Why NZ’s emissions trading scheme should have an auction reserve price



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New Zealand’s emission reduction target for 2030 is to bring emissions to 30% below 2005 levels, and to be carbon neutral by 2050.
from http://www.shutterstock.com, CC BY-ND

Suzi Kerr, Victoria University of Wellington

While people’s eyes often glaze over when they hear the words “emissions trading”, we all respond to the price of carbon.

Back in 2010, when the carbon price was around NZ$20 per tonne, forest nurseries in New Zealand boosted production. But when prices plunged thereafter, hundreds of thousands of tree seedlings were destroyed rather than planted, wiping out both upfront investment and new forest growth.

Emission prices have since recovered but no one knows if this will last. With consultation underway on improving the New Zealand Emissions Trading Scheme (NZ ETS), the government should seriously consider a “price floor” to rebuild confidence in low-emission investment.




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A new approach to emissions trading in a post-Paris climate


How a price floor works

If we want to make a smart transition to a low-emission economy, we need to change how we value emissions so people make the investments that deliver on our targets. Implementing a reserve price at auction – or a “price floor” – is a powerful tool for managing the risk that emission prices could fall for the wrong reasons and undermine much needed low-emission investments.

In New Zealand’s ETS, participants are required to give tradable emission units (i.e. permits) to the government to cover the emissions for which they are liable. A limit on unit supply relative to demand reduces total emissions and enables the market to set the unit price.

In the future, the government will be auctioning emission units into the market. A reserve price at auction, which is simple to implement, can help avoid very low prices. If private actors are not willing to pay at least the reserve price, the government would stop selling units and the supply to the market would automatically contract.

The government’s current ETS consultation document suggests that no price floor will be needed in the future because a limit on international purchasing will be sufficient to prevent the kind of price collapse we experienced in the past. However, that assessment neglects other drivers of this risk.

When low ETS prices are a pitfall

Ideally, ETS prices would respond to signals of the long-term cost of meeting New Zealand’s decarbonisation goals and achieving global climate stabilisation. With today’s information, we generally expect ETS prices to rise over time. For example, modelling prepared for the New Zealand Productivity Commission suggests emission prices could rise to at least NZ$75 per tonne, possibly over NZ$200 per tonne, over the next three decades.

However, ETS prices could also fall because of sudden technology breakthroughs or economic downturn. Even though some low-emission investors would lose the returns they had hoped for, this could be an efficient outcome because low ETS prices would reflect true decarbonisation costs. Technological and economic uncertainty imposes a genuine risk on low-emission investments that society cannot avoid.

But there is another scenario in which ETS prices fall while decarbonisation costs remained high. This could arise because of political risk. For example, if a major emissions-intensive industrial producer was to exit the market unexpectedly and it was unclear how the government would respond, or if a political crisis was perceived to threaten the future of the ETS, then emission prices could collapse and efficient low-emission investments could be derailed.

Even when remedies are on the way, it can take time to correct perceptions of weak climate policy intentions. The New Zealand government’s slow response to the impact of low-quality international units in the ETS from 2011 to mid-2015 is a vivid example of this.

A simple and effective solution

With a price floor, an ETS auction will respond quickly and predictably to unpredictable events that lower prices. A price floor signals the direction of travel for minimum emission prices and builds confidence for low-emission investors and innovators. It also provides greater assurance to government about the minimum level of auction revenue to expect.

It is important to note that ETS participants can still trade units amongst each other at prices below the price floor. The price floor simply stops the flow of further auctioned units from the government into the market until demand recovers again and prices rise.

We have three good case studies overseas for the value of a price floor.

  1. The European Union ETS did not have a price floor for correcting unexpected oversupply and prices dropped because of the global financial crisis, other energy policies and overly generous free allocation. It now has a complex market stability reserve for this purpose, although that operates with less ease and transparency than a reserve price at auction.

  2. To counteract low EU ETS prices, the UK created its own price floor as a “top up” to the EU ETS. Although this did not add to global mitigation beyond the EU ETS cap, it did drive down coal-fired generation in the UK.

