The harsh environment of the coastal strand community is characterized by wave-pounded beaches, shifting sands, relentless winds, and saline soils. Here species diversity is low in comparison to most other plant communities. Strand plants have evolved numerous adaptations for survival. Low, sprawling root systems are common, as are thick leathery or hairy leaves that help minimize water loss. Many strand plants have also developed physiological mechanisms that have enabled them to adapt to high-salt and low-nutrient soils. For example, saltbush, Atriplex spp., has evolved special cells for salt excretion on its stems and leaves. Sea rocket, Cakile maritima, and the non-native, curly-leaved European beach grass, Ammophila arenaria, are among the hardiest species and earliest colonizers of open sands. In more stabilized areas, beach pea, Lathyrus spp.; yellow bush lupine, Lupinus arboreus; pink and yellow sand verbena, Abronia spp.; beach morning-glory, Convolvulus soldanella; and gray-green silver beachweed, Ambrosia chamissonis, are common. The tough, rubbery Hottentot fig, Carpobrotus edulis, and the sea fig, C. chilense, are important non-native species. These succulents have thick, triangular stems and showy, pink or yellow flowers.