Almost 60 coral species around Lizard Island are ‘missing’ – and a Great Barrier Reef extinction crisis could be next


Michael Emslie

Zoe Richards, Curtin UniversityThe federal government has opposed a recommendation by a United Nations body that the Great Barrier Reef be listed as “in danger”. But there’s no doubt the natural wonder is in dire trouble. In new research, my colleagues and I provide fresh insight into the plight of many coral species.

Worsening climate change, and subsequent marine heatwaves, have led to mass coral deaths on tropical reefs. However, there are few estimates of how reduced overall coral cover is linked to declines in particular coral species.

Our research examined 44 years of coral distribution records around Lizard Island, at the northern end of the Great Barrier Reef. We found 16% of coral species have not been seen for many years and are at risk of either local extinction, or disappearing from parts of their local range.

This is alarming, because local extinctions often signal wider regional – and ultimately global – species extinction events.

Healthy coral near Lizard Island in 2011, top, then six years later after two bleaching events, bottom.
Healthy coral near Lizard Island in 2011, top, then six years later after two bleaching events, bottom.
Zoe Richards

Sobering findings

The Lizard Island reef system is 270 kilometres north of Cairns. It has suffered major disturbances over the past four decades: repeated outbreaks of crown-of-thorns seastars, category 4 cyclones in 2014 and 2015, and coral bleaching events in 2016, 2017 and 2020.

Our research focused on “hermatypic” corals around Lizard Island. These corals deposit calcium carbonate and form the hard framework of the reef.

We undertook hard coral biodiversity surveys four times between 2011 and 2020, across 14 sites. We combined the results with published and photographic species records from 1976 to 2020.

red fleshy coral with blue spots
Micromussa lordhowensis is popular in the aquarium trade.
Zoe Richards

Of 368 hard coral species recorded around Lizard Island, 28 (7.6%) have not been reliably recorded since before 2011 and may be at risk of local extinction. A further 31 species (8.4%) have not been recorded since 2015 and may be at risk of range reduction (disappearance from parts of its local range).

The “missing” coral species include:

  • Acropora abrotanoides, a robust branching shallow water coral that lives on the reef crest and reef flat has not been since since 2009
  • Micromussa lordhowensis, a low-growing coral with colourful fleshy polyps. Popular in the aquarium trade, it often grows on reef slopes but has not been seen since 2005
  • Acropora aspera, a branching coral which prefers very shallow water and has been recorded just once, at a single site, since 2011.

The finding that 59 coral species are at risk of local extinction or range reduction is significant. Local range reductions are often precursors to local species extinctions. And local species extinctions are often precursors to regional, and ultimately global, extinction events.

Each coral species on the reef has numerous vital functions. It might provide habitat or food to other reef species, or biochemicals which may benefit human health. One thing is clear: every coral species matters.




Read more:
The outlook for coral reefs remains grim unless we cut emissions fast — new research


reddish coral underwater
Acropa abrotanoides, one of the corals ‘missing’ from around Lizard Island.
Zoe Richards

A broader extinction crisis?

As human impacts and climate threats mount, there is growing concern about the resilience of coral biodiversity. Our research suggests such concerns are well-founded at Lizard Island.

Coral reef communities are dynamic, and so detecting species loss can be difficult. Our research found around Lizard Island, the diversity of coral species fluctuated over the past decade. Significant declines were recorded from 2011 to 2017, but diversity recovered somewhat in the three following years.

Local extinctions often happen incrementally and can therefore be “invisible”. To detect them, and to account for natural variability in coral communities, long-term biodiversity monitoring across multiple locations and time frames is needed.

Green coral
Acropora aspera has been recorded just once, at a single location, since 2011.
Anne Hoggett

In most locations however, data on the distribution and abundance of all coral species in a community is lacking. This means it can be hard to assess changes, and to understand the damage that climate change and other human-caused stressors are having on each species.

Only with this extra information can scientists conclusively say if the level of local extinction risk at Lizard Island indicates a risk that coral species may become extinct elsewhere – across the Great Barrier Reef and beyond.




Read more:
Is Australia really doing enough for the Great Barrier Reef? Why criticisms of UNESCO’s ‘in danger’ recommendation don’t stack up


The Conversation


Zoe Richards, Senior Research Fellow, Curtin University

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

Australia’s threatened species plan has failed on several counts. Without change, more extinctions are assured


Euan Ritchie, Deakin University and Ayesha Tulloch, University of SydneyAustralia is globally renowned for its abysmal conservation record – in roughly 230 years we’ve overseen the extinction of more mammal species than any other nation. The federal government’s Threatened Species Strategy was meant to address this confronting situation.

The final report on the five-year strategy has just been published. In it, Threatened Species Commissioner Dr Sally Box acknowledges while the plan had some important wins, it fell short in several areas, writing:

…there is much more work to do to ensure our native plants and animals thrive into the future, and this will require an ongoing collective effort.

Clearly, Australia must urgently chart a course towards better environmental and biodiversity outcomes. That means reflecting honestly on our successes and failures so far.

How did the strategy perform?

The strategy, announced in 2015, set 13 targets linked to three focus areas:

  • feral cat management
  • improving the population trajectories of 20 mammal, 21 bird and 30 plant species
  • improving practices to recover threatened species populations.

Given the scale of the problem, five years was never enough time to turn things around. Indeed, as the chart below shows, the report card indicates five “red lights” (targets not met) and three “orange lights” (targets only partially met). It gave just five “green lights” for targets met.

Year Five - Final Report
Summary of the Threatened Species Strategy’s targets and outcomes.
Department of Agriculture, Water and the Environment

Falling short on feral cats

Feral cats were arguably the most prominent focus of the strategy, despite other threats requiring as much or more attention, such as habitat destruction via land clearing.

However, the strategy did help start a national conversation about the damage cats wreak on wildlife and ecosystems, and how this can be better managed.

In the five years to the end of 2020, an estimated 1.5 million feral cats were killed under the strategy – 500,000 short of the 2 million goal. But this estimate is uncertain due to a lack of systematic data collection. In particular, the number of cats culled by farmers, amateur hunters and shooters is under-reported. And more broadly, information is scattered across local councils, non-government conservation agencies and other sources.




Read more:
One cat, one year, 110 native animals: lock up your pet, it’s a killing machine


Australia’s feral cat population fluctuates according to rainfall, which determines the availability of prey – numbering between 2.1 million and 6.3 million. Limited investment in monitoring makes it impossible to know whether the average of 300,000 cats killed each year over the past five years will be enough for native wildlife to recover.

The government also failed in its goal to eradicate cats from five islands, only achieving this on Dirk Hartog Island off Western Australia. Importantly, that effort began in 2014, before the strategy was launched. And it was primarily funded by the WA government and an industry offset scheme, so the federal government can’t really claim this success.

On a positive note, ten mainland areas excluding feral cats have been established or are nearly complete. Such areas are a vital lifeline for some wildlife species and can enable native species reintroductions in the future.

feral cat holds dead bird
Feral cats were eradicated from just one island under the strategy.
Mark Marathon/Threatened Species Recovery Hub

Priority species: how did we do?

The strategy met its target of ensuring recovery actions were underway for at least 50 threatened plant species and 60 ecological communities. It also made good headway into storing all Australia’s 1,400 threatened plant species in seed banks. This is good news.

