Avinoam Danin

Plants of Desert Dunes

With 84 Figures

Springer Contents

Introduction

Sand Deserts of the World . 2.1 Distribution of Sand Dunes 3 2.2 Sand Mobility 3 2.2.1 The Modes of Sand Movement 3 2.2.2 Ripples 5 2.2.3 as Modifiers of Local Dune Topography 8 2.2.4 Microbiotic Crust as a Sand Fixer 10 2.2.4.1 The Succession of Sand Crust Community 11 2.2.4.2 Disturbances of the Microbiotic Crust 15 2.2.4.2.1 Natural Disturbances 15 2.2.4.2.2 Destruction by Humans and Domestic Animals 17 2.2.4.3 Distribution of Microbiotic Crust on Sands 17

Environmental Stresses in the Sand Desert 21 Substrate Stability 21 .1 Sand Accretion 21 .2 Deflation 22 .3 Blowouts 22 .4 Injuries by Airborne Sand 23 3.2 Moisture Regime 23 3.3 Nutrients 24

4 Habitat Types of Desert Dunes 25 4.1 Mobile Dunes 25 4.1.1 Crest 25 4.1.2 Slipface 25 4.1.3 Dune Base, Plinth 26 4.2 Stable Dunes 26 4.3 Sites of Constant Deflation 26 4.4 Sand Covering Other Substrates 27 4.4.1 Mobile Sand Covering Sand Sheets 27 4.4.2 Sand Covering Hills or Plains of Hard or Soft Rocks 27 4.4.3 Sand Covering Salt Marshes 27 VIII Contents.

4.4.4 Sand Covering Shallow Aquifers of Fresh Water 29 4.4.5 Sand Covering Dry Water Courses (Wadis Arroyos) 29

5 Case Histories and Ecomorphological Types 31

5.1 Species Requiring Sand Accumulation - Stipagrostis scoparia Type 34 5.1.1 Stipagrostis scoparia 35 5.1.2 Stipagrostis acutiflora 38 5.1.3 Stipagrostis pungens 38 5.1.4 Stipagrostis pennata 39 5.1.5 and Other Southern African Species ... 39 5.1.6 Swallenia alexandrae 39 5.1.7 Panicum urvilleanum 40 5.1.8 Summary 41 5.2 Species Resistant to Deep Sand Cover or Removal - Calligonutn comosum Type 42 5.2.1 Calligonutn comosum 42 5.2.2 Artemisia monosperma 47 5.2.3 Pennisetum divisum and Panicum turgidum . .• 49 5.2.4 Lasiurus scindicus 49 5.2.5 Hilaria rigida 51 5.2.6 Tetradymia tetrameres 51 5.2.7 Psorothamnus polyadenius 52 5.2.8 Sarcobatus vermiculatus 52 5.2.9 Summary 54 5.3 Species of Areas with Modest Sand Cover or Removal - Stipagrostis plumosa Type 54 5.3.1 Stipagrostis plumosa 55 5.3.2 Stipagrostis drarii 57 5.3.3 Centropodia forskalii !,. 58 5.3.4 Cyperus macrorrhizus 59 5.3.5 Cyperus conglomeratus 65 5.3.6 Echinops philistaeus 65 5.3.7 Tiquilia plicata 65 5.3.8 Summary 66 5.4 Species Actively Resistant to Sand Deflation - Moltkiopsis ciliata Type 67 5.4.1 Moltkiopsis ciliata 67 5.4.2 Heliotropium digynum 69 5.4.3 Echiochilon fruticosum 69 5.4.4 Anchusa negevensis 71 5.4.5 Other Species with Rootborne Shoots 72 5.4.6 Summary 72 Contents IX

5.5 Passive Resistant Species to Sand Deflation - Convolvulus lanatus Type 73 5.5.1 Convolvulus lanatus 73 5.5.2 Cornulaca monacantha 74 5.5.3 Retama raetam '74 5.5.4 Thymelaea hirsuta 74 5.5.5 Summary 76 5.6 Herbaceous Perennial Species of Stable Sand Sheets - Type 76 5.6.1 Stipagrostis obtusa 76 5.6.2 77 5.6.3 Achnatherum hymenoides 80 5.6.4 Asphodelus ramosus 81 5.6.5 Summary 83 5.7 Shrubs and Semishrubs of Stable Sand Sheets - Hammada salicornica Type 85 5.7.1 Hammada salicornica 85 5.7.2 Anabasis articulata 86 5.7.3 Haloxylon persicum 86 5.7.4 Summary 87 5.8 Annuals and Facultative Annuals (Amphiphytes) 87 5.8.1 Stipagrostis ciliata 88 5.8.2 Centropodia forskalii 89 5.8.3 Plantago cylindrica 89 5.8.4 Eremobium aegyptiacum 89 5.8.5 Cutandia memphitica 90 5.8.6 Summary 92 5.9 Coastal Dunes Plants 93 5.9.1 Ammophila arenaria 93 5.9.2 Ammophila breviligulata 94 5.9.3 Spartina patens 95 5.9.4 Elymusfarctus 96 5.9.5 Cyperus capitatus 96 5.9.6 Cyperus sharonensis 97 5.9.7 Stipagrostis lanata 98 5.9.8 Abronia maritima 98 5.9.9 Herbaceous Perennial Species 99 5.9.10 Shrubs and Trees 99 5.9.11 Summary 100 5.10 Sand Grains Coating Leaves and Stems 100 5.10.1 Savignia parviflora 100 5.10.2 Ifloga.spicata 101 5.10.3 Ononis serrata and Other Ononis Species 102 5.10.4 Fagonia glutinosa and Other Fagonia Species 102 X Contents

