Scientific integrity must be defended, our planet depends on it



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To conserve Earth’s remarkable species, such as the violet sabrewing, we must also defend the importance of science.
Jeremy Kerr, Author provided

Euan Ritchie, Deakin University; James Watson, The University of Queensland; Jeremy Kerr, and Martine Maron, The University of Queensland

Science is the best method we have for determining what is likely to be true. The knowledge gained from this process benefits society in a multitude of ways, including promoting evidence-based decision-making and management. Nowhere is this more important than conservation, as the intensifying impacts of the Anthropocene increasingly threaten the survival of species.

But truth can be inconvenient: conservation goals sometimes seem at odds with social or economic interests. As a result, scientific evidence may be ignored or suppressed for political reasons. This has led to growing global trends of attacking scientific integrity.

Recent assaults on science and scientists under Donald Trump’s US administration are particularly extreme, but extend far more broadly. Rather than causing scientists to shrink from public discussions, these abuses have spurred them and their professional societies to defend scientific integrity.

Among these efforts was the recent March for Science. The largest pro-science demonstration in history, this event took place in more than 600 locations around the world.

We propose, in a new paper in Conservation Biology, that scientists share their experiences of defending scientific integrity across borders to achieve more lasting success. We summarise eight reforms to protect scientific integrity, drawn from lessons learned in Australia, Canada and the US.

March for science in Melbourne.
John Englart (Takver)

What is scientific integrity?

Scientific integrity is the ability to perform, use and disseminate scientific findings without censorship or political interference. It requires that government scientists can communicate their research to the public and media. Such outbound scientific communication is threatened by policies limiting scientists’ ability to publish, publicise or even mention their research findings.

Public access to websites or other sources of government scientific data have also been curtailed. Limiting access to taxpayer-funded information in this way undermines citizens’ ability to participate in decisions that affect them, or even to know why decisions are being made.

News of the rediscovery of the shrub Hibbertia fumana (left) in Australia was delayed until a development at the site of rediscovery had been permitted. Political considerations delayed protection of the wolverine (right) in the United States.
Wolverine – U.S. National and Park Service. _Hibbertia fumana_ – A. Orme

A recent case of scientific information being suppressed concerns the rediscovery, early in 2017, of the plant Hibbertia fumana in New South Wales. Last seen in 1823, 370 plants were found.

Rather than publicly celebrate the news, the NSW Office of Environment and Heritage was reportedly asked to suppress the news until after a rail freight plan that overlapped with the plants’ location had been approved.

Protecting scientists’ right to speak out

Scientists employed by government agencies often cannot discuss research that might relate to their employer’s policies. While it may not be appropriate for scientists to weigh in on policy recommendations – and, of course, constant media commentaries would be chaos – the balance has tipped too far towards restriction. Many scientists cannot publicly refer to their research, or that of others, let alone explain the significance of the findings.

To counter this, we need policies that support scientific integrity, an environment of transparency and the public’s right to access scientific information. Scientists’ right to speak freely should be included in collective bargaining agreements.

Scientific integrity requires transparency and accountability. Information from non-government scientists, through submitted comments or reviews of draft policies, can inform the policy process.

Although science is only one source of influence on policy, democratic processes are undermined when policymakers limit scrutiny of decision-making processes and the role that evidence plays in them.

Let science inform policy

Independent reviews of new policy are a vital part of making evidence-based decisions. There is room to broaden these reviews, inviting external organisations to give expert advice on proposed or existing policies. This also means transparently acknowledging any perceived or actual vested interests.

Australian governments often invite scientists and others to contribute their thoughts on proposed policy. The Finkel Review, for example, received 390 written submissions. Of course, agencies might not have time to respond individually to each submission. But if a policy is eventually made that seems to contradict the best available science, that agency should be required to account for that decision.

Finally, agencies should be proactively engaging with scientific groups at all stages of the process.

Active advocacy

Strengthening scientific integrity policies when many administrations are publicly hostile to science is challenging. Scientists are stuck reactively defending protective policies. Instead, they should be actively advocating for their expansion.

The goal is to institutionalise a culture of scientific integrity in the development and implementation of conservation policies.