The bad news is that, even with recovery actions, the population trajectories of most priority species failed to improve. For the 24 out of about 70 priority species where population numbers were deemed to have “improved” over five years, about 30% simply got worse at a slower rate than in the decade prior. This can hardly be deemed a success.

Mala with baby in pouch
Populations of the mala, or Rufous Hare-wallaby, were improving before the strategy.
Wayne Lawler/Australian Wildlife Conservancy

What’s more, the populations of at least eight priority species, including the eastern barred bandicoot, eastern bettong, Gilbert’s potoroo, mala, woylie, numbat and helmeted honeyeater, were increasing before the strategy began – and five of these deteriorated under the strategy.

The finding that more priority species recovery efforts failed than succeeded means either:

  • the wrong actions were implemented
  • the right actions were implemented but insufficient effort and funding were dedicated to recovery
  • the trajectories of the species selected for action simply couldn’t be improved in a 5-year window.

All these problems are alarming but can be rectified. For example, the government’s new Threatened Species Strategy, released in May, contains a more evidence-based process for determining priority species.

For some species, it’s unclear whether success can be attributed to the strategy. Some species with improved trajectories, such as the helmeted honeyeater, would likely have improved regardless, thanks to many years of community and other organisation’s conservation efforts before the strategy began.

Conservation worker releases woylie
The improved outlook for some species is due to conservation efforts before the federal strategy.
WA Department of Environment and Conservation



Read more:
Australia-first research reveals staggering loss of threatened plants over 20 years


What must change

According to the report, habitat loss is a key threat to more than half the 71 priority species in the strategy. But the strategy does not directly address habitat loss or climate change, saying other government policies are addressing those threats.

We believe habitat loss and climate change must be addressed immediately.

Of the priority bird species threatened by land clearing and fragmentation, the trajectory of most – including the swift parrot and malleefowl – did not improve under the five years of the strategy. For several, such as the Australasian bittern and regent honeyeater, the trajectory worsened.

Preventing and reversing habitat loss will take years of dedicated restoration, stronger legislation and enforcement. It also requires community engagement, because much threatened species habitat is on private properties.

Effective conservation also requires raising public awareness of the dire predicament of Australia’s 1,900-plus threatened species and ecological communities. But successive governments have sought to sugarcoat our failings over many decades.

Bushfires and other extreme events hampered the strategy’s recovery efforts. But climate change means such events are likely to worsen. The risks of failure should form part of conservation planning – and of course, Australia requires an effective plan for emissions reduction.

The strategy helped increase awareness of the plight our unique species face. Dedicated community groups had already spent years volunteering to monitor and recover populations, and the strategy helped fund some of these actions.

However, proper investment in conservation – such as actions to reduce threats, and establish and maintain protected areas – is urgently needed. The strategy is merely one step on the long and challenging road to conserving Australia’s precious species and ecosystems.




Read more:
‘Existential threat to our survival’: see the 19 Australian ecosystems already collapsing


The Conversation


Euan Ritchie, Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University and Ayesha Tulloch, DECRA Research Fellow, University of Sydney

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

Hundreds of Australian lizard species are barely known to science. Many may face extinction


E Vanderduys, Fourni par l’auteur

Jane Melville, Museums Victoria and Reid Tingley, Monash UniversityMost of the incredible diversity of life on Earth is yet to be discovered and documented. In some groups of organisms – terrestrial arthropods such as spiders and scorpions, marine invertebrates such as sponges and molluscs, and others – scientists have described fewer than 20% of species.

Even our knowledge of more familiar creatures such as fish and reptiles is far from complete. In our new research, we studied 1,034 known species of Australian lizards and snakes and found we know so little about 164 of them that not even the experts know whether they are fully described or not. Of the remaining 870, almost a third probably need some work to be described properly.

Map of Australia shaded in colours from blue to red.
Return on investment for taxonomic research on lizards and snakes in Australia. Red areas have high numbers of species and high conservation value. Hotspots include the Kimberley in WA, northern tropical savannas and also far north eastern QLD.
R. Tingley, Author provided

Documenting and naming what species are out there – the work of taxonomists – is crucial for conservation, but it can be difficult for researchers to decide where to focus their efforts. Alongside our lizard research, we have developed a new “return on investment” approach to identify priority species for our efforts.

We identified several hotspots across Australia where research is likely to be rewarded. More broadly, our approach can help target taxonomic research for conservation worldwide.

Why we need to look at species more closely

As more and more species are threatened by land clearing, climate change and other human activities, our research highlights that we are losing even more biodiversity than we know.

Conservation often relies on species-level assessments such as those conducted by the International Union for Conservation of Nature (IUCN) Red List, which lists threatened species. Although new species are being discovered all the time, a key problem is that already named “species” may harbour multiple undocumented and unnamed species. This hidden diversity remains invisible to conservation assessment.

The Roma Earless Dragon (Tympanocryptis wilsoni), described in 2014, lives only in grasslands in the western Darling Downs QLD and has recently been listed as Vulnerable in Queensland.
A. O’Grady, Author provided

One such example are the Grassland Earless Dragons (Tympanocryptis spp.) found in the temperate native grasslands of south-eastern Australia. These small secretive lizards were grouped within a single species (Tympanocryptis pinguicolla) and listed as Endangered on the IUCN Red List.

But recent taxonomic research split this single species into four, each occurring in an isolated region of grasslands. One of these new species may represent the first extinction of a reptile on mainland Australia and the other three have a high probability of being threatened.




Read more:
Why we’re not giving up the search for mainland Australia’s ‘first extinct lizard’


Scientists call documenting and describing species “taxonomy”. Our research shows the importance of prioritising taxonomy in the effort to conserve and protect species.

Taxonomists at work

Many government agencies do take some account of groups smaller than species in their conservation efforts, such as distinct populations. But these are often ambiguously defined and lack formal recognition, so they are not widely used. That’s where taxonomists come in, to identify species and describe them fully.

Our new research was a collaboration of 30 taxonomists and systematists, who teamed up to find a good way of working out which species should be a priority for taxonomic research for conservation outcomes. This new approach compares the amount of work needed with the likelihood of finding previously unknown species that are at risk of extinction.

Barrier Range Dragon (Ctenophorus mirrityana), described in 2013, is restricted to rocky ranges in western NSW and is listed as Endangered in NSW.
S. Wilson, Author provided

The research team, who are experts on the taxonomy and systematics of Australia’s reptiles, implemented this new approach on Australian lizards and snakes. This group of reptiles is ideal as a test case because Australia is a global hotspot of lizard diversity – and we also have a strong community of taxonomic experts.

Australia’s lizards and snakes

Of the 1,034 Australian lizard and snake species, we were able to assess whether 870 of them may contain undescribed species. This means we know so little about the remaining 164 species that even the experts could not make an informed opinion on whether they contain hidden diversity. There is so much still to learn!

Of the 870 species experts could assess, they determined 282 probably or definitely needed more taxonomic research. Mapping the distributions of these species indicated hotspot regions for this taxonomic research, including the Kimberley, the Tanami Desert region, western Victoria and offshore islands (such as Tasmania, Lord Howe and Norfolk Islands). Some areas in the Kimberley region had more than 60 species that need further taxonomic research.

