Banksia Oligantha - Distribution and Habitat

Distribution and Habitat

Banksia oligantha occurs over a range of about 100 kilometres (60 mi) in southern parts of the Avon Wheatbelt region of the Southwest Botanical Province of Western Australia. Four populations are known, containing about 1,700 adult plants in total:

• The first known population, at Wangelling Gully Nature Reserve in Tarwonga. This population appears to be in decline: in 1988 it was estimated as containing from 500 to 800 plants, but a 2001 survey found only 198 adults, 1 seedling, and 286 dead plants; and a 2004 survey found 135 adults, no seedlings, and 174 dead plants.
• A healthy population at Katanning, spanning two Native Settlement reserves and some private property. This population appears to be increasing; a 2004 survey found nearly 1400 adult plants and over 500 seedlings.
• A small population at Dudinin, spanning a nature reserve and private property. This population is apparently in decline. No seedlings have ever been reported at this location, and from 1997 to 2004 the number of reported adults feel from around 110 to 13.
• A recently discovered healthy population on private property at Toolibin. A 2004 survey counted 188 adults, 35 seedlings, and 36 dead plants.

The species grows in sand dunes of white, white-grey or yellow-brown sand, amongst a system of ephemeral salt creeks. Populations occur both in low-lying areas near creeks, and atop dunes. The vegetation has been described as low open woodland over heath, and as tall open shrubland with some scattered trees.