Giant carnivorous land snails are the newest species to move into Nelson's Brook Waimārama Sanctuary.
Photo: Department of Conservation
Thirty powelliphanta snails were collected from two Department of Conservation approved sites in Nelson - the Roding River catchment and a forestry block in the Maitai Valley - and released into the sanctuary by staff, volunteers, iwi and a handful of school children last month.
Among the largest snails in the world, powelliphanta are one of the most threatened species of invertebrates in Aotearoa and thrive in moist native forests and sub-alpine environments.
The Powelliphanta hochstetteri consobrina are also the first invertebrates to be translocated into the sanctuary.
Sanctuary ecologist Robert Schadewinkel said the snails were only known to live along within the Bryant and Richmond ranges between the Maitai River and the Roding River.
"It's a very geographically limited area that this subspecies are known to come from, but it happens that our sanctuary is right in the middle of these ranges and ridges and spurs, hence it was deemed appropriate to bring the snails into the sanctuary.
"The location we chose to release them is very close to the highest point of the sanctuary where we have moist deep soils and a cool climate which this species seems to prefer."
Several large Several powelliphanta marchanti shells and one live snail have been found in Totara Reserve Regional Park. Photo: Anthony Behrens
Schadewinkel said the sanctuary's predator proof fence and extensive trapping meant it was free of the snails main predators - rats, possums and pigs.
The snails largely prey on earthworms and slugs which they suck up with the help of 6000 tiny razor sharp teeth.
Brook Waimārama Sanctuary chief executive Ru Collin said the reintroduction of powelliphanta into the sanctuary would help the species to survive and thrive.
"Part of the ecosystem restoration will include the reintroduction of many locally extinct species into the sanctuary."
A survey will be conducted in five years to track the population of powelliphanta in the sanctuary. Due to their slow reproduction rate, the snails' population growth is expected to be modest, but steady.