The Western Swamp Tortoise (Pseudemydura umbrina) is critically endangered and has been recorded only from scattered localities in a narrow strip (3km to 5km wide) of the Swan Coastal Plain, running roughly parallel with the Darling Scarp, from Perth Airport at Guildford to near Pearce Royal Australian Air Force Base at Bullsbrook . During the 1960s numbers were estimated at around 300 within Twin Swamps and the Ellen Brook Nature Reserve, with the tortoise also still occurring near Midland, at Perth Airport, near Caversham and near Pearce . Numbers have now declined to less than 50 mature individuals.
Anecdotal information suggests that the species’ past stronghold was the clay soils of the Swan River Valley, the first part of Western Australia developed for agriculture. Almost all this land is now cleared and either urbanised, used for intensive agriculture, or mined for clay used in brick and tile manufacture. 
In 1970 a single juvenile was found at Five Mile Swamp in the southern part of Perth Airport. This was the third remaining population of Western Swamp Tortoises. No further evidence has been found indicating the presence of a population at Perth Airport, despite extensive surveying . The population at Ellen Brook Nature Reserve is the only one with naturally occurring mature individuals. The population at Twin Swamps Nature Reserve has been supplemented since 1994 with captive-bred individuals after the species was considered to have become pretty much extinct there during the 1980s. A third population was established at Mogumber Nature Reserve in August 2000 using captive-bred juvenile stock . The owners of Perth Airport want to develop their land rather than save any of this potentially suitable habitat for Western Swamp Tortoises.
The loss of habitat was and still is a critical cause of decline in numbers of Western Swamp Tortoise. Their long life, but slow reproduction rates, combined with highly specialised habitat requirements compound the problem .
The Friends of the Western Swamp Tortoise provides information and educational resources about Australia’s rarest reptile, including photos. Anyone can join the group and assist in recovery activities to move towards a sustainable Western Swamp Tortoise population and complement the work of the Western Swamp Tortoise Recovery Team. There are also photos at Lochman Transparencies and in the Landscope article below .