  3. California’s ETS was designed in conjunction with a large suite of emission reduction measures with complex interactions. Its reserve price at auction has ensured that a minimum and rising emission price has been maintained, despite uncertainties about the impact of other measures.

Keeping NZ on track for decarbonisation

In New Zealand, the Productivity Commission supports the concept of an auction reserve price in its final report on a transition to a low-emissions economy.

The only potential downside of a price floor is the political courage needed to set its level. It could be set at the minimum level that any credible global or local modelling suggests is consistent with New Zealand and global goals. The Climate Change Commission could provide independent advice on preferred modelling and an appropriate level. The merits of a price floor warrant cross-party support.

If the market operates in line with expectations, then the price floor has no impact on emission prices. But the price floor usefully guards against price collapse when the market does not go to plan.

The government, ETS participants and investors need to understand that international purchasing is not the only driver of downside price risk in the NZ ETS. A price floor would strengthen the incentives for major long-term investments in low-emission technologies, infrastructure and land uses in the face of uncertainty.

To reach New Zealand’s ambitious emission reduction targets for 2030 (a 30% reduction below 2005 levels) and beyond, bargain-basement emission prices need to stay a thing of the past.

This article was co-authored with Catherine Leining, a policy fellow at Motu Economic and Public Policy Research.The Conversation

Suzi Kerr, Adjunct Professor, School of Government, Victoria University of Wellington

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

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Eulogy for a seastar, Australia’s first recorded marine extinction



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The Derwent River Sea Star was only documented for 25 years before its extinction.
Blair Patulo, Museums Victoria, CC BY-NC

Tim O’Hara, Museums Victoria

We see the surface of the sea: the rock pools, the waves, the horizon. But there is so much more going on underneath, hidden from view.

The sea’s surface conceals human impact as well. Today, I am writing a eulogy to the Derwent River Seastar (or starfish), that formerly inhabited the shores near the Tasman Bridge in Hobart, Tasmania. It is Australia’s first documented marine animal extinction and one of the few recorded anywhere in the world.




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https://giphy.com/embed/TgFkyRxbZCTLx8OEqF

The Derwent River Seastar, preserved in the Tasmanian Museum and Art Gallery, Hobart. Credit: Christy Hipsley, Museums Victoria/University of Melbourne

Scientists only knew the Derwent River Seastar for about 25 years. It was first described in 1969 by Alan Dartnall, a former curator of the Tasmanian Museum and Art Gallery. It was found on and off until the early 1990s but scientists noted a decline in numbers. Targeted surveys in 1993 and 2010 failed to find a single individual.

It was listed as critically endangered by the Tasmanian and Australian governments. But now, like a long-lost missing person, it is time to call it: the Derwent River Seastar appears extinct.

It is actually quite hard to document the extinction of marine animals. There is always hope that it will turn up in some unusual spot, somewhere in that hidden world. Australia has an ambitious plan to create high-resolution maps of 50% of our marine environment by 2025. This is a formidable task. But it is a reflection of our lack of knowledge about the oceans that, 20 years after the launch of Google Maps and despite an enormous effort in the interim, much of Australia’s seafloor in 2025 will be still largely known from the occasional 19th-century depth sounding, or imprecise gravity measurements from satellites.

We do notice when big animals go. There used to be a gigantic dugong-like creature called Steller’s Sea Cow, which lived in the North Pacific Ocean until it was hunted to oblivion by 1768. There is no mistaking that loss.

Steller’s Sea Cow, which grew up to 10 metres long and weighed between five and ten tonnes, was hunted to extinction in 1768.
Paul K/Flickr, CC BY

But the vast majority of the estimated 1 million to 2 million marine animals are invertebrates, animals without backbones such as shells, crabs, corals and seastars. We just don’t monitor those enough to observe their decline.

We noticed the Derwent River Seastar because it was only found at a few sites near a major city. Its story is intertwined with the usual developments that happen near many large ports. The Derwent River became silty and was at times heavily polluted by industrial and residential waste. The construction of the Tasman Bridge in the early 1960s cannot have helped.

