalahari are therefore extremely pure. The soils are mostly of low water-holding capacity. Because they are heavily leached in higher rainfall areas, the loss of mineral nutrients and organic matter results in low fertility.
They are characteristically reddish due to the oxidation of their high iron and aluminium content, which also accounts for the presence in many areas of ferricrete hardpan horizons a metre or two below the surface, impeding root and water penetration and resulting in the formation of extensive areas of laterite.
The natural vegetation types that cover both arenosols and ferralsols — predominantly miombo woodlands — are well adapted to these soil conditions and the untransformed landscape gives the appearance of great vitality and luxuriance. The diverse climatic and weather conditions experienced across Angola result from many atmospheric, oceanic and topographic driving forces.
First, the geographic position of Angola, stretching from near the Equator to close to the Tropic of Capricorn, across 14 degrees of latitude, accounts for the overall decrease in solar radiation received and thus annual mean temperatures experienced from north to south. The latitudinal decrease in mean annual temperature is illustrated by data from stations in the hot northwest and northeast Cabinda: Secondly, both temperature and precipitation are influenced by altitude.
The decrease in mean annual temperature can be illustrated from sites below the Chela escarpment to the highest weather station in the country: i. Although Angola is located in the tropics, it does not have a tropical climate. This is due to the influence of the Namib Desert, cold Benguela currents, and relief climate in the interior parts. In Angola, there are about one thousand religious communities.
They are mainly the Ovimbundu tribe of coastal and Central Highlands regions. The rest are Protestants, especially Kimbundu and Bakongo.
The Protestant denominations and Catholics do charity work; they provide medical care, education, and crop seeds among other valuables to the needy. Portuguese culture has only influenced religion and language. Different tribes in Angola maintain their own cultures but mixed culture is evident in cities since the colonial period.
The festivals were held in all provincial headquarters lasting twenty days. The country's southernmost point can be found in the Cuando Cubango Province. This part of Angola is very close to the town of Dirico, where Angola and Namibia connect. The easternmost point of Angola is located in the province of Moxico. While it is clear that Angola's extreme point in the east is on the border between Zambia and Angola, the exact location of this point remains unknown. The greatest level of precision that has been discovered so far is that the easternmost point is somewhere along the border's river.
As number eighty-five on the list of northernmost points ranked by proximity to the North Pole, Angola's most extreme point in the north is part of the Namibe Province. Since populations fluctuate, this number is likely to rise and fall on a daily basis.
The total population of Angola, as of , is roughly 31,, people. The population density of Angola can be found by dividing the population size by the total area.
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