A transnational movement to defend science will improve the odds that good practices will be retained and strengthened under more science-friendly administrations.

The monarch butterfly, now endangered in Canada, and at risk more broadly.
Jeremy Kerr

Many regard science as apolitical. Even the suggestion of publicly advocating for integrity or evidence-based policy and management makes some scientists deeply uncomfortable. It is telling that providing factual information for policy decisions and public information can be labelled as partisan. Nevertheless, recent research suggests that public participation by scientists, if properly framed, does not harm their credibility.

Scientists can operate objectively in conducting research, interpreting discoveries and publicly explaining the significance of the results. Recommendations for how to walk such a tricky, but vital, line are readily available.

Scientists and scientific societies must not shrink from their role, which is more important than ever. They have a responsibility to engage broadly with the public to affirm that science is indispensable for evidence-based policies and regulations. These critical roles for scientists help ensure that policy processes unfold in plain sight, and consequently help sustain functioning, democratic societies.


The ConversationThe authors would like to acknowledge the contribution of Dr Carlos Carroll, a conservation biologist at the Klamath Center for Conservation Research.

Euan Ritchie, Senior Lecturer in Ecology, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University; James Watson, Associate Professor, The University of Queensland; Jeremy Kerr, University Research Chair in Macroecology and Conservation, University of Ottawa, and Martine Maron, ARC Future Fellow and Associate Professor of Environmental Management, The University of Queensland

This article was originally published on The Conversation. Read the original article.

Is the Murray-Darling Basin Plan broken?


Ross M Thompson, University of Canberra

A recent expose by the ABC’s Four Corners has alleged significant illegal extraction of water from the Barwon-Darling river system, one of the major tributaries of the Murray River. The revelations have triggered widespread condemnation of irrigators, the New South Wales government and its officials, the Murray-Darling Basin Authority and the Basin Plan itself.

If the allegations are true that billions of litres of water worth millions of dollars were illegally extracted, this would represent one of the largest thefts in Australian history. It would have social and economic consequences for communities along the entire length of the Murray-Darling river system, and for the river itself, after years of trying to restore its health.

Water is big business, big politics and a big player in our environment. Taxpayers have spent A$13 billion on water reform in the Murray-Darling Basin in the past decade, hundreds of millions of which have gone directly to state governments. Governments have an obligation to ensure that this money is well spent.

The revelations cast doubt on the states’ willingness to do this, and even on their commitment to the entire Murray-Darling Basin Plan. This commitment needs to be reaffirmed urgently.

Basic principles

To work out where to go from here, it helps to understand the principles on which the Basin Plan was conceived. At its foundation, Australian water reform is based on four pillars.

1. Environmental water and fair consumption

The initial driver of water reform in the late 1990s was a widespread recognition that too much water had been allocated from the Murray-Darling system, and that it had suffered ecological damage as a result.

State and Commonwealth governments made a bipartisan commitment to reset the balance between water consumption and environmental water, to help restore the basin’s health and also to ensure that water-dependent industries and communities can be strong and sustainable.

Key to this was the idea that water users along the river would have fair access to water. Upstream users could not take water to the detriment of people downstream. The Four Corners investigation casts doubt on the NSW’s commitment to this principle.

2. Water markets and buybacks

The creation of a water market under the Basin Plan had two purposes: to allow water to be purchased on behalf of the environment, and to allow water permits to be traded between irrigators depending on relative need.

This involved calculating how much water could be taken from the river while ensuring a healthy ecosystem (the Sustainable Diversion Limit). Based on these calculations, state governments developed a water recovery program, which aimed to recover 2,750 gigalitres of water per year from consumptive use, through a A$3 billion water entitlement buyback and a A$9 billion irrigation modernisation program.

This program hinged on the development of water accounting tools that could measure both water availability and consumption. Only through trust in this process can downstream users be confident that they are receiving their fair share.

3. States retain control of water

Control of water was a major stumbling block in negotiating the Murray-Darling Basin Plan, because of a clash between states’ water-management responsibilities and the Commonwealth’s obligations to the environment.

