Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Sand dune ecology describes the biological and physico-chemical interactions that are a characteristic of sand dunes. Sand dunes provide a range of habitats for a range of unusual, interesting and characteristic plants that can cope with disturbed habitats. In the UK these may include restharrow Ononis repens, sand spurge Euphorbia arenaria and ragwort Senerio vulgaris – such plants are termed ruderals.