attractions, most notably the Walpole-Nornalup National Park's Valley of the Giants, which includes a "Tree Top Walk". Conservation The main threat to the biodiversity of the Warren region is the South West's epidemic of dieback, a disease caused by the introduced plant pathogen Phytophthora cinnamomi. Introduced animals such as feral cats, foxes and rats prey on native wildlife and occupy ecological niches to the detriment of native species. Populations are controlled through 1080 baiting as part of the highly successful Western Shield program. Other threats include human activities related to infrastructure and silviculture, such as roads changing surface runoff patterns, and changes to the fire regime. Because so much of the Warren region is already protected, it has low priority under Australia's National Reserve System. Protected areas 45.47% of the ecoregion is in protected areas. Protected areas include: Boorara-Gardner National Park Boyndaminup National Park Bramley National Park Brockman National Park D'Entrecasteaux National Park Easter National Park Forest Grove National Park Gloucester National Park Greater Beedelup National Park Greater Dordagup National Park Greater Hawke National Park Hilliger National Park Jane National Park Leeuwin-Naturaliste National Park Mount Frankland National Park Mount Frankland North National Park Mount Frankland South National Park Mount Lindesay National Park Mount Mason Nature Reserve Mount Roe National Park Mount Shadforth Nature Reserve Sir James Mitchell National Park Scott National Park Shannon National Park Torndirrup National Park Two Peoples Bay Nature Reserve Walpole-Nornalup National Park Warren National Park West Cape Howe National Park William Bay National Park Biogeography The Warren region first appeared in Ludwig Diels' 1906 biogeographical regionalisation of Western Australia. Diels' concept of Warren region was effectively all the land south of a line from Albany to Busselton; thus it included a substantial area east of Margaret River that is now part of the Jarrah Forest region. The region was not recognised as one of Edward de Courcy Clarke's "natural regions" in 1926, but was resurrected in Charles Gardner's regionalisations of the 1940s and 1950s. In 1980, John Stanley Beard published a phytogeographical regionalisation of the state based on data from the Vegetation Survey of Western Australia. This new regionalisation included a "Warren Botanical District" that is essentially identical with the present-day Warren. By 1984, Beard's phytogeographic regions were being presented more generally as "natural regions", and as such were given more widely recognisable names. Thus the "Warren Botanical District" became the "Karri Forest Region". When the