10 of New Zealand's most endangered species to keep an eye on for 2020

Metrosideros bartlettii/Bartlett's rātā, or rātā moehau, one of New Zealand's most endangered species. Photo / Peter de Lange

The Māui's dolphin is held up as the poster child of New Zealand's endangered species, but the mammal is far from the only species struggling to cope in New Zealand's water, forests and rivers. These are the 10 of the country's native species to keep an eye on in 2020 as they face the biggest fight for survival.

In a country with 4000 threatened species, conservation in New Zealand is often about picking winners.

What makes our species so special is the number that are native - found nowhere else in the world largely because of the millions of years our land spent in happy isolation.

But that isolation is something that has made so many of our species vulnerable.

In 750 years since humans arrived, bringing various predators along with them, New Zealand lost a third of its indigenous land and freshwater birds, around 18 per cent of endemic seabirds, three of seven species of frogs, at least 12 invertebrates, up to 11 types of plants, and a fish, a bat and perhaps three known reptiles.

Some of the most threatened species today are well-known, such as māui dolphins and kākāpō, but others are also clinging to survival.

There are, for example, as few as 200 Chatham Island tāiko remaining. In Northland, only 13 Bartlett's rata are left.

The Department of Conservation's budget and energy can extend only to active interventions for a few hundred of the remaining endangered species - the exercise involves a careful balance of funding, community input, national identity and research.

An additional $76 million in the Government's budget over the next four years to tackle the biodiversity crisis has seen an increase in interventions.

DoC kākāpō technical adviser Daryl Eason said what made the unique parrot so special was that it had no close relatives, and also poor breeding and genetics, so if it was left to its own devices it would most likely become extinct.

Meanwhile, some other endangered species had more varied and resilient genetics, meaning they could perform well provided there was appropriate predator control.

Last summer's prolific rimu fruiting saw the greatest kākāpō breeding season since the intensive management programme began back in 1995, with 72 chicks reaching an age when they could leave the nest (the previous highest was 34).

But the fungal infection Aspergillosis, discovered on island Whenua Hou in July, ended up killing nine kākāpō from the 2019 cohort - two adult females and seven chicks.

Eason said the situation was still "very good" for the endemic parrot, but DoC would be keeping a close eye on what caused the infection outbreak through 2020 and beyond.

Along with DoC's work, Eason said programmes like Predator Free 2050 and backyard trapping initiatives would all help to turn around the situations for New Zealand's threatened species.

"Kākāpō were once found all over New Zealand. The habitat is there, so if we are really able to boost our predator control then they should be able to return to the mainland."

10 endangered species to keep an eye on for 2020 and beyond

1. Tara iti/New Zealand fairy tern

Population: 35-40

Found: Northland and north Auckland beaches

Threats: Predators, habitat loss and human disturbance

With fewer than 40 birds, the tara iti is critical despite intensive management and has teetered on the brink of extinction since the 1980s.

While its population might seem alarmingly low, the number of birds that once roamed the country dropped to a frightening 10 individuals a few decades ago.

There are just 35-40 tara iti/New Zealand fairy tern left in the country. Photo / File

Major threats to the bird include predators - mainly cats, ferrets and black-billed gulls - and habitat destruction.

The birds would naturally nest in sand dunes and estuarine areas - which are havens from storms and king tides - but housing pressures and property developments have increasingly pushed them onto exposed beaches.

The last few seasons had proven devastating for their breeding, with last year just two chicks hatching, and one breeding female dying. In the previous year five chicks fledged.

Nests in exposed areas could be blown away by high winds, preventing parent birds finding their eggs.

King tides could also wash them away.

Beachgoers and motorists who roamed the dunes and upper beach areas also risked trampling their nests.

Various projects are underway to restore nesting sites around the Kaipara Harbour, and Mangawhai, Te Arai and Waipu beaches.

2. Kākāpō

Population: 210 birds (November 2019)

Found: Whenua Hou/Codfish Island and Anchor Island

Threats: Habitat loss and predation by rats, cats, and stoats

The flightless "parrot of the night" was once plentiful and with few natural predators nested at ground level. This made it vulnerable to introduced predators and was now classed as "nationally critical".

The bird only survives on predator-free island sanctuaries and receives some of the most intense protective measures. All birds carry radio transmitters and are intensively monitored and managed.

Despite nine kākāpō dying this year from fungal disease the population is looking the best in years thanks to a bumper breeding season last summer. Photo / File

A bumper breeding season this year saw a record 72 chicks leave the nest, but fears were raised for the species after the fungal infection Aspergillosis was discovered on Whenua Hou in July.

By December the infection had killed nine kākāpō.

Still, the species is in its best shape in years and DoC staff will be keeping a close watch on fledgling chicks ahead of the next breeding season when the rimu tree next fruits.

3. Chatham Island tāiko

Population: 200-250

Found: Chatham Islands

Threats: Predation by cats, pigs, weka and rodents

The Chatham Island tāiko is one of the rarest seabirds in the world with just 200-250 thought to exist. About 35 breeding burrows are currently known.

They breed only in dense forests at the southern end of main Chatham Island.

The Chatham Island tāiko is one of the world's rarest seabirds with just 200-250 remaining. Photo / File

During the breeding season, the birds feed mainly south and east of the colonies, ranging thousands of kilometres.

During the winter exodus, they disperse widely across the Pacific Ocean from the Tasman Sea to South America, and into tropical seas.

An intensive conservation programme is run annually to protect this summer-nesting seabird.