In this map, red hotspot areas have lower species diversity but still a very high average return on investment. National hotspots include Tasmania, western Victoria and the Tanami Desert region in WA and NT.
R. Tingley, Author provided

We found 17.6% of the 282 species that need more taxonomic research contained undescribed species that would probably be of conservation concern, and 24 had a high probability of being threatened with extinction. Taxonomists know that there are undescribed species because there is some data available already but the description of these species – the process of defining and naming – has not been done.

These high-priority species belong to a range of families including geckos, skinks and dragons found across Australia.

The high number of undescribed species, especially those with significant likelihood of being endangered, was a shock to even the experts. The IUCN currently estimates only 6.3% of Australian lizards and snakes require taxonomic revision, but this is obviously a significant underestimate.

A race against extinction

Beyond lizards, there is a huge backlog of species awaiting description.

Recent projects have used genetic analyses to discover unknown species, including a $180 million global BIOSCAN effort aiming to identify millions of new species. However, genetics is only a first step in the formal recognition of species.




Read more:
About 500,000 Australian species are undiscovered – and scientists are on a 25-year mission to finish the job


The taxonomic process of documenting, describing and naming species requires multiple further steps. These steps include a comprehensive diagnostic assessment using a combination of evidence, such as genetics and morphology, to uniquely distinguish each species from another. This process requires a high level of familiarity and scholarship of the group in question.

The Mt Elliot Sunskink (Lampropholis elliotensis), described in 2018, is found in leaf litter of highland rainforest above 600m on Mt Elliot in Bowling Green Bay National Park. Queensland, and is probably Vulnerable.
C. Hoskin, Author provided

Among the Australian lizards and snakes alone, there is a backlog of 59 undescribed species for which only the final elements of taxonomic research are awaiting completion.

To work through these taxonomic backlogs – let alone species that are so far entirely unknown – resources need to be invested in taxonomy, including research funding and increased provision of viable career paths.

Without taxonomic research, the conservation assessment of these undocumented species will not proceed. There are untold numbers of species needing taxonomic research that are already under threat of extinction. If we don’t hurry, they may go extinct before we even know they exist.The Conversation

Jane Melville, Senior Curator, Terrestrial Vertebrates, Museums Victoria and Reid Tingley, Lecturer, Monash University

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

The 50 beautiful Australian plants at greatest risk of extinction — and how to save them


Caley’s grevillea (Grevillea caleyi) occurs in Sydney. It needs fire to germinate but burns are hard to carry out near urban areas.
Tony Auld, Author provided

Jennifer Silcock, The University of Queensland; Jaana Dielenberg, Charles Darwin University; Roderick John Fensham, The University of Queensland, and Teghan Collingwood, The University of QueenslandAs far as odds go, things don’t look promising for the slender-nerved acacia (Acacia leptoneura), a spiky plant with classic yellow-ball wattle flowers. With most of its habitat in Western Australia’s wheat belt cleared for agriculture, it was considered extinct for more than 160 years.

Now, just two plants are known in the world, and they’re not even in the same place. This species is among many Australian plants that have come perilously close to extinction.

To help prevent the loss of any native plant species, we’ve assembled a massive evidence base for more than 750 plants listed as critically endangered or endangered. Of these, we’ve identified the 50 at greatest risk of extinction.

The good news is for most of these imperilled plants, we already have the knowledge and techniques needed to conserve them. We’ve devised an action plan that’s relatively easy to implement, but requires long-term funding and commitment.

What’s driving the loss?

There are 1,384 plant species and subspecies listed as threatened at a national level. Twelve Australian plant species are considered probably extinct and a further 21 species possibly extinct, while 206 are officially listed as critically endangered.

Yellow wattle
Two known plants of slender nerved acacia (Acacia leptoneura) remain, about 1 kilometre apart. Propagation attempts have been unsuccessful and the genetic diversity is probably very low.
Joel Collins, Author provided

Australian plants were used, managed and celebrated by Australia’s First Nations people for at least 60,000 years, but since European colonisation, they’ve been beset by a range of threats.

Land clearing, the introduction of alien plants, animals, diseases, and interruptions to ecological processes such as fire patterns and flooding have taken a heavy toll on many species. This is particularly the case in the more densely populated eastern and southern parts of the continent.

Close-up of yellow flower
Ironstone pixie mop (Petrophile latericola) occurs on a soil type that’s been heavily cleared for agriculture, and is suspected to be susceptible to an introduced root-rot fungus. In 2020 fewer than 200 plants remained, in poor condition.
Andrew Crawford, Author provided

Things aren’t improving. Scientists recently compiled long-term monitoring of more than 100 threatened plant species at 600 sites nationally. And they found populations had declined on average by 72% between 1995 and 2017.

This is a very steep rate of decline, much greater than for threatened mammal or bird populations.




Read more:
Australia-first research reveals staggering loss of threatened plants over 20 years


On the brink

Many species listed as threatened aren’t receiving targeted conservation action or even baseline monitoring, so an important first step in preventing extinctions was identifying the species at greatest risk.

To find the top 50, we looked at the evidence: all available published and unpublished information and expert surveys of over 120 botanists and land managers.
They’re targeted by our Action Plan for Australia’s Imperilled Plants.

Action Plan for Australia’s Imperilled Plants.

Thirty of the species in the plan have fewer than 50 mature individual plants remaining.

And 33 are known only from a single location, such as the Grampians pincushion-lily (Borya mirabilis), which occurs on one rocky outcrop in Victoria. This means the entire population could be destroyed by a single event, such as a major bushfire.

A dead-looking gum tree on agricultural land
About 2,000 Morrisby’s gums were growing in the early 1990s, but by 2016 fewer than 50 remained. Climate change and damage from insects and animals threaten those left. Protecting trees with fencing has led to new seedlings.
Magali Wright, Author provided
Fewer than 10 lax leek-orchids (Prasophyllum laxum) remain. Declines are ongoing due to drought and wildfire, and the South Australian species only occurs on private property not managed for conservation. Proposed recovery actions include habitat protection and establishing the orchid and its mycorrhizal fungi in conservation reserves.
Shane Graves, Author provided
Fewer than 15 woods well spyridium (Spyridium fontis-woodii) shrubs remain on a single roadside in South Australia. Research into threats and germination requirements is urgently needed, plus translocation to conservation reserves.
Daniel Duval/South Australian Seed Conservation Centre, Author provided

So how can we protect them?

Some of the common management actions we’ve proposed include:

  • preventing further loss of species’ habitat. This is the most important action required at a national scale
  • regularly monitoring populations to better understand how species respond to threats and management actions
  • safely trialling appropriate fire management regimes, such as burning in areas where fires have been suppressed
  • investing in disease research and management, to combat the threat of phytophthora (root-rot fungus) and myrtle rust, which damages leaves
  • propagating and moving species to establish plants at new sites, to boost the size of wild populations, or to increase genetic diversity
  • protecting plants from grazing and browsing animals, such as feral goats and rabbits, and sometimes from native animals such as kangaroos.
Once common, the dwarf spider-orchid (Caladenia pumila) wasn’t seen for over 80 years until two individual plants were found. Despite intensive management, no natural recruitment has occurred. Propagation attempts have successfully produced 100 seedlings and 11 mature plants from seed. This photo shows botanist Marc Freestone hand-pollinating dwarf spider-orchids.
Marc Freestone, Author provided
Only 21 mature plants of Gillingarra grevillea (Grevillea sp. Gillingarra) remain on a disturbed, weedy rail reserve in southwestern WA. Half the population was destroyed in 2011 due to railway maintenance and flooding. Habitat protection and restoration, and translocations to conservation reserves are needed to ensure its survival.
Andrew Crawford, Author provided

Another common issue is lack of recruitment, meaning there’s no young plants coming up to replace the old ones when they die. Sometimes this is because the processes that triggered these plants to flower, release seed or germinate are no longer occurring. This can include things like fire of a particular intensity or the right season.

