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Exclusive: Britons fail to eat 178m bags of salad every year, say Tesco and government waste body Wrap, in study highlighting food waste

Britons throw away 40% of the bagged salad they buy every year, according to the latest data, with 37,000 tonnes – the equivalent of 178m bags – going uneaten every year.

The figures from the government’s waste advisory body Wrap are being published on Wednesday by the supermarket giant Tesco to highlight that prepared salads are still among the UK’s most wasted household foods. Past studies have shown that the average UK family throws away £700 of food each year.

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Crowds cheer as ‘Big Don’, a massive sea turtle, is released off the Florida Keys on World Turtle Day after being rehabilitated from injuries from an encounter with a fishing line. The 200-pound (91 kilogram) loggerhead turtle was nursed back to health with antibiotics, vitamins and a healthy diet of squid and fish

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Australian Energy Regulator loses costly Federal Court battle to control how much NSW network operators can charge for power.

Wenlock Edge, Shropshire This is the cow parsley moment, its blossom making foamy bow waves against hawthorn hedges along the road

The lanes are luminous with the white pulse of May: cow parsley, hawthorn, hogweed, garlic, stichwort. In fields there are pale lambs and dandelion clocks and stands of horse chestnut in candle. White on green. Green on white.

It is evening and the birds are fractious. I am listening to an old story so nearly forgotten that its retelling sounds strange and new.

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Queensland has officially become the Solar State with new figures confirming that combined solar rooftops are now Queensland’s largest power station.

AGL today announced the appointment of Melissa Reynolds to the newly created role of Chief Customer Officer and the promotion of Richard Wrightson to the position of Executive General Manager, Wholesale Markets.

National Transport Commission (NTC) and Austroads publish national guidelines to support Australian autonomous vehicle trials.

Clean Energy Innovation Fund completes $26m capital raising, easily surpassing its $20 million target with help from some big investors.

New contract signed in Arizona reveals record low price for large scale solar in US, and a stunning reduction in the price of battery storage. The new combined solar and storage deal of below 4.5c/kWh cuts previous prices by more than 60 per cent and is far cheaper than a peaking gas plant.

The results for Ausnet underline case for a rethink on who should pay for new grid connections. This would force a proper consideration of distributed generation at the time the network extension is built.

What’s that you say? Australia has ‘clean coal power stations’? Well, it depends how you define ‘clean coal’.

Donald Trump’s 2018 budget would eliminate agencies within the Department of Energy that fund energy technology projects.

Coalition seeks feedback on proposed funding for Port Augusta solar tower plant, but already appears to have agreed to equity funds rather than a loan.

Power Purchase Agreement to provide Competitive Solar Electricity Rates to United States Air Force for 25 Years.

Flamingos expend less energy standing on one leg than in a two-legged stance, scientists confirm.

Daimler is planning to build its second battery storage system manufacturing facility in Germany.

The last thing the spider saw before everything went black. Flickr/Nicola Albertini, CC BY-NC-ND

This is an article from Curious Kids, a new series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

If a huge huntsman spider is sucked into a vacuum cleaner, can it crawl out later? I really, really need to know. – Lucy, age 8, Ivanhoe.

Editor’s note: for such an important question, we consulted two experts – a vacuum cleaner design expert and a spider expert.

Simon Lockrey, industrial design research fellow and former vacuum cleaner design engineer: It certainly could, depending on the vacuum cleaner.

If there is a clear way out, the huntsman could make its escape when the vacuum is turned off. That’s assuming the spider survived being sucked up, that there were surfaces it could stick to, and there were gaps big enough to squeeze through.

However, sometimes escape is not possible. This is because some vacuum cleaners have internal “doors” that only open on the way in, and not the way out. Think of a trap door that only opens one way! We had those in some of the vacuums I helped to design.

Not all vacuums have this feature. It is mainly for machines that have short openings and get tipped up a lot, such as hand-held vacuums. So without that one-way door, a spider may have a chance to escape.

But the big question is whether a spider would even survive being sucked into a vacuum cleaner at all. Put it this way: when a spider enters a high-speed cyclonic machine, it may be travelling super quick. Speeds vary depending on the model. However, there are new digital motors that can rotate five times quicker than a Formula 1 engine – that’s 120,000 revolutions per minute!

