Australia’s threatened birds declined by 59% over the past 30 years


Elisa Bayraktarov, The University of Queensland and Jaana Dielenberg, The University of Queensland

Australia’s threatened birds declined by nearly 60% on average over 30 years, according to new research that reveals the true impact on native wildlife of habitat loss, introduced pests, and other human-caused pressures.

Alarmingly, migratory shorebirds have declined by 72%. Many of these species inhabit our mudflats and coasts on their migration from Siberia, Alaska or China each year.




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These concerning figures are revealed in our world-first Threatened Bird Index. The index, now updated with its second year of data, combines over 400,000 surveys at more than 17,000 locations.

It’s hoped the results will shed light on where conservation efforts are having success, and where more work must be done.

Bringing conservation efforts together

The index found a 59% fall in Australia’s threatened and near threatened bird populations between 1985 and 2016.

Migratory shorebirds in South Australia and New South Wales have been worst hit, losing 82% and 88% of their populations, respectively. In contrast, shorebirds in the Northern Territory have increased by 147% since 1985, potentially due to the safe roosting habitat at Darwin Harbour where human access to the site is restricted.

Habitat loss and pest species (particularly feral cats) are the most common reasons for these dramatic population declines.

Many of Australia’s threatened species are monitored by various organisations across the country. In the past there has never been a way to combine and analyse all of this evidence in one place.




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The Threatened Species Recovery Hub created the index to bring this information together. It combines 17,328 monitoring “time series” for threatened and near threatened bird species and subspecies. This means going back to the same sites in different years and using the same monitoring method, so results over time can be compared.

Over the past year the amount of data underpinning the index has grown considerably and now includes more than 400,000 surveys, across 43 monitoring programs on 65 bird species and subspecies, increasing our confidence in these alarming trends.

Threatened species like the Gilbert’s Whistler, Chestnut quail-thrush and Swift parrot are all on the decline.
Glenn Ehmke, BirdLife Australia, Author provided

About one-third of Australia’s threatened and near threatened birds are in the index but that proportion is expected to grow. As more quality data becomes available, the index will get more powerful, meaningful and representative. For the first time Australia will be able to tell how our threatened species are going overall, and which groups are doing better or worse, which is vital to identifying which groups and regions most need help.

Finding the trends

Trends can be calculated for any grouping with at least three species. A grouping might include all threatened species in a state or territory, all woodland birds or all migratory shorebirds.

The 59% average decrease in threatened bird relative abundance over the last 30 years is very similar to the global wildlife trends reported by the 2018 Living Planet Report. Between 1970 and 2014, global average mammal, fish, bird, amphibian and reptile populations fell by 60%.

One valuable feature of the Threatened Species Index is a visualisation tool which allows anyone to explore the wealth of data, and to look at trends for states and territories.

For instance, in Victoria by 2002 threatened birds had dropped to a bit more than half of their numbers in 1985 on average (60%), but they have remained fairly constant since then.

We can also look at different bird groups. Threatened migratory shorebirds have had the largest declines, with their numbers down by more than 72% since 1985. Threatened terrestrial birds, on the other hand, have decreased in relative abundance by about 51% between 2000 and the year 2016, and show a relatively stable trend since 2006.

Eastern Great Egret, and Bar-tailed Godwit. Pictures kindly provided by Glenn Ehmke, BirdLife Australia.

Making the index better

The index is being expanded to reveal trends in species other than birds. Monitoring data on threatened mammals and threatened plants is being assembled. Trends for these groups will be released in 2020, providing new insights into how a broader range of Australia’s threatened species are faring.

This research is led by the University of Queensland in close partnership with BirdLife Australia, and more than 40 partners from research, government, and non-government organisations. Collaboration on such a scale is unprecedented, and provides extremely detailed information.




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The index team are continuing to work with monitoring organisations across Australia to expand the amount of sites, and the number of species included in the index. We applaud the dedicated researchers, managers and citizen scientists from every corner of the country who have been assembling this data for the nation.

We’d also like to hear from community groups, consultants and other groups that have been monitoring threatened or near-threatened species, collecting data at the same site with the same method in multiple years.

The Threatened Species Index represents more than just data. Over time it will give us a window into the results of our collective conservation efforts.


