How community conservation can protect bittern/matuku-hūrepo and wetland habitats
They may not look picturesque, in the way a Coromandel beach might. The waters aren’t shimmering blue. Things don’t just soar here; they creep and wriggle. Birds don’t just chirp; they croak and boom.
Yet the Hauraki and Coromandel’s wetlands are magical places. Wetlands are ecosystems including rivers, lakes, streams, ponds, swamps, bogs, estuaries, natural springs and more. Wetland plants such as harakeke have long been used by Māori for clothing, mats, medicine and dyes. Wetland fish were valuable food sources and feathers of wetland birds were used to adorn korowai (cloaks).
These ecosystems have many surprising ecological benefits. Acting as filters, wetlands improve water quality by capturing sediment and nutrients and filtering out contaminants. Wetlands act as a buffer zone, protecting coastlines from erosion while also soaking up large amounts of water, reducing the impact of flooding. In dry periods, wetlands slowly release water, reducing the impacts of drought. Certain types of wetlands, including peatlands, sequester large amounts of carbon and help mitigate the impacts of climate change.
Did you know: Wetlands support the greatest concentration of wildlife – more than any other habitat in New Zealand?
DOC Biodiversity Rangers Ben Gordon (Coromandel) and Ken Brown (Hauraki) say these ecosystems are home to many rare and threatened plants, birds and fish species.
“Many native fish including migratory galaxiids/whitebait, eel/tuna, black mudfish/waikaka and bullies live in our wetlands.” says Ken.
Aotearoa has more than 50 native freshwater fish species and 76% are threatened with extinction or at risk of becoming threatened (NIWA).
Uniquely adapted plants like mosses, ferns, orchids, sundews and rushes form intricate carpets across wetlands, filtering and improving water quality.
Threatened bird species such as the Australasian bittern/matuku-hūrepo, brown teal/pāteke, fernbird/mātātā, banded rail/moho pererū, and white heron/kōtuku rely on remnant wetlands to survive.
Wetlands are under threat
In the past, these soggy areas of land were often drained for urban development and agriculture. Over 90% of Aotearoa’s wetlands have been lost and their wildlife faces continued serious threat. Human activity still threatens our remaining wetlands. Ongoing development, forestry sediment, agricultural run-off and damage from stock grazing can further degrade these ecosystems.
“Unfortunately, wetlands are also havens for introduced predators and their impact on wildlife is devastating,” says Ben. “Possums, hedgehogs, mustelids, feral cats and rodents eat wetland birds and their eggs. Rats will also eat whitebait eggs, such as those of the shortjaw kōkopu. Rabbits and possums eat wetland plants, while magpies are aggressive to native birds. We can restore wetlands through activities including reflooding drained pastures, installing fish passages over obstacles like fords, planting and predator control.”
Bittern/matuku-hūrepo are under threat
Once found in flocks of 100 birds, bittern/matuku-hūrepo are now often solitary, and facing extinction. The total population has plummeted to less than 800, making them now classified as ‘nationally critical’ – rarer than kiwi and as threatened as kākāpō. Bitterns are indicators of freshwater health, showing that our wetlands face significant pressures and threats. These birds hunt by sight, relying on high water quality to hunt eels and fish, but polluted waterways make this difficult.
Wetland ecosystems are strongly interconnected. With the significant reduction of freshwater habitats, native fish populations are also declining. As fish are a crucial food source for wetland birds, it’s important to follow whitebait fishing regulations to sustainably manage this precious taonga. Habitat pressures mean bittern/matuku-hūrepo are forced to spend more time near the roadside. Due to a lack of fish, they feed on lizards warming up on roads and the birds don’t flee from oncoming cars.
“In the last 12 months, five bittern/matuku-hūrepo deaths in the Coromandel resulting from vehicle strikes have been reported to the Whitianga Office,” says Ben. A new partnership has been formed to focus on the recovery of this precious bird, involving Bittern Conservation Trust, Predator Free Hauraki Coromandel, Department of Conservation, and Waikato Regional Council.
Bittern Conservation Trust trustee Paul Johnson is asking the community for help monitoring matuku-hūrepo during October.
“Monitoring helps grow our understanding of where the birds live and breed so we can better protect them and ensure they survive. Matuku-hūrepo are very cryptic birds, so we count their population by listening to the males’ mating call – a haunting booming sound that echoes through the wetland. As females don’t boom, monitoring methods including thermal imagery and drones are being trialed,” says Paul.
How you can help
Volunteer for the Matuku Survey during October. Observers will be in wetlands across the Coromandel, listening for bittern at dawn or dusk.
Check out the Going, Going Gone – Wetlands exhibition at the Mercury Bay Museum until 30 November. Local adults – $10, kids – free.
Keep your dogs away from wetland areas – dogs may harass and kill vulnerable wetland birds and their chicks.
Slow down when driving near wetlands – Matuku-hūrepo won’t flee from oncoming cars. Slow down safely and allow them to move.
Predator Control – join or sponsor a Community Conservation Group that undertakes predator control around wetlands.
Wetlands are an integral part of healthy landscapes and one of the world’s most productive environments. Together we can protect wetlands and all the cryptic creatures lurking in the reeds.
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