Populations of threatened bird species in Australia halved in the past 30 years, according to a new national Threatened Bird Index.
The index is the first part of a large data consolidation project being undertaken by the Threatened Species Recovery Hub, along with the University of Queensland and Birdlife Australia.
It consolidated more than 180,000 surveys from 35 monitoring programs on 43 bird species that are listed as vulnerable, endangered, and critically endangered and found an average population decline of 52% between 1985 and 2015.
Populations of migratory shorebirds species dropped by an average of 70% over the same period.
The index will be updated annually and be expanded to a broader threatened species index, covering mammals, plants and freshwater species, over the next few years.
An online application allows researchers to create a specific index for types of bird, state or territory, threatened species status and type of habitat.
Birdlife Australia head of research James O’Connor said the index should be read as an indicator of the health of the country.
“One of our visions is that the Alan Kohler on the Channel Two news presents the threatened species index from time to time in his reporting and it becomes just part of that reporting landscape,” O’Connor told Guardian Australia.
Lead researcher Dr Elisa Bayraktarov, from the University of Queensland, said the index was currently biased toward high-profile species in the eastern states but would become robust as data from other species and other locations was added.
“When we kicked off we had data on about 100 species but not all data is created equal so we were only able to use the data which matched the statistical assumptions that we can actually use to calculate the trends,” Bayraktarov told Guardian Australia.
As more data is added, she said, the index would “become more powerful and representative”.
Bayraktarov said that by showing gaps in available data, the index could also be used to direct future research.
It is based off the Living Planet Index, which last month reported a 60% decline in global animal populations since 1970.
But unlike its global counterpart the Australian project relies mainly on raw, unpublished data which has required the cooperation of more than 70 organisations, community groups and researchers to consolidate.
“For some reason not much data on threatened species in Australia is published and it really exists on people’s computers, in reports of recovery teams and state and territory repositories, or in paper form somewhere,” Bayraktarov said. “So it was quite a big challenge and endeavour to get all this data, get it in the right shape or form that it actually can be added and uploaded to our database, and then carry out a rigorous assessment.”
The index uses bird populations in 1985 as a baseline, although the number of species included increased in the late 1990s. Some species included in the dataset, such as the Kangaroo Island Glossy Black Cockatoo, have grown in numbers over that time as a result of sustained recovery efforts.
But most have not. O’Connor said many threatened birds, such as the critically endangered King Island brown thornbill, were not represented in the index because there was so little data available.
“The index is biased toward species that do have a community or a champion or a recovery team that are keeping an eye on them … and there are quite a few species out there that don’t have a monitoring plan, or a recovery plan, or a recovery program attached to them,” he said.
“It’s hard to say whether those species are doing better or worse than those in the index but you would not be super confident that they were doing any better without having any kind of recovery program attached to them.”