From the 1920s a series of marine pests were accidentally introduced by live oysters imported from New Zealand, or by hitching a ride on ships. Some of these pests are now abundant in southeast Tasmanian waters and eat or compete with local species.




Read more:
Australia relies on volunteers to monitor its endangered species


The Derwent River Seastar has been a bit of an enigma. From the start, it was mistakenly classified as belonging to group of seastars (poranids) otherwise known from deep or polar habitats. Some people wondered whether it was an introduced species as well, one that couldn’t cope with the Derwent environment.

However, we used a CT scanner at the School of Earth Sciences, University of Melbourne, to look at the internal skeleton of one of the few museum specimens. Sure enough, it has internal struts to strengthen the body, which are characteristic of a different group of seastars (asterinids) that have adapted to coastal environments and are sometimes restricted to very small areas.

https://giphy.com/embed/3ksOMV7xcoVKhOXVE2

CT scan showing the internal structure of the seastar. Source: Christy Hipsley, Museums Victoria/University of Melbourne

Is this seastar like a canary in a coal mine, a warning of a wave of marine extinctions? Sea levels are rising with global warming, and that is going to be a big problem for life adapted to living along the shoreline. Mangroves, salt marsh, seagrass beds, mud flats, beaches and rock platforms only form at specific water depths. They are going to need to follow rising sea levels and reform higher up the shoreline.

Coastal life can take hundreds to thousands of years to adjust to these sorts of changes. But in many places we don’t have a natural environment anymore. Humans will increasingly protect coastal property by building seawalls and other infrastructure, especially around towns and bays. This will mean far less space for marine animals and plants.




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Rising seas will displace millions of people – and Australia must be ready


We need to start planning new places for our shore life to go – areas they can migrate to with rising sea levels. Otherwise, the Derwent River Seastar won’t be the last human-induced extinction from these environments.The Conversation

Tim O’Hara, Senior Curator of Marine Invertebrates, Museums Victoria

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

It’s teamwork: how dolphins learn to work together for rewards



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Two bottlenose dolphins (Tursiops truncatus) cooperate in a button-pressing task requiring precise behavioural synchronization.
Dolphin Research Center, Author provided

Stephanie King, University of Western Australia

Cooperation can be found across the animal kingdom, in behaviours such as group hunting, raising of young, and driving away predators.

But are these cooperating animals actively coordinating their behaviour, or are they simply acting individually to accomplish the same task at the same time?

In a study, published today in Proceedings of the Royal Society B, we showed that bottlenose dolphins actively coordinate their behaviours. That is, they can learn to work together and synchronise their actions to solve a cooperation task and receive a reward.




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Testing teamwork

For this study, conducted at the Dolphin Research Center in the Florida Keys, we created a task in which pairs of dolphins had to swim across a lagoon and each press their own underwater button at the same time (within a 1-second time window).

Each trial began with both dolphins and their respective trainers located at the opposite side of the lagoon from the buttons, about 11 metres away. The trainers would either both give a “press the button” hand signal at the same time, or one trainer would give the signal first, while the second trainer asked her dolphin to wait up to 20 seconds before giving the signal.

If the dolphins pressed their buttons at the same time, a computer played a “success” sound, and the dolphins returned to their trainers for fish and social praise.

If the dolphins pressed their buttons at different times, a “failure” sound was played and the trainers moved on to the next trial.

The strict timing requirement meant they had to work together. If their goal was simply “press my button”, then when they were sent at different times, they would press at different times. To succeed, they had to understand their goal as “press the buttons together”.

The question, then, was whether the dolphin sent first would wait for the other dolphin before pressing its button, and whether they could figure out a way to coordinate precisely enough to press simultaneously.

Two bottlenose dolphins (Tursiops truncatus) cooperate in a button-pressing task requiring precise behavioural synchronisation.
Dolphin Research Center, Author provided

Swim fast, or coordinate?

We found that the dolphins were able to work together with extreme precision even when they had to wait for their partner. Interestingly, their behavioural strategies and the coordination between them changed as they learned the task.

Keep in mind that the dolphins had to figure out that this was a cooperative task. There was nothing about the situation that told them in advance that the buttons had to be pressed at the same time.

