The vegetation of Africa. A descriptive memoir to accompany the Unesco / AETFAT / UNSO

354 Pages·2017·26.57 MB·English

by  White F.

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Natural resources research XX
Other titles in the series
Natural resources research
I. A review of the natural resources of the African
continent
II. Bibliography of African hydrology
III. Geological map of Africa with explanatory note
IV. Review of research on latérites
V. Functioning of terrestrial ecosystems at the
primary production level. Proceedings of the
Copenhagen Symposium
VI. Aerial surveys and integrated studies. Proceed­
ings of the Toulouse Conference
VII. Agroclimatological methods. Proceedings of the
Reading Symposium
VIII. Proceedings of the Symposium on the Granites
of West Africa: Ivory Coast, Nigeria, Cameroon,
March 1965
IX. Soil biology. Reviews of research
X. Use and conservation of the biosphere
XI. Soils and tropical weathering. Proceedings of
the Bandung Symposium, 16 to 23 November
1969
XII. Natural resources of humid tropical Asia
XIII. Computer handling of geographical data
XIV. Tropical forest ecosystems. A state-of-knowl-
edge report
XV. Review of research on salt-affected soils
XVI. Tropical grazing land ecosystems. A state-of-
knowledge report
XVII. Vegetation map of South America: explanatory
notes
XVIII. Case studies on desertification
XIX. Solar electricity
The vegetation
of Africa
A descriptive memoir
to accompany the Unesco/AETFAT/UNSO
vegetation map of Africa
by F. White
Unesco
d Oi '5 Z.^'l / 2eif\ odo. 2*1
/
Published in 1983 by the United Nations
Educational, Scientific and Cultural Organization,
7 Place de Fontenoy, 75700 Paris
Printed by Courvoisier S.A., 2300 La Chaux-de-Fonds
The designations employed and the presentation of the material
in this publication do not imply the expression of any opinion
whatsoever on the part of Unesco, AETFAT or UN SO
concerning the legal status of any country or territory, or of its
authorities, or concerning the delimitations of the frontiers of
any country or territory.
ISBN 92-3-101955-4
© Unesco 1983
Printed in Switzerland
Preface
The new vegetation map of Africa has been compiled vegetation with that of other continents, whereas in the
by the Vegetation Map Committee of the Association text it is possible to deal effectively with complicated
pour l’Étude Taxonomique de la Flore de l’Afrique Tro­ spatial and dynamic relationships.
picale (AETFAT) in collaboration with Unesco and the While the legend of the map is composite (English
United Nations Sudano-Sahelian Office (UNSO). It and French), this accompanying memoir, because of its
comprises three map sheets at a scale of 1:5000000, a length, has been prepared in separate English and
legend, and the present accompanying memoir. French versions. The memoir aims to provide a succinct
An earlier AETFAT Vegetation Map of Africa South though comprehensive account of the vegetation of the
of the Sahara was published in 1958 with financial sup­ African mainland, Madagascar and the other offshore
port from Unesco. It soon went out of print, and at the islands. Brief introductory chapters deal with geology,
fifth plenary meeting of AETFAT held in Genoa and climate, soils, animals, fire, land use and conservation.
Florence in 1963 a small committee was asked to look Their purpose is merely to provide an entrée to the
into the possibility of preparing a new edition. At about specialist literature and to introduce important topics
this time, Unesco had convened a Standing Committee which recur elsewhere in the main text.
on Classification and Mapping of Vegetation on a The vegetation of the main floristic regions is
World Basis, and had initiated a programme of mapping described individually in twenty-two chapters, which
the world’s vegetation at a scale of 1:5000000. In this comprise the greater part of the text. For each region the
connection, AETFAT was invited to participate in the salient features of the flora, geology and climate are also
preparation of a new and more detailed vegetation map described, and a black-and-white map is provided. The
of the whole of Africa as part of the world series. latter illustrates topographic features mentioned in the
It was originally intended that all the maps in this text and summarizes the regional climate by means of
series should use a uniform legend and colour scheme, climatic diagrams. For each of the main vegetation
but, because of the complexity of the subject-matter and types, references to source materials and other impor­
the diversity of approaches, this objective has not been tant publications, published photographs and profile
fully achieved. Hence, the map of Africa differs in some diagrams (if available), as well as major synonymy, are
important respects from the Unesco-FAO Vegetation given.