Probably a spider’s best bet would be to lay low until the vacuum cleaner is emptied, and then make a getaway from the bin it is emptied into.

Maggie Hardy, spider expert: When a spider is sucked up by a vacuum cleaner, it first needs to avoid being killed by the low pressure that sucks air and dirt into the vacuum. And second, the spider will have to heal from any damage (scratches, or even lost legs) caused by travelling through the brushes, hoses and chambers inside the vacuum cleaner.

We know spiders can survive in low pressure (like you find in a vacuum) and in low gravity, thanks to some research carried out in space by NASA.

The very first spiders in space were sent for an experiment designed by an American high school student named Judith Miles, in 1973. She wanted to find out how the “spidernauts” would respond to weightlessness in low gravity, because spiders on Earth use both wind and gravity to properly construct their webs. Two more spidernaut experiments were conducted on the International Space Station in 2008 and 2009, and you can compare the results you get on Earth with what the astronauts found in space.

Spiders in space.

The most recent study, in 2011, found that with some practice spidernauts build webs that are very similar to the ones spiders build on Earth.

Spiders have an exoskeleton (their skeleton is on the outside of their body). Spider movement depends on them being able to inflate and deflate their legs, so if they lose a leg sometimes there isn’t enough pressure for them to move their legs. If a spider loses one or more of its legs it will usually regrow them in the next moult (the next time they shed their exoskeleton).

Spiders are a delightful and important part of the natural world, and if they are in your house they are generally lost.

You can build your own spider hospital, in case you do find an injured spider in or around your home. Of course, first you should check with an adult or an expert to make sure the spider isn’t dangerous, and never pick up a spider with your hands – have an adult use a large piece of cardboard, or a plastic container.

How to make a spider hospital.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. You can:

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
* Tell us on Facebook

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Please tell us your name, age and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Simon Lockrey worked for Dyson as a design engineer from 2007-2009. He has not received any funding from Dyson in his subsequent academic role at RMIT. He does receive funding from various government, NFP/ NGO, and industry partners for research on sustainability, innovation and design.

Maggie Hardy has received funding from The University of Queensland and UniQuest Pty Ltd.

Partula snails were driven to extinction in the wild by introduced predators. Wikimedia Commons

In 1977, on the islands of French Polynesia, government authorities released a predatory snail. They hoped this introduction would effectively control another species of invasive snail, previously introduced to supply escargot.

Instead, by the early 1980s, scientists reported alarming declines of native snail populations. Within ten years, 48 native snail species (genus Partula) had been driven to extinction in the wild.

The extinction of the Partula is notorious partially because these snails were, before going extinct, the study subjects of the first test in nature of Darwin’s theory of evolution by natural selection.

In the decades since, attempts to control and eradicate invasive species have become common, generally with far better results.

However, our paper, published today in Nature Ecology and Evolution, highlights the importance of scientific evidence and independent assessments when deciding whether to control or eradicate invasive species.

From islands to continents

Increasingly, large-scale invasive species control initiatives are being proposed worldwide. As early as 2018, a herpes virus will be released in Australia’s largest river system, targeting invasive common carp. As part of its Threatened Species Strategy, Australia is also planning to kill two million feral cats.

Across the Tasman Sea, New Zealand has made a bold commitment to remove three groups of invasive predators entirely by 2050.

New Zealand looks to eradicate three groups of invasive predators: rodents, mustelids, and the common brushtail possum. Geoff Whalan/Flickr, CC BY-NC-SA

It’s not just Australians and Kiwis making ambitious invasive species control proposals: bounties are being paid to catch invasive fish in the United States. The European Union has blacklisted 37 species of plants and animals within 4 million square kilometres, many of which are well-established and will be targeted by control (not preventative) measures.

Meanwhile, new gene editing technology has made the continental-scale eradication of invasive species a real possibility, for example by implementing gene drives that reduce breeding success. If you haven’t heard of it, CRISPR is a startling new biotechnology that makes genetic modification of plants and animals much easier. It offers new potential solutions to some of the world’s worst environmental, agricultural and human health problems.

These schemes will be implemented across large and complex social-ecological systems, and some options – like releasing a virus or genetically engineered species – may be irreversible.

Managing risk

While these projects may yield great benefits, we must be aware of the potential risk of unexpected and undesirable outcomes.

