The Spatial Portal uses a variety of map layers. The basemaps come from Google, OpenStreetmap and a simple world political boundary outline map useful for publishing thumbnails of species distributions. The environmental and contextual layers come from over 60 international and national agencies. See http://spatial.ala.org.au/layers for a list of the layers with some metadata containing links to the data providers.
There are two types of layers in the Spatial Portal, environmental layers that contain continuous values (e.g., temperature, ph) and contextual layers that contain class values (e.g., states and territories, bioregions).