Assemblages of plants and invertebrate animals of tumulus (organic mound) springs of the Swan Coastal Plain are ecological communities in Western Australia.
At the edge of the Gnangara Mound, where heavy guildford clays meet the bassandean dune system, bogs and swamps are created by the discharge of water from this aquifer.
Penetration of water produced by regional hydrological forces alter and increase the size of the mounds by pushing material to the surface through the peat layers.
Flora of flooded gums (Eucalyptus rudis), bracken fern (Pteridium esculentum) and rushes (from the plant families Cyperaceae, Juncaceae and Restionaceae) occur around the springs.
Altered fire regimes, involving blazes of higher intensity and the exploitation of the associated aquifers directly threaten the remaining tumulus spring assemblages.