As a result, the Murray-Darling Basin Authority sits outside of both state and Commonwealth governments, and states have to draw up water management plans that are subject to approval by the authority.

The states are responsible for enforcing these plans and ensuring that allocations are not exceeded. The Murray-Darling Basin Authority cannot easily enforce action on the ground – a situation that generates potential for state-level political interference, as alleged by the Four Corners investigation.

4. Trust and transparency

The Murray-Darling Basin Plan was built on a foundation of trust and transparency. The buyback scheme has transformed water into a tradeable commodity worth A$2 billion a year, a sizeable chunk of which is held by the Commonwealth Environmental Water Office.

Water trading has also helped to make water use more flexible. In a dry year, farmers with annual crops (such as cotton) can choose not to plant and instead to sell their water to farmers such as horticulturists who must irrigate to keep their trees alive. This flexibility is valuable in Australia’s highly variable climate.

Yet it is also true that water trading has created some big winners. Those with pre-existing water rights have been able to capitalise on that asset and invest heavily in buying further water rights, an outcome highlighted in the Four Corners story.

More than A$20 million in research investment has been devoted to ensuring that the ecological benefits of water are optimised – most notably through the Environmental Water Knowledge and Research and Long Term Intervention Monitoring programs. What is not clear is whether water extractions and their policing have been subjected to a similar degree of review and rigour.

What next for the Murray-Darling Basin?

The public needs to be able to trust that all parties are working honestly and accountably. This is particularly true for the downstream partners, who are the most likely victims of management failures upstream. Without trust in the upstream states, the Murray-Darling Basin Plan will unravel.

State governments urgently need to reaffirm their commitment to the four pillars that underpin the Murray-Darling Basin Plan, and to reassure the public that in retaining control of water they are operating in good faith.

Finally, rigour and transparency are needed in assessing the Basin Plan’s methods and environmental benefits, and the operation of the water market. The Productivity Commission’s review of national water policy, and its specific review of the Murray-Darling Basin Plan next year, will offer a clear opportunity to reassure everyone that the A$13 billion of public money that has gone into water reform in the past decade has been money well spent.

The ConversationOnly then will the fragile trust that underlies the water reform process be maintained and built.

Ross M Thompson, Chair of Water Science and Director, University of Canberra

This article was originally published on The Conversation. Read the original article.

Plant hormone boost for New Zealand’s critically endangered night parrot



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The flightless, nocturnal and sweet-smelling kākāpō was thought to be extinct, but during the 1970s, two remnant populations were discovered. One, in Fiordland, included only males.
From Wikimedia Commons, CC BY-ND

Janet Pitman, Victoria University of Wellington

New Zealand’s nocturnal and flightless parrot, the kākāpō, may be famous for trying to mate with the head of biologist Mark Carwardine, but this unique species is facing some serious challenges.

With fewer than 160 birds alive, kākāpō are critically endangered. One reason for their dwindling numbers is that they only breed every few years, when native trees produce masses of edible fruit or seeds.

Our research suggests that the birds’ breeding success depends on oestrogen-like hormones (phytoestrogens) found in these native plants.

Kākāpō are so rare that each bird has its own name. Sirocco was hand-reared as a chick and has become accustomed to people.

Hormone boost from plants

Our study included kākāpō (Strigops habroptilus) and two other New Zealand native parrots, the endangered kākā (Nestor meridionalis) and kea (Nestor notabilis). All three have infrequent breeding success.

Kākāpō in particular have a low reproductive rate and together with the kākā, only breed successfully every three or four years, during mast years, when mass fruiting of native trees occurs.

2016 was a mast year and a record breeding season for kākāpō – the best since New Zealand’s Department of Conservation began managing and monitoring the night parrots 25 years ago.

This link between the parrots’ successful breeding and high levels of fruiting in native plants has focused our investigations on potential stimulants present in their food plants that might activate or improve reproduction.

One hypothesis is that steroid-like compounds in the fruits of certain native plants provide a trigger for breeding. It proposes that kākāpō don’t produce enough of the hormone oestrogen to make a fertile egg, but by eating these fruits and the phytoestrogens they contain, the birds supplement their own hormone levels.