Unfortunately, for some plants we don’t yet know what triggers are required, and further research is essential to establish this.

Now we need the political will

Our plan is for anyone involved in threatened flora management, including federal, state, territory and local government groups, First Nations, environment and community conservation groups, and anyone with one of these plants on their land.

The Border Ranges lined fern (Antrophyum austroqueenslandicum) and its habitat are exceedingly rare. It’s threatened by drought and climate change, and fewer than 50 plants remain in NSW. If the threat of illegal collection can be controlled, the species would benefit from re-introduction to Queensland’s Lamington National Park.
Lui Weber, Author provided

Plants make Australian landscapes unique — over 90% of our plant species are found nowhere else in the world. They’re also the backbone of our ecosystems, creating the rich and varied habitats for our iconic fauna to live in. Plants underpin and enrich our lives every day.

Now we have an effective plan to conserve the Australian plants at the greatest risk of extinction. What’s needed is the political will and resourcing to act in time.




Read more:
Undocumented plant extinctions are a big problem in Australia – here’s why they go unnoticed


The Conversation


Jennifer Silcock, Post-doctoral research fellow, The University of Queensland; Jaana Dielenberg, University Fellow, Charles Darwin University; Roderick John Fensham, Associate Professor of Biological Sciences, The University of Queensland, and Teghan Collingwood, Research Technician, The University of Queensland

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

Worried about Earth’s future? Well, the outlook is worse than even scientists can grasp



Daniel Mariuz/AAP

Corey J. A. Bradshaw, Flinders University; Daniel T. Blumstein, University of California, Los Angeles, and Paul Ehrlich, Stanford University

Anyone with even a passing interest in the global environment knows all is not well. But just how bad is the situation? Our new paper shows the outlook for life on Earth is more dire than is generally understood.

The research published today reviews more than 150 studies to produce a stark summary of the state of the natural world. We outline the likely future trends in biodiversity decline, mass extinction, climate disruption and planetary toxification. We clarify the gravity of the human predicament and provide a timely snapshot of the crises that must be addressed now.

The problems, all tied to human consumption and population growth, will almost certainly worsen over coming decades. The damage will be felt for centuries and threatens the survival of all species, including our own.

Our paper was authored by 17 leading scientists, including those from Flinders University, Stanford University and the University of California, Los Angeles. Our message might not be popular, and indeed is frightening. But scientists must be candid and accurate if humanity is to understand the enormity of the challenges we face.

Girl in breathing mask attached ot plant in container
Humanity must come to terms with the future we and future generations face.
Shutterstock

Getting to grips with the problem

First, we reviewed the extent to which experts grasp the scale of the threats to the biosphere and its lifeforms, including humanity. Alarmingly, the research shows future environmental conditions will be far more dangerous than experts currently believe.

This is largely because academics tend to specialise in one discipline, which means they’re in many cases unfamiliar with the complex system in which planetary-scale problems — and their potential solutions — exist.

What’s more, positive change can be impeded by governments rejecting or ignoring scientific advice, and ignorance of human behaviour by both technical experts and policymakers.

More broadly, the human optimism bias – thinking bad things are more likely to befall others than yourself – means many people underestimate the environmental crisis.

Numbers don’t lie

Our research also reviewed the current state of the global environment. While the problems are too numerous to cover in full here, they include:

  • a halving of vegetation biomass since the agricultural revolution around 11,000 years ago. Overall, humans have altered almost two-thirds of Earth’s land surface

  • About 1,300 documented species extinctions over the past 500 years, with many more unrecorded. More broadly, population sizes of animal species have declined by more than two-thirds over the last 50 years, suggesting more extinctions are imminent




Read more:
What is a ‘mass extinction’ and are we in one now?


  • about one million plant and animal species globally threatened with extinction. The combined mass of wild mammals today is less than one-quarter the mass before humans started colonising the planet. Insects are also disappearing rapidly in many regions

  • 85% of the global wetland area lost in 300 years, and more than 65% of the oceans compromised to some extent by humans

  • a halving of live coral cover on reefs in less than 200 years and a decrease in seagrass extent by 10% per decade over the last century. About 40% of kelp forests have declined in abundance, and the number of large predatory fishes is fewer than 30% of that a century ago.

State of the Earth's environment
Major environmental-change categories expressed as a percentage relative to intact baseline. Red indicates percentage of category damaged, lost or otherwise affected; blue indicates percentage intact, remaining or unaffected.
Frontiers in Conservation Science

A bad situation only getting worse

The human population has reached 7.8 billion – double what it was in 1970 – and is set to reach about 10 billion by 2050. More people equals more food insecurity, soil degradation, plastic pollution and biodiversity loss.

High population densities make pandemics more likely. They also drive overcrowding, unemployment, housing shortages and deteriorating infrastructure, and can spark conflicts leading to insurrections, terrorism, and war.




Read more:
Climate explained: why we need to focus on increased consumption as much as population growth


Essentially, humans have created an ecological Ponzi scheme. Consumption, as a percentage of Earth’s capacity to regenerate itself, has grown from 73% in 1960 to more than 170% today.

High-consuming countries like Australia, Canada and the US use multiple units of fossil-fuel energy to produce one energy unit of food. Energy consumption will therefore increase in the near future, especially as the global middle class grows.

Then there’s climate change. Humanity has already exceeded global warming of 1°C this century, and will almost assuredly exceed 1.5 °C between 2030 and 2052. Even if all nations party to the Paris Agreement ratify their commitments, warming would still reach between 2.6°C and 3.1°C by 2100.

people walking on a crowded street
The human population is set to reach 10 billion by 2050.
Shutterstock

The danger of political impotence

Our paper found global policymaking falls far short of addressing these existential threats. Securing Earth’s future requires prudent, long-term decisions. However this is impeded by short-term interests, and an economic system that concentrates wealth among a few individuals.

Right-wing populist leaders with anti-environment agendas are on the rise, and in many countries, environmental protest groups have been labelled “terrorists”. Environmentalism has become weaponised as a political ideology, rather than properly viewed as a universal mode of self-preservation.

Financed disinformation campaigns against climate action and forest protection, for example, protect short-term profits and claim meaningful environmental action is too costly – while ignoring the broader cost of not acting. By and large, it appears unlikely business investments will shift at sufficient scale to avoid environmental catastrophe.

Changing course

Fundamental change is required to avoid this ghastly future. Specifically, we and many others suggest:

  • abolishing the goal of perpetual economic growth

  • revealing the true cost of products and activities by forcing those who damage the environment to pay for its restoration, such as through carbon pricing

  • rapidly eliminating fossil fuels

  • regulating markets by curtailing monopolisation and limiting undue corporate influence on policy

  • reigning in corporate lobbying of political representatives

  • educating and empowering women across the globe, including giving them control over family planning.

