Using molecular tools to identify New Zealand endemic earthworms in a mine restoration project

Abstract

A restoration ecology project was commenced on the West Coast region of New Zealand to re-establish the local fauna of endemic Powelliphanta spp. carnivorous landsnails at an opencast coal mine site after mining activities. The aim of the current research is to provide recommendations for the use of earthworms to improve the restoration of ecological communities, especially the landsnails. To provide such recommendations, different aspects of the ecology and bio-systematics of the New Zealand endemic earthworm fauna have been studied using molecular techniques. About 1,500 earthworm individuals have been collected across 17 sampling sites in the Stockton mine area. In New Zealand, 173 endemic earthworm species are known. Only minor revisions to the earthworms’ taxonomic status have been made since 1959. Species identification was performed by morphological analysis (following Lee’s taxonomic key) and molecular analysis (using the mitochondrial 16S gene). The latter analyses conducted on a selection of 83 individuals revealed the existence of at least 17 different taxa, most of which are probably undescribed species. Some of these earthworm species are predated by an endangered carnivorous landsnail, Powelliphanta augusta Walker, Trewick & Barker. Because the conservation of P. augusta may rely greatly on the understanding of their diet, earthworm DNA was sought after in the snails’ feces, using molecular analyses. Molecular analyses have been helpful in establishing an inventory of the species present in the study site, facilitating new species taxonomic descriptions and elucidating the predatorprey relationship.

Key words:

• Earthworms
• landsnails
• New Zealand
• restoration
• mining
• DNA