Populations of some Australian mammals declined by more than a third over two decades, but sites with clear conservation management saw improvements in their populations of 46%, according to new research.
The figures are the first tranche of data in Australia’s Threatened Species Index for mammals, which combines data from monitoring programs across the country to track trends in threatened species populations.
A similar database already exists for birds and is collated by researchers working with the Threatened Species Recovery Hub in collaboration with state agencies and NGOs.
The first tranche collates data for 57 threatened and near-threatened mammal species, including the northern quoll and the yellow-footed rock wallaby. It covers the years 1995-2016 across 1,186 different locations.
Populations of the mammals at these sites declined on average by 38%
, but the researchers found a source for optimism at locations where conservation measures had been put in place. At sites with clear conservation management efforts, populations increased on average by 46%. Only 155 of the 1,186 locations had active conservation work in place.
At 15 feral cat and fox-free sites, the populations of threatened and near-threatened mammals had increased five-fold.
Elisa Bayraktarov, a researcher at the University of Queensland and the co-leader of the index, said the data showed investment in conservation “pays off”.
“It does tell us we should drive more investment, especially in those mammals that are doing so badly elsewhere,” she said.
The research found where there was no active conservation work, populations had declined on average by 60%.
John Woinarski, a conservation biologist who is part of the research team, said animals in predator-free havens fared well, with the burrowing bettong and bridled nail-tailed wallaby among species to show large improvements in these areas.
“However, havens cover only 0.1% of Australia’s total area, so they are only one part of the solution to Australia’s long-term biodiversity loss, and they are not a solution for species that are declining for reasons other than cats and foxes,” he said.
The data will be gradually updated to cover more mammals and more locations. At present, the index includes very little monitoring data for New South Wales and the ACT, but updates are expected in the next tranche due in November.
Bayraktarov said the index in its current form was probably “underestimating the decline in Australia”.
The research team is looking for contributions to future iterations of the index from any scientists and groups collecting standardised monitoring data.
The national environment laws set up to protect threatened species are currently under independent review. The statutory review of the Environment Protection and Biodiversity Conservation (EPBC) Act occurs once every 10 years and is due to publish its final report in October.
Environment groups have long called for an overhaul of the act, which has been failing to stem Australia’s rate of extinction.
Last week, six organisations asked for the review’s timeframes to be extended because of the disruption caused by the back-to-back bushfire and coronavirus crises.