The native rimu tree produces a lot of berry fruit during mast years every two to four years.
Veronika Meduna, CC BY-ND

This increases the production of egg yolk protein, which in turn leads to eggs that have a better chance of being fertilised successfully.

We know from other studies that kākāpō seek out the fruit from the native rimu tree (Dacrycarpus cupressinum) during mast years. We believe that this is how kākāpō get extra oestrogen from their diet, and that rimu and other native plants provide a hormone boost that is key to kākāpō reproduction.

A kākāpō chick, newly hatched.
Andrew Digby / NZ Department of Conservation, CC BY-ND

Parrots more sensitive to oestrogen

In our current study, conducted by PhD graduate Dr Catherine Davis, we examined the receptivity of New Zealand and Australian parrots to a range of steroid compounds, including oestrogens, and compared it to those of other birds.

We tested various native plant species for oestrogenic content and we found that indeed there is a high amount of phytoestrogens in some of New Zealand’s native plants.

We then looked at the receptivity of parrots to this plant hormone. We studied the genetic makeup of the receptor that is activated by oestrogens in kākāpō, kea, kākā, kākāriki, the Australian cockatiel, and compared this with those in the chicken.

We found that the parrots’ oestrogen receptor was different. All of the parrot species have a unique sequence in the receptor gene, which may make them more sensitive to oestrogen, compared to other bird species, or humans.

In parrots, this receptor contains an extra eight amino acids in the region that binds the hormone.

Most kākāpō live on Codfish Island, a predator-free sanctuary island at the southern end of New Zealand. The Department of Conservation checks the birds regularly, particularly during breeding seasons.
Veronika Meduna, CC BY-ND

Increasing fertility

By adding this amino acid sequence to a computer modelling programme based on the human oestrogen receptor, we have shown that this difference in the parrot-specific receptor would change the strength with which it binds to the oestrogen hormone.

The down-stream effects of this may be an increased sensitivity to plant oestrogens in parrots. This research supports the notion that the parrots’ oestrogen receptor responds differently to oestrogenic compounds in native trees in New Zealand during mast years.

We have previously confirmed the presence of oestrogenic activity in key compounds present in rimu and tōtara (Podocarpus totara), as well as extracts from a number of New Zealand plant species that kākāpō are known to graze. However, the chemical structures of the oestrogenic materials of most New Zealand native plants are not known.

The question remains why the rate of successful breeding of kākāpō in mast years is lower than that of other parrot species. The identification of plant chemicals capable of binding to the parrot oestrogen receptor together with information about plant grazing behaviours of parrots may provide new insights into the conservation of the species that are in decline.

The ConversationWith further research, we are hoping to identify the specific compound in native plants that elicits these oestrogenic properties. This information may enable us to synthesise this compound in the lab. It could then be administered in some way to increase the fertility of our native parrots.

Janet Pitman, Senior Lecturer in Reproductive Biology and Biotechnology, Victoria University of Wellington

This article was originally published on The Conversation. Read the original article.

On the origins of environmental bullshit



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Children play in the DDT fog left by the ‘fog truck’ in a New Jersey neighbourhood.
George Silk/LIFE 1948

David Schlosberg, University of Sydney

This article is part of an ongoing series from the Post-Truth Initiative, a Strategic Research Excellence Initiative at the University of Sydney. The series examines today’s post-truth problem in public discourse: the thriving economy of lies, bullshit and propaganda that threatens rational discourse and policy.

The project brings together scholars of media and communications, government and international relations, physics, philosophy, linguistics, and medicine, and is affiliated with the Sydney Social Sciences and Humanities Advanced Research Centre (SSSHARC), the Sydney Environment Institute and the Sydney Democracy Network.


I grew up in the Long Island suburbs of New York and have vivid memories of running behind the “fog trucks”. These trucks went through the neighbourhoods spraying DDT for mosquito control until it was banned in 1972.

I didn’t know it until much later, but that experience, and exposure, was extended due to the pesticide industry’s lies and tactics – what is now labelled “post-truth”.

Rachel Carson published Silent Spring in 1962. It was a beautifully written, if distressing, bit of what we today call “research translation”. The “silent spring” was the impact of DDT as songbird species were killed off.