To help them learn, we started by sending them simultaneously and gradually increased the timing difference between them.

When one dolphin figured out the game first, if their partner was sent first on a particular trial, they knew that the partner (who had not figured out the game) was not going to wait.

So in the early phases, we found that many successes were achieved not by the first dolphin waiting, but by the second dolphin swimming extremely fast to catch up.

But once both animals understood the task, this behaviour disappeared and the timing of their button presses became extremely precise (with the time difference between button presses averaging just 370 milliseconds).

This shows that both partners now understood that they didn’t need to swim fast to succeed; instead, they needed to synchronise their actions.

Wait for it… a delayed start but the dolphins still work together.

Synchrony in the wild

In the wild, dolphins synchronise their behaviour in several contexts. For example, mothers and calves will surface and breathe at the same time, and males in alliances will perform the same behaviours at the same time in coordinated displays.

Triple synchronous dive by a trio of allied male bottlenose dolphins (Tursiops aduncus) in Shark Bay, Western Australia.
Stephanie King / The Dolphin Alliance Project, Author provided

The synchrony in these displays can be remarkably precise, and is thought to actively promote cooperation between partners.




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The results of our study suggest that this behavioural synchronisation that dolphins show in the wild may not be a hardwired response to a specific context, but may in fact be a generalised ability that they can apply to a variety of situations.


Kelly Jaakkola, director of research at the Dolphin Research Center, contributed to this research and this article. She can be contacted at kelly@dolphins.org.The Conversation

Stephanie King, Branco Weiss Research Fellow, University of Western Australia

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

An artist’s surreal view of Australia – created from satellite data captured 700km above Earth



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Infrared and visible light satellite data is recoloured to produce striking images of Australia.
Grayson Cooke , Author provided

Grayson Cooke, Southern Cross University

There are more than 4,800 satellites orbiting Earth. They bristle with sensors – trained towards Earth and into space – recording and transmitting many different wavelengths of electromagnetic radiation.

Governments and media corporations rely on the data these satellites collect. But artists use it too, as a new way to image and view the Earth.

I work with Geoscience Australia and the “Digital Earth Australia” platform to produce time-lapse images and video of Australian landforms using satellite data.

My Open Air project, produced through a collaboration with Australian painter Emma Walker and the music of The Necks, features macro-photography of Emma Walker’s paintings set against time-lapse satellite imagery of Australia.

Open Air will be launched in Canberra on September 20, 2018.

Trailer: Open Air – showing Lake Gairdner in South Australia with turquoise desert, red salt lakes and pink clouds (Grayson Cooke 2017).



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Open access to satellite data

We see satellites as moving pin-pricks in the night sky, or occasionally – as with the recent return to Earth of the Chinese Tiangong space station – as streaks of light. And most us would have heard about satellite data being used for surveillance, for GPS tracking and for media broadcasting.

But artists can divert satellite data away from a purely instrumental approach. They can apply it to produce new ways of seeing, understanding and feeling the Earth.

Of course satellites are expensive to launch and maintain. The main players are either powerful corporate providers like Intelsat, enormous public sector agencies like NASA and the European Space Agency (ESA), or private sector startups with links to these groups.

Luckily, many of these agencies make their data freely available to the public.

The NASA/US Geological Survey Landsat program makes 40 years of Earth imaging data available through Earth Explorer. The ESA provides data from their Sentinel satellites to users of the Copernicus Open Access Hub.

In Australia, Geoscience Australia‘s Digital Earth Australia platform provides researchers and the public with access to Australian satellite data from a range of agencies.

Landsat 8 image acquired in Australia in May 2013 over Cambridge Gulf and the Ord River estuary in Western Australia. Visible light bands highlight the different types of water within the estuary. Shortwave and near infrared bands highlight the mangroves and vegetation on the land.
Geoscience Australia, Author provided

Understanding and processing the data

Making satellite imaging data accessible, though, is not the same thing as making it usable. There is considerable technical know-how required to process satellite data.

The Landsat and Sentinel satellites are used by scientists and the private sector to monitor environmental change over time, using what is known as “remote sensing”. They travel in the low Earth orbit range, around 700km above the Earth and circle the Earth in around 90 minutes. After numerous orbits, they return to the exact same spot every 16 days.

