IBRA regions represent a landscape based approach to classifying the land surface of Australia from a range of continental data on environmental attributes. The dataset is derived from data and information provided from State and Territory Nature Conservation agencies regionalisations and aggregated to 80 biogeographic regions for Australia. These biogeographic regions have been delineated, each reflecting a unifying set of major environmental influences which shape the occurrence of flora and fauna and their interaction with the physical environment.; ; IBRA Version 4.1 is regarded as the best available GIS representation of the original IBRA Version 4.0 map presented in Thackway and Cresswell (1995). This product is occasionally referenced, for example, in the Determinations Threatened Species under the New South Wales (NSW) Threatened Species Conservation Act (1995).; ; PLEASE NOTE: IBRA 4.1 has been superseded by subsequent versions. For later IBRA versions or a full Australia wide coverage of IBRA 4.1 go to http://www.environment.gov.au/parks/nrs/science/bioregion-framework/ibra/index.html