Carson tried to expose the chemical industry’s disinformation. For doing so, she was roundly and untruthfully attacked as a communist and an opponent of progress. Silent Spring was one of the most popular and vetted overviews of environmental science of all time. Yet lies and bullshit prevented a decent policy response for a decade.

Back in the day DDT was used with nearly no restrictions. From American Experience/PBS.

And the lies won’t go away. In 2007, one of the think-tanks responsible for climate science misinformation, the Competitive Enterprise Institute, began reiterating one of the main refuted claims about Carson. She was said to be responsible for millions of deaths due to the ban on DDT to control mosquitoes that spread malaria.

The reality is that while DDT was banned for agriculture in the US – and spraying on kids in suburban neighbourhoods – it was never banned for anti-malarial use. Even now. But the political right and the dirtiest chemical industry players in all of industrial capitalism have long painted environmentalists as killers – of people, progress and jobs.

It’s a carefully manufactured campaign of lies and disinformation. As a result, many people believe Carson is a flat-out mass murderer – not a hero who beautifully blended care for human health and nonhuman nature in one of the most important and challenging books of the 20th century.

Lies and smears have a long history

This anti-environmentalist tactic of countering critiques of industrial impacts on the planet with lies, obfuscation and defamation has a long history. It goes back at least to establishment attacks on the US municipal housekeeping movement in the progressive era of the late 19th and early 20th century.

The urban environmental movement probably began in the 1880s with the Ladies Health Protective Association in New York, the City Beautiful movement, Waring’s White Wings city cleaners, and more.

This 1913 municipal housekeeping poster shows many home duties related to government, but the movement’s members were smeared as unworthy women.
Internet Archive Book Images/flickr

Municipal housekeeping in particular was primarily a women’s movement to clean up cities. This eventually led to the development of formal offices of public health and public planning in local governments.

The opposition – from meatpackers to fertiliser makers to the waste industry – labelled these women bad housekeepers. They argued that the only reason women wanted to “mother” and keep house in the community was because they were so bad at such things at home – that municipal housekeeping was only a movement against domestic housekeeping.

In other words, they were not real women and were unconcerned with anyone but themselves.

Not surprisingly, the polluting industries were at the heart of such bullshit attacks. And in both this example from the early 20th century and the Carson example from the 1960s, industry used a very gendered attack as part of the post-truth campaign.

The theme of industrial lies covering environmental damage continued in the 1980s in the Pacific Northwest timber wars. Once again, environmentalists were scapegoated for the loss of timber jobs.

Efforts to protect the spotted owl were blamed for the loss of jobs due to timber industry automation.
USFS/flickr, CC BY

These job losses were primarily due to automation. But the controversy over the endangered spotted owl allowed the timber industry to create another narrative – that environmentalists cared about birds more than jobs, that they wouldn’t be happy until the economy was devastated, and that all of the changes that harmed timber workers were due to environmental regulation – not the industry itself.

The attack on science ramped up then as well. When scientists declared that each pair of owls needed a certain exclusive range, and so protecting them from extinction would entail preserving whole forests, the industry-captured Forest Service simply shrank the recommendation.

The very real environmental science was dismissed. Subsequent policy was based in fantasy, wishful thinking and the lies of the industry. The timber wars were another example of science on the one hand and industry lies – supported by government – on the other.

The history of climate change denialism since the 1980s has really been the culmination of the attack on environmental science.

It has been based on the production of lies developed by the fossil fuel industry through industry-funded conservative think-tanks, laundered through conservative foundations, spun and repeated by right-wing media outlets, and adopted as ideology by the Republican Party. Its representatives are supported by even more industry and conservative funding of elections, or face opposition from others if they don’t comply.

This is, as Riley Dunlap and Aaron McCright have written, a well-funded, highly complex and relatively co-ordinated denial machine. It includes “contrarian scientists, fossil fuel corporations, conservative think tanks, and various front groups”, along with “amateur climate bloggers … public relations firms, astroturf groups, conservative media and pundits, and conservative politicians”.