Landsat and Sentinel satellites are equipped with sensors that record reflected electromagnetic radiation in a range of wavelengths. Some of these wavelengths fall within the visible light part of the spectrum (between 390-700 nanometers). In that sense, satellites image the Earth in a way comparable to a digital camera.

This image shows the percentage of time since 1987 that water was observed by the Landsat satellites on the floodplain around Burketown and Normanton in northern Queensland. The water frequency is shown in a colour scale from red to blue, with areas of persistent water observations shown in blue colouring, and areas of very infrequent water observation shown in red colouring.
Geoscience Australia, Author provided



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But the satellites also record other wavelengths, particularly in the near and shortwave infrared range. Vegetation, water and geological formations reflect and absorb infrared light differently to visible light. Recording these wavelengths allows scientists to track, for instance, changes in vegetation density or surface water location that indicate drought, flood or fire.

A single satellite image is made up of numerous bands recording data in very specific wavelengths. Getting a full-colour image requires processing in a GIS application to combine them, and assign the bands to either red, green or blue in an output image.

Images collected over 12 months at the Gulf of Carpentaria – 2016.
Grayson Cooke, Author provided

Bringing creativity to the data

This is where creativity can enter the picture. Being able to create false colour images that combine infrared and visible light in different ways allows me to produce beautifully surreal images of Australian landforms.

The image below shows the variance in environmental conditions over 12 months in 2016 at the Stirling Range National Park in WA.

A false colour image of Stirling Range National Park created by combining data relating to infrared and visible light.
Grayson Cooke, Author provided

Because geoscientists need clear images of the earth’s surface to analyse, they filter clouds from the data. I chose to take the opposite approach, highlighting the incredible array of meteorological conditions experienced by the country.

Clouds passing over the Eyre Peninsula in 2016.
Grayson Cooke, Author provided

There are many other artists working with satellite data. Clement Valla’s Postcards from Google Earth focuses on glitches in Google’s mapping algorithm, and bio-artist Suzanne Anker uses satellite imaging to produce extruded 3D environments in petri dishes.

Working with the Nevada Museum of Art, photographer Trevor Paglen will launch the Orbital Reflector satellite as an inflatable, visible sculpture, a prompt for wonder and reflection.

Artists place satellite data and usage in new contexts. They question surveillance practices and expose scientific tools and representations to new audiences outside science and the private sector.

The thousands of satellites winging their way around the Earth represent power and possibility, a chance to look again at the intersection between humankind and a changing planet.


“Open Air” will be officially launched at the National Film and Sound Archive in Canberra on September 20. It will also screen at the Spectra conference in Adelaide in October.The Conversation

Grayson Cooke, Associate Professor, Deputy Head of School (Research), Southern Cross University

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

Giving environmental water to drought-stricken farmers sounds straightforward, but it’s a bad idea


Erin O’Donnell, University of Melbourne and Avril Horne, University of Melbourne

Deputy Prime Minister Michael McCormack last week suggested the government would look at changing the law to allow water to be taken from the environment and given to farmers struggling with the drought.

This is a bad idea for several reasons. First, the environment needs water in dry years as well as wet ones. Second, unilaterally intervening in the way water is distributed between users undermines the water market, which is now worth billions of dollars. And, third, in dry years the environment gets a smaller allocation too, so there simply isn’t enough water to make this worthwhile.




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To help drought-affected farmers, we need to support them in good times as well as bad


In fact, the growing political pressure being put on environmental water holders to sell their water to farmers is exactly the kind of interference that bodies such as the Commonwealth Environmental Water Holder were established to avoid.

The environment always needs water

The ongoing sustainable use of rivers is based on key ecosystem functions being maintained, and this means that environmental water is needed in both wet and dry years. The objectives of environmental watering change from providing larger wetland inundation events in wet years, to maintaining critical refuges and basic ecosystem functions in dry years.

Prolonged dry periods cause severe stress to ecosystems, such as during the Millennium Drought when many Murray River red gums were sickened by salinity and lack of water. Environmental water is essential for ecosystem survival during these periods.

