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AFRICA ENVIRONMENT OUTLOOK 2
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OUR ENVIRONMENT, OUR WEALTH
CHAPTER 7
BIODIVERSITY Lead Authors: Robert J. Scholes, Wolfgang Kuper, Reinette Biggs Contributing Authors: Evans Mwangi, Jeanny Raharimampionona, Peter Lowry, ElHadji Sene, Peter Ashton, Stephen Blake, Christopher O. Justice
REGIONAL SYNTHESIS
Broad geographical patterns Ecosystems are broadly arranged in a latitudinal
Biodiversity
for
pattern (White 1983), with increasing species
development and improving human well-being. It is the
offers
multiple
opportunities
richness towards the equator (Mutke and Barthlott
basis for essential environmental services upon which
2005). However, plant species richness is also high in
life on Earth depends. Thus, its conservation and
the winter-rainfall Mediterranean climate regions of
sustainable use are of critical importance.
Northern Africa and the southern Cape (Cowling and
The opportunities and challenges associated with
others 1996). In between are the subtropical deserts,
biodiversity typically apply over large geographical
which are generally a zone of lower diversity: for
extents, although one or two issues may be more
example, a vast part of the Sahara, the Ténéré, is
important at any given location. To avoid repetition,
home to only 20 plant species in an area of about
particular issues are highlighted in the sub-regional
200 000 km2. Overlaid on these latitudinal patterns
sections, not because they are restricted to those areas,
are pockets of rich biodiversity with small distribution
but
there.
ranges, particularly in tropical montane areas
Deforestation is discussed under Central Africa, while
(Rahbek 1995). From Ethiopia to the Cape,
relations between protected areas and adjacent
mountains contain several centres of endemism for
populations are dealt with under Eastern Africa.
birds, mammals, and plants (Fjeldsa and Lovett
Riparian biodiversity is discussed in Northern Africa,
1997, de Klerk and others 2002). One of the most
climate change and invasive alien species (IAS) in
globally important centres of endemism is the coastal
Southern Africa, desertification in Western Africa, and
mountain range in the eastern part of Madagascar
endemism in the Western Indian Ocean (WIO) islands.
(Goodman and Benstead 2003).
because
they
are
best
illustrated
Habitat degradation and resource overexploitation are
The increasing richness of plants and vertebrates
discussed in this regional synthesis, because they are
toward the equator is related primarily to climatic
overwhelmingly important as drivers of biodiversity loss
factors, such as water availability (Mutke and others
throughout Africa.
2001), however the diversity of land variations, such as topographic, is also important. There are
INVENTORY OF RESOURCES
exceptions to this: some areas with harsh climates
Africa is well endowed with both variety and abundance
including, the Namib Desert and the Karoo in the
of living things, together referred to as biological
west of South Africa have an estimated 4 500 plant
diversity, or biodiversity. That biodiversity, with some
species, a third to one-half of which are endemic
exceptions, is currently in a better condition than in
(Davis and others 1994).
many parts of the world. Biodiversity can be considered at three major levels:
Spatial patterns of diversity vary for different species, and the diversity and abundance of different
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The genetic variation within populations;
species influence each other. For example, the Cape is a
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The number, relative abundance and uniqueness of
centre of plant diversity of global importance, but not a
species; and
centre of diversity for mammals, birds, snakes and
The variety, extent and condition of ecosystems.
amphibians (Figure 1). The Central Zambezian Miombo
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