These underwater photos show Norfolk Island reef life still thrives, from vibrant blue flatworms to soft pink corals



A big coral bommie in the lagoon at Norfolk Island.
John Turbull , Author provided

John Turnbull, UNSW

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this new series, we’ve invited them to share their unique photos from the field.


Two weeks ago, I found myself hitting the water on Norfolk Island, complete with a survey reel, slate and camera.

Norfolk Island is a small volcanic outcrop located between New Caledonia and New Zealand, 1,400 kilometres east of Australia’s Gold Coast. It’s surrounded by coral reefs, with a shallow lagoon on the south side that looks out on two smaller islands: Nepean and Phillip.

The island is picturesque, but like marine environments the world over, Norfolk Marine Park is subject to pressures from climate change, fishing pressure, habitat change and pollution.

I was diving in the marine park as a volunteer for Reef Life Survey, a citizen science program where trained SCUBA divers survey marine biodiversity in rocky and coral reefs around the world. We first surveyed Norfolk Island in 2009, then again in 2013, with an eight year hiatus before our return this month.

While the scientific analysis of our data is yet to be done, we can make anecdotal observations to compare this year’s findings with prior records and photographs. This time, our surveys turned up several new sightings and observations.

A wrinkly orange nudibranch nestled in algae
A red-ringed nudibranch (Ardeadoris rubroannulata). This beautiful little mollusc was a couple of centimetres long, nestled on the side of a wall covered in colourful algae. I had to look twice to notice it, but recognised it as a species I had seen before in Sydney. It had previously only been recorded in the Coral Sea, the east coast of Australia and Lord Howe island, so it was nice to get a record of it even further east in the Pacific.
John Turnbull, Author provided

What we saw

Diving under the waves in Norfolk Marine Park takes you into a world of crackling, popping reef sounds through clear blue water, with darting tropical fish, a tapestry of algae and hard and soft corals in pink, green, brown and red.

In these surveys we record fish species including their size and abundance, invertebrates such as urchins and sea stars, and habitat such as coral cover. This allows us to track changes in marine life using standardised scientific methods.

Emily Bay is a sheltered swimming beach at the eastern end of the lagoon, great for snorkelling too thanks to the diverse corals just below the surface.
John Turbull, Author provided
An orange fish near a mound of orange coral
Banded parma are quite territorial — they charge you as you approach their turf. This one is guarding what it regards as its own personal coral clump.
John Turbull, Author provided

Given recent major marine heatwaves and bleaching events in Australia, we were pleased to see healthy corals on many of our survey sites on Norfolk. We even felt there had been increases in coral cover at some sites.

This may be due to Norfolk’s location. The island is further south than most Australian coral reefs, which means it has cooler seas, and it’s surrounded by deeper water. I’m a marine ecologist involved in soft coral monitoring at the University of NSW, so I particularly noticed the wonderful diversity and size of soft corals.

Healthy brown coral garden
This photo shows the structure corals provide for fish and other animals to shelter in. They are the foundation for the whole tropical marine community. The corals here are a healthy brown — which comes from the symbiotic algae in their tissues – with no signs of bleaching.
John Turbull, Author provided
Soft pink coral
The soft corals on Norfolk Island are some of the largest I’ve seen. Their structure is made up of soft tissue, often inflated by water pressure, rather than hard skeleton.
John Turbull, Author provided
Close-up of white, wrinkly coral
Hard corals come in a diversity of shapes and sizes, including this massive form growing on the side of rock wall.
John Turbull, Author provided

I noticed generally low numbers of large fish such as morwong and sharks on our survey sites. Some classes of invertebrate were also rare on this year’s surveys, particularly sea shell animals like tritons and whelks.

Urchins, on the other hand, were common, particularly the red urchin. Some sites also had numerous black long-spined urchins and large sea lamingtons.

These invertebrate observations follow patterns we see in eastern and southern Australia, where there are declines in the numbers of many invertebrate species, and increases in urchin barrens — regions where urchin populations grow unchecked.

