Date: 23 July 2009
The Department of Conservation says a research project has provided important information for the management of native land snails collected from the Mt Augustus Mine on the Stockton Plateau.
Estimates produced by tracking small groups of Powelliphanta Augusta snails within three release sites indicates that the annual survival rate needs to be increased by between 6% and 45% for long-term population persistence.
West Coast Conservator Mike Slater says although the estimates are based on limited knowledge of growth rates and reproductive potential, they do reflect significant variation in survival due to habitat differences.
“This information indicates that Mt Rochfort Summit and an undisturbed remnant area outside the mine provide the best habitat conditions to support the snails in the future,” Mr Slater said.
In 2006 Solid Energy undertook a painstaking grid search of an area to be mined and transferred 6139 snails to a captive facility at Hokitika. A panel of experts assessed all the available habitat options which led to the release of 3913 snails into the three best areas available. An additional1800 were held in captivity as an insurance to minimise the risk of extinction.
Mr Slater said the next round of management is likely to focus on enhancing existing habitat at Mt Rochfort Summit and planning for rehabilitation of the mine site.
“Research is already underway with captive snails which may reveal faster growth rates or higher reproductive output than was used to generate the current survival estimates,” Mr Slater said.