Only three endemic frogs live in New Zealand. Two, the Archey and Hochstetter frogs, live in the sanctuary.<\/p>\n
Mahakirau Forest Estate Society\u2019s operations manager and conservation advocate Sara Smerdon said the results were \u201cpretty confronting\u201d. <\/p>\n
More than 90% of ferret guts tested contained frog DNA, indicating an \u201calarming\u201d level of predation and raising concerns for native ecosystems. <\/p>\n
Sara Smerdon is Conservation Advocate at the Mahakirau Sanctuary, as well as a landowner and the sanctuary’s operations manager. <\/p>\n
Estate history<\/p>\n
Mahakirau Estate covers about 600ha and has thousands of species, including Forest Ringlet butterflies \u201con the brink of extinction\u201d, the rare Coromandel striped gecko, and k\u014dkopu (native fish). <\/p>\n
The land was divided into 24 properties under the QEII covenant. Landowners had responsibilities for animal and plant control. <\/p>\n
Smerdon is one of 24 landowners at Mahakirau, living among the species she aims to preserve. <\/p>\n
\u201cThere are Archey\u2019s frogs and rare geckos right under our feet,\u201d she told the Waikato Herald. <\/p>\n
\u201cI think that\u2019s one of the keys to the success of our project; is that we actually live in with the creatures that we are protecting.\u201d<\/p>\n
More than 2000 stoats have been removed from the sanctuary since the trust started in 2001. <\/p>\n
Stoats are just one of many predators roaming the estate. There are also mice, rats, weasels, possums, pigs, feral cats, and other \u201cintroduced threats\u201d. <\/p>\n
\u201cThey are just like eating everything … It\u2019s just annihilating.\u201d<\/p>\n
Smerdon has been doing predator control at the sanctuary for more than 15 years, \u201csaving species\u201d. <\/p>\n
She needed to know what\u2019s in a predator\u2019s \u201cseasonal diet\u201d to understand which protected animals were at risk.<\/p>\n
Pig study<\/p>\n
Smerdon reached out to Waikato Regional Council for eDNA testing after a Department of Conservation worker monitoring a nearby field uncovered \u201cvisual evidence\u201d of Archey and Hochstetter frogs in pigs\u2019 guts.<\/p>\n
There were a \u201cfew scenarios\u201d of people finding this before, but there had \u201cnever been solid evidence until then\u201d. <\/p>\n
\u201cHe was pulling out like 50 frog arms and legs [from pigs].\u201d<\/p>\n
With both frog species living at Mahakirau, she wanted to know if the same was happening there.<\/p>\n
The first testing round did not show visual evidence, but she said it produced a peak sample of 53% of pigs containing Archey and Hochstetter frog DNA.<\/p>\n
It increased to more than 75% during the frog emergence season. <\/p>\n
Smerdon said Archey frogs were among the most commonly detected prey in pigs.<\/p>\n
She felt frogs were a target for pigs after a hunter pulled almost 60 frogs from one pig. <\/p>\n
\u201cYou\u2019d have to say that pig is targeting frogs.\u201d <\/p>\n
Remains of multiple Archey’s and Hochstetter’s frogs recovered from the stomach of a ferret caught at Mahakirau Sanctuary. Photo \/ Sara Smerdon <\/p>\n
Ferret study<\/p>\n
Smerdon has been collecting ferrets at Mahakirau for more than five years. She uses them for genetic testing to see how the species disperse, how far they roam and where they come from. <\/p>\n
She decided to have the guts of frozen \u201cfresh ferrets\u201d eDNA tested at the same time as pigs. <\/p>\n
She described the ferrets she used as \u201cthe highlight\u201d of her trapping career \u2013 two caught in one trap at once.<\/p>\n
However, the results were \u201calarming\u201d.<\/p>\n
\u201cWe slit it open, and frog parts just rolled out … my heart sank,\u201d she said. <\/p>\n
\u201cThat one [had] four individual frogs, and I could see there was Archey, as well as a Hochstetter foot in one.\u201d<\/p>\n
Smerdon continued testing, leading to frog DNA being detected in 90% of ferrets\u2019 guts.<\/p>\n
She believed ferrets, like pigs, were targeting frogs and \u201cfishing for eel\u201d.<\/p>\n