A coal plant
The true cost of environmental damage should be borne by those responsible.
Shutterstock

Don’t look away

Many organisations and individuals are devoted to achieving these aims. However their messages have not sufficiently penetrated the policy, economic, political and academic realms to make much difference.

Failing to acknowledge the magnitude and gravity of problems facing humanity is not just naïve, it’s dangerous. And science has a big role to play here.

Scientists must not sugarcoat the overwhelming challenges ahead. Instead, they should tell it like it is. Anything else is at best misleading, and at worst potentially lethal for the human enterprise.




Read more:
Mass extinctions and climate change: why the speed of rising greenhouse gases matters


The Conversation


Corey J. A. Bradshaw, Matthew Flinders Professor of Global Ecology and Models Theme Leader for the ARC Centre of Excellence for Australian Biodiversity and Heritage, Flinders University; Daniel T. Blumstein, Professor in the Department of Ecology and Evolutionary Biology and the Institute of the Environment and Sustainability, University of California, Los Angeles, and Paul Ehrlich, President, Center for Conservation Biology, Bing Professor of Population Studies, Stanford University

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

Australia-first research reveals staggering loss of threatened plants over 20 years


Ayesha Tulloch, University of Sydney; Elisa Bayraktarov, The University of Queensland; Hugh Possingham, The University of Queensland; Jaana Dielenberg, Charles Darwin University; Jennifer Silcock, The University of Queensland; Micha Victoria Jackson, The University of Queensland, and Nathalie Butt, The University of Queensland

When it comes to threatened species, charismatic animals usually get the most attention. But many of Australia’s plants are also in grave danger of extinction, and in many cases, the problem is getting worse.

New Australia-first research shows the population sizes of our threatened plants fell by almost three-quarters, on average, between 1995 and 2017. The findings were drawn from Australia’s 2020 Threatened Species Index, which combines data from almost 600 sites.

Plants are part of what makes us and our landscapes unique. They are important in their own right, but also act as habitat for other species and play critical roles in the broader ecosystem.

This massive data-crunching exercise shows that a lot more effort is needed if we want to prevent plant extinctions.

Plants, such as WA’s Endangered Foote’s grevillea, make our landscape unique.
Andrew Crawford / WA Department of Biodiversity Conservation and Attractions

Spotlight on plants

Australia’s plant species are special – 84% are found nowhere else in the world. The index shows that over about 20 years up to 2017, Australia’s threatened plant populations declined by 72%. This is faster than mammals (which declined by about a third), and birds (which declined by about half). Populations of trees, shrubs, herbs and orchids all suffered roughly similar average declines (65-75%) over the two decades.

Of the 112 species in the index, 68% are critically endangered or endangered and at risk of extinction if left unmanaged. Some 37 plant species have gone extinct since records began, though many others are likely to have been lost before scientists even knew they existed. Land clearing, changed fire regimes, grazing by livestock and feral animals, plant diseases, weeds and climate change are common causes of decline.




Read more:
Undocumented plant extinctions are a big problem in Australia – here’s why they go unnoticed


Vulnerable plant populations reduced to small areas can also face unique threats. For example, by the early 2000s Foote’s grevillea (Grevillea calliantha) had dwindled to just 27 wild plants on road reserves. Road maintenance activities such as mowing and weed spraying became a major threat to its survival. For other species, like the button wrinklewort, small populations can lead to inbreeding and a lack of genetic diversity.

Fire, interrupted

Threatened plant conservation in fire-prone landscapes is challenging if a species’ relationship with fire is not known. Many Australian plant species require particular intensities or frequencies of burns for seed to be released or germinate. But since European settlement, fire patterns have been interrupted, causing many plant populations to decline.

Three threatened native pomaderris shrubs on the NSW South Coast are a case in point. Each of them – Pomaderris adnata, P. bodalla and P. walshii – have failed to reproduce for several years and are now found only in a few locations, each with a small number of plants.

Experimental trials recently revealed that to germinate, the seeds of these pomaderris species need exposure to hot-burning fires (or a hot oven). However they are now largely located in areas that seldom burn. This is important knowledge for conservation managers aiming to help wild populations persist.

Endangered sublime point pomaderris (Pomaderris adnata) requires high fire temperatures to germinate.
Jedda Lemmon /NSW DPIE, Saving our Species

Success is possible

A quarter of the species in the threatened plant index are orchids. Orchids make up 17% of plant species listed nationally as threatened, despite comprising just 6% of Australia’s total plant species.

The endangered coloured spider-orchid (Caladenia colorata) is pollinated only by a single thynnine wasp, and relies on a single species of mycorrhizal fungi to germinate in the wild.

Yet even for such a seemingly difficult species, conservation success is possible. In one project, scientists from the Royal Botanic Gardens Victoria, aided by volunteers, identified sites where the wasp was still naturally present. More than 800 spider orchid plants were then propagated in a lab using the correct symbiotic fungus, then planted at four sites. These populations are now considered to be self-sustaining.

In the case of Foote’s grevillea, a plant translocation program has established 500 plants at three new sites, dramatically improving the species’ long-term prospects.

Orchid flower
The coloured spider orchid, found in South Australia and Victoria, is endangered.
Noushka Reiter/Royal Botanic Gardens Victoria

But we aren’t doing enough

Both federal environment laws and the national threatened species strategy are under review. Submissions by research institutions and others have noted a lack of data, recovery actions and conservation funding for plants.

Our research found threatened plant populations at managed sites suffered declines of 60% on average, compared to 80% declines at unmanaged sites. This shows that while management is beneficial, it is not preventing overall declines.

New data on threatened species trends are added to the plant index each year, but many species are missing from the index because they aren’t being monitored.




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


Monitoring of threatened species is undertaken by government and non-government groups, community groups, Indigenous organisations, citizen scientists, researchers and individuals. Without it, we have no idea if species are recovering or heading unnoticed towards extinction.

Woman measuring the height of a plant
Monitoring is essential to know if conservation actions are working.
Rebecca Dillon / WA Department of Biodiversity Conservation and Attractions

Australia has about 1,800 threatened species. Of these, 77% – or 1,342 species – are plants. However the index received monitoring data for only 10% of these plants, compared to 35% of threatened birds, which make up only 4% of threatened species.

If you’re keen to get involved in plant monitoring, it involves just a few simple steps:

  • find a local patch with a threatened plant species

  • revisit it once or twice a year to count the number of individuals in a consistent, well-defined area

  • use the same method and the same amount of effort each visit

  • take great care to not disturb the plant or its habitat when looking for it

  • contribute your data to the index.

Saving Australia’s flora

Australia must urgently change the way we prioritise conservation actions and enact environment laws, if we hope to prevent more plant extinctions.

Critical actions include stopping further habitat loss and more funding for recovery actions as well as extinction risk assessments. It is important that these assessments adhere to consistent criteria. This is something the common assessment method, agreed to by all states and territories, seeks to achieve.

Finally, more funding for research into the impacts of key threats (and how to manage them) will help ensure our unique flora are not lost forever.

Prof Hugh Possingham and Dr Ayesha Tulloch discuss the 2020 findings of the Threatened Plant Index.

