Plants of Desert Dunes

Based on three decades of field experience in southwest Asia, southern Africa, and the southwest United States, the author summarizes the major adaptations of plants to desert dunes. This integrative study of plant and diaspore morphology, reactive growth, life cycles, and environmental factors explains and predicts plant distribution. Many kinds of dune syndromes, plant case studies and vegetation transects are discussed and illustrated to clarify the significance of adaptations to specific habitat factors. Although the focus is on vascular plants, the development of microbiotic soil crust, its function, and its composition are discussed as well.

Inhalt

1 Introduction.- 2 Sand Deserts of the World.- 2.1 Distribution of Sand Dunes.- 2.2 Sand Mobility.- 2.2.1 The Modes of Sand Movement.- 2.2.2 Ripples.- 2.2.3 Plants as Modifiers of Local Dune Topography.- 2.2.4 Microbiotic Crust as a Sand Fixer.- 2.2.4.1 The Succession of Sand Crust Community.- 2.2.4.2 Disturbances of the Microbiotic Crust.- 2.2.4.2.1 Natural Disturbances.- 2.2.4.2.2 Destruction by Humans and Domestic Animals.- 2.2.4.3 Distribution of Microbiotic Crust on Sands.- 3 Environmental Stresses in the Sand Desert.- 3.1 Substrate Stability.- 3.1.1 Sand Accretion.- 3.1.2 Deflation.- 3.1.3 Blowouts.- 3.1.4 Injuries by Airborne Sand.- 3.2 Moisture Regime.- 3.3 Nutrients.- 4 Habitat Types of Desert Dunes.- 4.1 Mobile Dunes.- 4.1.1 Crest.- 4.1.2 Slipface.- 4.1.3 Dune Base, Plinth.- 4.2 Stable Dunes.- 4.3 Sites of Constant Deflation.- 4.4 Sand Covering Other Substrates.- 4.4.1 Mobile Sand Covering Sand Sheets.- 4.4.2 Sand Covering Hills or Plains of Hard or Soft Rocks.- 4.4.3 Sand Covering Salt Marshes.- 4.4.4 Sand Covering Shallow Aquifers of Fresh Water.- 4.4.5 Sand Covering Dry Water Courses (Wadis Arroyos).- 5 Plant Case Histories and Ecomorphological Types.- 5.1 Species Requiring Sand Accumulation - Stipagrostis scoparia Type.- 5.1.1 Stipagrostis scoparia.- 5.1.2 Stipagrostis acutiflora.- 5.1.3 Stipagrostis pungens.- 5.1.4 Stipagrostis pennata.- 5.1.5 Stipagrostis sabulicola and Other Southern African Species.- 5.1.6 Swallenia alexandrae.- 5.1.7 Panicum urvilleanum.- 5.1.8 Summary.- 5.2 Species Resistant to Deep Sand Cover or Removal - Calligonum comosum Type.- 5.2.1 Calligonum comosum.- 5.2.2 Artemisia monosperma.- 5.2.3 Pennisetum divisum and Panicum turgidum.- 5.2.4 Lasiurus scindicus.- 5.2.5 Hilaria rigida.- 5.2.6 Tetradymia tetrameres.- 5.2.7 Psorothamnus polyadenius.- 5.2.8 Sarcobatus vermiculatus.- 5.2.9 Summary.- 5.3 Species of Areas with Modest Sand Cover or Removal - Stipagrostis plumosa Type.- 5.3.1 Stipagrostis plumosa.- 5.3.2 Stipagrostis drarii.- 5.3.3 Centropodia forskalii.- 5.3.4 Cyperus macrorrhizus.- 5.3.5 Cyperus conglomeratus.- 5.3.6 Echinops philistaeus.- 5.3.7 Tiquilia plicata.- 5.3.8 Summary.- 5.4 Species Actively Resistant to Sand Deflation - Moltkiopsis ciliata Type.- 5.4.1 Moltkiopsis ciliata.- 5.4.2 Heliotropium digynum.- 5.4.3 Echiochilon fruticosum.- 5.4.4 Anchusa negevensis.- 5.4.5 Other Species with Rootborne Shoots.- 5.4.6 Summary.- 5.5 Passive Resistant Species to Sand Deflation - Convolvulus lanatus Type.- 5.5.1 Convolvulus lanatus.- 5.5.2 Cornulaca monacantha.- 5.5.3 Retama raetam.- 5.5.4 Thymelaea hirsuta.- 5.5.5 Summary.- 5.6 Herbaceous Perennial Species of Stable Sand Sheets - Stipagrostis obtusa Type.- 5.6.1 Stipagrostis obtusa.- 5.6.2 Stipagrostis ciliata.- 5.6.3 Achnatherum hymenoides.- 5.6.4 Asphodelus ramosus.- 5.6.5 Summary.- 5.7 Shrubs and Semishrubs of Stable Sand Sheets - Hammada salicornica Type.- 5.7.1 Hammada salicornica.- 5.7.2 Anabasis articulata.- 5.7.3 Haloxylon persicum.- 5.7.4 Summary.- 5.8 Annuals and Facultative Annuals (Amphiphytes).- 5.8.1 Stipagrostis ciliata.- 5.8.2 Centropodia forskalii.- 5.8.3 Plantago cylindrica.- 5.8.4 Eremobium aegyptiacum.- 5.8.5 Cutandia memphitica.- 5.8.6 Summary.- 5.9 Coastal Dunes Plants.- 5.9.1 Ammophila arenaria.