Map of the Mediterranean Basin and the Unesco Vegeta­ Publication of the Vegetation Map of Africa forms
tion Map of South America. The classification used for part of Unesco’s long-term programme for the synthesis
the African map also diverges in some respects from that and diffusion of information on natural resources. The
recommended in the Unesco publication International map thus complements other maps such as the vegeta­
Classification and Mapping of Vegetation (Ecology and tion maps of the Mediterranean Basin and of South
Conservation Series No. 6, 1973). It is based almost America, the FAO-Unesco Soil Map of the World or the
entirely on physiognomy and floristic composition of small-scale map showing the world distribution of arid
the vegetation, and not on climate, although a few com­ regions. It is also related to a number of other Unesco
parative climatic terms such as moist and dry are initiatives for synthesis of information at regional and
occasionally used in the designation of the mapping international levels in order to promote the integrated
units. Otherwise, vegetation and climate are dealt with management of natural resources. Mention might thus
separately, and separate climatic maps are given in the be made of A Review of the Natural Resources of the
text for each of the major phytogeographic regions. African Continent (1963), the more recent Unesco-
A feature of the Unesco/AETFAT/UNSO Vegeta­ UNEP-FAO state-of-knowledge reports on tropical
tion Map of Africa is that, in the legend, the mapping forest ecosystems (1978) and tropical grazing land eco­
units are grouped in the traditional manner according to systems (1979), and a series of national case studies on
physiognomy, whereas in the text, here, they are grouped desertification (1980). Several issues in the Man and the
according to the floristic regions in which they occur. Biosphere (MAB) Technical Notes Series also deal with
There are thus two interconnected classifications, which problems of natural resources and their management in
can be used independently but are fully cross-refer­ the African region, including a review of ecological
enced. The legend permits easy comparison of African approaches to land use in the Sahel (MAB Technical
Notes 1, 1975), a study on traditional strategies and Nations Trust Fund for Sudano-Sahelian Activities
modem decision-making in the management of natural established by the Secretary-General for that purpose;
resources in Africa (MAB Technical Notes 9, 1978) and (c) managing the Trust Fund and implementing, from
an analysis of trends in research and in the application the resources of the Fund, in accordance with the
of science and technology for arid-zone development relevant rules and regulations of the United Nations,
(MAB Technical Notes 10, 1979). projects not undertaken bilaterally or multilaterally;
The United Nations Sudano-Sahelian Office and (d) monitoring, reporting and disseminating know­
(UNSO) was established by the Secretary-General of ledge on drought-related and desertification-control
the United Nations in 1973, in the aftermath of the programmes.
severe 1968-73 drought which devastated the economy As is shown in Figure 1 (see page 12), the Sudano-
and social life of the Sahelian region, to initiate and Sahelian region extends over a large portion of Africa.
assist in the implementation of the medium- and long­ Consequently, it is hoped that the information contained
term recovery and rehabilitation programme in the eight in the Vegetation Map of Africa and in the accompany­
countries of the area, namely, Cape Verde, Chad, Gam­ ing memoir will provide a synthesis of knowledge on
bia, Mah, Mauritania, Niger, Senegal and Upper Volta. African vegetation that will be useful as a source of
Since that time, UN SO has developed into the principal reference in land-use planning as well as in training for
body and central co-ordinating point of the United the purposes of drought recovery and rehabilitation and
Nations system mandated by the General Assembly and of desertification control.
