The fire is out, but Tongariro is now at risk of losing its unique biological legacy

The sight of flames tearing across Tongariro National Park last week was heartbreaking for lovers of the landscape. It was also potentially disastrous for a world-renowned alpine ecosystem.

With aerial footage exposing the scale of the wildfire – nearly 3,000 hectares was burned – the impact on spiritually and ecologically important land could well be severe.

The Department of Conservation is now working to assess the damage. Ecologists, iwi and conservationists will be anxious to learn just what has been lost.

The disaster should also raise questions about how we fund, manage and protect these vulnerable habitats in a warming world where change is often outpacing conservation efforts.

What may have been lost

For ecologists who have studied the national park’s rare plant communities, the true toll might not be measured in hectares burned, but in the loss of irreplaceable genetic diversity.

Alpine zones such as Tongariro National Park – a dual World Heritage area – are geological anomalies where species diversity is uniquely high. The flames swept through extensive sub-alpine shrubland and tussock grassland, strongholds for rare species.

These likely included native shrubs such as monoao (Dracophyllum), the alpine shrub daisies (Celmesia) and important rongoa (medicinal) plants such as piripiri (Acaena emittens).

Micro-habitats hosting specialist species will have been at particular risk.

The demise of just a single population can be devastating for species like the recently described and threatened herb Cardamine panatohea. It would diminish the genetic trait that gives them the ability to evolve and adapt to future change.

This biological richness is a direct result of millions of years of isolation, where flora retreated uphill during periods of change. It led to a unique pattern where biodiversity increases with elevation – the opposite of most places worldwide.

Along with the ecological devastation, fire’s impact on mana whenua, Ngati Hikairo ki Tongariro, whose identity is inextricably linked to the health of the maunga, cannot be overstated.

Why the risks are rising

Having existed through thousands of years of volcanism, Tongariro’s landscape is no stranger to heat and fire. The current threat, however, is magnified by human-driven pressures.

For instance, native plants such as the red tussock Chionochloa rubra are naturally fire-resilient and able to re-sprout after light surface burns. Increasingly, that resilience is being overwhelmed.

The combination of hotter, drier summers and increased tourist traffic is leading to deep, hot fires – not light surface burns – and introducing higher risks of accidental ignition.

This means an event that might have occurred once every thousand years is now happening over decades, accelerating faster than the native flora can recover.

The most concerning threat follows the flames: what ecologists call “regime shift”.

The fire exposes large tracts of bare earth, creating a perfect opportunity for introduced exotics. Invasive weeds such as heather, gorse, broom and pine – all possessing vast seed banks and fire-stimulated germination – rapidly colonise the open space.

They out-compete slower native species, threatening to tip the ecosystem from a resilient native tussock landscape into a highly flammable, invasive weed monoculture.

The transformation of the starting point of the country’s most famous day walk into a weed-choked landscape would fundamentally devalue the visitor experience, detracting from the mana (esteem) of our national parks.

Investing in resilience

For now, an iwi-supported ten-year rahui over the fire ground provides time for the whenua (land) to heal and for restoration to begin.

At the same time, there is an urgent need for research on seed ecology and the propagation of native species to guide effective recovery.

For the successful long-term resilience of these ecosystems, we must fundamentally rethink our approach to management and funding, while also looking beyond park boundaries.

In places like Tongariro, the presence of State Highway 1 and the surrounding areas means parks are constantly interacting with disturbed and invaded adjacent land.

Consequently, the biologically and ecologically suitable space for native species is shrinking rapidly, even though the park boundaries on a map aren’t moving.

Protecting this national treasure requires controlling weeds and fire risks on the land surrounding the park, treating the landscape as a whole, interconnected system. Recovery must be guided by both science and cultural knowledge – and it must be properly resourced.

A dedicated budget for iwi-led restoration should be one priority. This is the most effective way to coordinate re-vegetation and sustain weed management efforts, leveraging local community knowledge and deep connection to the whenua.

And it must be accompanied by a reversal of the trend of cutting conservation science. The erosion of the knowledge base through the loss of skilled scientists and resource managers has left the Department of Conservation with reduced capacity to effectively guide long-term recovery efforts.

Our alpine systems – the mountains we tramp, climb, ski and travel through every day – represent the heart of Aotearoa’s ecological and cultural identity.

The increasing frequency of extreme events, fuelled by climate change, combined with the pressure of invasive weeds, threatens to dismantle these unique ecosystems layer by layer. To prevent ecological tragedy like we have just witnessed, we must invest now.

Julie Deslippe receives funding from the Royal Society of New Zealand Marsden Fund and is a Rutherford Dicovery Fellow funded to do Plant Ecology research in Tongariro National Park.