Date: 9th September 2026
Above: Woodworthia in matagouri (Central Otago). Credit: Samuel Purdie
Audrey Austin, Youth Trustee for the Whakatipu Reforestation Trust, puts the spotlight on the inter-species relationships holding together some of the Whakatipu’s trickiest ecosystems
Matagouri are dense, spike-covered bushes common around our region, particularly in barren, sub-alpine environments or river beds. They are covered with thick spikes and small leaves with beautiful white mini-flowers appearing in spring. Have you ever gazed over the golden schist-covered hills of central Otago and noticed patches of matagouri clinging to the barren landscape? The story of their survival in some of the driest ecosystems in Aotearoa is much more complex than the cling-and-hope strategy they might seem to be deploying.
A baby jewelled gecko in matagouri, Central Otago. Can you spot it? Credit: Samuel Purdie
Matagouri have evolved smaller leaves to conserve water evaporation during times of drought. On the other hand, this reduces their ability to photosynthesise and produce energy, contributing to the slow-growing nature we know today. In these conditions, other resources, like nitrogen, become incredibly important to maximise the small amount of energy they have. Nitrogen is essential for plant growth, forming a key part of chlorophyll – needed for photosynthesis – as well as the proteins plants rely on to grow and function. Historically, Aotearoa’s soils are relatively nitrogen-poor which means colonising plants like matagouri have to extract it from the air.
Unfortunately there are few enzymes (proteins that help break or build chemicals) that can break down nitrogen gas into forms they need like ammonium. Usually, these enzymes are only found in bacteria, fungi and algae so matagouri have evolved a symbiotic relationship with a group of bacteria called Frankia. By using an enzyme called nitrogenase, Frankia is capable of breaking down nitrogen gas into more useful ammonium molecules. Because nitrogenase breaks down in the presence of oxygen, Frankia uses precious resources to create specialised structures called vesicles which shield the nitrogenase so it can keep producing ammonium. In return, matagouri supplies the bacteria with glucose so it can produce sufficient energy to grow and repair. Matagouri also create nodules around their roots which create the perfect oxygen-poor environment for these bacteria to thrive.
Matagouri and Frankia bacteria don’t just benefit each other but they also create a nitrogen-rich micro-ecosystem where other plants can begin to thrive. Next time you see matagouri around our district or at a Whakatipu Reforestation Trust community plant day, take a moment to appreciate the intricate multi-species relationship that creates a better environment for the whole ecosystem.
Moths are one of our most under-studied groups of organisms in New Zealand and yet they play a pivotal role in our ecosystem. A study centered in the Cardona area revealed a family of moths, Oecophoridae or concealer moths, may play a larger role as a pollinator in alpine ecosystems than we previously thought. Named for the leaf-litter shelters their larvae build to conceal themselves, Oecophoridae are a global family of moths. Of the roughly 200-250 species that live in New Zealand, the large majority of these are found nowhere else in the world. They range in color from drab, white-grey to bright green with intricate patterns.
Atomotricha chloronota Credit: Samuel Purdie
The study, concentrating on Mt Cardrona, used pollen samples from moth individuals to identify the plants they were visiting. This highlighted that concealer moths were pollinating four main native plant genera including Dracophyllum, Acaena, Veronica and Wahlenbergia. This highlighted the importance of our moth populations in our alpine environments where more ‘typical’ pollinators like birds and honey bees, struggle in the hard climate. To do this, concealer moths have evolved symbiotic relationships with these plant species over thousands of years. Moths find flowers by scent and subtle visual cues so many species in the genera mentioned above have evolved white flowers to better reflect light. As the moths drink the flower’s high-energy nectar through a long, straw-like proboscis, pollen catches on hair around their body and is transferred to the next plant it visits. This pollinates the flowers and allows them to reproduce while the moths are supplied with energy-rich food to help them survive in the harsh alpine environment.
In this study, a greater portion of moths carried pollen at higher alpine sites suggesting most become more important as pollinators the higher up you go. In the low-lands of Aotearoa, birds and bees are some of the most obvious pollinators there are. This behaviour has yet to be described in concealer moths overseas suggesting our species may have evolved unique mutualistic relationships with our plant species after centuries of isolation.
At our Whakatipu Reforestation Trust nursery, we grow Hebe (Veronica) cuppressoides, H. hectorii, H. odora, H. propinqua, H. rakaiensis and H. salicifolia. Although these moths are not the primary pollinators at our lowland planting sites, growing these native species helps preserve the vital plant life that sustains Aotearoa’s unique alpine ecosystems. You can find out more about native plants in the Whakatipu basin here.
Amongst the ramble of Olearia and Coprosma sp. in WRT’s community planting sites, you may have noticed a drab, grey shrub perhaps resembling nature’s version of a pin-cushion. This peculiar grey-land shrub is a Melicytus alpinus, also known–quite rightly–as porcupine shrub.
Its Latin name is slightly misleading as it’s actually found around 2000 meters above sea level, right down the the coast in open landscapes, but its common name encapsulates it perfectly. The dense shrub is packed with thick speckled branches and little 1cm long leaves usually condensed into a rounded pin-cushion shape squeezed into rock crevices. Like many other plants around Aotearoa, it evolved complex inter-species relationships to survive in their sometimes harsh environments.
The clue is in their beautiful flowers and fruit. The flowers are inconspicuous, cream-yellow coloured blooms which grow over spring and develop into little purple-patched berries throughout the summer. To protect these precious gems from the rain and wind on 1200 metre slopes, they only grow on the underside of the stems, along with its leaves, leaving the outer wind-breaking branches to bear the force of the south-western gale. Otherwise, its flowers would simply be blown off the plant before it had even finished growing. Not only does it help them resist the elements, it also avoided herbivory when our large mega-fauna like moa still roamed the landscape.
So, if a porcupine shrub tucks its berries deep inside a tangle of branches, how on earth does its seed spread anywhere? In lowland forests, many plants use bright berries to lure birds who then drop the seeds elsewhere wrapped in a nutrient-rich package of fertiliser. In the high alpine however, it’s the lizards that play this same role. Native and endemic skinks and geckos seek refuge in the sheltered core of the porcupine shrub, where the white and purple spotted berries are very attractive to their lizard-eyes. They gobble up the juicy fruit and when they leave to find another place to hide, they deposit the seed in a ready-made nutrient package. Passing through the lizard’s digestive system increases the chance of germination as well as providing a kick start in sometimes very harsh conditions. All the while, our lizards benefit from the energy rich berries and shelter these plants give them.
Using these clever techniques, the porcupine shrub can propagate in harsh environments. Occasionally, on a summer’s day you might see a skink hiding away in a porcupine shrub at our Whakatipu Reforestation Trust, Whitechapel site. Take a moment to appreciate the intricate multi-species relationship that creates a better environment for the whole ecosystem.
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