5.10.5 Silene villosa 102 5.10.6 Dicoria canescens 102 5.10.7 Summary 104 5.11 Microbiotic Crust 104 5.11.1 Cyanobacteria and Green Algae .-.-.-.. -104 5.11.2 Lichens and Fungi 106 5.11.3 Mosses 107 5.11.4 Summary 108

6 Typical Transects in a Few Plant Communities and Their Edaphic Relationships Ill 6.1 A Successional Sequence in the Haluza Dunes, Israel Ill 6.1.1 The Heliotropium digynum-Stipagrostis scoparia Community 115 6.1.2 The Stipagrostis scoparia-Artemisia monosperma Community 115 6.1.3 The Echinopsphilistaeus-Artemisia monosperma Community 116 6.1.4 The Stipagrostis plumosa-Artemisia monosperma Community 117 6.1.5 The Stipagrostis plumosa-Convolvulus lanatus Community 117 6.1.6 Changes in Soil Texture During Plant Succession 117 6.1.7 Summary 117 6.2 Stable Dunes on Old Sandstones in the Yamin-Rotem Plain, Israel 118 6.3 Dunes Covering Stable Sand Sheets in Northern Sinai 120 6.4 Sand Covering Salt Marshes in Sinai, Namibia, and California 121 6.5 Sand Covering Fresh Water Aquifers 121 6.6 Sand Covering Limestone Hills, Western Sinai .; 123 6.6.1 Anabasis articulata-Astragalus camelorum Community on Shallow Sand 124 6.6.2 Retama raetam Shrubs on Sands up to 2 m Deep 125 6.6.3 Stipagrostis scoparia Dominating Deep Mobile Sand 126 6.6.4 Anabasis articulata-Fagonia glutinosa Community on Sand Covering Alluvial Plain "... 126 6.6.5 Anabasis articulata-Artemisia monosperma Community .... 126 6.6.6 Reg Vegetation in Wadis with Nonsandy Substrate 126 6.6.7 Summary 126 6.7 Eureka Dunes, California 127 6.7.1 Alluvial Fans Dominated by Larrea tridentata 127 6.7.2 Sand Covering Alluvium, Dominated by Atriplex polycarpa ... 127 6.7.3 Thick and Slightly Mobile Sand Dominated by Psorothamnus polyadenius 128 Contents - XI

6.7.4 Mobile Sand Dominated by Swallenia alexandrae 128 6.7.5 Summary 129 6.8 The Kelso Dunes, California '.'. 129 6.8.1 Alluvial Plain Dominated by Larrea tridentata 130 6.8.2 Plinth Dominated by Hilaria rigida 130 6.8.3 Mobile Sand Dominated by Panicum urvilleanum 131 6.8.4 Dune Crest 131 6.8.5 Summary 131

7 Plant Adaptations to Environmental Stresses in Desert Dunes 133

7.1 Convergence and Adaptation 133 7.2 Reactive Growth and Sand Mobility 133 7.2.1 Adjustment to Changing Soil Surface 134 7.2.1.1 Species Indifferent to Changes in the Soil Surface 134 7.2.1.2 Species Adjusting the Crown Position of Their Seedlings ..... 134 7.2.1.3 Renewal Buds Close to Soil Surface 135 7.2.1.4 Species with Renewal Buds Above Soil Surface 135 7.2.1.5 Rootborne Shoots 135 7.3 Adaptations of the Main Organs 136 7.3.1 The Overall Plant 136 7.3.1.1 Canopy Density 136 7.3.1.2 Plant Silhouette 138 7.3.2 Stems 139 7.3.2.1 Aboveground Stems 139 7.3.2.2 Subterranean Stems 139 7.3.2.2.1 Rhizomes 140 7.3.2.2.2 Rhizodes 140 7.3.2.2.3 Orthogeocorms 140 7.3.3 Leaves 141 7.3.3.1 Leaf Shape 141 7.3.3.2 Leaf Indumentum 142 7.3.4 Roots 142 7.3.4.1 Shootborne Roots 143 7.3.4.2 Rootborne Shoots 143 7.3.4.3 Root System Morphology 144 7.3.4.4 Special Functions of Roots 144 7.3.4.4.1 Absorption of Dew, Fog, and Condensed Water 144 7.3.4.4.2 Rhizosheaths 144 7.3.4.4.3 Mycorrhizae 148 7.3.5 Seed Dispersal 149 7.3.5.1 Dragged Diaspores 149 7.3.5.2 Rolling Diaspores 150 7.3.5.3 Creeping or Bouncing Diaspores 151 t

XII Contents

7.3.5.4 Conclusions and Comparison with Seed Dispersal Among Island Plants 152

8 Comparison Between Plants of Desert Dunes, Extreme Desert, and Coastal Dunes 153 8.1 Comparison of Desert and Coastal Dunes 153 8.2 Morphological Differences Between Dune Plants of Desert and Coastal Areas 155 8.3 Morphological Evidence for Delimiting Dunes of Extreme Desert and Desert 156

Appendix List of Higher Plant Names with Authors, Synonyms, and Family Name 157

References 161

Subject Index 171

Plant Name Index 175