Coal mines in New Zealand have refined methods of stripping native wetland tussockland and subalpine shrubland ecosystems as minimally disturbed sods. The technique, referred to here as direct transfer (DT), was first used in the early 1990s to establish lowland beech/podocarp forest seedlings, particulary in soils with Phytophthora cinnamoni. In the mid 2000s it was used to strip most of the last remaining habitat of the carnivorous (giant) land snail, Powelliphanta augusta from which 5000 snails were placed in refrigerated captivity. Some snails were inadvertently transferred within sods. Over the last few years, more snails have been released into the rehabilitated areas.
Results/Conclusions
This paper reports factors that mean direct transfer is the only technique that can achieve successful rehabilitation in the short (10 year) timeframe that required: it conserves the highly organic soils with low-permeability that retain high soil moisture, and the earthworm fauna on which the snails dominantly feed. The technique also favours rapid recovery of dense groundcover that further protects the long-lived snails from dehydration, and provides cover from mammalian predators if multi-species pest control is stopped. The paper reviews 'success' and 'closure' critiera, and suggests refinements aimed at increasing resilience of direct transfer to invasion from unwanted plants (both native and non-native).