A prime example is the project to remove invasive carp from a million square kilometres of Australia’s rivers. Some scientists have expressed concern about the potential for the virus to jump species, and the effects of having hundreds of tonnes of dead fish fouling waterways and sapping oxygen from the water. The CSIRO and those planning the release of the virus suggest it is safe and effective.

Despite extensive media reporting giving the impression that the plan is approved to go ahead, the National Carp Control Plan has yet to publish a risk assessment, and is planning to deliver a report in 2018.

Removing well-established invasive species can create unforeseen consequences. These species can play significant roles in food webs, provide shelter for native animals, support ecosystem services, and their sudden death can disrupt ecological processes that are important to native species.

For example, a large amount of time and effort was spent in removing the non-native tamarix (or “salt cedar”) in the southwestern United States, because of the belief it was harming the water table.

Yet, subsequent research has indicated that the negative effects of tamarix have been exaggerated. In some areas, the plant is actually used by large numbers of endangered flycatchers to nest and fledge their young.

A corn bunting perches on a blooming tamarix. Georgios Alexandris/shutterstock A science-based solution

In our paper, we highlight a series of considerations that should be addressed before plunging into large-scale invasive species control.

Fundamentally, there must be a demonstrable ecological and social benefit from control or eradication, above and beyond the purely ideological. At first this might seem facile, but invasive species control initiatives are often highly politicised, with science taking a back seat. Given scarce funding for conservation, it is crucial that resources are not squandered on programmes that may not deliver - or could cause environmental damage.

We must avoid assuming that attempting to control invasive species will, by default, solve our environmental problems. This means addressing the full range of human pressures which negatively affect biodiversity. We must also consider how removing an influential invasive species could benefit other invasive species, harm native species through increased predation and competition, or alter ecological processes or habitat.

Comprehensive risk-benefit assessment of invasive species control programs allow decision-makers to proactively avoid, manage or accept these risks.

For example, tonnes of decomposing carp post-virus may cause short-term water quality issues, or the death of native species. Ultimately, however, these risks could be acceptable if the virus is effective, and allows native species a window of opportunity to recover.

Large-scale invasive species control demands careful investigation of the risks and rewards. We hope our paper can provide policy-makers with better guidelines for science-based decision-making.

R. Keller Kopf has applied for funding from the Fisheries Research and Development Corporation to assess the: Ecological, Social and Socio-Economic Risks of Releasing Koi Herpes Virus to Control Common Carp in Australia.

Dale Nimmo receives funding from the Australian Research Council, the Australian Academy of Science, the Hermon Slade Foundation, the Department of Parks and Wildlife, and the Department of Land, Water and Planning.

Paul Humphries receives funding from the MDBA Environmental Water Knowledge and Research Program and has received funding from the MDBA Native Fish Strategy. He is a collaborator on an application for funding from the Fisheries Research and Development Corporation in relation to the Koi Herpes Virus to Control Common Carp in Australia..

Dingoes can help manage devastating red fox and feral cat numbers, but only if we let enough of them live in key areas. Bobby Tamayo, Author provided

Dingoes could be the key to controlling red foxes and other invasive predators, but only if we encourage them in large enough numbers over a wide enough area, our research shows.

Interest in re-introducing or restoring top predators, like dingoes and wolves, has been fuelled by recent studies demonstrating their important roles in their ecosystems. They can especially be vital in suppressing the abundance of lower-order competitors or “mesopredators”, like red foxes and possibly feral cats (which can have devastating effects on native species).

But researchers have found top predators aren’t always successful in reducing mesopredator numbers. Until now, such variation has been linked to human presence, land-use changes and environmental factors such as landscape productivity.

However, our research, published yesterday in Nature Communications, found that a key factor for success is high numbers of dingoes and wolves across their natural range.

The density effect

If you look at how species are typically distributed across a landscape – their range – ecological theory predicts there’ll be lower numbers at the outer edges of their range.

If you do need large numbers of top predators to effectively suppress mesopredators, the core of their range is potentially the best place to look.

We tested this idea, looking at the dingo in Australia and the grey wolf in North America and Europe. The mesopredators included the red fox in Australia, the coyote in North America and the golden jackal in Europe.

