Powelliphanta Hochstetteri
This carnivorous land snail is the largest snail in the world and found in the upper reaches of the Park, Wainui Valley and Falls River catchment.
In a first for New Zealand, in the spring of 2016 Dr Brian Lloyd–assisted by Dr Ruth Bollongino–attached tiny radio transmitters to ten Powelliphanta hochstetteri snails near Canaan Downs to investigate their ranging behaviour and activity. The snails in this study were from the sub-species P.h. hochstetteri, ranked as in gradual decline. They were monitored, day and night for the next 41 days.
This is the first time snails had been radio-tracked at night in New Zealand, giving a unique insight into the carnivorous land snail’s behaviour. Results found snails are active for one or two nights and then have longer periods of inactivity, preferring to move on warm, moist nights. Unsurprisingly they don’t travel great distances, on average just 1.32m, although one did travel 3.8m.
Interestingly, the snails tended to move in a straight line with a slight left bias. None went back to the same spot, which indicates they are not territorial and don’t seem to have a home base.
The information from the snail tracking will help improve the accuracy and precision of population estimates from mark-recapture and other survey methods. Two hundred snails were also tagged and monitoring will be repeated to survey population changes over time.
Learn more about Powelliphanta hochstetteri