Under existing rules, environmental water holders can sell and buy water so as to deliver maximum benefits at the places and times it is most needed.

But during dry years the environmental water holders receive the same water allocations as other users. So it’s very unlikely there will be any “spare” water during drought. During a dry period, the environment is in urgent need of water to protect endangered species and maintain basic ecosystem functions.

We should be cautious when environmental water is sold during drought, as this compromises the ability of environmental water holders to meet their objectives of safeguarding river health. When the funds from the sale are not used to mitigate the loss of the available water to the environment, this is even more risky.

Secure water rights support all water users

In response to McCormack’s suggestion, the National Irrigators’ Council argued that compulsorily acquiring water from the environment can actually hurt farmers who depend on the water market as a source of income or water during drought.

Water markets are underpinned by clear legal rights to water. In other words, the entitlements the environment holds are the same as those held by irrigators. If the government starts treating environmental water rights as barely worth the paper they’re printed on, farmers would have every reason to fear that their own water rights might similarly be stripped away in the future.

Maintaining the integrity of the water market is important for all participants who have chosen to sell water, based on reasonable expectations of how prices will hold up.

Can taking environmental water actually help farmers?

As federal Water Resources Minister David Littleproud noted this week, environmental water is only about 8% of total water allocations in storage throughout the Murray Darling Basin. In the southern basin, it is still only about 14%. This means that between 86% and 92% of water currently sitting in storage is already allocated to human use, including farming.

There are calls for the Commonwealth government to treat the drought as an emergency and to take (or “borrow”) water from environmental water holders. But the Murray-Darling Basin Plan already has specific arrangements in place for emergencies in which critical human water needs are threatened.

The current situation in New South Wales is not an emergency under the plan. Water resources across the northern Murray-Darling Basin are indeed low, but storages in the southern basin are still 50-75% full. Although many licence holders in NSW received zero water in July’s round of allocations, high-security water licences are at 95-100%. In northern Victoria, most high-reliability water shares on the Murray are at 71% allocation.

The situation can therefore be managed using existing tools, such as providing direct financial support to farming communities and buying water on the water market.

Environmental water is an investment, not a luxury

As Australia’s First Nations have known for millennia, a healthy environment is not an optional extra. It underpins the sustainability and security of the water we depend on. When river flows decline, the water becomes too toxic to use.




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Water has been allocated to the environment throughout the Murray-Darling Basin to prevent the catastrophic blue-green algal blooms and salinity problems we have experienced in the past. If we want safe, secure water supplies for people, livestock and crops, we need to keep these key river ecosystems alive and well during the drought.

In the past decade alone, Australia has spent A$13 billion of taxpayers’ money to bring water use in the Murray-Darling Basin back to sustainable levels. If we let our governments treat the environment like a “water bank” to spend when times get tough, this huge investment will have been wasted.The Conversation

Erin O’Donnell, Senior Fellow, Centre for Resources, Energy and Environment Law, University of Melbourne and Avril Horne, Research fellow, Department of Infrastructure Engineering, University of Melbourne

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

How much plastic does it take to kill a turtle? Typically just 14 pieces



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Plastic bags, balloons, and rope fragments were among more than 100 pieces of plastic in the gut of a single turtle.
Qamar Schuyler, Author provided

Britta Denise Hardesty, CSIRO; Chris Wilcox, CSIRO; Kathy Ann Townsend, University of the Sunshine Coast, and Qamar Schuyler, CSIRO

We know there is a lot of plastic in the ocean, and that turtles (and other endangered species) are eating it. It is not uncommon to find stranded dead turtles with guts full of plastic.

But we weren’t really sure whether plastic eaten by turtles actually kills them, or if they just happen to have plastic inside them when they die. Another way to look at it would be to ask: how much is too much plastic for turtles?

This is a really important question. Just because there’s a lot of plastic in the ocean, we can’t necessarily presume that animals are dying from eating it. Even if a few animals do, that doesn’t mean that every animal that eats plastic is going to die. If we can estimate how much plastic it takes to kill a turtle, we can start to answer the question of exactly how turtle populations are affected by eating plastic debris.