This article also received input from James O’Connor (BirdLife Australia) and Hugh Possingham (The Nature Conservancy).The Conversation

Elisa Bayraktarov, Postdoctoral Research Fellow in Conservation Biology, The University of Queensland and Jaana Dielenberg, Science Communication Manager, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Some sharks have declined by 92% in the past half-century off Queensland’s coast



File 20181213 110256 12uk62c.jpg?ixlib=rb 1.1
Scalloped hammerhead entangled in a Queensland shark control net at Magnetic Island, Townsville.
Courtesy of Nicole McLachlan

George Roff, The University of Queensland and Christopher Brown, Griffith University

There has been a striking decline in the number of large sharks caught off Queensland’s coast over the past 50 years, suggesting that populations have declined dramatically.

Our study, published today in the journal Communications Biology, used historical data from the Queensland Shark Control Program.

Catch numbers of large apex sharks (hammerheads, tigers and white sharks) declined by 74-92%, and the chance of catching no sharks at any given beach per year has increased by as much as seven-fold.

Coinciding with ongoing declines in numbers of sharks in nets and drum lines, the probability of recording mature male and females has declined over the past two decades.

Tiger sharks have undergone a 74% decline in numbers over the past half century.
Juan Oliphant/www.oneoceandiving.com

Our discovery is at odds with recent media reports of “booming” shark numbers reaching “plague” along our coastlines. The problem with those claims is that we previously had little idea of what the “natural” historical shark population would have been.

Why is the decline of sharks on the Queensland coastline a cause for concern? Large apex sharks have unique roles in coastal ecosystems, preying on weak and injured turtles, dolphins and dugongs, actively scavenging on dead whale carcasses, and connecting coral reefs, seagrass beds and coastal ecosystems.

Australia’s mixed view on sharks

As a nation, Australia has a long history with sharks. Some of the oldest stories in the world were written by the indigenous Yanyuwa people in the Northern Territory some 40,000 years ago, describing how the landscape of their coastal homeland was created by tiger sharks.

European settlers in the late 18th and early 19th centuries further described Australian coastlines as being “chock-full of sharks”, and upon visiting Sydney in 1895, the US author Mark Twain remarked:

The government pays a bounty of the shark; to get the bounty the fishermen bait the hook or the seine with agreeable mutton; the news spreads and the sharks come from all over the Pacific Ocean to get the free board. In time the shark culture will be one of the most successful things in the colony.

With the rise of Australian beach and surf culture, and the growing population density in coastal communities in the mid-20th century, increasing numbers of unprovoked fatal encounters with sharks occurred along the Queensland and New South Wales coastlines.

White sharks were extensively targeted and killed in “game fishing” tournaments, and harmless grey nurse sharks were hunted almost to extinction through recreational spearfishing in the 1950s and 1960s.

Yet despite this long history of shark exploitation, the historical baseline populations of sharks off Australia’s east coast were largely unknown.

Historical photograph of contractors measuring sharks removed from QSCP nets on the Gold Coast in the early years of the program (3rd November 1963).

Through mesh nets and baited drumlines, the Queensland Shark Control Program targets large sharks, with the aim of reducing local populations and minimise encounters between sharks and humans. Records of shark catches dating back as far as the 1960s provide a unique window into the past on Queensland beaches.

While we will never know exactly how many sharks roamed these waters more than half a century ago, the data points to radical changes in our coastal ecosystems since the 1960s.

The exact causes of declining shark numbers are difficult to pinpoint, largely because of a lack of detailed records from commercial or recreational fisheries before the 2000s. The Queensland government also acknowledges that the program itself has a direct impact on shark populations by selectively removing large, reproductively mature sharks from the population.

The data indicates that two hammerhead species – the scalloped and great hammerheads, both of which are listed as globally endangered – have declined by as much as 92% in Queensland over the past half century.

Similarly, the once-abundant white sharks have also shown no sign of recovery, despite a complete ban on commercial and recreational fishing in Queensland, implemented more than two decades ago.

The idea that shark populations are reaching “plague” proportions in recent years may represent a classic case of shifting baseline syndrome. Using shark numbers from recent history as a baseline may give a false perception that populations are “exploding”, whereas records from fifty years ago indicate that present day numbers are a fraction of what they once were.

Our results indicate that large shark species are becoming increasingly rare along Australia’s coastline. We should not be concerned about a “plague” of sharks, but rather the opposite: the fact that previously abundant apex shark species are increasingly at risk.The Conversation

George Roff, Postdoctoral Research Fellow, The University of Queensland and Christopher Brown, Research Fellow, Australian Rivers Institute, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.