Going to bat for at-risk mammal

A Wairarapa tangata whenua group is developing a programme to protect New Zealand’s rarest mammal.

The initiative, spearheaded by Rangitāne o Wairarapa Tina Te Pū environment team member Amber Craig, aims to protect and monitor critically endangered lesser short-tailed bat populations in the region.

Conservation groups believe the Tararua short-tailed bat colony – which is threatened by mustelids, cats, rats, and possums – is the last remaining subspecies population south of Whanganui.

“If we have our taonga in these places, we can’t just watch them die,” Craig said.

The native short-tailed bat, which has a population of about 200, was first detected in 1998 inside the Tararua Forest Park at Waiōhine River.

“I live down the Waiōhine gorge, so it’s a personal project for my whānau [Ngāti Kahukuraawhitia],” Craig said.

“From a mana whenua, tāngata whenua perspective, the discovery of the new short-tailed bats is very triggering in terms of making sure we don’t repeat the same mistakes.”

By “mistakes”, Craig is referring to a 2005 attempt to ensure the survival of bats from the Waiōhine Valley colony by relocating 25 pregnant bats from Waiōhine to Pukaha Mount Bruce – a world first – and then moving the 20 bat pups they produced to predator-free Kāpiti Island.

Sadly, however, after arriving on the island, the bats developed a disease affecting their ear pinnae and, although they were taken to Auckland Zoo for intervention, they later died.

The question now for Craig “is how do we holistically look after them? Like Miramar, do we become a pest-free region from the Tararua ranges to the Remutaka’s?”

The bat protection project will be guided by kaumātua alongside a team and include community input, but she said it is important that mātauranga Māori [Māori knowledge] forms the foundation.

Craig also believes the species’ survival is dependent on collaboration efforts between mana whenua, community groups, the Department of Conservation [DoC], and Greater Wellington Regional Council [GWRC], which recorded native short-tailed bats through acoustic monitoring in the Pākuratahi river corridor over Remutaka Hill during the past summer.

Although they had previously been recorded in Carterton and South Wairarapa District Council areas, “short-tailed bats have not been recorded in the Wellington Region in over seven years and were thought extinct in the lower North Island”, a GWRC spokesperson said.

“The presence of this highly vulnerable species pays testament to the ongoing pest control undertaken by Greater Wellington.

“This record will inform further monitoring to understand the size and spread of this population, conservation efforts and pest management strategies in the environment.”

GWRC data and monitoring manager James Luty said it is “unclear” how many of the bats there are in the Wellington Region.

“Their small size and nocturnal nature make it difficult to accurately estimate the size of their populations at any one time.

“Mana whenua have long known that pekapeka [bats] are living in the area, and the data we have collected is the very beginning of our work in this space.”

DoC Wairarapa operations manager Kathy Houkamau said that automatic bat detectors were used between 2011 and 2015 to monitor annual trends in bat activity around the known roosts and wider catchment.

“Surveys undertaken in the summer of 2014/2015 revealed low bat activity,” she said.

“Only five potential passes were detected 200m from the roost area, and another five potential passes 750m away.

“Acoustic surveys were undertaken from 2015 to 2019 across approximately 10,000ha of the lower Waiōhine catchment with no confirmed bat detections.

“Based on these results, it seemed likely that the bat population was no longer present in the survey area.”

Sustainable Wairarapa Inc bat group coordinator Julia Ryan said the group does acoustic recordings for the echolocation “pings” of bats.

Ryan said it isn’t a surprise the group hasn’t recorded any short-tailed bats.

“They have different patterns of activity and feeding and tend to only survive in areas of deep bush,” she said.

“That doesn’t mean that there aren’t other populations around the region that we haven’t found yet.”