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In our research, published today in Nature Scientific Reports, we looked at nearly 1,000 turtles that had died and washed up on beaches around Australia or were found in nets. About 260 of them we examined ourselves; the others were reported to the Queensland Turtle Stranding Database. We carefully investigated why the turtles died, and for the ones we examined, we counted how many pieces of plastic they had eaten.

Some turtles died of causes that were nothing to do with plastic. They may have been killed by a boat strike, or become entangled in fishing lines or derelict nets. Turtles have even been known to die after accidentally eating a blue-ringed octopus. Others definitely died from eating plastic, with the plastic either puncturing or blocking their gut.

One of the first meals eaten by this sea turtle post-hatchling turned out to be deadly. It died from consuming more than 20 tiny pieces of plastic, many of which were about the same size as a grain of rice.
Kathy Townsend, Author provided

Some turtles that were killed by things like boat strikes or fishing nets nevertheless had large amounts of plastic in their guts, despite not having been killed by eating plastic. These turtles allow us to see how much plastic an animal can eat and still be alive and functioning.

The chart below sets out this idea. If an animal drowned in a fishing net, its chance of being killed by plastic is zero – and it falls in the lower left of the graph. If a turtle’s gut was blocked by a plastic bag, its chance of being killed by plastic is 100%, and it’s in the upper right.

The animals that were dead with plastic in their gut, but had other possible causes of death have a chance of death due to plastic somewhere between 0 and 100% – we just don’t know, and they can fall anywhere in the graph. Once we have all the animals in the plot, then we can ask whether we see an increase in the chance of death due to plastic as the amount of plastic in an animal goes up.

Conceptual framework for estimating the probability of death due to plastic debris ingestion. Figure provided by the authors.

We tested this idea using our turtle samples. We looked at the relationship between the likelihood of death due to plastic as determined by a turtle autopsy, and the number of pieces of plastic found inside the animals.

Unsurprisingly, we found that the more plastic pieces a turtle had inside it, the more likely it was to have been killed by plastic. We calculated that for an average-sized turtle (about 45cm long), eating 14 plastic items equates to a 50% chance of being fatal.




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That’s not to say that a turtle can eat 13 pieces of plastic without harm. Even a single piece can potentially kill a turtle. Two of the turtles we studied had eaten just one piece of plastic, which was enough to kill them. In one case, the gut was punctured, and in the other, the soft plastic had clogged the turtle’s gut. Our analyses suggest that a turtle has a 22% chance of dying if it eats just one piece of plastic.

A green sea turtle that died after consuming 13 pieces of soft plastic and balloons, which blocked its gastrointestinal system.
Kathy Townsend

A few other factors also affected the animals’ chance of being killed by plastic. Juveniles eat more debris than adults, and the rate also varies between different turtle species.

Now that we know how much is too much plastic, the next step is to apply this to global estimates of debris ingestion rates by turtles, and figure out just how much of a threat plastic is to endangered sea turtle populations.The Conversation

Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO; Chris Wilcox, Senior Research Scientist, CSIRO; Kathy Ann Townsend, Lecturer in Animal Ecology, University of the Sunshine Coast, and Qamar Schuyler, Research Scientist, Oceans and Atmospheres, CSIRO

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

It’s hard to spread the idiot fruit



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Idiospermum is otherwise known as “idiot fruit” or ribbonwood.
via Wikimedia Commons, CC BY-SA

Stuart Worboys, James Cook University

Sometimes, in rainforest research, the only way to go is up. Twenty years ago I chose the rare rainforest tree Idiospermum australiense as a research subject for my Master’s degree, and some months into the project I discovered it only produces flowers high in the canopy.




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So, after a short course in single-rope technique, I found myself dangling 15 metres up in the rainforest canopy, surrounded by its sweetly fragrant, rose-like flowers. I followed the flowering process over a 24-hour period, taking photographs and catching potential pollinators. The tree is known locally as the “idiot fruit” (a loose translation of its scientific name) and there was I, dangling on a thin rope in its canopy, watching tiny insects. Oh, the irony.


