A Gisborne-based forestry company says it is committed to protecting colonies of critically threatened long-tailed bats discovered in Tairāwhiti forestry blocks.
The bats are the New Zealand native pekapeka-tou-roa, which are listed as “nationally critical” by the Department of Conservation - the highest threat ranking.
According to the DoC website, causes of the decline in the long-tail bat population include clearance and logging of lowland forests.
Other factors are the cutting of old-age trees for firewood, urban expansion and agricultural intensification, predation by introduced animals, and displacement.
Aratu Forests manager of environment Richard Powell said efforts to protect the bats began in Huanui Forest in 2010 and the company, working with DoC and other experts, formally introduced a bat management plan in 2018.
Extending the monitoring led to bats also being found at Kopua Forest and Waimanu Forest.
“People will be surprised how widespread bats are in the district,” said Powell.
“We want to increase the public’s knowledge of bats in our region.”
Aratu Forest technical forester Kirby Scammell said the bats were “cool”.
Some people thought bats “are not real” but they could be found “in someone’s backyard in certain areas”, Scammell said.
Tairāwhiti appears to be a stronghold for the long-tailed bat because of several large areas of remnant native forest scattered around the region.
Powell said long-tailed bats preferred to roost in natural cavities and beneath the bark of mature native tree species but were also starting to use mature exotic trees large enough to contain flaking bark and natural cavities.
Forests with riparian habitats were especially suitable for bats because of the increased abundance of insects they fed on.
Aratu Forests, using acoustic recorders, recorded 577 “bat passes” or bat calls after 836 hours (nearly 35 days) at Huanui Forest.
The recorders, using software developed by DoC, are capable of picking up the different frequencies of long-tail and short-tail bats.
It appears the forest has a relatively large population of long-tail bats.
Powell said the “bat passes” did not provide information on bat numbers as the same bat could be recorded more than once.
But it appeared bat numbers were increasing, he said.
The bat management programme includes protecting roosting and breeding resources.
This includes protecting feeding corridors and stream water quality alongside commercial harvesting operations.
All practical steps were taken during roading and harvesting operations to protect remnant indigenous forest areas, individual trees or stands of trees which benefitted bat habitat, Powell said.
As new areas of the pine plantation areas in the forests were harvested, Aratu worked to ensure bats would not be harmed in the process, he said.
This included large, mature lone standing exotic trees located within 150 metres of primary streams being assessed for bats, and a 20-metre riparian setback being instigated throughout the area.
Pest control is a key issue with cats and ship rats the main predators.
Possums also cause habitat damage and create competition for roost spaces, while hedgehogs consume a large number of invertebrates, so may be causing competition for food resources with the long-tailed bat.
Aratu uses trappers and shooters.
“Shooters are made up of both professional cullers as well as recreational hunters,” Powell said.
“Recreational hunters are staff, contractors and members of the general public that apply for hunting permits via our website.”
Powell said Aratu also worked alongside groups such as Waimata Catchment Group, Whangara Catchment Group, Uawanui Group and DoC.
“Having a collaborative relationship with these other groups assists us in planning the future of the business while keeping the environment front of mind.”
Bat facts
● The long-tailed bat (Chalinolobus tuberculatus) belongs to a widespread family and is closely related to five other species of wattled or lobe-lipped bats in Australia and elsewhere.
● Long-tailed bats are widely distributed throughout mainland New Zealand, Stewart Island, Little Barrier and Great Barrier islands and Kapiti Island. They are more commonly seen than short-tailed bats as they fly at dusk along forest edges and because some populations have persisted in urban and rural landscapes.
● Long-tailed bats are smaller than the short-tailed bat, chestnut brown in colour, have small ears and weigh 8–11 grams and can fly at speeds of 60kmh. They are believed to produce only one offspring each year.
● A bat colony can have a range of more than 100 square kilometres.
● An aerial insectivore, they feed on small moths, midges, mosquitoes and beetles.
Source: Department of Convservation