other United Nations organs (a) to assist the eight The task of preparing the map and memoir has been
drought-stricken Sahelian countries—members of the a very long and complex one, and Unesco expresses its
Permanent Inter-State Committee for Drought Control sincere thanks to the AETFAT Vegetation Map
in the Sahel (CILSS)—in the implementation of their Committee in seeing the work through to fruition. The
medium and long-term recovery and rehabilitation pro­ committee was made up of the following specialists:
grammes; and (b) to act as the arm of the United A. Aubréville, L.A.G. Barbosa, L.E. Codd, P. Duvi-
Nations responsible for assisting, on behalf of the gneaud, H. Gaussen, R.E.G. Pichi-Sermolli, H.Wild and
United Nations Environment Programme (UNEP), F. White (Secretary). In publishing the new Vegetation
eighteen countries of the Sudano-Sahelian region in the Map of Africa, Unesco is especially grateful to Mr Frank
implementation of the Plan of Action to Combat Deser­ White of Oxford University (United Kingdom), who
tification, as a joint UNDP/UNEP venture (Djibouti, compiled the vegetation map on behalf of the AETFAT
Ethiopia, Guinea, Guinea-Bissau, Kenya, Nigeria, Vegetation Map Committee and who is the author of the
Somalia, Sudan, Uganda and the United Republic of present memoir. The views expressed herein are those of
Cameroon, in addition to the eight countries mentioned the author and are not necessarily shared by Unesco and
above). byUNSO.
UNSO’s work, undertaken in close collaboration Unesco also thanks the Oxford University Press for
with the Sudano-Sahelian countries, CILSS and the the preparation of successive proofs of the map.
respective United Nations agencies, is focused primarily In finalizing the map and memoir, an attempt has
on: (a) assisting the countries and CILSS in the plan­ been made to use up-to-date forms of geographic names.
ning and programming of priority projects and pro­ However, the designations employed and the delimita­
grammes in the field of drought-related medium- and tions of frontiers on the map and in the accompanying
long-term recovery and rehabilitation activities and text do not imply the expression of any opinion what­
desertification control; (b) providing assistance in the soever on the part of Unesco or UNSO concerning the
mobilisation of the necessary resources for implement­ legal or constitutional status of any country, territory,
ing such projects and programmes, either on bilateral or city or area or of its authorities, or concerning the
multilateral bases, or by contributions to the United delimitation of its frontiers or boundaries.
Contents
Introduction 9
Acknowledgements 13
List of former names of countries 15
Part One Environment, land use and conservation
1. Geology and physiography 19
2. Climate and plant growth 23
3. Soils 26
4. Animals 29
5. Fire, land use and conservation 32
Part Two Regional framework, classification and mapping units
Introduction 37
6. Regional framework 39
7. Classification 44
8. Mapping units 56
Part Three Vegetation of the floristic regions
Introduction 69
THE AFRICAN MAINLAND
I. The Guineo-Congolian regional centre of endemism 71
II. The Zambezian regional centre of endemism 86
III. The Sudanian regional centre of endemism 102
IV. The Somalia-Masai regional centre of endemism 110
V. The Cape regional centre of endemism 131
VI. The Karoo-Namib regional centre of endemism 136
VII. The Mediterranean regional centre of endemism 146
Vili/IX. The Afromontane archipelago-like regional centre of endemism
and the Afroalpine archipelago-like region of extreme floristic impoverishment 161
X. The Guinea-Congolia/Zambezia regional transition zone 170
XI. The Guinea-Congolia/Sudania regional transition zone 175
XII. The Lake Victoria regional mosaic 179
XIII. The Zanzibar-Inhambane regional mosaic 184
XIV. The Kalahari-Highveld regional transition zone 190
XV. The Tongaland-Pondoland regional mosaic 197
XVI. The Sahel regional transition zone 203
XVII. The Sahara regional transition zone 216
XVIII. The Mediterranean/Sahara regional transition zone 225
MADAGASCAR AND OTHER OFFSHORE ISLANDS
XIX. The East Malagasy regional centre of endemism 234
XX. The West Malagasy regional centre of endemism 240
XXI. Other offshore islands 244
AZONAL VEGETATION
XXII. Mangrove, halophytic and fresh-water swamp vegetation 260
Glossary and index of vernacular names of vegetation types and habitat 269
Geographical bibliography 271
Alphabetical bibliography 275
Index of plant names 325
Introduction
The new Vegetation Map of Africa and its accompany­ The purpose of the map is not to provide detailed
