It appears these ceramic snails are the only snails we have left. I have seen precisely one live one in the past two years (which I promptly squashed…). There are a few slugs to be found – but only a few – maybe one under the dozens of pots I moved yesterday. Gardener’s delight. Where did they all go?
The most reasonable explanation is that the resident bobtail goannas have developed a taste for them. Their numbers have certainly increased steadily over the years as we have turned our grass paddock into a garden with habitat; and they tend to frequent the places the snails used to.
It seems organic methods and a laissez faire management style can yield an unexpected win.