Different arbuscular mycorrhizal inoculants affect the growth and survival of Podocarpus cunninghamii restoration plantings in the Mackenzie Basin, New Zealand

There is increasing interest in the use of arbuscular mycorrhizal fungi (AMF) for ecological restoration, as AMF can improve plant nutrition and growth. However, some AMF can have negative effects on plant growth. It is therefore critical that restoration strategies incorporate appropriate AMF. This research investigated differences in growth and survival of Podocarpus cunninghamii (mountain tōtara) cuttings with six different AMF inoculums, with the aim of choosing the most appropriate mycorrhizal species for restoration success. Cuttings of P. cunninghamii were inoculated with AMF ranging from indigenous to exotic, including commercially available AMF and AMF isolated from remnant P. cunninghamii forest and ex-agricultural grassland. Plant growth and survival was compared after two seasons at a high country restoration site in the Mackenzie Basin. Plants treated with forest and indigenous AMF had significantly greater survival than those treated with commercial AMF. Forest AMF also resulted in significantly greater P. cunninghamii growth than all the other treatments. This has potentially important implications for restoration, as improved growth and survival of native woody species can improve restoration success by increasing establishment success and reducing management costs.