We looked at three regions in our study. Predator distribution is shown for: a) coyotes (hashed) and grey wolves (orange) in Saskatchewan, North America (present day); b) golden jackals (hashed) and grey wolves (orange) in Bulgaria and Serbia (present day); and c) red foxes (hashed) and dingoes (orange) in Queensland, Australia (in the 1950s). Predator images: Doug McLaughlin; Bobby Tamayo, Harley Kingston/flickr, Larry Lamsa/flickr

We used information from bounty hunting programs, as these provide data on predator numbers across a wide geographical area. In the case of Australia we used historic data from the 1950s, as this is the most recent reliable information about red fox and dingo distribution. The actual population numbers of red foxes and dingoes have changed substantially since then, but the nature of their interactions – which is what we were investigating – has not.

We determined that top predators exist in higher numbers at the core of their ranges in comparison to the edges. We then looked at mesopredator numbers across the range edges of their respective top predator.

Predator bounties and top predator range edges in each continent. The number of bounties (representing the number of animals killed) are given for each hunting unit in North America (collated from 1982 to 2011) and Europe (collated from 2000 to 2009), whereas each square in Australia represents the number of bounties in a 100-by-100km area (collated from 1951 to 1952). Top predators are in a–c. Mesopredators are in d–f. Darker colours within each hunting unit indicate greater bounty return numbers and, by inference, a higher abundance for the respective predator. Dashed black lines indicate top predator range edges. Australia was divided into two sections for the analysis (east and west) as shown.

The results, which were consistent across the three continents, suggest that top predators can suppress mesopredators effectively (even completely) but only in the core of their geographic range, where their numbers are highest.

In other words, abundant top predators can exert disproportionate mesopredator control once their numbers increase past a certain point.

Example of the results from Australia (western side of Queensland). The blue lines indicate the abundance of each predator (note that the values on the y-axis are scaled so do not reflect actual numbers). The black dashed line indicates where there is a sharp change in predator abundance (the breakpoint). The red dashed lines indicate 95% confidence intervals (a measure of uncertainty) either side of the breakpoint. Distance values less than zero relate to areas outside the dingoes’ range, while distance values greater than zero relate to areas within the range. In summary, abundances of the red fox decline sharply as you move further into the range of the dingo. The ‘enemy constraint hypothesis’

The relationship we uncovered is now formalised as the “Enemy Constraint Hypothesis”. It could apply to other predator dyads, where two animals compete for similar resources – even relationships involving parasites and pathogens.

Our findings are important for understanding species interactions and niches, as well as the ecological role of top predators. It could explain why other studies have found top predators have little influence on mesopredators: they were looking at the edge, not the core, of the top predators’ range.

This is a conceptual model of the Enemy Constraint Hypothesis. On the edge of a top predator’s range, mesopredator abundance should decline as top predator numbers increase. The breakpoint for the mesopredator indicates where their population nears zero. The breakpoint for the top predator indicates where their abundance starts to decline sharply on the edge of the range. How many top predators do we need?

Dingoes can be vital for reducing red fox and possibly feral cat numbers. In our case studies the ranges of each top predator were limited primarily by human use of the land and intensive shooting, trapping and poisoning.

Killing pack animals like dingoes can fracture social groups, potentially altering their natural behaviour and interactions with other species. Future studies on predator interactions therefore need to consider the extent to which the animals are acting in response to human intervention.

If we want to benefit from the presence of top predators, we need to rethink our approach to management – especially where they are subjected to broad-scale control, as the dingo is in some parts of Australia.

Changing our relationship with top predators would not come without its challenges, but high extinction rates around the world (and especially in Australia) clearly indicate that we urgently need to change something. If this includes restoring top predators, then we need to think big.

Thomas Newsome receives funding from Deakin University, The University of Sydney, the National Geographic Society for Research and Exploration, Seattle City Lights, Washington Department of Fish and Wildlife, and Newmont Tanami Operations. He is Treasurer of the Australasian Wildlife Management Society and a member of the Australian Mammal Society and the Ecological Society of Australia.

• Study by UN and Columbia finds ‘proliferation’ of cases instigated by citizens
  
• Lion’s share of court cases are in US but number also growing around the world
  

Governments around the world are increasingly being challenged in court to do more to combat the threat of climate change, with litigation ranging from a group’s attempt to stop an airport runway in Austria to a Pakistani farmer suing his government over its failure to adapt to rising temperatures, a new study has found.

Related: Trump treading water over climate change deal, says deputy UN chief

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