The expansion of urchin barrens can threaten biodiversity in a region, as large numbers of a single species of urchin can out-compete multiple species of other invertebrates, over-graze algae and reduce habitat suitable for fish.

Red urchin beside coral
The abundant red urchin competes for space with other invertebrates, such as this one encrusting hard coral.
John Turbull, Author provided
Fat, black and white urchins beneath a coral mound
Lamingtons are an Australian cake (although there are claims they were invented in NZ!) and I love this descriptive common name for the Tripneustes gratilla urchin. The sea lamingtons on Norfolk appear particularly fat and happy, as they cluster in sheltered grooves during the day to avoid predators. They can also be different colours — I’ve seen them on the east coast of Australia in orange and cream, even with stripes.
John Turbull, Author provided
Two spindly shrimp beneath coral
A pair of banded cleaner shrimp, which grow to 9cm long. They advertise their fish cleaning services with their distinct banding and white antennae.
John Turbull, Author provided

A highlight of any survey dive is when you find an animal you suspect may not have been recorded at a location before, and I had several of those on this trip.

I recorded first sightings for Reef Life Survey of blue mao mao, convict surgeonfish, the blue band glidergoby, sergeant major (a damselfish), chestnut blenny, Susan’s flatworm, red-ringed nudibranch, fine-net peristernia and an undescribed weedfish.

While some of these sightings are yet to be confirmed by specialists, they gave a buzz of excitement each night as we searched the records to confirm our suspicions of a new find.

A school of large blu fish
This big school of drummer circled us for several minutes on our first survey dive at Nepean Island. If you look closely you can see one of the fish is different, in the top right. This is one of a few blue mao mao circulating in the school – and a first sighting for Reef Life Survey at Norfolk. You might also notice another species in the school, the darker spotted sawtail down the bottom of the photo.
John Turbull, Author provided
A vibrant blue ribbon-like worm with an orange stripe
Susan’s flatworm is a colourful invertebrate listed as living only in the Indian Ocean and Indonesia. This sighting from Norfolk Island is a new record in the Pacific Ocean. When I first saw this little worm at the end of a survey, I wondered if it was anything special. Just as well I took the photo anyway!
John Turbull, Author provided

Recruiting the locals

Other highlights for me included the warm welcome we received from the local community on Norfolk and the great turnout we had at our community seminar. Everyone I spoke to was supportive and encouraging when they heard we were on the island as volunteers doing surveys, and several people expressed interest in getting involved.

This is great news, as the best outcome is for local people to be trained to conduct their own local surveys.

An underwater SCUBA selfie
Tyson, Sal, Jamie, Toni and me taking an underwater selfie on the west side of Phillip Island, 10 metres below the surface. It’s harder than on land, with your fins off the ground, everyone moving and bubbles to deal with.
John Turbull, Author provided

Ideally we will return for comprehensive surveys of our 17 sites every two years or so, allowing us to plot trends over time. Only then can we hope to understand what is really happening in our marine environment, and make evidence-based conservation decisions. Having a skilled local team would make this easier and more likely to happen.

In any case, our 2021 surveys in Norfolk Marine Park, conducted by our team of five dedicated volunteers and supported by many others, give us one more essential point in time in the Norfolk series, and gave me some great memories to boot.

You can view my full photo album from the Norfolk Island survey here.




Read more:
Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles


The Conversation


John Turnbull, Postdoctoral research associate, UNSW

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

Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles



Dragon springtails (pictured) are widely distributed in forests of eastern Australia — yet they’re still largely unknown to science.
Nick Porch, Author provided

Nick Porch, Deakin University

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this series, we’ve invited them to share their unique photos from the field.


Which animals are quintessentially Australian? Koalas and kangaroos, emus, tiger snakes and green tree frogs, echidnas and eastern rosellas, perhaps. And let’s not forget common wombats.

Inevitably, most lists will be biased to the more conspicuous mammals and birds, hold fewer reptiles and frogs, and likely lack invertebrates — animals without a backbone or bony skeleton — altogether.

