The Vegetation of Egypt the Vegetation of Egypt

The Vegetation of Egypt The Vegetation of Egypt

M.A. Zahran In association with A.J. Willis

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ISBN 978-0-412'31510-7

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A catalogue record for this book is available from the British Library

Library of Congress Cataloging-in-Publication data Zahran, M.A The vegetation of EgyptlM.A. Zahran, AJ. Willis. p. cm. Includes bibliographical references and index. ISBN 978-0-412-31510-7 ISBN 978-94-015-8066-3 (eBook) DOI 10.1007/978-94-015-8066-3 1. Botany-Egypt-Ecology. 2. Phytogeography-Egypt. 3. Plant communities-Egypt. 1. Willis, AJ. (Arthur John), 1922- . II. Title. QK403.Z34 1992 92-2512 581. 962-dc20 CIP CONTENTS

About the authors vii Preface ix Foreword xi Introduction xiii 1 Egypt: the gift of the Nile 1 2 Physiography, climate and soil-vegetation relationships 4 2.1 Geological characteristics 4 2.2 Geographical characteristics 6 2.3 The climate of Egypt 7 2.4 Soil-vegetation relationships 9 3. The Western Desert 15 3.1 General features 15 3.2 The western Mediterranean coastal belt 16 3.3 The oases and depressions 52 3.4 Gebel Uweinat 111 4 The Eastern Desert 117 4.1 Geology and geomorphology 117 4.2 Ecological characteristics 118 5 The Sinai Peninsula 261 5.1 Geomorphology 261 5.2 Climate 267 5.3 Water resources 269 5.4 The vegetation 270 6 The Nile region 303 6.1 Geomorphology 303 6.2 Climate 308 6.3 Vegetation types 308 VI Contents 7 The history of the vegetation: its salient features and future study 365 7.1 The history of the vegetation 365 7.2 Future study of phytosociology and plant ecology 375 7.3 The main types of vegetation and its features: synopsis 377 References 380 Species index 395 Subject index 413 ABOUT THE AUTHORS

Professor Mahmoud Abdel Kawy Zahran was born in Samalut (Minya Province, Upper Egypt) on 15 January 1938. He graduated (BSc 1959) from the Faculty of Science, Cairo University where he got his MSc (1962) and PhD (1965) degrees in the field of plant ecology. Professor Zahran worked as research assistant and researcher in the National Research Centre (1959-1963) and Desert Research Institute (1963-1972) of Cairo. In October 1972 he was appointed Assistant Professor in the Faculty of Science, Mansoura University and promoted to the professorship of plant ecology in November 1976. He joined the Faculty of Meteorology and Environmental Studies of King Abdul Aziz University, Jeddah, Saudi Arabia from November 1977 to March 1983. For his scientific work in plant ecology, Professor Zahran received the State Prize of Egypt from the Academy of Scientific Researches and Technology (1983), the First Class Gold Medal of the Egyptian President (1983), the Diploma of the International Cultural Council of Mexico (1987) and the major Prize of Mansoura University in Basic Sciences (1991). Apart from this book, Professor Zahran is a co-author of four refer• ence books (Wet Coastal Ecosystems, 1977, Ecology of Halophytes, 1982, Dry Coastal Ecosystems, 1992 and Crop Stress, 1992) and two student books. He has published more than 65 papers dealing with the ecology of the vegetation in Egypt and Saudi Arabia. Emeritus Professor Arthur J. Willis, Ph.D., D.Sc., F.I. Biol, F.L.S., graduated in Botany at the University of Bristol, England, and joined the staff there in 1947 as Demonstrator. He subsequently became Junior Fellow in Physiological Ecology, Lecturer and Reader in Botany, but left Bristol in 1969 to become the Head of the Department of Botany of the University of Sheffield. Here he remained Head and also Honorary Director of the Natural Environment Research Council Unit of Comparative Plant Ecology until retirement in 1987. Professor Willis is the author of An Introduction to Plant Ecology (1971) and a contributor to a number of books, most recently (1990) the last edition of the Weed Control Handbook: Principles. He has Vlll About the authors written about a hundred papers in scientific journals, spanning the fields of plant ecology, the British flora, bryophytes, coastal systems, particularly sand dunes, plant physiology, especially nitrogen me• tabolism and water relations, and palaeobotany. He was a general editor of the extensive series of books titled Contemporary Biology, an editor of the Journal of Ecology and is the current editor of the Biological Flora of the British [sles. PREFACE

