A rare animal in Victoria that is common elsewhere

The Yellow-faced Whip Snake (Demansia psammophis) is a slender, fast-moving, large-eyed snake, to about 80 cm long, which feeds mainly on lizards.  It is poisonous but is not considered to be dangerous to humans. It is restricted in Victoria to mallee vegetation in the far north-west of the state where the rainfall is less than 300 mm a year.  It has been classified as near threatened for Victoria.

There are only 24 records for the Whip Snake in the Victorian Illustrated Fauna Information System the earliest of which is from Red Cliffs, near the Murray River, in 1928.  All but three localities are within the Murray-Sunset National Park, so apart from the fact that the species is uncommon there is no immediate threat, hence the near threatened classification.  Although it is rare in Victoria the Yellow-faced Whip Snake is common in other parts of Australia.  Distribution maps in major herpetological books show it to be one of the most widespread Australian snakes which is found in a range of ecosystems from the coast to dry country in all mainland states.  Whatever conservation measures that may be planned for Victorian populations it would appear as if that would be irrelevant to the conservation of the species as a whole.  The Yellow-faced Whip Snake is an excellent example of the argument that conservation programs should not take into account artificial boundaries, such as state borders.  Nevertheless, there is reason to be cautious in all such cases, and there are some specific questions that may be asked of this approach for the Whip Snake.   

The national distribution maps of the Yellow-faced Whip Snake in several authoritative publications (e.g. Reptiles and Amphibians of Australia by Harold Cogger) show it as present throughout almost all of Victoria, including the alps and coastal areas.  It also shows it as present across all of NSW, South Australia and Queensland as well as most of Western Australia.  Although these maps are not meant to be highly accurate they do nevertheless misrepresent the real story.  Clearly, for Victoria, the map vastly overestimates the species range.  This is also true for NSW, Western Australia and Queensland where, although the species is very common, 90% of the records (based on information from databases in those states) extend no more than 250 km inland from the coast.  In South Australia, the Whip Snake is more widely ranging, but it is by no means a common species, there are only 75 records in the DEH database and just 15 of these are within national parks or conservation reserves.

When site data collected by museums and wildlife survey groups is looked at a little more carefully it is clear that the Yellow-faced Whip Snake is by no means evenly distributed across its range.  Its greatest abundance and density is along the eastern and western sea-boards and the inland populations are much more sparsely distributed.  The Victorian populations are geographically close to a small cluster of records in NSW, a few km east of Mildura and another few records in SA near Renmark.  All of them are within 100 km of the Murray River.  The next nearest records in either state are several hundred km away.  Any conservation program in Victoria would do well to recognise the possibility that future taxonomic research could determine that the populations in this area represent a distinct sub-species and that the Victorian populations are the only ones within a conservation reserve.  This isn't a fanciful notion as geographically isolated populations of wide-ranging species are often segregated into new species and sub-species after close study, and there are already three sub-species of the Whip Snake that have been recognised, two of which have fairly closely circumscribed geographic ranges.