A small remote Aboriginal community in the Northern Territory comprises an average 343 people. But fewer are present at any time, as seven in every 50 of the men aged between 20 and 39 years of age is in jail. So is one in every 50 of the women in that age group. They are part of a mass incarceration phenomenon that has led Australia to record its historically highest nationwide Indigenous detention rate.

These are the missing ones. They include the breadwinners, fathers, mothers, mentors and leaders of the community. In the settlements that make up half the Northern Territory’s population beyond Darwin, the impact of these missing people is magnified because there is no one to take their places.

“The community grieves for that person who’s been incarcerated. There’s also the shame. The stigma comes back to the whole community.”

Even the babies who would otherwise be born into a thriving community are lost, thinning the potential ranks of the next generation, as a result of the high proportion of men and women of peak childbearing age being locked up, according to new statistic-crunching research at Charles Darwin University .

This is not merely a Top End blight, according to Gail Wallace, a 62-year-old Jerrinja community leader in Nowra on the New South Wales south coast.

“We don’t have the isolated communities you have in the Northern Territory and Western Australia, but we still have the high statistics. And a lot of our people too, in the city, are becoming really isolated as a result of members of their families being taken away and incarcerated,” she says.

“We’ve become a much poorer community, economically and emotionally. The community grieves for that person who’s been incarcerated. There’s also the shame. The stigma comes back to the whole community.”

The 10,000 or so Indigenous people spread throughout five communities around Nowra live in the alarming circumstances highlighted by the Australian Bureau of Statistics (ABS) finding that over the past decade, as the entire national prison population has grown, Indigenous over-representation in custody has ballooned by 50 per cent.

It’s a mother of a problem. Indigenous women are being locked up more often and account for more than one-third of females in prison, even though they only make up 2 per cent of the population, according to the ABS.

Being fatherless is tough, too. Wallace tells of a mother of three primary-school-aged offspring who was left so poverty-stricken and distressed when her partner was jailed for domestic violence that grandparents, aunts and uncles had to chip in with money and get the kids to school. She believes it is a reason many women do not report domestic violence.

“What if you have three or four members of your extended family incarcerated? It’s drawing on a community that’s already impoverished and depressed and suffering transgenerational trauma, so it’s just a miserable existence, isn’t it, really. There is a financial burden on the whole community because of our culture: the caring and the sharing. I share everything I have with my family, with my nieces and nephews and grandkids, my cousins and extended family,” says Wallace, who grew up at the Orient Point reserve near Nowra. Until last year she co-ordinated the region’s innovative Indigenous “circle sentencing” project as an alternative court process for local Aboriginal people.

Now renamed Jerrinja, the Orient Point settlement holds surprises for those who think all Aboriginal culture resides in the north. The older fishermen still use traditional techniques, knowing, for instance, which fish will abound when the pigface plant is flowering. Some residents still collect wild honey from the forests near Jervis Bay and some retain Jerrinja words and songs.

But colonisation ripped the south coast people away from their roots. And it imported the lust for detention, unleashed disproportionately on the Indigenous population.

Wallace says that many young Aboriginal people stray because they’re poor, they’ve been cut off from culture and “a lot of people suffer from self-depreciation from 200 years of demonisation and racism”. As underdogs themselves, they tend to have sympathy for jailed offenders, making prison no deterrent.

Wallace lost her son Terence to drugs, mental illness and jail, and finally 10 years ago, when he was aged 29, to suicide. She reckons that the system was unable to deal with his dual diagnosis of substance abuse and mental illness, offering treatment for one or the other, but not both. The sportsman who loved surfing and cycling was imprisoned for domestic violence at 26, leaving Gail and other family members to help raise his two small children. His daughter is now 16 and his son 17.

“They’ve got no father to help them through life,” Wallace says simply.

In communities where many people in their prime have been lost to prison, children suffer stigma, as well as the strain of assuming unexpected responsibilities and being left short of role models, the Northern Institute’s team, led by Hannah Payer at Charles Darwin University, has found in its literature review of the phenomenon of hyper-incarceration.

In the Northern Territory, the Indigenous detention rate has risen dramatically over a decade and almost doubled from 8.3 times that of other citizens in 2004 to 15.4 times now, according to the ABS. Affected communities are likely to be poorer, less healthy and more fragmented, casting a shadow into the future, the institute’s report says.

Drilling down into the statistics, such as the shocking fact that 86 in every 100 Northern Territory prisoners is Aboriginal, the team found that at any given time, 14 per cent of the 20- to 39-year-old males might be incarcerated.

“These proportions have the potential to create severe dysfunction in terms of population structures, and social and economic impacts on affected communities,” the report warns.

Researchers studying hyper-detention rates among mainly African Americans in the United States have developed the idea of an ecology of incarceration, according to Chris Cunneen, professor of criminology at the University of New South Wales.

“The prison doesn’t just touch the person in prison, but the consequences have been woven into the community,” Cunneen says.

“The US research talks about the idea of a tipping point, where you have such high levels of incarceration – of women and particularly of men – it causes a high degree of destabilisation and so increases the level of crime.”

Both here and in the US, studies show that people are recycled through the prison system, moving in and out of their communities, which disrupts marital relationships, forces parents to do it alone, and increases the risk of foster care and juvenile offending.

“Incarceration becomes a model for children,” says Cunneen, whose own research famously found that Australia is better at keeping Aboriginal people in detention than at school or university.

Between the ages of 10 and 17, Indigenous youths are about 24 times more likely to be in detention than other Australians of the same age, according to the Australian Institute of Criminology.

To show how disruptive criminalisation and incarceration are to Aboriginal families, Cunneen turns to the NSW Young People in Custody Health Survey of 2009.

“The data shows that Aboriginal young people [in custody] are younger, more likely to have been in care … to already be parents themselves and were more than twice as likely to have had a parent imprisoned,” he says.

Cunneen is part of a team writing a book making the case for “justice reinvestment”, which aims to cut detention rates so that the money can go back into the communities to tackle the root problems that lead to incarceration.

The north-western NSW town of Bourke is championing the cause and taking it slowly, which Cunneen thinks is important because it allows the community to drive it. In the US, justice reinvestment has been used to cut prison numbers, but the cost savings did not go back to the communities, he says.

Gail Wallace says that circle sentencing, where elders sit with a magistrate to decide the fate of offenders, is a start and should be expanded from the nine courts in NSW. She wants to see “circles everywhere”.

Handling petty crime, so that people are not locked up for amassing fines, just takes understanding, she says.

“We had an elderly gentleman who didn’t believe in the legal system. He drove his car around with cardboard numberplates, and he drove without a licence and also without insuring and registering his car. He ended up with $11,000 in fines,” she says.

Wallace called the State Debt Recovery Office and organised for the man to work off his fines as a handyman at an Aboriginal cultural centre.

“Today he has his licence. The car’s registered and insured. He felt so good about getting rid of those fines,” she says.

Wallace is not soft on the need to punish serious violent offences. “Our laws were taken away and we were introduced to laws that there is no respect for. Naturally, there will be people misbehaving themselves. We need to convince the [Indigenous] community that no matter what laws, whether it’s their laws or our laws, there’s got to be laws around violence and ways of addressing it.”

But as an activist trying to reform the criminal justice system, she is struggling with the sense of hopelessness that mass incarceration inflicts on Indigenous communities, so that even the new record high raises barely a flicker of protest around the nation.

“It’s not even a shock within the Aboriginal community, because that’s the way it’s been since colonisation,” Wallace says. “Everything that’s done to our people is accepted, isn’t it, as a way of life.”