The goal is simple and clear: no regulation on industry, and what environmental sociologist Robert Brulle calls the “institutionalisation of delay” on climate policy. The tools are simple as well: lies, obfuscation, defamation and the creation of an image of scientific uncertainty.

What is the current state of affairs after 30 years of this climate denial machine?

In the US, at least 180 congressional members and senators are declared climate deniers. They’ve received more than US$82 million in campaign contributions from the fossil fuel industry and its partners.

This is a long, complicated and well-trod story told, among others, by Naomi Oreskes in Merchants of Doubt, and by Michael Mann in The Madhouse Effect. It has been going on a long time.

The history is important, as a problematic front-page story in The New York Times, How GOP Leaders Came to View Climate Change as Fake Science, illustrates. The report includes an explanatory sentence that is jaw-dropping for its misunderstanding and reshaping of the issue:

The Republican Party’s fast journey from debating how to combat human-caused climate change to arguing that it does not exist is a story of big political money, Democratic hubris in the Obama years and a partisan chasm that grew over nine years like a crack in the Antarctic shelf, favouring extreme positions and uncompromising rhetoric over co-operation and conciliation.

So it was “big political money” – not the industry, not the Koch brothers’ campaign, not an all-out effort to shift public opinion, just “political money”. Democratic hubris becomes a central reason for Republicans believing in fake science. The argument is that this was a reaction to President Barack Obama’s regulatory approach in his second term, as if denialism didn’t exist before 2012.

And then there’s the idea that this is a bipartisan problem – of extreme positions and uncompromising rhetoric – rather than one the anti-environmental right created.

Brulle took to Twitter to criticise the story – primarily the short timeframe. Clearly, climate obfuscation doesn’t start in 2008, when The New York Times story starts. The climate change denial machine has been up and running since at least 1988, 20 years longer than the story suggests.

Brulle was also livid that a story on the social aspects of climate discourse did not cite a single expert. This was despite there being hundreds of peer-reviewed articles and books on the denial machine.

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So even the major media refuse to clearly expose the undermining of real environmental science, and the creation of lies and bribes to distort public policymaking. But this work is out there. It’s really the thorough work done on the climate denial machine that lays out the methodology of the development of environmental distortions, lies and post-truth discourse.

And, again, this is the core example of the evolution of environmental bullshit: a long history of industry creation of lies; conservative funding of think-tanks, front groups and the echo chamber; the development of an ideological imperative of denialism; and then the necessity of completely groundless bullshit to shore up the lies. It’s all there.

This methodology has clearly been used here in Australia. Graham Redfearn, writing for the desmog blog and The Guardian, has done amazing and thorough work on the denial machines in the US and Australia – and their links. In Australia, a clear link exists between climate denialism and the coal industry.

Many on the right, including the current and past prime ministers, parrot the lies and PR language of the industry – energy poverty, coal is cheap, clean coal is possible, 10,000 jobs, etc. It’s a tale as old as tobacco, lead, timber wars and DDT. It’s as old as industries that know their products do public harm, but lie to keep them in use.

The point here is simply to acknowledge what many have argued about the whole idea of “post-truth” – it’s not anything new, but just more of the same.

Environmentalists have long seen the propagation of lies, piles of bullshit, the dismissal of science, and the creation of mythologies as a consistent core of corporate misbehaviour – and, unfortunately, conservative ideology.


You can read other pieces in the post-truth series here.

The ConversationThe Democracy Futures series is a joint global initiative between The Conversation and the Sydney Democracy Network. The project aims to stimulate fresh thinking about the many challenges facing democracies in the 21st century.

David Schlosberg, Professor of Environmental Politics and Co-Director Sydney Environment Institute, University of Sydney

This article was originally published on The Conversation. Read the original article.

Who’s afraid of the giant African land snail? Perhaps we shouldn’t be



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Giant African land snails can grow up to 15cm long.
Author provided

Luke S. O’Loughlin, La Trobe University and Peter Green, La Trobe University

The giant African land snail is a poster child of a global epidemic: the threat of invasive species. The snails are native to coastal East Africa, but are now found across Asia, the Pacific and the Americas – in fact, almost all tropical mainlands and islands except mainland Australia.