- 5.9.2 Ammophila breviligulata.- 5.9.3 Spartina patens.- 5.9.4 Elymusfarctus.- 5.9.5 Cyperus capitatus.- 5.9.6 Cyperus sharonensis.- 5.9.7 Stipagrostis lanata.- 5.9.8 Abronia maritima.- 5.9.9 Herbaceous Perennial Species.- 5.9.10 Shrubs and Trees.- 5.9.11 Summary.- 5.10 Sand Grains Coating Leaves and Stems.- 5.10.1 Savignia parviflora.- 5.10.2 Ifloga spicata.- 5.10.3 Ononis serrata and Other Ononis Species.- 5.10.4 Fagonia glutinosa and Other Fagonia Species.- 5.10.5 Silene villosa.- 5.10.6 Dicoria canescens.- 5.10.7 Summary.- 5.11 Microbiotic Crust.- 5.11.1 Cyanobacteria and Green Algae.- 5.11.2 Lichens and Fungi.- 5.11.3 Mosses.- 5.11.4 Summary.- 6 Typical Transects in a Few Plant Communities and Their Edaphic Relationships.- 6.1 A Successional Sequence in the Haluza Dunes, Israel.- 6.1.1 The Heliotropium digynum-Stipagrostis scoparia Community.- 6.1.2 The Stipagrostis scop aria-Artemisia monosperma Community.- 6.1.3 The Echinops philistaeus-Artemisia monosperma Community.- 6.1.4 The Stipagrostisplumosa-Artemisia monosperma Community.- 6.1.5 The Stipagrostis plumosa - Convolvulus lanatus Community.- 6.1.6 Changes in Soil Texture During Plant Succession.- 6.1.7 Summary.- 6.2 Stable Dunes on Old Sandstones in the Yamin-Rotem Plain, Israel.- 6.3 Dunes Covering Stable Sand Sheets in Northern Sinai.- 6.4 Sand Covering Salt Marshes in Sinai, Namibia, and California.- 6.5 Sand Covering Fresh Water Aquifers.- 6.6 Sand Covering Limestone Hills, Western Sinai.- 6.6.1 Anabasis articulata-Astragalus camelorum Community on Shallow Sand.- 6.6.2 Retama raetam Shrubs on Sands up to 2 m Deep.- 6.6.3 Stipagrostis scoparia Dominating Deep Mobile Sand.- 6.6.4 Anabasis articulata-Fagonia glutinosa Community on Sand Covering Alluvial Plain.- 6.6.5 Anabasis articulata-Artemisia monosperma Community.- 6.6.6 Reg Vegetation in Wadis with Nonsandy Substrate.- 6.6.7 Summary.- 6.7 Eureka Dunes, California.- 6.7.1 Alluvial Fans Dominated by Larrea tridentata.- 6.7.2 Sand Covering Alluvium, Dominated by Atriplex polycarpa.- 6.7.3 Thick and Slightly Mobile Sand Dominated by Psorothamnus polyadenius.- 6.7.4 Mobile Sand Dominated by Swallenia alexandrae.- 6.7.5 Summary.- 6.8 The Kelso Dunes, California.- 6.8.1 Alluvial Plain Dominated by Larrea tridentata.- 6.8.2 Plinth Dominated by Hilaria rigida.- 6.8.3 Mobile Sand Dominated by Panicum urvilleanum.- 6.8.4 Dune Crest.- 6.8.5 Summary.- 7 Plant Adaptations to Environmental Stresses in Desert Dunes.- 7.1 Convergence and Adaptation.- 7.2 Reactive Growth and Sand Mobility.- 7.2.1 Adjustment to Changing Soil Surface.- 7.2.1.1 Species Indifferent to Changes in the Soil Surface.- 7.2.1.2 Species Adjusting the Crown Position of Their Seedlings.- 7.2.1.3 Renewal Buds Close to Soil Surface.- 7.2.1.4 Species with Renewal Buds Above Soil Surface.- 7.2.1.5 Rootborne Shoots.- 7.3 Adaptations of the Main Organs.- 7.3.1 The Overall Plant.- 7.3.1.1 Canopy Density.- 7.3.1.2 Plant Silhouette.- 7.3.2 Stems.- 7.3.2.1 Aboveground Stems.- 7.3.2.2 Subterranean Stems.- 7.3.2.2.1 Rhizomes.- 7.3.2.2.2 Rhizodes.- 7.3.2.2.3 Orthogeocorms.- 7.3.3 Leaves.- 7.3.3.1 Leaf Shape.- 7.3.3.2 Leaf Indumentum.- 7.3.4 Roots.- 7.3.4.1 Shootborne Roots.- 7.3.4.2 Rootborne Shoots.- 7.3.4.3 Root System Morphology.- 7.3.4.4 Special Functions of Roots.- 7.3.4.4.1 Absorption of Dew, Fog, and Condensed Water.- 7.3.4.4.2 Rhizosheaths.- 7.3.4.4.3 Mycorrhizae.- 7.3.5 Seed Dispersal.- 7.3.5.1 Dragged Diaspores.- 7.3.5.2 Rolling Diaspores.- 7.3.5.3 Creeping or Bouncing Diaspores.- 7.3.5.4 Conclusions and Comparison with Seed Dispersal Among Island Plants.- 8 Comparison Between Plants of Desert Dunes, Extreme Desert, and Coastal Dunes.- 8.1 Comparison of Desert and Coastal Dunes.- 8.2 Morphological Differences Between Dune Plants of Desert and Coastal Areas.- 8.3 Morphological Evidence for Delimiting Dunes of Extreme Desert and Desert.- List of Higher Plant Names with Authors, Synonyms, and Family Name.- References.- Plant Name Index.