As well as the relatively well-known invertebrate fauna of the Thames coastal marshes, there are several ecological groups of species respresented in the region, which are frequently found together at sites near the Thames. These are species that are normally associated with heathland and sandy habitats (for example, the Red Data Book (RDB) mining-bee Andrena florea – Fig. 1), species that are coastal and often found on dune systems, and species of calcareous or chalk grassland habitats.