Yet, despite their fearsome reputation, our research on Christmas Island’s invasive snail population suggests the risk they pose to native ecosystems has been greatly exaggerated.

Giant African land snails certainly have the classic characteristics of a successful invader: they can thrive in lots of different places; survive on a broad diet; reach reproductive age quickly; and produce more than 1,000 eggs in a lifetime. Add it all together and you have a species recognised as among the worst invaders in the world.

The snails can eat hundreds of plant species, including vegetable crops (and even calcium-rich plaster and stucco), and have been described as a major threat to agriculture.

They have been intercepted at Australian ports, and the Department of Primary Industries concurs that the snails are a “serious threat”.

Despite all this, there have been no dedicated studies of their environmental impact. Some researchers suggest the risk to agriculture has been exaggerated from accounts of damage in gardens. There are no accounts of giant African land snails destroying natural ecosystems.

Quietly eating leaf litter

In research recently published in the journal Austral Ecology, we tested these assumptions by investigating giant African land snails living in native rainforest on Christmas Island.

Giant African land snails have spread through Christmas Island with the help of another invasive species: the yellow crazy ant.

Until these ants showed up, abundant native red land crabs ate the giant snails before they could gain a foothold in the rainforest. Unfortunately, yellow crazy ants have completely exterminated the crabs in some parts of the island, allowing the snails to flourish.

We predicted that the snails, which eat a broad range of food, would have a significant impact on leaf litter and seedling survival.

Unexpectedly, the snails we observed on Christmas Island confined themselves to eating small amounts of leaf litter.
Author provided

However, our evidence didn’t support this at all. Using several different approaches – including a field experiment, lab experiment and observational study – we found giant African land snails were pretty much just eating a few dead leaves and little else.

We almost couldn’t distinguish between leaf litter removal by the snails compared to natural decomposition. They were eating leaf litter, but not a lot of it.

We saw almost no impact on seedling survival, and the snails were almost never seen eating live foliage. In one lab trial, we attempted to feed snails an exclusive diet of fresh leaves, but so many of these snails died that we had to cut the experiment short. Perhaps common Christmas Island plants just aren’t palatable.

It’s possible that the giant African land snails are causing other problems on Christmas Island. In Florida, for example, they carry parasites that are a risk to human health. But for the key ecological processes we investigated, the snails do not create the kind of disturbance we would assume from their large numbers.

We effectively excluded snails from an area by lining a fence with copper tape.
Author provided

The assumption that giant African land snails are dangerous to native plants and agriculture comes from an overriding sentiment that invasive species are damaging and must be controlled.

Do we have good data on the ecological impact of all invasive species? Of course not. Should we still try to control all abundant invasive species even if we don’t have evidence they are causing harm? That’s a more difficult question.

The precautionary principle drives much of the thinking behind the management of invasive species, including the giant African land snail. The cost of doing nothing is potentially very high, so it’s safest to assume invasive species are having an effect (especially when they exist in high numbers).

But we should also be working hard to test these assumptions. Proper monitoring and experiments give us a true picture of the risks of action (or inaction).

The ConversationIn reality, the giant African land snail is more the poster child of our own knee-jerk reaction to abundant invaders.

Luke S. O’Loughlin, Research fellow, La Trobe University and Peter Green, Head of Department, Ecology, Environment and Evolution, La Trobe University

This article was originally published on The Conversation. Read the original article.

Rising carbon dioxide is making the world’s plants more water-wise


Pep Canadell, CSIRO; Francis Chiew, CSIRO; Lei Cheng, CSIRO; Lu Zhang, CSIRO, and Yingping Wang, CSIRO

Land plants are absorbing 17% more carbon dioxide from the atmosphere now than 30 years ago, our research published today shows. Equally extraordinarily, our study also shows that the vegetation is hardly using any extra water to do it, suggesting that global change is causing the world’s plants to grow in a more water-efficient way.

Water is the most precious resource needed for plants to grow, and our research suggests that vegetation is becoming much better at using it in a world in which CO₂ levels continue to rise.

The ratio of carbon uptake to water loss by ecosystems is what we call “water use efficiency”, and it is one of the most important variables when studying these ecosystems.