\u201cThey are definitely seeking out frogs as part of their staple diet.\u201d <\/p>\n
Ecosystem<\/p>\n
The animals are moving between the forest floor, canopy and waterways, and eating across the ecosystem. <\/p>\n
Smerdon said the impact is \u201cgenerational\u201d. <\/p>\n
They have found eggshells in stoats from eDNA testing, showing a \u201cclear sign\u201d of juvenile and adult birds inside their guts. <\/p>\n
\u201cThat\u2019s taking the whole life cycle out.\u201d<\/p>\n
They\u2019ve also found ferrets that have eaten gravid frogs carrying eggs. <\/p>\n
\u201cSo it\u2019s taking out the eggs of the next generation.\u201d<\/p>\n
Smerdon said Archey frogs live for 40 years and their habitat is about 1sq m.<\/p>\n
\u201cIf a pig or a ferret goes into their habitats and finds a frog, they are taking out generational frogs. <\/p>\n
\u201cWe don\u2019t have that many [frogs around].\u201d<\/p>\n
She said results show \u201chow broadly these predators exploit that biodiversity\u201d. <\/p>\n
A ferret and the native frog remains recovered from its stomach at Mahakirau Sanctuary. Photo \/ Sara Smerdon <\/p>\n
\u2018New findings\u2019<\/p>\n
Paul Dutton, Waikato Regional Council senior scientist for terrestrial ecology, said eDNA testing complements traditional monitoring methods. <\/p>\n
The council has used it since 2019.<\/p>\n
\u201cThe results of eDNA testing always need to be critically examined due to the risk of contamination during any phase of testing,\u201d Dutton said.<\/p>\n
He said Smerdon reached out for testing between 2023 and 2025 following \u201cobservations of frog predation\u201d.<\/p>\n
\u201cThe results revealed native species DNA \u2013 including threatened species \u2013 in gut swab samples.\u201d <\/p>\n
While some predator-prey associations \u201cwere new findings\u201d, the pattern was \u201cnot unexpected given the opportunistic feeding behaviour\u201d of the predators. <\/p>\n
Dutton said the results demonstrated the \u201cremarkable breadth of native fauna\u201d, whose predation would be \u201cextremely difficult to detect\u201d without it. <\/p>\n
He said looking at a predator\u2019s guts is an additional tool for understanding ecological interactions.<\/p>\n
Smerdon recommends other conservationists use eDNA testing. <\/p>\n
\u201cHoning in on [their guts] is one of the best ways of finding out if you have a presence of these species in your environment. <\/p>\n
\u201cThen you can wrap your predator control and monitoring surveys around that.<\/p>\n
\u201cWe need to be using all these tools that are available to us.\u201d <\/p>\n
Malisha Kumar is a multimedia journalist based in Hamilton. She joined the Waikato Herald in 2023 after working for Radio 1XX in Whakat\u0101ne.<\/p>\n","protected":false},"excerpt":{"rendered":"Only three endemic frogs live in New Zealand. Two, the Archey and Hochstetter frogs, live in the sanctuary.…\n","protected":false},"author":2,"featured_media":590304,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[77486,95,290699,1763,42037,4058,155286,5818,1866,1874,1391,290700,290698,111,139,69,254,99375,8205,6289,60895,147,1361,1961,406],"class_list":["post-590303","post","type-post","status-publish","format-standard","has-post-thumbnail","category-wildlife","tag-advisory","tag-and","tag-archey","tag-article","tag-confronting","tag-contains","tag-coromandels","tag-eating","tag-find","tag-found","tag-frogs","tag-hochstetter","tag-mahakirau","tag-new-zealand","tag-newzealand","tag-nz","tag-photos","tag-pigs","tag-rare","tag-readers","tag-sanctuary","tag-science","tag-that","tag-this","tag-wildlife"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/590303","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=590303"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/590303\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/590304"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=590303"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=590303"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=590303"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}