CORRECTION: A previous version of this article incorrectly stated that reviews of federal environment laws and the threatened species strategy found a lack of data, recovery actions and conservation funding for plants. While those problems were identified in public submissions to the reviews, the reviews themselves are not yet finalised.The Conversation

Ayesha Tulloch, DECRA Research Fellow, University of Sydney; Elisa Bayraktarov, Postdoctoral Research Fellow in Conservation Biology, The University of Queensland; Hugh Possingham, Professor, The University of Queensland; Jaana Dielenberg, University Fellow, Charles Darwin University; Jennifer Silcock, Post-doctoral research fellow, The University of Queensland; Micha Victoria Jackson, Postdoctoral research fellow, The University of Queensland, and Nathalie Butt, Postdoctoral Fellow, The University of Queensland

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

Humans are changing fire patterns, and it’s threatening 4,403 species with extinction



The Leadbeater’s possum, one of thousands of species threatened by changing fire regimes.
Shutterstock

Luke Kelly, University of Melbourne; Annabel Smith, The University of Queensland; Katherine Giljohann, University of Melbourne, and Michael Clarke, La Trobe University

Last summer, many Australians were shocked to see fires sweep through the wet tropical rainforests of Queensland, where large and severe fires are almost unheard of. This is just one example of how human activities are changing fire patterns around the world, with huge consequences for wildlife.

In a major new paper published in Science, we reveal how changes in fire activity threaten more than 4,400 species across the globe with extinction. This includes 19% of birds, 16% of mammals, 17% of dragonflies and 19% of legumes that are classified as critically endangered, endangered or vulnerable.




Read more:
Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)


But, we also highlight the emerging ways we can help promote biodiversity and stop extinctions in this new era of fire. It starts with understanding what’s causing these changes and what we can do to promote the “right” kind of fire.

How is fire activity changing?

Recent fires have burned ecosystems where wildfire has historically been rare or absent, from the tropical forests of Queensland, Southeast Asia and South America to the tundra of the Arctic Circle.

Exceptionally large and severe fires have also been observed in areas with a long history of fire. For example, the 12.6 million hectares that burnt in eastern Australia during last summer’s devastating bushfires was unprecedented in scale.

The post-fire landscape in Flinders Chase National Park, Kangaroo Island, three months after an extremely large and severe bushfire last summer.
Luke Kelly

This extreme event came at a time when fire seasons are getting longer, with more extreme wildfires predicted in forests and shrublands in Australia, southern Europe and western United States.

But fire activity isn’t increasing everywhere. Grasslands in countries such as Brazil, Tanzania, and the United States have had fire activity reduced.

Extinction risk in a fiery world

Fire enables many plants to complete their life cycles, creates habitats for a wide range of animals and maintains a diversity of ecosystems. Many species are adapted to particular patterns of fire, such as banksias — plants that release seeds into the resource-rich ash covering the ground after fire.

But changing how often fires occur and in what seasons can harm populations of species like these, and transform the ecosystems they rely on.

We reviewed data from the International Union for Conservation of Nature (IUCN) and found that of the 29,304 land-based and freshwater species listed as threatened, modified fire regimes are a threat to more than 4,403.

Most are categorised as threatened by an increase in fire frequency or intensity.

For example, the endangered mallee emu-wren in semi-arid Australia is confined to isolated patches of habitat, which makes them vulnerable to large bushfires that can destroy entire local populations.

Likewise, the Kangaroo Island dunnart was listed as critically endangered before it lost 95% of its habitat in the devastating 2019-2020 bushfires.

Large bushfires threaten many birds, such as the mallee emu-wren.
Ron Knight/Wikimedia, CC BY

However, some species and ecosystems are threatened when fire doesn’t occur. Frequent fires are an important part of African savanna ecosystems and less fire activity can lead to shrub encroachment. This can displace wild herbivores such as wildebeest that prefer open areas.

How humans change fire regimes

There are three main ways humans are transforming fire activity: global climate change, land-use and the introduction of pest species.

Global climate change modifies fire regimes by changing fuels such as dry vegetation, ignitions such as lightning, and creating more extreme fire weather.

What’s more, climate-induced fires can occur before the dominant tree species are old enough to produce seed, and this is reshaping forests in Australia, Canada and the United States.

Humans also alter fire regimes through farming, forestry, urbanisation and by intentionally starting or suppressing fires.

Introduced species can also change fire activity and ecosystems. For example, in savanna landscapes of Northern Australia, invasive gamba grass increases flammability and fire frequency. And invasive animals, such as red foxes and feral cats, prey on native animals exposed in recently burnt areas.




Read more:
Fire-ravaged Kangaroo Island is teeming with feral cats. It’s bad news for this little marsupial


Importantly, cultural, social and economic changes underpin these drivers. In Australia, the displacement of Indigenous peoples and their nuanced and purposeful use of fire has been linked with extinctions of mammals and is transforming vegetation.

We need bolder conservation strategies

A suite of emerging actions — some established but receiving increasing attention, others new — could help us navigate this new fire era and save species from extinction. They include:

In Africa, reintroducing grazing animals such as rhinoceros create patchy fire regimes.
Sally Archibald, Author provided

Where to from here?

The input of scientists will be valuable in helping navigate big decisions about new and changing ecosystems.

Empirical data and models can monitor and forecast changes in biodiversity. For example, new modelling has allowed University of Melbourne researchers to identify alternative strategies for introducing planned or prescribed burning that reduces the risk of large bushfires to koalas.

New partnerships are also needed to meet the challenges ahead.

At the local and regional scale, Indigenous-led fire stewardship is an important approach for fostering relationships between Indigenous and non-Indigenous organisations and communities around the world.

Frank Lake, a co-author on our new paper, works with Yurok and Karuk fire practitioners, shown here burning under oaks.
Frank Lake, U.S Department of Agriculture Forest Service Pacific Southwest Research Station.

And international efforts to reduce greenhouse gas emissions and limit global warming are crucial to reduce the risk of extreme fire events. With more extreme fire events ahead of us, learning to understand and adapt to changes in fire regimes has never been more important.




Read more:
The world’s best fire management system is in northern Australia, and it’s led by Indigenous land managers


The Conversation


Luke Kelly, Senior Lecturer in Ecology and Centenary Research Fellow, University of Melbourne; Annabel Smith, Lecturer in Wildlife Management, The University of Queensland; Katherine Giljohann, Postdoctoral research fellow, University of Melbourne, and Michael Clarke, Professor of Zoology, La Trobe University

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

How to reverse global wildlife declines by 2050


Wouter Taljaard/Shutterstock

Michael Obersteiner, University of Oxford; David Leclère, International Institute for Applied Systems Analysis (IIASA), and Piero Visconti, International Institute for Applied Systems Analysis (IIASA)

Species are going extinct at an unprecedented rate. Wildlife populations have fallen by more than two-thirds over the last 50 years, according to a new report from the World Wildlife Fund. The sharpest declines have occurred throughout the world’s rivers and lakes, where freshwater wildlife has plummeted by 84% since 1970 – about 4% per year.

But why should we care? Because the health of nature is intimately linked to the health of humans. The emergence of new infectious diseases like COVID-19 tend to be related to the destruction of forests and wilderness. Healthy ecosystems are the foundation of today’s global economies and societies, and the ones we aspire to build. As more and more species are drawn towards extinction, the very life support systems on which civilisation depends are eroded.