This book is an attempt to compile and integrate the information documented by many botanists, both Egyptians and others, about the vegetation of Egypt. The first treatise on the flora of Egypt, by Petrus Forsskäl, was published in 1775. Records of the Egyptian flora made during the Napoleonic expedition to Egypt (1778-1801) were provided by AR. Delile from 1809 to 1812 (Kassas, 1981). The early beginning of ecological studies of the vegetation of Egypt extended to the mid-nineteenth century. Two traditions may be re• cognized. The first was general exploration and survey, for which one name is symbolic: Georges-Auguste Schweinfurth (1836-1925), a German scientist and explorer who lived in Egypt from 1863 to 1914. The second tradition was ecophysiological to explain the plant life in the dry desert. The work of G. Volkens (1887) remains a classic on xerophytism. These two traditions were maintained and expanded in further phases of ecological development associated with the es• tablishment of the Egyptian University in 1925 (now the University of Cairo). The first professor of botany was the Swedish Gunnar Täckholm (1925-1929). He died young, and his wife Vivi Täckholm devoted her life to studying the flora of Egypt and gave leadership and inspiration to plant taxonomists in Egypt for some 50 years. She died in 1978. The second professor of botany in Egypt was F.W. Oliver (1929- 1932) followed by the British ecologist F.J. Lewis (1935-1947). This episode marked the beginning of plant ecological studies by Egyptian scientists in two principal traditions: ecophysiological and synecological studes of the vegetation. The pioneers are AM. Migahid, AH. Montasir and M. Hassib who started their scientific work in 1931. About 1950, two schools of research emerged. These were mainly concemed with a survey of natural vegetation and the phytosociological analysis of plant communities. One was centred in the University of Alexandria led by T.M. Tadros (1910-1972) who followed the Zürich-Montpellier School. The second is centred in the University of Cairo and led by M. Kassas who followed the Anglo-American school of phytosociology. During the last 30 years, researches in plant ecology continue with x Preface refined methodologies and creation of new research units in the several provincial universities opened in Egypt. We warmly thank Professor Dr M. Kassas, Faculty of Science, University of Cairo, for his great encouragement and assistance in the production of this book, and for supplying many references. We are also much indebted to Dr Sekina M. Ayyad for her help with the section on the history of the vegetation, to Dr P.D. Moore for his use• ful comments on this section, and to Professor L. Boulos, Dr T.A Cope and Professor M.N. EI-Hadidi for their kind assistance with nomen• clature. The valued sponsorship of this book by UNEP and UNESCO is highly appreciated and has much facilitated its production.

M.A Zahran AJ. Willis FOREWORD

Egypt is a cross-road territory with its Mediterranean front connect• ing it with Europe with which it has had biotic exchanges during the Glacials and the Interglacials, and today we know that routes of migratory birds converge through Egypt. Two highway corridors join Egypt with tropical Mrica and beyond: the Nile Valley and the basin of the Red Sea. The Sinai Peninsula is the bridge between Mrica and Asia. Its cultural and ethnic history bears testimony to complexities of this position, as does its natural history. Attempts to unravel the mysteries of its cultural history have involved scholars from all over the world, and collections of its legendary heritage abound in museums of the capitals of the world. The natural history of Egypt was not less fortunate, contributions of international scien• tists to biological, geological and geographical surveys of Egypt in• clude a wealth of research, and this book, compiled by two scholars from Mansoura and Sheffield, is a most welcome example of inter• national collaboration. The history of vegetation antedates that of human culture, but plant life as we see it today has been influenced in every way by human action, exploitation, destruction, husbandry, introductions, etc. An attempt to compile a comprehensive inventory of various aspects of plant growth and ecological relationships in plant communities requires indefatigable enthusiasm and stamina. The authors have both given of their time, energy and toil with infinite generosity, and achieved a formidable objective. The plan of the book is set in a sequence that makes it readable and that facilitates access to detailed description of sampIe areas. Intro• ductory parts are brief and the main space (Chapters 3-6) is devoted to addressing available information on plant life in the chief eco• geographic sections of the country: Western Desert, Eastern Desert, Sinai Peninsula and the Nile region. A final chapter refers to the history of the vegetation and to topics on which further investigation is required. With this structure the text will be most useful for stu• dents and for research workers interested in pursuing studies on the ecology and the geography of plant life in Egypt. It is hoped that it XlI Foreword will interest school teachers and encourage them to take their pupils out to the nearby fields and adjoining deserts. For Me, it is a very special pleasure, having now completed 50 years of studying plant life in Egypt, to welcome this book and to congratulate Professor Zahran and Professor Willis for their remark• able achievement and to thank them for the unremitting effort that they have both invested in this worthwhile work.

