Tongariro’s Unique Ecosystem Up In Flames – Expert Reaction

Native creatures and habitats across Tongariro National
Park have been disrupted by a massive 3,000 hectare
blaze.

The Department of Conservation says its staff
will
assess the site when safe to do so, to
understand the scale of the damage.

The
SMC asked experts to comment.

Katerina
Pihera-Ridge, Indigenous planner and Indigenous flammability
co-lead, Bioeconomy Science Institute,
comments:

“For Māori, our relationship
with Te Taiao – our environment and place, is inherent and
enduring. However, that connection is challenged by land use
changes, introduced species, climate shifts, and
restrictions on kaitiaki practices – all of which have
combined to increase wildfire risk.

“In Aotearoa,
current wildfire preparedness does not match the growing
risk. We know the whakapapa of fire, forest, and whenua, and
that knowledge matters now more than ever. No one wants to
watch their taonga burn and stories be
lost.

“Globally, fire-prone regions are turning to
Indigenous practitioners for cultural fire approaches to
land management and ecosystem restoration. Reconnecting with
cultural fire practices is relevant today, and Iwi
leadership and partnerships with other Indigenous peoples,
sciences and agencies – promote new methods and
solutions.

“Wildfire planning and resilience is not
just ‘nice to have’ – it is a real opportunity for a
frontline strategy in wildfire preparedness and local
solutions.”

No conflict of
interest.

Dr Nicola Day, Senior Lecturer,
Fire Ecologist, School of Biological Sciences, Victoria
University of Wellington,
comments:

“Tongariro National Park has a
range of native species that are already facing decline, and
increased fire activity with climate change presents a
further risk to native biodiversity. The alpine area is
covered with native grasses and shrubs that provide
important habitat for native reptiles, birds, and
invertebrates. The pictures and reports suggest that tussock
grassland and woody shrubs are what are burning, and it
looks similar to what the Lake Ōhau area looked like after
the 2020 fire.

“Our research from other native
alpine and subalpine areas that have burned, like Pukaki and
Ōhau, suggest that recovery of vegetation is quite quick.
Woody species take longer to recover. Surprisingly, we’ve
found that many of our native species in tussock grasslands
can survive fires, but so can many exotic species. We do
tend to see an increase in non-native grasses like browntop
for a period of time after fire, and this can persist for
decades.

“The funny thing about fires is that the
vegetation that comes back after a fire is typically quite
flammable. So, with drier and warmer conditions combined
with more flammable plants after fires, this could lead to
more frequent fire events and that could have massive
impacts on native plants and animals. With more fires, our
landscapes might look quite different in the
future.

“Fires are going to become more common in NZ
and even though a lot of our plants can bounce back quickly,
more fires will cause changes to our
landscapes.”

Conflict of interest statement: “I
currently receive funding from the Department of
Conservation and Bioprotection
Aotearoa.”

Associate Professor Julie
Deslippe, Plant Ecologist, Victoria University of
Wellington, comments:

“The 2,800-hectare
wildfire in Tongariro National Park, a UNESCO natural and
cultural World Heritage Site, has profound implications for
the conservation of our native flora. The fire swept through
extensive subalpine and alpine shrubland and tussock
grassland communities, strongholds for rare and regionally
endemic species of deep ecological and cultural
significance. Native shrubs such monoao (Dracophyllum spp.),
the alpine shrub daisies (Celmesia spp.) and important
rongoā plants like piripiri (Acaena emittens) are heavily
affected. Microhabitats hosting specialist species are at
particular risk; the loss of even a single population can be
devastating for species like the recently described,
nationally critical Cardamine panatohea, known from only two
alpine flush sites in the park.

“Fire has always
shaped the flora and fauna of this volcanic landscape, but
the combined pressures of climate change, invasive weeds,
and conversion of surrounding lands to pasture and forestry
now threaten irreversible degradation. When fire exposes
bare ground, introduced exotics like heather, gorse, broom,
and pines, with vast seed banks and fire-stimulated
germination rapidly colonise, outcompeting native species
that are slower to recruit.

“On Monday, Ngāti
Hikairo kaumātua Ngaehe Wanikau spoke movingly on TVNZ of
the ecological and emotional toll of these legacies. The
iwi-supported ten-year rāhui on commercial activity
provides time for the whenua to heal and for restoration to
begin. Yet there is an urgent need for research on seed
ecology and the propagation of native species to guide
effective recovery. Equally vital is a dedicated budget for
iwi-led restoration, enabling coordinated revegetation and
sustained weed management to secure the long-term resilience
of our national treasure.”

No conflicts of
interest.

Professor George Perry, Fire
Ecologist, School of Environment, University of Auckland,
comments:

“Around the world, large
wildfires are becoming more
frequent and more intense as climate and
land-use changes. Recent events in the Port Hills, Lake
Tekapo, and Tongariro show us that the landscapes of
Aotearoa-New Zealand are also becoming more vulnerable to
fire. Climate models suggest that extreme fire weather (hot,
dry, and windy) that facilitate fire spread will likely
become more frequent by the end of this
century.