I’m an invertophile, fascinated by our rich terrestrial invertebrate fauna, so my list will be different. I’m enchanted by stunning dragon springtails, by cryptic little Tasmanitachoides beetles, and by the poorly known allothyrid mites, among thousands of others.

Australia’s terrestrial invertebrate multitude contains several hundred thousand uniquely Australian organisms. Most remain poorly known.

To preserve our biodiversity, we first must ask: “which species live where?”. For our invertebrates, we are a long way from knowing even this.

The Black Summer toll

Last year, a team of scientists estimated that the Australian 2019-2020 bushfires killed, injured or displaced three billion animals. That was a lot. But it was also a woefully inadequate estimate, because it only accounted for mammals, reptiles, birds and frogs.

Hidden from view, many trillions more invertebrates burned or were displaced by the fires. And yes, invertebrates are animals too.

A mite from the family Bdellidae (on the right) has captured a springtail, and is using its piercing mouthparts to suck it dry. Mites and springtails are among the most abundant animals on the planet.
Nick Porch, Author provided

Admittedly, it’s hard to come to terms with invertebrates because they’re often hard to find and difficult to identify. Most species are inconspicuous, even if they belong to incredibly abundant groups, such as mites and springtails, which can occur in numbers exceeding 10,000 per square metre.

Most invertebrates are poorly known because there are so many species and so few people working on them. In fact, it’s likely only a quarter to one-third of Australia’s terrestrial invertebrate fauna is formally described (have a recognised scientific name).

A translucent land snail
Meredithina dandenongensis, a species from the wet forests of Victoria. It can be found during the day under rotting logs. The land snail family Charopidae contains hundreds of species across wetter parts of southern and eastern Australia.
Nick Porch, Author provided

One of the problems invertebrates have, in terms of attracting attention, is that many are not easily seen with the naked eye.

Macrophotography can magnify these wonders for a view into a world most of us are completely unfamiliar with. Even then, it often will be hard to know what we see. Everyone will recognise a kangaroo, but who can identify an allothyrid mite?

The photo below shows an undescribed species of mite from the family Allothyridae, from Mount Donna Buang in Victoria. The mite family Allothyridae has three described Australian species, and dozens more awaiting description.

An undescribed Allothyridae species. Just one of the many species in this group waiting to be studied.
Nick Porch, Author provided

This collage shows a selection of mites found in the forests of southeastern Australia. It’s likely many of the species shown here are unknown to science.

Mites are a very ancient and diverse group. They can be found abundantly in most terrestrial habitats but are rarely seen because most are several millimetres long or smaller.
Nick Porch, Author provided

A deeply ancient lineage

Animal ecologists, most of whom work on vertebrates, often joke that I “study the ‘food’, haha…”. They think they’re funny, but this reflects a deep seated bias — one extending from scientists to the wider public. This limits the development of a comprehensive understanding of biodiversity that has flow-on effects for conservation more broadly.

It’s true: invertebrates are food for larger animals. But their vital role in maintaining Australia’s ecosystems doesn’t end there.

Every species has an evolutionary history, a particular habitat, a set of behaviours reflecting that history, and a role to play in the ecosystem. And many terrestrial invertebrates belong to especially ancient lineages that record the deep history of Australia’s past.

The moss bug family Peloridiidae, for example, dates back more than 150 million years. For context, the kangaroo family (Macropodidae) is likely 15-25 million years old.

Their history is reflected in the breakup of the ancient supercontinent, Gondwana. In fact, Australian species of moss bugs are more closely related to South American species than to those from nearby New Zealand.

A bronze-coloured beetle with delicate, translucent wings
Chasoke belongs to the beetle family Staphylinidae, which is currently considered the largest family of organisms on Earth, with more than 60,000 scientifically described species. Mt. Donna Buang, Victoria.
Nick Porch, Author provided

This is a common pattern in terrestrial invertebrate groups. It reflects how the New Zealand plate separated from the remainder of Gondwana about 80 million years ago, while the Australian plate remained connected to South America via Antarctica.

Similar stories can be told from across the invertebrate spectrum. The photo below shows a few examples of these relics from Gondwana.