Our confirmation of a global trend of increasing water use efficiency is a rare piece of good news when it comes to the consequences of global environmental change. It will strengthen plants’ vital role as global carbon sinks, improve food production, and might boost water availability for the well-being of society and the natural world.

Yet more efficient water use by the world’s plants will not solve our current or future water scarcity problems.

Changes in global terrestrial uptake of carbon dioxide, water use efficiency and ecosystem evapotranspiration during 1982-2011.

Boosting carbon uptake

Plants growing in today’s higher-CO₂ conditions can take up more carbon – the so-called CO₂ fertilisation effect. This is the main reason why the terrestrial biosphere has taken up 17% more carbon over the past 30 years.

The enhanced carbon uptake is consistent with the global greening trend observed by satellites, and the growing global land carbon sink which removes about one-third of all CO₂ emissions generated by human activities.

Increasing carbon uptake typically comes at a cost. To let CO₂ in, plants have to open up pores called stomata in their leaves, which in turn allows water to sneak out. Plants thus need to strike a balance between taking up carbon to build new leaves, stems and roots, while minimising water loss in the process. This has led to sophisticated adaptations that has allowed many plant species to conquer a range of arid environments.

One such adaptation is to close the stomata slightly to allow CO₂ to enter with less water getting out. Under increasing atmospheric CO₂, the overall result is that CO₂ uptake increases while water consumption does not. This is exactly what we have found on a global scale in our new study. In fact, we found that rising CO₂ levels are causing the world’s plants to become more water-wise, almost everywhere, whether in dry places or wet ones.

Growth hotspots

We used a combination of plot-scale water flux and atmospheric measurements, and satellite observations of leaf properties, to develop and test a new water use efficiency model. The model enables us to scale up from leaf water use efficiency anywhere in the world to the entire globe.

We found that across the globe, boreal and tropical forests are particularly good at increasing ecosystem water use efficiency and uptake of CO₂. That is due in large part to the CO₂ fertilisation effect and the increase in the total amount of leaf surface area.

Importantly, both types of forests are critical in limiting the rise in atmospheric CO₂ levels. Intact tropical forest removes more atmospheric CO₂ than any other type of forest, and the boreal forests of the planet’s far north hold vast amounts of carbon particularly in their organic soils.

Meanwhile, for the semi-arid ecosystems of the world, increased water savings are a big deal. We found that Australian ecosystems, for example, are increasing their carbon uptake, especially in the northern savannas. This trend may not have been possible without an increase in ecosystem water use efficiency.

Previous studies have also shown how increased water efficiency is greening semi-arid regions and may have contributed to an increase in carbon capture in semi-arid ecosystems in Australia, Africa and South America.

Trends in water use efficiency over 1982-2011.
CREDIT, Author provided

It’s not all good news

These trends will have largely positive outcomes for the plants and the animals (and humans) consuming them. Wood production, bioenergy and crop growth are (and will be) less water-intensive under climate change than they would be without increased vegetation water use efficiency.

But despite these trends, water scarcity will nevertheless continue to constrain carbon sinks, food production and socioeconomic development.

Some studies have suggested that the water savings could also lead to increased runoff and therefore excess water availability. For dry Australia, however, more than half (64%) of the rainfall returning to the atmosphere does not go through vegetation, but through direct soil evaporation. This reduces the potential benefit from increased vegetation water use efficiency and the possibility for more water flowing to rivers and reservoirs. In fact, a recent study shows that while semi-arid regions in Australia are greening, they are also consuming more water, causing river flows to fall by 24-28%.

The ConversationOur research confirms that plants all over the world are likely to benefit from these increased water savings. However, the question of whether this will translate to more water availability for conservation or for human consumption is much less clear, and will probably vary widely from region to region.

Pep Canadell, CSIRO Scientist, and Executive Director of the Global Carbon Project, CSIRO; Francis Chiew, Senior Principal Research Scientist, CSIRO; Lei Cheng, Postdoctoral research fellow, CSIRO; Lu Zhang, Senior Principal Research Scientist, CSIRO, and Yingping Wang, Chief research scientist, CSIRO

This article was originally published on The Conversation. Read the original article.