The Conversation, CC BY

Intricate floral movements

Idiospermum australiense (also known as “ribbonwood”, or the “dinosaur tree”) makes for a fascinating and relatively approachable study subject. It is rare, with scattered populations covering a total of just 23 km². Known populations are mostly close to roads in very wet lowland tropical rainforests of Far North Queensland’s wet tropics.




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My research sites were idyllic locations close to crystal clear streams, and the tedium of solo field work would occasionally be broken by the wollock-a-woo call of the colourful wompoo pigeon or a wandering curious cassowary.

The hours of observations high in the forest canopy revealed an intricate process of floral movements that allow the plant to control their insect pollinators and prevent self-pollination.

The flowers of Idiospermum start as small spherical buds. Over a period of two days, the numerous cream-coloured, petal-like structures (called “tepals”) unfurl. They emit a fragrance that is sweet and fruity, and attract large numbers of small beetles and thrips (minute insects with fringed wings).

At the centre of the flower, the stamens are covered by a ring of hard rigid tepals, and the stigma – the female part of the flower – is accessible to pollinators via an open crater. But on the third day, things start to change. The stamens move and block the crater, while the ring of hard rigid tepals lifts and the stamens release their pollen. Pollinators can now feast on a reward of messy, sticky pollen, but are prevented from moving that pollen onto the flower’s stigma, thus preventing self-pollination.

Fertilisation only occurs if a pollen-covered insect enters the central crater in a newly opened flower elsewhere. Meanwhile, the ageing flowers start to change colour, first to a pale pink, then slowly deepening to crimson. If pollination has occurred, the flower will develop into a fruit containing one, rarely two, seeds.

The rose-like flowers of Idiospermum are cream-coloured when they first open, and fade to a deep crimson red over their 10-14 day life.
Wet Tropics Management Authority

The seeds themselves are remarkable. At up to 225 grams, they are probably the largest seed produced by any Australian plant (apart from the coconut). Unlike other rainforest plants with large fruits, they are not dispersed by cassowaries.

In fact, these enormous seeds have no known disperser: instead, they fall and germinate where they come to rest. The starchy reserves and protective poisons contained in the seed give the young seedling a great start in the dark and dangerous environment of the forest floor. But arguably, these seeds are the reason for the tree’s rarity. Their lack of a disperser, and reliance on a humid environment to prevent potentially fatal desiccation, may be the reason why their distribution is so restricted.

Refugees from deep time

Idiospermum occurs in just three widely separated populations, one in the Daintree, and two others 150km to the south, in the foothills of Queensland’s two highest mountains. They grow in “environmental refugia”: habitats, usually close to rain-attracting mountains, that have remained climatically stable for millions of years while the remainder of the continent has dried out. These refuges provide a safe and stable habitat for an extraordinary diversity of plants found nowhere else, including many that have been described as “primitive”.

“Primitive species” are modern species whose lineage branched off at a very early stage in the evolution of flowering plants, and who have retained primitive anatomical and genetic features that are similar to those seen in fossils of ancestral flowering plants.

The concentration of ancient flowering plant lineages within Queensland’s wet tropics makes the region internationally significant. With some 15 of the world’s 27 ancient plant families occurring within its 2 million hectares, it can be considered a living museum showcasing the evolution of the flowering plants.

The massive seeds, weighing up to 225 g, are probably the largest of any Australian plant (apart from the coconut).
Photo Neil Hewitt, Cooper Creek Wilderness, Daintree Rainforest.

Among the flora of the wet tropics, Idiospermum is truly iconic. It is the only member of its family (the Calycanthaceae) in the southern hemisphere: its closest relatives grow in China and North America. Its attractive, fragrant flowers retain a set of features seen in fossils some 88 million years old.




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It occurs in beautiful lowland rainforest locations, where it can often be easily found due to the scattering of seeds around its base. Idiospermum provides a focus for the region’s flora – its beauty, its rarity, its relictual nature, and its significance on a world scale.The Conversation

Stuart Worboys, Laboratory and Technical Support Officer, Australian Tropical Herbarium, James Cook University

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