4. Kakī/black stilt

Population: 150

Found: Mackenzie Basin, Canterbury

Threats: Habitat loss due to farming and hydroelectric development, predation by feral cats and ferrets, human interference

Once the common stilt of New Zealand, the black stilt is now critically endangered, with a breeding population confined to the Mackenzie Basin of South Canterbury and North Otago.

The kakī/black stilt has bounced back from a low of 23 birds in the 1980s to about 150 today. Photo / File

DoC has intensively managed the highly-threatened birds since 1981 when their population declined to a low of just 23. There are now 128 adult kakī living in the wild.

Despite intensive management and a captive breeding site near Twizel, they remain the world's rarest wading birds.

Nearly all wild black stilts stem from intensive management, especially captive management.

5. Bartlett's rātā/rātā moehau

Population: 13 adult trees (down from 34 known in 1992)

Found: Northland

Threats: Browsing animals, fire and myrtle rust

Bartlett's rātā can grow up to 30 metres tall and have spongy, tissue-like bark that is readily flaking.

It is only found in Northland where it is only known from three forest remnants near Spirits Bay. It is a cousin of pohutukawa.

Metrosideros bartlettii/Bartlett's rātā, or rātā moehau, one of New Zealand's most endangered species. Photo / Peter de Lange

An "epiphyte", the tree starts life perched in the branches of another tree - usually pūriri, taraire, rewarewa and tree ferns - and sends its roots towards the ground to eventually establish itself as a stand-alone tree.

The species is at severe risk from animals, fire and myrtle rust. Rātā moehau also supports two endemic liverworts which are also now at severe risk of extinction.

6. Pimelea eremitica/Roimata o Tohe

Population: 24 plants in a single site

Found: Maunganui Bluff in Northland

Threats: Goats

Pimelea eremitica/Roimata o Tohe is a low-growing sprawling shrub with greyish-hairy thin flexible leaves. It inhabits a single site at Maunganui Bluff in Northland, which is threatened by goats.

Pimelea eremitica/nga roimata o Tohe, one of New Zealand's most endangered species. Photo / Peter de Lange

The coastal shrub lives on an exposed summit among short exotic grassland and low shrubs amongst basalt boulders

7. Clianthus puniceus/kākābeak

Population: One plant in the wild

Found: Near Kaipara Harbour

Threats: Summer droughts, competition from weeds, and browsing animals, including rodents

There are two species of kākābeak. One is doing OK but the other is in very serious trouble.

There is just one of these kaka beak plants remaining in the wild. Photo / File

Clianthus puniceus is a rare small bushy shrub with drooping clusters of pink, red or white sharp-tipped flowers. As of 2005 only one plant was known from the wild, at a single site near the Kaipara Harbour.

The plant grows in short coastal scrub on a slope of rock debris at the base of eroding mudstone cliffs.

Its close cousin, Clianthus maximus (kaka beak) is found commonly in cultivation as an ornamental plant but is rare in the wild.

8. Red Mistletoe/Peraxilla tetrapetala

Population: Declining

Found: Beech forests

Threats: Introduced brush-tailed possums

Red mistletoe, (pikirangi, pirita, roeroe, pirinoa) is classified as at-risk/declining.

Red mistleton /Peraxilla tetrapetala is an endemic parasitic plant, and browsed on by possums. Photo / File

It grows from the mountains to the sea as a hemi parasite – mainly on beech trees but also pōhutukawa and pūriri.

The most obvious threat is the introduced brush-tailed possums that heavily browse mistletoes.

9. Bryde's whale

Population: 70 individuals

Found: Tīkapa Moana/Hauraki Gulf

Threats: Ship strike

The world population of Bryde's whale is estimated at around 90,000, while there are only about 70 living in an area extending from the Hauraki Gulf Marine Park in the south to Parengarenga Harbour in the Far North.

Only 70 Bryde's whales are believed to remain in New Zealand's waters, featured predominantly around Tīkapa Moana/Hauraki Gulf. Photo / File

They are often seen off Tiritiri Matangi and Waiheke Islands, particularly from September to May and fewer animals there during the winter.

Collision by ships is the main threat for Bryde's whales in the Hauraki Gulf.

10. Māui dolphin

Population: Between 57-75 over the age of one year

Found: West Coast of the North Island

Threats: Set netting, disease, resource exploration, boat strike

Māui dolphins lay claim to being the world's smallest dolphin, and one of the rarest.

With a population thought to be just over 50 found on the West Coast of the North Island from Maunganui Bluff to Whanganui, they are described as nationally critical.

Māui dolphin are found close inshore, and as such activities such as boating and fishing – particularly set netting, can pose a threat to their survival.

Littering and pollution and boat strike are also an issue.

Just 57-75 maui dolphins are believed to remain. Photo / File

They have also been shown to be susceptible to disease including toxoplasmosis and brucellosis.

A Marine Mammal Sanctuary was created in 2008 as a part of the Hector's and Māui dolphin Threat Management Plan from Maunganui Bluff to Oakura, and restrictions to set nets and trawling occurs in much of the Māui dolphin's range.

Within the sanctuary boundaries, restrictions were placed on seabed mining activities and acoustic seismic survey work.

In 2013 the sanctuary was extended to include more of the Māui dolphin's range in the Taranaki region, and the Government this year proposed to extend even further the area where fishing vessels are banned from using trawl nets.

This recent extension has been opposed by Seafood New Zealand, which says toxoplasmosis - spread by cat faeces - posed a greater threat than fishing vessels. Meanwhile, Greenpeace wants a full ban of all gill netting and trawling from Māui and Hector's habitat out to 100 metres.