eDNA testing reveals elusive animals

Environmental DNA (eDNA) testing has revealed the presence of several threatened and elusive native species within a traditional Māori food and resource gathering (mahika kai) restoration area.

With the support of the EPA’s Wai Tuwhera o te Taiao programme and the Wai Ora Fund, the Trust has been undertaking eDNA testing throughout the Waiau catchment. eDNA testing is a technique that identifies the presence of flora and fauna in water samples by detecting the tiny traces of genetic material left behind by every living thing.

Over the last two years, the Trust has taken tests at seven different sites along the Waiau catchment, as part of its efforts to better understand which native species call the area home.

This journey started with eDNA samples being taken at Te Kōawa Tūroa o Takitimu in May 2022 by tamariki from Te Anau School. From this they have built on the monitoring and now have a baseline and seasonal data from four sites within or near the restoration project.

Tane Hemi and Jack Lloyd from Te Anau School recording the details on the eDNA sample for Redcliff Creek. Photo credit: Vanessa Horwell

“The results were surprising,” says the Trust’s Programme Manager, Vanessa Horwell.

“We were really blown away by what we’ve been finding. We were especially excited to detect lamprey/kanakana and kōaro (which are part of the whitebait run) in the lower Redcliff Creek. They are a taonga species and a source of mahika kai for Māori,” says Vanessa.

Pouched lamprey/kanakana/piharau are jawless, migratory fish and are from an ancient lineage that have existed for more than 360 million years. They only breed at the end of their life and die after spawning.

“Three of the fish species we’ve detected, the kanakana, Gollum galaxias, and the Southern flathead galaxias, are classed as threatened - nationally vulnerable, which means they are facing high risk of extinction in the medium term.”

The Gollum and Southern Flathead galaxias belong to an ancient, scaleless fish family called Galaxiidae – named for the galaxy-like gold flecks on their backs. The Gollum galaxias was first discovered in 1990 and is found only in Southland, Catlins and Rakiura/Stewart Island. Gollums were detected at all the sites tested.

The spotless crake (Porzana tabuensis plumbea), or pūweto as it is known to Maori, is a cryptic bird of freshwater wetlands throughout North Island and much of South Island. Photo credit: Laurie Boyle

“Our eDNA testing has also detected the furtive wetland-dwelling spotless crake/pūweto in the Jericho valley, which we didn’t know was in this area. They’re very elusive and relatively infrequently seen.”

Spotless crake/pūweto numbers have declined dramatically since people began draining wetlands and they are now classed as at risk.

Vanessa says the presence of these vulnerable and at-risk species demonstrates the growing biodiversity within Te Kōawa Tūroa o Takitimu and the impact of allowing the land to regenerate.

“It’s incredible what Papatūānuku can achieve, with a bit of time and some human help.”

The Trust’s restoration efforts include intensive pest and weed control, as well as extensive native plantings of mahika kai (food) and rokoā (rongoā/medicinal) species.

Trustee Dr Jane Kitson, who is a freshwater ecologist and environmental scientist, says “the restoration project is holistic, encompassing Kāi Tahu’s “ki uta, ki tai” (from the mountains to the sea) philosophy to resource management, trying to restore the area and enhance its mahika kai values.”

“The recent completion of our baseline eDNA survey is a really important first step in tracking the biodiversity of the area and also starting to understand how the changing seasons impact the creatures found in the Waiau catchments,” says Dr Kitson, who is also an executive member of Ōraka Aparima Rūnaka.

Using eDNA technology has empowered the community to reconnect with their environment in a hands-on way, Dr Kitson says.

A recent example of this was a hīkoi Dr Kitson led with Kāi Tahu whānau where eDNA testing was undertaken, alongside cultural monitoring methods at several nohoanga (seasonal campsite) locations along the Waiau.

Whānau taking eDNA samples at Whare Creek during the hīkoi. From left: Jane Kitson, Sharon Weir and Jess McCallum. Photo credit: Vanessa Horwell

“It was a wonderful opportunity for our whānau to reconnect with the Waiau, and the nohoanga sites, strengthen and make new connections with each other. At a lower river nohoanga site the eDNA testing detected wai kōura (freshwater crayfish) and wai kākahi (freshwater mussels), but they weren’t detected elsewhere in the catchment. It would be great to find out the distribution of these mahika kai species across the catchment.”

“Using eDNA testing has allowed us to build an incredible picture of the many different animals in our awa. It will also help us to understand the seasonal and long-term changes in the area and hopefully help us to better target our restoration efforts.”

“One example of this might be further attempts to confirm the distribution of the spotless crake and other birds in our wetland, perhaps using bird call monitoring techniques. This knowledge will help us find ways to help this bird within the valley.”

“If we don’t know what’s there, we don’t know what to protect.”

For the full eDNA results, please read our Waiau Awa Mahika Kai Study - eDNA monitoring report.

To read this article on the EPA website, please click here. Thank you to Alisa Yong from the Environmental Protection Agency for writing this story.

Thanks to the EPA’s Wai Tuwhera o te Taiao programme and the Te Wai Māori Trust’s Wai Ora Fund for funding the eDNA testing, and to Te Rūnanga o Ngāi Tahu and Meridian Energy Power Up Fund for funding the hīkoi where whānau were able to take the eDNA test samples.