Kauri Snails

Recently PF Olsen was alerted to the presence of Kauri Snails (naturally uncommon) within a newly acquired plantation forest in Northland. Kauri snails are endemic to New Zealand and can grow up to 80 mm in diameter. They have rich brown coloured shells which are shaped like a flattened spiral. Although they are called a kauri snail, they are seldom found near kauri trees because the ground is often too dry for its favourite food—the earthworm. They are highly mobile and have been known to move 10 metres in 2 weeks. Once widespread in Northland before human settlement altered or destroyed their habitat, currently their main threat is predation by introduced animals (possums, rats, pigs).

In the case of Paerata Forest, investigation revealed that the snails were using concrete fence posts (for induction heat or a source of lime?), located within the plantation areas, as habitat during the daytime. As this is the first time that kauri snails have been reported as using plantation forests for habitat, it was essential that steps were taken to ensure that the snails were protected. While a search to find a Kauri Snail expert yielded no results, consultation with local Department of Conservation (DOC) staff proved to be more helpful.

DOC manages the Wildlife Act 1953, which dictates the steps and processes for species management, including the translocation of a species from one area to another. It was quickly realised by all parties that any snails found would need to be moved to a safer location to avoid them from being squished by forestry machinery. While DOC staff worked on the paperwork required to ensure that snails could be handled and moved in a legal manner, Steve McManus was brought on board as the person to find and move the snails, with a nearby DOC Reserve identified as the best place for relocation.

At the same time contractors were also briefed on what to do if they came across more concrete fence posts and snails. Chilly bins were provided to each crew so that if Steve is unavailable then they have the means to relocate the snails themselves. Because of their cannibalistic and carnivorous behaviour, it is a good idea to keep kauri snails isolated from each other where possible, so the crews have been warned not to overcrowd the chilly bins, and to release the snails as soon as they are able to.

This is the latest example of native species using plantation forests for habitat, and is also a good example of how, by working together, practical outcomes can be achieved that protect our native species whilst still allowing forestry operations to continue.

PF Olsen would like to thank Wise on Wood for notifying us about the snails in the first instance, and to DOC Whangarei staff for working with us through this new and unique situation.