“Before humans arrived, fire was rare in
Aotearoa, and most of our native plants do not have the
kinds of fire-adaptations seen where fire is more frequent.
As a result, sensitive vegetation, such as the sub-alpine
shrublands of Tongariro, may be very slow to recover from
fire. By contrast, some introduced species, such as gorse,
are highly flammable and potentially favoured in post-fire
environments. The vegetation, such as mānuka shrublands,
that often dominates in the two or three decades after fire
can also burn easily. Thus, there is a risk of “fire
traps”, where fire-begets-fire, slowing or even stopping
forests from recovering and locking the landscape into a
cycle of burning.

“These changes raise urgent
questions:

• How will our ecosystems cope with more
  frequent fires?
• Could native forests become trapped
  in cycles of burning?
• What are the direct and
  indirect social and economic costs associated with shifting
  patterns of fire activity?

“The nearly 3000 ha
Tongariro fire shows us that these challenges are no longer
confined to fire-prone regions like California or
southeastern Australia. Aotearoa must prepare for life in a
hotter, more fire-prone world.”

Conflict of
interest statement: “No conflicts of interest. I am
working on various fire projects that DoC have
funded.”

Dr Janet Wilmshurst, Ecosystem
Resilience research team, Bioeconomy Science Institute,
comments:

“Tongariro is a UNESCO World
Heritage Park with a dual mandate to preserve highly
significant natural and cultural features, attracting vast
visitor numbers. Before Māori arrival, Tongariro National
Park was largely covered in dense forest and natural fires
were infrequent. Māori-era fires cleared forest from the
northern and eastern slopes of the volcanoes creating a
landscape of inaka, mānuka, kānuka and totatoa scrub and
tussock grasslands. Early European sheep farmers later
maintained the tussock cover through frequent fires. They
also introduced fire-adapted weeds including rapidly
spreading broom, gorse and heather which have been replacing
the tussock. In addition, wilding pines from adjacent
plantations are threatening to turn vast areas into dense
pine forest.

“The volatile oil-packed foliage of the
native scrub and woody weed species, and their fine twiggy
growth, provides ideal fuel for hot, destructive fires.
However, ignitions have been relatively rare since grazing
ceased in the park, but the combination of flammability
traits, fire-adapted weed spread, and climate change along
with increasing visitor numbers and infrastructure has now
increased the risk of ignitions and large hot fires. This
volatile mix has made the management of fire-prone
ecosystems throughout New Zealand increasingly difficult and
expensive. It also calls for an integrated management
approach that protects ecologically and culturally sensitive
fire-prone areas, infrastructure and our tourism
economy.

“Weed control, educating visitors about
fire risk, banning open fires and replacing fireplaces in
huts with gas heating, and even closing the park at times of
heightened risk (for example during prolonged drought) might
be some options. More radical options might include
long-term restorative rāhui to the most sensitive
ecological and cultural areas, allowing them the centuries
they need to return to a weed-supressing forest of
podocarps, beech and broadleaves that will finally release
these ecosystems out of a weedy fire-trap where fire begets
fire.”

Note: This expert comment was prepared by
Janet Wilmshurst, with Peter Bellingham, Matt McGlone and
Sarah Richardson, of the Bioeconomy Science Institute
(Manaaki Whenua – Landcare Research Group) Ecosystems
Resilience research team. The Bioeconomy Science Institute
undertakes research on the ecological effects of fires,
including fire-adapted ecosystems.

No conflict
of interest declared.

Shana Gross, Fire
Ecologist, Bioeconomy Science Institute,
comments:

“Each wildfire is a unique event
due to the combination of the fire environment (topography,
fuels (in this case vegetation), and weather). These drive
the fire behaviour. Therefore, every wildfire provides a
learning opportunity to improve our understanding of fire
behaviour and recovery (both ecological and social). These
lessons help us better prepare for future events, ideally
reducing future impact.

“Key ecological questions
following a fire are around recovery – what species
survive and what regenerates. Unfortunately weeds often
follow fires and can change the future disturbance regime,
sometimes favouring future fires. While weeds can invade
following a fire, the success of different species will be
dependent on the distance to seed source, how hot the fire
burned, and what is left behind.

“Wildfires rarely
burn everything – even high severity fires will often have
unburned or moderately burned islands of vegetation. These
islands of vegetation remain for a variety of reasons –
tied to fuel availability (i.e. some plant species may have
held more moisture or in general be harder to burn) and
shifts in weather. These islands also offer seed sources for
regeneration – ideally of native species, but in some
cases weedy species.

“The foundation question that
we would investigate following a wildfire would be around
fire behaviour – how the fire burnt through different
fuels under the weather conditions. This background
information can provide critical data points for fuel models
that underly fire simulation models, as well as provide the
foundation for understanding recovery. Recovery following a
fire will look different depending on the species present
before and after, and the magnitude of the disturbance. When
you lose the fire effects information you lose a piece of
the puzzle to understand future recovery from other fire
events. Unfortunately, this information needs to be captured
quickly either during the fire and/or following the fire
before major rain events wash away
indicators.”

No conflict of interest
declared.

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