Warren bioregion

Warren, also known as Karri Forest Region and the Jarrah-Karri forest and shrublands ecoregion, is a biogeographic region in southern Western Australia. Located in the southwest corner of Western Australia between Cape Naturaliste and Albany, it is bordered to the north and east by the Jarrah Forest region. Its defining characteristic is an extensive tall forest of Eucalyptus diversicolor (karri). This occurs on dissected, hilly ground, with a moderately wet climate. Karri is a valuable timber and much of the karri forest has been logged over, but less than a third has been cleared for agriculture. Recognised as a region under the Interim Biogeographic Regionalisation for Australia (IBRA), and as a terrestrial ecoregion by the World Wide Fund for Nature, it was first defined by Ludwig Diels in 1906. The Warren region is defined as the coastal sandplain between Cape Naturaliste and Albany. Extending from the ocean to the edge of the Yilgarn craton plateau, for most of its extent it may be adequately approximated as the land within ten kilometres (6 mi) of the coast. North of Point D'Entrecasteaux, however, it extends inland almost as far as Nannup and Manjimup. It has an area of about 8,300 square kilometres (3200 mi2), making it about 2.7% of the South West Province, 0.3% of the state, and 0.1% of Australia. It is bounded to the north and east by the Jarrah Forest region. Much of the region is unpopulated, but there are a number of towns with substantial populations, most notably Margaret River, Augusta, Pemberton, Walpole, Denmark and Albany. Warren has a hilly topography, caused by two factors: the underlying geology, which consists of infolded metamorphic rock of the Leeuwin Complex and Archaean granite of the Albany-Fraser Orogen; and the dissection of rivers such as the Blackwood, Warren, Shannon and Frankland. The western extent of the region takes in the Leeuwin-Naturaliste Ridge, an 80 kilometre (50 mi) long strip of coastal limestone on top of a ridge of granite, with an extensive cave system.