Peloridiid bugs — such as Hemiodoecus leai China, 1924 (top left) — are restricted to the wettest forests where they feed on moss. Top right: A new species of Acropsopilio (Acropsopilionidae) harvestman from the Dandenong Ranges. Bottom left: a new velvet worm from the Otway Ranges. Bottom right: Tasmanitachoides hobarti from Lake St Clair in central Tasmania.
Nick Porch, Author provided

Their fascinating evolution

Overprinting this deep history are the changes that occurred in Australia, especially the drying of the continent since the middle Miocene, about 12-16 million years ago.

This continent-wide drying fragmented wet forests that covered much of the continent, resulting in the restriction of many invertebrate groups to pockets of wetter habitat, especially along the Great Dividing Range and in southwestern Australia.




Read more:
Trapdoor spider species that stay local put themselves at risk


A consequence of this was the evolution in isolation of many “short-range endemic” species.

A short-range endemic species means their geographic distribution is less than 10,000 square kilometres. A short-range endemic mammal you might be familiar with is Leadbeater’s possum, restricted to the wet forests of the Victorian Central Highlands.

A long, brown and orange thrips with six legs.
This is Idolothrips spectrum, the largest thrips in the world. It’s called the giant thrips, even though it’s less than 10mm long. Dandenong Ranges, Victoria.
Nick Porch, Author provided

But short-range endemism is much more common in invertebrates than other organisms. This is because many invertebrates are poor dispersers: they don’t move between habitat patches easily. They may also maintain viable populations in small areas of suitable habitat, and are frequently adapted to very specific habitats.

Take Tropidotrechus, pictured below, a genus of beetles mostly restricted to the same region as Leadbeater’s possum. They, however, divide the landscape at a much finer scale because they’re restricted to deep leaf litter in cool, wet, forest gullies.

As Australia dried, populations of Tropidotrechus became isolated in small patches of upland habitat, evolving into at least seven species across the ranges to the east of Melbourne.

Tropidotrechus victoriae, Victoria’s unofficial beetle emblem (left). Related described and undescribed species are found in the nearby Central Highlands and South Gippsland ranges (right)
Nick Porch, Author provided

Discoveries waiting to happen

The trouble with knowing so little about Australia’s extraordinary number of tiny, often locally unique invertebrates, is that we then massively underestimate how many of them are under threat, or have been badly hit by events like the 2019-2020 fires.

If we wish to conserve biodiversity widely, rather than only the larger charismatic wildlife, then enhancing our knowledge of our short-range species should be a high priority.

One shiny green beetle on top of another
You don’t necessarily need specialist equipment to take pictures of our fascinating invertebrates. This is a phone picture of mating Repsimus scarab beetles (relatives to the Christmas beetles). It was taken at Bemboka in NSW, which burnt during the 2019-2020 fires.
Nick Porch, Author provided

We’ve only just scratched the surface of Australia’s wonderful invertebrate fauna, so there are enough discoveries for everyone.

You can join iNaturalist, a citizen science initiative that lets you upload images and identify your discoveries. Perhaps you’ll discover something new — and a scientist just might name it after you.




Read more:
Want to teach kids about nature? Insects can help


The Conversation


Nick Porch, Senior Lecturer in Environmental Earth Science, Deakin University

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

Would you do this at home? Why we are more likely to do stupid things on holidays



http://www.shutterstock.com

Denis Tolkach, James Cook University and Stephen Pratt, The University of the South Pacific

As the COVID pandemic took hold in March, Ohio’s Brady Sluder went to Miami for spring break, despite urgent calls for people to stay home and socially distance.

Interviewed by CBS News, Sluder’s arrogant justfication for his trip went viral.

If I get corona, I get corona. At the end of the day, I’m not gonna let it stop me from partying […] about two months we’ve had this trip planned.

A week later — now an international “celebrity” for all the wrong reasons — he was forced to issue a grovelling apology.

If you think Sluder’s partying was stupid, we share your feelings.

With the festive season upon us, as the pandemic continues, we can only hope covidiots listen to the rules. As many of us also head off on summer breaks, now is also a good time to reflect on stupidity in tourism.