Even for hard-nosed observers like the World Economic Forum, biodiversity loss is a disturbing threat with few parallels. Of the nine greatest threats to the world ranked by the organisation, six relate to the ongoing destruction of nature.

A digger tears down trees in a Malaysian rainforest.
New infectious diseases tend to emerge in places at the forefront of environmental destruction.
Rich Carey/Shutterstock

Economic systems and lifestyles which take the world’s generous stocks of natural resources for granted will need to be abandoned, but resisting the catastrophic declines of wildlife that have occurred over the last few decades might seem hopeless. For the first time, we’ve completed a science-based assessment to figure out how to slow and even reverse these trends.

Our new paper in Nature featured the work of 60 co-authors and built on efforts steered by the Intergovernmental Panel on Biodiversity and Ecosystem Services. We considered ambitious targets for rescuing global biodiversity trends and produced pathways for the international community to follow that could allow us to meet these goals.




Read more:
How forest loss has changed biodiversity across the globe over the last 150 years


Bending the curve

The targets of the UN Convention on Biological Diversity call for global trends of terrestrial wildlife to stop declining and start recovering by 2050 or earlier. Changes in how land is used – from pristine forest to cropland or pasture – rank among the greatest threats to biodiversity on land worldwide. So what are the necessary conditions for biodiversity to recover during the 21st century while still supporting growing and affluent human societies?

Two key areas of action stand out from the rest. First, there must be renewed ambition from the world’s governments to establish large-scale conservation areas, placed in the most valuable hotspots for biodiversity worldwide, such as small islands with species found nowhere else. These reserves, in which wildlife will live and roam freely, will need to cover at least 40% of the world’s land surface to help bend the curve from decline to recovery for species and entire ecosystems.

The location of these areas, and how well they are managed, is often more important than how big they are. Habitat restoration and conservation efforts need to be targeted where they are needed most – for species and habitats on the verge of extinction.

A downward sloping line showing wildlife declines splits into three alternative trajectories, where biodiversity increases, plateaus and crashes by 2050.
The next 30 years will prove pivotal for Earth’s biodiversity.
Leclère et al. (2020), Author provided

Second, we must transform our food systems to produce more on less land. If every farmer on Earth used the best available farming practices, only half of the total area of cropland would be needed to feed the world. There are lots of other inefficiencies that could be ironed out too, by reducing the amount of waste produced during transport and food processing, for example. Society at large can help in this effort by shifting towards healthier and more sustainable diets, and reducing food waste.

This should happen alongside efforts to restore degraded land, such as farmland that’s becoming unproductive as a result of soil erosion, and land that’s no longer needed as agriculture becomes more efficient and diets shift. This could return 8% of the world’s land to nature by 2050. It will be necessary to plan how the remaining land is used, to balance food production and other uses with the conservation of wild spaces.

Without a similar level of ambition for reducing greenhouse gas emissions, climate change will ensure the world’s wildlife fares badly this century. Only a comprehensive set of policy measures that transform our relationship with the land and rapidly scale down pollution can build the necessary momentum. Our report concludes that transformative changes in our food systems and how we plan and use land will have the biggest benefits for biodiversity.

But the benefits wouldn’t end there. While giving back to nature, these measures would simultaneously slow climate change, reduce pressure on water, limit nitrogen pollution in the world’s waterways and boost human health. When the world works together to halt and eventually reverse biodiversity loss, it’s not only wildlife that will thrive.The Conversation

Michael Obersteiner, Director, Environmental Change Institute, University of Oxford; David Leclère, Researcher in Ecosystem Services and Management (ESM) Program, International Institute for Applied Systems Analysis (IIASA), and Piero Visconti, Research Scholar, Ecosystem Services and Management Programme, International Institute for Applied Systems Analysis (IIASA)

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

New research reveals these 20 Australian reptiles are set to disappear by 2040



Cape Melville leaf-tailed gecko
Conrad Hoskin, Author provided

Hayley Geyle, Charles Darwin University and David Chapple, Monash University

Action came too late for the Christmas Island forest skink, despite early warnings of significant declines. It was lost from the wild before it was officially listed as “threatened”, and the few individuals brought into captivity died soon after.

Australia is home to about 10% of all known reptile species — the largest number of any country in the world. But many of our reptiles are at risk of the same fate as the Christmas Island forest skink: extinction.

In new research published today, we identified the 20 terrestrial snakes and lizards (collectively known as “squamates”) at greatest risk of extinction in the next two decades, assuming no changes to current conservation management.

Preventing extinctions of Australian lizards and snakes.

While all 20 species meet international criteria to be officially listed as “threatened”, only half are protected under Australian environmental legislation— the Environment Protection and Biodiversity Conservation (EPBC) Act. This needs urgent review.

Many of these reptiles receive little conservation action, but most of their threats can be ameliorated. By identifying the species at greatest risk of extinction, we can better prioritise our recovery efforts — we know now what will be lost if we don’t act.

Six species more likely than not to go extinct

Our research team — including 27 reptile experts from universities, zoos, museums and government organisations across the country — identified six species with greater than 50% likelihood of extinction by 2040.

This includes two dragons, one blind snake and three skinks. Experts rated many others as having a 30-50% likelihood of extinction over the next 20 years.

More than half (55%) of the 20 species at greatest risk occur in Queensland. Three live on islands: two on Christmas Island and one on Lancelin Island off the Western Australian coast.

Two more species are found in Western Australia, while the Northern Territory, the Australian Capital Territory, Victoria and New South Wales each have one species.




Read more:
Australia’s smallest fish among 22 at risk of extinction within two decades


Each of the 20 species at greatest risk occur in a relatively small area, which partly explains the Queensland cluster — many species in that state naturally have very small distributions.

Most of the top 20 occupy a total range of fewer than 20 square kilometres, so could be lost to a single catastrophic event, such as a large bushfire.

A map of Australia showing where the 20 snakes and lizards are located
The approximate locations of the 20 terrestrial snakes and lizards at greatest risk of extinction.
Author provided

So why are they dying out?

Reptile species are declining on a global scale, and this is likely exacerbated by climate change. In Australia, where more than 90% of our species occur nowhere else in the world, the most threatened reptiles are at risk for two main reasons: they have very small distributions, and ongoing, unmitigated threats.

The Cape Melville leaf-tailed gecko meets this brief perfectly. This large and spectacular species was only discovered in 2013, on a remote mountain range on Cape York. It’s threatened by virtue of its very small distribution and population size, and by climate change warming and drying its upland habitat.

Arnhem Land gorges skink
The Arnhem Land gorges skink is considered more likely than not to become extinct by 2040. Threats include changes to food resources and habitat quality, feral cats, and possibly poisoning by cane toads.
Chris Jolly

Habitat loss is also a major threat for the top 20 species. Australia’s most imperilled reptile, the Victoria grassland earless dragon, used to be relatively common in grasslands in and around Melbourne. But the grasslands this little dragon once called home have been extensively cleared for agriculture and urban development, and now cover less than 1% of their original extent.




Read more:
Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)


Little conservation attention

For most reptile species, there has been less conservation work to address the declines, partly because reptiles have historically received less scientific attention than birds or mammals.

