When it comes to threatened species in Australia, land snails will not be the first animal that comes to mind.
Few people know Australia has native land snails, let alone that some are on the brink of extinction.
However, since records have been kept, more species of land snails have become extinct throughout the world than any other animal group.
Why are snails becoming extinct?
One of the reasons for the high rate of extinctions is that many species of land snail have small distributions (i.e. they only live in a small area) often with highly specialised (very specific) habitat requirements. Many species are (or were) confined to single islands or mountain peaks.
What are some specific examples?
One group of closely related snails, all members of the genus Adclarkia, have very small distributions within the Brigalow Belt bioregion of Queensland. These are:
- The Dawson River snail or Boggomoss snail (Adclarkia dawsonensis)
- The Dulacca woodland snail (Adclarkia dulacca)
- The Brigalow woodland snail (Adclarkia cameroni).
The Brigalow Belt bioregion extends from northern inland New South Wales to the Townsville region of central Queensland and is characterised by once extensive woodlands dominated by a tree called Brigalow (Acacia harpophylla).
The Brigalow Belt has fertile soils which are highly suitable for agriculture, hence over 90% of the Brigalow woodlands have gone. These fertile soils are also home to these three species of Adclarkia, all of which are listed as threatened under Commonwealth and state legislation due to extensive loss of their habitat.
The Dawson River snail or Boggomoss snail (Adclarkia dawsonensis)
This snail, as its name suggests, is found in a small area associated with the Dawson River and its tributaries between Taroom and Theodore. It survives in remnant patches of floodplain and riparian woodlands, and also around some of the ‘boggomoss’ springs of the region.
The Dulacca woodland snail (Adclarkia dulacca)
This snail has its distribution centred around the small town of Dulacca. Its favoured Brigalow habitat has been extensively cleared in the region and it now survives in a few remnants on private property and roadsides.
The Brigalow woodland snail (Adclarkia cameroni)
Of the three species, the Brigalow woodland snail (Adclarkia cameroni) has the largest distribution – extending from west of Toowoomba to the Yuleba district. Although it occurs within Brigalow woodlands, it also favours the heavy soils associated with the Condamine River and its tributaries.
All of the species of Adclarkia shelter in leaf litter by day and under logs and other ground debris. They are active at night after rain. Virtually nothing is known of the biology of any of the species.
Boobook Ecological Consulting’s Director and Principal Ecologist Craig Eddie has been studying Australian native land snails for over 35 years. Based at Roma, in the heart of the Brigalow Belt, Craig has been able to study all three species of Adclarkia including piecing together their distribution and habitat preferences. Craig undertakes targeted surveys for these species to ensure their conservation requirements are considered for the many development projects that continue within the Brigalow Belt.
To find out more about our land snail research, contact us.