We may be tempted to think a stupid person has certain demographic or psychological characteristics. However, anyone can behave stupidly, especially in unfamiliar environments — like holidays — where it is difficult to judge the right course of action.

The laws of human stupidity

In our recently published journal article on stupidity in tourism, we see stupidity as an action without insight or sound judgement. This results in losses or harm to the perpetrator and others. In a holiday context, it can negatively affect tourists themselves, as well as other people, animals, organisations, or destinations.

Young people partying on a beach in Florida.
When bars were shut in Florida Spring Break revellers headed to the beach.
Julio Cortez/AP/AAP

In 1976, Italian economist Carlo Cipolla published a definitive essay called The Basic Laws of Human Stupidity. Although we prefer to focus on stupid behaviour rather than stupid people, we agree with his five laws:

  1. Always and inevitably, everyone underestimates the number of stupid individuals in circulation.

  2. The probability that a certain person (will) be stupid is independent of any other characteristic of that person.

  3. A stupid person is a person who causes losses to another person or a group of persons while himself deriving no gain and even possibly incurring losses.

  4. Non-stupid people always underestimate the damaging power of stupid individuals. In particular, non-stupid people constantly forget dealing with or associating with stupid people always and everywhere turns out to be a costly mistake.

  5. A stupid person is the most dangerous type of person.

Why is stupid behaviour so dangerous? Because it is irrational and so the outcome is unpredictable.

Who could have thought so many people would die when taking a selfie that you can now take out insurance on the act? Or that aeroplane passengers would throw coins into engines for good luck?

What causes stupidity?

How can we better understand our own stupid behaviour, or recognise it in others? Stupidity is generally caused by an excess of one or more of the following factors:

  • the person believing they know everything
  • the person believing they can do anything
  • the person being extremely self-centred
  • the person believing nothing will harm them
  • the person’s emotions (for example, fear or anger)
  • the person’s state (for example, exhausted or drunk).

Why stupid behaviour is more likely on holidays

Tourists can be affected by all of these factors.

Leisure tourism, by its nature, is a very self-centred and pleasure-seeking activity. People often travel to relax and enjoy themselves.




Read more:
Memories overboard! What the law says about claiming compensation for a holiday gone wrong


In pursuit of trying something new or escaping their daily routine, people may go to places with very different cultures or practices than their own, or try things they wouldn’t normally do — such as adventure activities. As a result, individuals can act differently while on holidays.

There also seem to be fewer social constraints. Tourists may not follow rules and social norms while travelling, because relatives, friends, colleagues, bosses are less likely to find out. Of course, tourists may not be aware of the commonly-accepted rules of where they travelling, as well.

All of the above increases the likelihood of stupidity. And one certainly doesn’t need to travel overseas to be stupid. A case in point is a tourist who snuck into Uluru-Kata Tjuta National Park, which was closed-off in August due to COVID concerns in the local indigenous community. The woman injured her ankle and had to be rescued.

The importance of thinking first

So, what to do about stupid tourist behaviour?

Strict regulation, physical barriers, warning signs and other punitive measures alone may not work. This is seen in the case of a man who climbed over a zoo fence in 2017 to avoid the entry fee. He ended up being mauled to death by a tiger.

Tourists walking beyond a 'do not go beyond this point' sign.
Physical barriers alone do not prevent stupid behaviour.
http://www.shutterstock.com

Education of tourists on how to behave during travels has some effect. But more importantly, tourists need to be self-aware. They need to consider what is likely to happen as a result of their behaviour, how likely is it that things will go wrong, and whether they would do this at home.

While stupidity is impossible to eliminate, it can be less frequent and do much less damage, if we take time to reflect on our behaviour and attitudes.

So, have fun during the holiday … but don’t be stupid!




Read more:
Australians don’t have a ‘right’ to travel. Does COVID mean our days of carefree overseas trips are over?


