Native frogs rehomed during Brynderwyns roading project
‘Remarkable’ 600 Hochstetter’s frogs found
Afrog expert has called the discovery of 600 native Hochstetter’s frogs during the Brynderwyn Hills’ roading project “remarkable” and says it shows the area must be a significant habitat for the species.
The Advocate was told about the huge number of frogs during a recent media tour of the project site.
Neither the NZ Transport Agency Waka Kotahi (NZTA) nor the Department of Conservation (DoC) will confirm the number of frogs found, as both say they are waiting on a formal report process.
However, the Advocate understands that site works destroyed the frogs’ habitat and they were relocated out of the alignment area but further along the same water course.
NZTA director of regional relationships Steve Mutton said the agency had been working closely with DoC to minimise adverse effects on the frogs and other resident taonga species.
A field ecology team was monitoring those species within the site and relocating wildlife as necessary within the requirements of the Wildlife Act.
He said culvert extensions required the removal of habit. A project ecology team manually searched impacted gullies and any Hochstetter’s frogs found were relocated to areas outside the works’ footprint along the same water course that they already inhabit as per DoC approved management plans.
“Salvage” to date had also included snail and lizard species. A sniffer dog was on site to look for kiwi but hadn’t found any so far.
The agency wouldn’t confirm the numbers of each species that had been relocated so far. Figures would not be released until after it had prepared and presented a report to mana whenua and DoC.
DoC also declined to comment on numbers of species relocated, saying it was awaiting the report.
According to the New Zealand Herpetological Society’s website, the Hochstetter’s frog is New Zealand’s most widespread and commonly encountered native frog species.
While classified as at risk — declining due to a multitude of threats, they have fared much better than other native frogs because of their more aquatic nature. They are almost exclusively associated with small forested catchments or seepages.
However, the society said like all frogs, Hochstetter’s were highly sensitive to environmental changes including those caused by infrastructure projects such as the work being done in the Brynderwyn Hills — involving earth movement, habitat destruction, and potential contamination of waterways.
Herpetologist (amphibian and reptile specialist) and Otago University ecology lecturer Jo Monks said to find 600 Hochstetter’s within a single development was “pretty remarkable” as the species, now confined to the north of the North Island, “isn’t doing super well overall”.
It was difficult to say if the relocation of the frogs would be a success as there was not much known about the effectiveness of relocating frogs and amphibians.
Monks said that unless a really thorough survey is carried out as to where frogs are being relocated to then they may potentially compete with resident individuals in the new location.
“And if there aren’t any resident frogs in this case at that new location it kind of suggests that
"The discovery shows the importance of ecological survey work ahead of major infrastructure projects."
perhaps that environment isn’t quite as suitable for whatever reason.
“So unless there’s other mitigation measures put in place to compensate for that then you can’t really expect them to do as well in the new spot.”
Monks didn’t know how much work had gone into a Brynderwyn Hills’ survey — and neither NZTA nor DoC would disclose the process to the Advocate at this stage.
However, Monks thought it would take at least a week of nighttime surveys or day-time rocklifting surveys — in good weather for frogs.
She said this discovery showed the importance of ecological survey work ahead of major infrastructure projects.
Monks said she had strong concerns about the Government’s proposed suite of legislative changes, including how its fasttrack approvals bill, might affect necessary surveys ahead of similar works in future.
Partners in biosecurity Viki Heta (Ngā Hāpu o Te Rāwhiti and Ngāti Kuta rāua Ko Patukeha) and Arana (Rana) Rewha were honoured for their work in biosecurity in New Zealand.
Heta and Rewha are this year’s Biosecurity Awards Supreme winners for their work in fighting caulerpa seaweed and also championing the eradication of Sika deer.
Biosecurity Minister Andrew Hoggard said strong biosecurity was vital and underpinned New Zealand’s economy, flora and fauna.
“Rana’s in-depth knowledge of local ocean currents and hydrology is helping response teams to identify and target their efforts to prevent further spread of this destructive seaweed in Northland Te Tai Tokerau.”
Hoggard added that their work in the eradication of Sika deer in Russel Forest and Ngaiotonga Scenic Reserve led to a 20-year forest health plan to restore the health and biodiversity of the area.
“The New Zealand Biosecurity Awards celebrate inspiring and diverse biosecurity champions who are making significant contributions to biosecurity in New Zealand.”
Hoggard said this year’s finalists and winners represent a high calibre of New Zealanders who are leading efforts to protect our way of life and our unique environment for future generations.
“I’d like to congratulate to all our winners and finalists in this year’s New Zealand Biosecurity Awards and thank them for their ongoing commitment to biosecurity and their communities.”
"Rana’s in-depth knowledge of local ocean currents and hydrology is helping response teams to identify and target their efforts to prevent further spread of this destructive seaweed in Northland Te Tai Tokerau." Biosecurity Minister Andrew Hoggard