Causes and consequences of changes to New Zealand’s fungal biota

This paper briefly reviews advances in knowledge of the non-lichenised fungi of New Zealand over the past 25 years. Since 1980, the number of species recorded from New Zealand has doubled, and molecular techniques have revolutionised studies on fungal phylogeny and our understanding of fungal distribution, biology and origins. The origins of New Zealand’s fungi are diverse; a few appear to be ancient, whereas many have arrived in geologically more recent times following trans-oceanic dispersal. Some of these more recent arrivals have evolved subsequently to form local endemic species, while others may be part of larger populations maintained through regular, trans-oceanic gene flow. Although questions remain about which fungi truly are indigenous and which are exotic, about one-third of the fungi recorded from New Zealand are likely to have been introduced since human settlement. While most exotic species are confined to human-modified habitats, there are some exceptions. These include species with potential to have significant impacts at the landscape scale. Examples from saprobic, pathogenic, endophytic and ectomycorrhizal fungi are used to discuss the factors driving the distribution and dispersal of New Zealand’s fungi at both global and local scales, the impact that historical changes to New Zealand’s vascular plant and animal biota have had on indigenous fungi, and the broader ecological impact of some of the exotic fungal species that have become naturalised in native habitats. The kinds of fungi present in New Zealand, and the factors driving the distribution and behaviour of those fungi, are constantly changing. These changes have occurred over a wide scale, in both time and space, which means New Zealand’s indigenous fungi evolved in response to ecological pressures very different from those found in New Zealand today.