We also still don’t fully understand just how many species there are in Australia. New reptile species are being scientifically described at an average rate of 15 per year (a higher rate than for other vertebrate groups) and many new reptiles are already vulnerable to extinction at the time of discovery.

The Mount Surprise slider, a light-brown snake
The Mount Surprise slider is threatened by invasive plant species and cattle compacting sandy soils.
Stephen Zozaya, Author provided

To make matters worse, few reptiles in Australia are well-monitored. Without adequate monitoring, we have a poor understanding of population trends and the impacts of threats. This means species could slip into extinction unnoticed.

Reptiles also lack the public and political profile that helps generate recovery support for other, (arguably) more charismatic Australian threatened animals — such as koalas and swift parrots — leading to little resourcing for conservation.

Lessons from the past

Only one Australian reptile, the Christmas Island forest skink, is officially listed as extinct, but we have most probably lost others before knowing they exist. Without increased resourcing and management intervention, many more Australian reptiles could follow the same trajectory.

The Roma earless dragon sitting up on hind legs.
Habitat loss and degradation due to agriculture is a major threat to the Roma earless dragon. It has not been listed under Australian legislation.
A. O’Grady Museums Victoria, Author provided

But it’s not all bad news. The pygmy bluetongue skink was once thought to be extinct until a chance discovery kick-started a long conservation and research program.

Animals are now being taken from the wild and relocated to new areas to establish more populations, signifying that positive outcomes are possible when informed by good science.

And the very restricted distributions of most of the species identified here should allow for targeted and effective recovery efforts.

By identifying the species at greatest risk, we hope to give governments, conservation groups and the community time to act to prevent further extinctions before it’s too late. Neglect should no longer be the default response for our fabulous reptile fauna.




Read more:
A hidden toll: Australia’s cats kill almost 650 million reptiles a year


The Conversation


Hayley Geyle, Research Assistant, Charles Darwin University and David Chapple, Associate Professor in Evolutionary and Conservation Ecology, Monash University

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

The Tasmanian tiger was hunted to extinction as a ‘large predator’ – but it was only half as heavy as we thought



Smithsonian Institution/colourised by D.S. Rovinsky

Douglass Rovinsky, Monash University; Alistair Evans, Monash University, and Justin W. Adams, Monash University

Until it was hunted to extinction, the thylacine – also known as the Tasmanian tiger or Tasmanian wolf – was the world’s largest marsupial predator. However, our new research shows it was in fact only about half as large as previously thought. So perhaps it wasn’t such a big bad wolf after all.

Although the thylacine is widely known as an example of human-caused extinction, there is a lot we still don’t know about this fascinating animal. This even includes one of the most basic details: how much did the thylacine weigh?

An animal’s body mass is one of the most fundamental aspects of its biology. It affects nearly every facet of its biology, from biochemical and metabolic processes, reproduction, growth, and development, through to where the animal can live and how it moves.

For meat-eating predators, body mass also determines what the animal eats – or more specifically, how much it has to eat at each meal.

Catching and eating other animals is hard work, so a predator has to weigh the costs carefully against the benefits. Small predators have low hunting costs – moving around, hunting, and killing small prey doesn’t cost much energy, so they can afford to nibble on small animals here and there. But for bigger predators, the stakes are higher.

Almost all large predators – those weighing at least 21  kilograms – focus their efforts on prey at least half their own body size, getting more bang for the buck. In contrast, small predators below 14.5 kg almost always catch prey much smaller than half their own size. Those in between typically take prey less than half their size, but sometimes switch to a larger meal if some easy prey is there for the taking – or if the predator is getting desperate.

The mismeasure of the thylacine

Scan of article from Launceston Examiner
The March 14, 1868 edition of the Launceston Examiner featured tales of a ‘hyena’ that managed to kill 25 sheep.
trove.nla.gov.au

Few accurately recorded weights exist for thylacines – only four, in fact. This lack of information has made estimating their average size difficult. The most commonly used average body mass is 29.5kg, based on 19th-century newspaper accounts.

This suggests the thylacine would probably have taken relatively large prey such as wallabies, kangaroos and perhaps sheep. However, studies of thylacine skulls suggest they didn’t have strong enough skulls to capture and kill large prey, and that they would have hunted smaller animals instead.

This presented a problem: if the thylacine was as big as we thought, it shouldn’t be able to live solely on small prey. But what if we’ve had the weight wrong the whole time?




Read more:
Why did the Tasmanian tiger go extinct?


Weighing an extinct animal

Man taking a scan of a stuffed thylacine
Ben Myers of Thinglab scans a Museums Victoria thylacine.
CREDIT, Author provided

Our new research, published today in Proceedings of the Royal Society B, addresses this weighty issue. Our team travelled throughout the world to museums in Australia, the United States, the United Kingdom and Europe, and 3D-scanned 93 thylacines, including whole mounted skeletons, taxidermy mounts, and the only whole-body ethanol-preserved thylacine in the world, in Sweden.

Based on these scans, we created new equations to estimate a thylacine’s mass, based on how thick their limbs were – because their legs would have had to support their entire weight.

We also compared the results of these equations with a new method of digitally weighing 3D specimens. Based on a 3D scan of a mounted skeleton, we digitally “filled in the spaces” to estimate how much soft tissue would have been present, and then used our new formula to calculate how much this would weigh. Taxidermy mounts were easier as there was no need to infer the amount of soft tissue. The most artistic member of our team digitally sculpted lifelike thylacines around the scanned skeletons, and we weighed them, too.

Building and weighing a thylacine. Scanned skeletons (lop left) were surrounded by digital ‘convex hulls’ (top right), which then had their volume and mass calculated. The skeletons were then used in digitally sculpting lifelife models (bottom left), each with their own unique stripes (bottom right).
Rovinsky et al.

Our calculations unanimously told a very different story from the 19th-century periodicals, and from the commonly used estimate. The average thylacine weighed only about 16.7 kg – not 29.5 kg.




Read more:
Friday essay: on the trail of the London thylacines


Tall tales on the tiger trail

This means the previous estimate, based on taking 19th-century periodicals at face value, was nearly 80% too large. Looking back at those old newspaper reports, many of them in retrospect have the hallmarks of “tall tales”, told to make a captured thylacine seem bigger, more impressive and more dangerous.

It was based on this suspected danger that the thylacine was hunted and trapped to extinction, with private bounties already placed on them by 1840, and government-sponsored extermination by the 1880s.

Graphic showing the size of thylacines relative to a woman
Thylacines were much smaller in stature than humans or grey wolves.
Rovinsky et al., Author provided

The thylacine was much smaller than previously thought, and this aligns with the smaller prey size suggested by the earlier studies. Predators below 21 kg – in which we should now include the thylacine – all tend to hunt prey smaller than half their size. The “Tasmanian wolf” probably wasn’t such a danger to Tasmanian farmers’ sheep after all.

By rewriting this fundamental aspect of their biology, we are closer to understanding the role of the thylacine in the ecosystem – and to seeing exactly what was lost when we deliberately hunted it to extinction.The Conversation

Douglass Rovinsky, PhD Candidate, Monash University; Alistair Evans, Associate Professor, Monash University, and Justin W. Adams, Senior Lecturer, Department of Anatomy and Developmental Biology, Monash University

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