The High Rainfall Zone is one of three biogeographic zones into which south west

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

is divided, the others being the Transitional Rainfall Zone and the Low Rainfall Zone. The zones were first defined by

Stephen Hopper Stephen Donald Hopper AC FLS FTSE (born 18 June 1951) is a Western Australian botanist. He graduated in Biology, specialising in conservation biology and vascular plants. Hopper has written eight books, and has over 200 publications to his n ...

in his 1979 paper ''Biogeographical aspects of speciation in the southwest Australian flora''. Initially they were defined in terms of rainfall, with the High Rainfall Zone being that part of the south west with annual rainfall of more than 800 millimetres (31 in). However, following the publication of

John Stanley Beard John Stanley Beard (15 February 1916 – 17 February 2011) was a British-born forester and ecologist who resided in Australia. Beard studied at the University of Oxford where he completed his doctoral thesis on tropical forestry. While working ...

phytogeographic Phytogeography (from Greek φυτόν, ''phytón'' = "plant" and γεωγραφία, ''geographía'' = "geography" meaning also distribution) or botanical geography is the branch of biogeography that is concerned with the geographic distribution o ...

regionalisation of Western Australia in 1980, it was recognised that Hopper's zones could be defined as aggregates of Beard's botanic districts. The High Rainfall Zone was subsequently re-defined as equivalent to Beard's "Darling Botanical District", later renamed the "South-west Forest Region". When the

Interim Biogeographic Regionalisation for Australia The Interim Biogeographic Regionalisation for Australia (IBRA) is a biogeographic regionalisation of Australia developed by the Australian government's Department of Sustainability, Environment, Water, Population, and Communities. It was devel ...

(IBRA) was published in the 1990s, Beard's regionalisation was adopted as the baseline for Western Australia. The South-west Forest Region was divided into three IBRA regions:

Warren A warren is a network of wild rodent or lagomorph, typically rabbit burrows. Domestic warrens are artificial, enclosed establishment of animal husbandry dedicated to the raising of rabbits for meat and fur. The term evolved from the medieval Angl ...

Jarrah Forest Jarrah forest is tall open forest in which the dominant overstory tree is ''Eucalyptus marginata'' (jarrah). The ecosystem occurs only in the Southwest Botanical Province of Western Australia. It is most common in the biogeographic region named in ...

and

Swan Coastal Plain The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geol ...

. Hence the High Rainfall Zone is now defined as the aggregate of these three IBRA regions.

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Further reading