ing text is the fruit of some fifteen years of co-opera­ information on any particular area for the benefit of
tion between Unesco and AETFAT (Association residents in that area, since that information is usually
pour l’Étude Taxonomique de la Flore de l’Afrique available locally in published or unpublished form and
Tropicale). is also inappropriate on maps of this scale. Rather, the
In 1965 the AETFAT Vegetation Map Committee, purpose is to indicate to local residents in broad terms
consisting of A. Aubréville, L. A. G. Barbosa, L. E. Codd, the manner in which the main features of their local
P. Duvigneaud, R.E.G. Pichi-Sermolli, H. Wild and vegetation can be related to the main features of African
F. White (Secretary), to which the late H. Gaussen was vegetation as a whole. Another major objective is to pro­
subsequently co-opted, was asked to collaborate with vide a framework on a continental scale within which
Unesco in the preparation of a new vegetation map of more detailed local studies can be conducted and
Africa as part of the latter’s programme of mapping the compared. Inevitably, in simplifying larger-scale maps
world’s vegetation at a scale of 1:5000000. arbitrary decisions cannot be avoided and deliberate
The materials used in compiling this map turned out omissions must be made. This should be borne in mind
to be exceedingly diverse. Those used for the first draft by users of the map, especially those seeking local detail.
included: It is for considerations such as these that some features
of altitudinal zonation have been deliberately sup­
1. Original contributions by Duvigneaud, Pichi-Sermolli and pressed. It would have been cartographically possible to
Gaussen for Zaire, the Ethiopian region, and the Maghreb have shown a more complete and accurate zonation but
and Madagascar respectively. the small gain in factual content would not have been
2. Large-scale maps which were being prepared for indepen­ commensurate with the effort and costs involved.
dent publication elsewhere by Wild & Barbosa for the
A few years elapsed between the completion of the
Flora Zambesiaca region (1:2 500000) and by Barbosa for
first draft of the map and its publication. This time was
Angola (1:2 500000).
put to good use since it provided many opportunities
3. The remarkably detailed and accurate map of the Veld
types of South Africa (1:1500000) by Acocks. Codd for testing the accuracy of the map. This was done in
advised on the adaptation and simplification of this work different ways, as follows:
for the present purpose.
4. Several published and unpublished maps of parts of franco­ 1. Several ecologists, travelling extensively in Africa, have
phone Africa communicated by Aubréville. been able to check the map against vegetation on the
5. For much of the remainder of Africa, a large number of ground. I, myself, in the course of three journeys in East,
vegetation maps at various scales, which had been prepared Central and Southern Africa, undertaken for other pur­
for a wide variety of purposes. poses, have been able to check the accuracy of several
6. For the few parts of Africa without vegetation maps of any pattem lines. The Maghreb was also specifically visited to
description, correspondence with a host of local specialists, check the map and collect information for the accompany­
many of whom are members of AETFAT, has supplied the ing text.
missing information. 2. Earlier drafts of the map were exhibited at the plenary con­
gresses of AETFAT held in Munich in 1970 and Geneva in
I have been responsible for attempting to standardize 1974, when members of AETFAT, whose collective experi­
the source materials and weave them into a coherent ence, which embraces the whole of Africa, were invited to
comment on the map. By this means several inaccuracies
whole. In doing this I have continued to receive the
were avoided.
unstinted help of the committee members and many
3. For those parts of Africa I have not visited a collection of
others, but I must bear full responsibility for the final
vegetation photographs, published and unpublished, was
presentation and the imperfections which remain. assembled in order to check whether the physiognomy they
The map and the descriptive memoir cover not only portray agrees with that one would expect from the map.
the whole of Africa and the large island of Madagascar,
but also all ecologically important islands in the eastern All this checking has led to some significant corrections,
South Atlantic and western Indian Oceans, though space but for much of Africa the accuracy of the map, within
could only be found for a very brief treatment. the objectives set out above, was confirmed. For a few