M. Kassas Cairo INTRODUCTION

Six zones of vegetation have been recognized by phytogeographers on aglobaI scale. Each zone is occupied by similar types of vegetation, with the same periods of growth and the same general adaptations to environment. The divisions are exclusively climatic and ecological; the systematic relations of the plants are not taken into consideration. These zones of vegetation are: the northern glacial zone, with a very short growth period (in the arctic and high altitudes); the northern zone of cold winters, with a growth period of 4-7 months; the north• ern zone of hot summers, comprising regions of the subtropics; the tropical zone, with no significant seasonal interruption of growth; and in the southern hemisphere the zone of the hot summers; and the cold zone. In the northern zone ofhot summers there is no real winter, but there may be some interruption of growth in January. Xerophytism is weIl marked, although some regions are wet. Forest, maquis, chaparral, steppe and prairie are common in this zone. As indicated by Hassib (1951), the vegetation of Egypt belongs to this northern zone of hot summers. According to Eig's system (1931-1932), Egypt comprises four floral provinces: 1. Mediterranean Province: This comprises the region around the Mediterranean Sea. It has mild winters with plentiful rain and dry summers. It is the region of evergreen maquis (except in Egypt) and forest associations. The northern Mediterranean coast of Egypt belongs here. 2. North African-Indian Desert Province: This is also known as the Saharo-Sindian Province. It encompasses the great desert from the Atlantic coast of Morocco to the deserts of Sind, Punjab and South Mghanistan. The air is extremely dry, temperatures are high, rainfaIl is low, salty ground is abundant, there are few species and individual plants and the vegetation is uniform. The greater part of Egypt belongs here. 3. Central Asiatic Province: This is also known as the Irano-Turanian Province. It comprises a large region stretching east towards China XIV Introduction and Japan, west to the Mediterranean, north to the Northern extratropical deserts and south to the North African-Indian deserts. There is little rain, rather long dry periods, great temperature differences, an almost complete absence of forest growth, and a rich occurrence of species and endemies. The mountain region of Sinai and certain enclave areas in the Eastern Desert, e.g. Galala mountains of Egypt, belong here. 4. African Forest and Steppe Province: This is also known as the Sudano--Deccanian Province. It comprises a belt of broad steppes and savannas from the Atlantic Ocean south of Sahara and north of the Equatorial Forest region, through Sonegambia to Eritrea and Ethiopia and through tropical Arabia and India, including the Deccan. There are tropical summer rains and dry and warm win• ters. The vegetation is dominated by, for example, tropical Acacias and the grasses Panicum and Andropogon. This is the region of steppes and savannas and the park forests which lose their leaves during the dry period. As an enclave the Gebel Elba mountainous region in the southeast of Egypt belongs here.

For its unique position midway between Africa and Asia, with its long coasts ofboth the Mediterranean Sea in the north (c.970 km) and the Red Sea in the east (c.ll00 km), Egypt has attracted the atten• tion of explorers and botanists for very many years. Hundreds of studies on the vegetation of Egypt have been published which when assembled together and integrated, as attemped here, would form a valuable scientific base for further studies. In the numerous descriptions of vegetation and plant communities given in this book it has inevitably been necessary to rely heavily on accounts compiled by many authors. The majority of these accounts compiled by many authors. The majority of these accounts follow the Anglo-American School of phytosociology, referring to dominant and associated species, and characterizing communities by their domin• ants or co-dominants. Some accounts, however, of types of vegetation are in accordance with continental phytosociology and original de• scriptions are necessarily followed here. In general, types of communities are distinguished mainlyon the basis of features of the plants, including their structure, the fioristic composition of the vegetation and its overall appearance (physio• gnomy). Characteristics of the habitat are, however, also taken into account, including, for example, the geomorphology. Among important structural features of the vegetation are the number of layers which may be recognized: often a tree layer, shrub layer, subshrub layer or suffrutescent layer and a ground layer, but Introduction xv one or more of these may be lacking. The layer containing the domin• ant, which usually constitutes the major part of the perennial plant cover, normally has the greatest effect on the physiognomy. The habit of the plant mayaIso be distinctive e.g. succulents, grasses and woody species. Important characters of the habitat concern the nature of the substratum and geomorphological features such as the situation of the community or the stand Ca visually fairly homogeneous unit of vegetation, often of a single species) in relation to drainage systems and the nature and depth of surface material or deposits forming the soil. The texture and depth of soil control the capacity for the storage of water; a shallow soil soon dries after the rainy season whereas a deep soil may provide a subsurface reserve of moisture. This book is divided into seven chapters. The first presents Egypt as apart of the arid region of the world and describes how far the River Nile is important to its life and fertility. In Chapter 2 the physiography of Egypt including its main geolo• gical and geographical characteristics, climatic features and soil• vegetation relationships are described. The main subject of the book, the description of the vegetation types ofEgypt, is covered in four chapters entitled the Western Desert, the Eastern Desert, the Sinai Peninsula and the Nile region. The chapter on the Western Desert is in three parts: 1. The western section of the Mediterranean coastal land, i.e. the coast of the Western Desert; 2. The Inland Oases and Depressions; 3. Gebel Uweinat CUweinat Mountain). There are two parts in the chapter on the Eastern Desert: 1. The Red Sea coastal land; 2. The inland desert. The chapter on the Sinai Peninsula is in two parts: 1. The coastal belts: a) The eastern section of the Mediterranean coastalland of Egypt; b) The west coast of the Gulf of Aqaba and the east coast of the Gulf of Suez; 2. The inland desert and mountains. The chapter on the Nile region is an account of the plant life of the River Nile and its banks from Aswan northwards to its mouth in the Mediterranean Sea. It describes also the vegetation of the northern lakes and that of the middle Cdeltaic) section of the Mediterranean coastal land of Egypt. XVI Introduction In each of the four main chapters, before descriptions of the vegeta• tion types, the local geomorphology, climate and habitat types of that particular region are described. A concluding chapter provides an account of the history of the vegetation, indicates fields in plant ecology on which further research is needed and gives a summary of the main types of vegetation in Egypt.