Widespread flying fox deaths a 'disaster' for forest ecosystems

A suspected flying fox mass starvation event along the east coast of Australia could disrupt the health of forest ecosystems, experts warn.

Wildlife carers between the New South Wales Mid North Coast and Victoria have been inundated with reports of malnourished, deceased or dying grey-headed flying foxes over the last few months.

The bat species is suspected to have been impacted by a lack of nectar on flowering trees due to drought conditions, forcing them to seek out food closer to the ground.

University of Newcastle conservation professor Matt Hayward said less nectar would have a ripple effect on other species too.

"Lots of Australian birds rely on nectar [as well as] flying foxes … so we could see a really big decline in all of those species," Mr Hayward said.

As keystone pollinators, he said the flying foxes played a vital role in maintaining forest ecosystems, with species relying on the bat's nightly seed dispersal.

Forest pollinators

There are 11 colonies of grey headed flying foxes across the Hunter region, including a nationally significant colony of 40,000 at the Blackbutt Nature Reserve in Newcastle.

Flying up to 50 kilometres each night, the bats disperseseeds they have eaten from trees, generating forest ecosystems.

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"So they're dispersing those seeds over really broad areas in the appropriate habitat for other species," Mr Hayward said.

"Given that the climate is changing so rapidly we really need to ensure that genes [for plants] are being transferred over those distances.

"Plants are really going to need that kind of ability, to move and disperse, that flying foxes provide for them."

Mr Hayward said with the bats under even more stress, the species could be pushed further to the brink.

"Flying foxes [were already] vulnerable before this drought," he said.

"And so now any pressure being put on them with habitat clearing or droughts is just going to put more pressure on the species and push them closer to extinction."

'This is a crisis'

Hunter Wildlife said it has received an unprecedented number of calls this week for dead or dying flying foxes.

Volunteer Kerry Walker said it needed to be treated as an emergency.

"If we don't have [the bats] then we don't have the gum trees, then we don't have a whole lot of different species of birds or animals … it becomes a domino effect.

"This is just another huge pressure on those [forest] species and the threatened species status will just collapse down the chain."

Lyssavirus concerns

NSW Health said in the last two weeks, from September 28 to October 10, 43 people were assessed after being bitten by bats, and it had issued an alert for Lyssavirus risks.

Eight of those were in the Hunter region.

The fatal disease, part of the rabies virus group, is transmitted through bat saliva, through bites or scratches, and can cause swelling of the brain.

Hunter New England Health physician David Durheim said humans typically wanted to help animals when they were injured but it was important to understand the risks.

"We hate to see animals struggling and particularly those lovely flying foxes with their very big eyes," Dr Durheim said.

"So if [bats] are affected by disease or starvation, currently a major issue, and we see them ailing, our first instinct is to help them."