Weevil, once thought extinct, still struggling

SHARE

by Paul Gorman

Canterbury’s ugly and rare knobbled weevil is fighting for its life after a bad few years at the Burkes Pass Scenic Reserve.

In 2015, the 12mm-16mm long Canterbury knobbled weevil Hadramphus tuberculatusnamed the country’s second-most threatened species by the Endangered Species Foundation of New Zealand.

Five years ago almost to the day, there were an estimated 50 to 200 weevils living off the speargrass in the 3ha site near the top of Burkes Pass.

Department of Conservation invertebrate ecology technical adviser Warren Chinn now believed there were fewer than 30 of the lumpy-backed weevils in the reserve, possibly as few as a dozen.

“It’s hard not to be despondent. The [reserve] population has declined.

“I would say it’s still extant but it’s looking more likely they could be living on the neighbouring property on the other side of the road.

“We have to remember an absence of evidence is not evidence of absence.”

The 2015 endangered species list put the weevils in third place behind the most endangered, the Maui dolphin, and the runner-up, the Mokohinau stag beetle.

The knobbled weevil has already given New Zealand environmentalists a scare, having been thought extinct between 1922 and 2004, when they were found in the Burkes Pass reserve.

Looking after the weevils was hard and time-consuming work for department staff and volunteers, Mr Chinn said.

Many factors conspired against their survival.

“This is a good example of how multiple effects on an organism’s environment have a multiplying effect on their demise, including predators, fires, changing land use, weeds.”

Staff at the department’s Twizel area office would be happy to hear from anyone who wanted to support work, either with their time or financially, to help save the weevils, he said.

Marked … Department of Conservation invertebrate ecology expert Warren Chinn gives a weevil the once over. PHOTO: DEPARTMENT OF CONSERVATION
Don’t fence me in … A captivity cage, which provides shelter for weevils and speargrasses, at the Burkes Pass reserve. PHOTO: DEPARTMENT OF CONSERVATION