The Conversation


Denis Tolkach, Senior Lecturer, James Cook University and Stephen Pratt, Professor, The University of the South Pacific

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

Photos from the field: Australia is full of lizards so I went bush to find out why



A lace monitor (Varanus varius)
Kristian Bell, Author provided

Kristian Bell, Deakin University

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this new series, we’ve invited them to share their unique photos from the field.


Though it may not be as famous a stereotype as shrimps on the barbie, deadly snakes or Vegemite, Australia is renowned in certain scientific circles for being the “land of the lizards”.

Australia has a higher diversity of lizards than anywhere else in the world. The number of different species within a single part of remote, central Australia well exceeds similar desert environments, such as the Kalahari in Africa, or the US.

Over the last 50 years, scientists have tried to understand the cause of this extraordinary and unique diversity.

Some suggest unpredictable resources in the arid outback, such as sporadic rain, favour low-energy animals like lizards over birds and mammals. Others claim a high diversity of termites allows lots of different termite-eating lizards to co-exist.




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


Or perhaps the presence of shrubs, sparse trees and grass clumps provide a variety of niches (microhabitats) for tree and litter dwelling species. Despite these many hypotheses, no consensus has ever been reached.

My research explores the role of spinifex, a spiky clumping grass that’s typically found in the arid outback, often in conjunction with lizard diversity hotspots.

With many species found nowhere else on earth, some Australian lizards are threatened with extinction. Understanding how and why lizards use this iconic outback plant can help us conserve them, by predicting how they might respond to disturbances such as habitat loss and climate change.




Read more:
Spinifex grass would like us to stop putting out bushfires, please


Following many trips to the outback, I was surprised to find locals who had never encountered some of the species I was studying. Taking photographs of these often small and overlooked animals helps me to better engage the community and raise the wider public profile of lizards, compared to other, more “charismatic” native animals.

A thriving desert ecosystem

All 60 species of spinifex grasses (members of the Triodia genus) are found only in Australia. Although spinifex habitats cover more than one-fifth of mainland Australia, the plant is little-known and little-loved by non-naturalists.

Spinifex clumps on red dirt
A typical mallee ecosystem where we conduct our research, with plenty of spinifex clumps interspersed with the many-stemmed trunks, characteristic of mallee eucalypts.
Kristian Bell, Author provided

Spinifex typically forms a spiky and impenetrable clump that provides useful, and in some cases essential, resources to lizards, birds, mammals and invertebrates.

But despite the close association of many lizard species to spinifex, we still don’t know exactly why reptiles like it so much.




Read more:
I walked 1,200km in the outback to track huge lizards. Here’s why


Three ideas dominate. First, spinifex may contain lots of food for lizards, such as termites or ants.

Alternatively, the spiky, needle-like leaves of spinifex may offer small lizards a great place to hide from predators. And finally, temperatures deep within a dense spinifex hummock can be very cool compared to the searing desert heat, where temperatures can reach a scorching 50℃.

My research aim is to work out which, if any, of these explanations is true. I do this by measuring variables such as temperature, invertebrate abundance and risk of becoming prey, in spinifex and other plants.

Alongside my supervisors, I have also conducted behaviour trials on a couple of spinifex-loving lizard species: the mallee ctenotus (Ctenotus atlas) and the mallee dragon (Ctenophorus spinodomus).

Setting up behavioural trial enclosures. After more than 100,000 recorded observations, we are only beginning to better understand why lizards like using spinifex.
Kristian Bell, Author provided

We have recorded 230,000 temperatures, caught 16,089 invertebrates, constructed 112 lizard models and classified 143,627 behavioural observations. But such is the complicated nature of the work, we’re only partially closer to understanding the lizard-spinifex relationship. So far, our data suggests temperature is a key component.




Read more:
Does Australia really have the deadliest snakes? We debunk 6 common myths


The photos below are generally a result of good fortune and spending inordinate amounts of time in wild places. Pictures of some of the smaller, more skittish animals were taken upon release from pitfall traps.

A close-up of mallee ctenotus, a striped lizard
Mallee ctenotus (Ctenotus atlas)
Kristian Bell, Author provided
A profile of a mallee dragon
Mallee dragon (Ctenophorus spinodomus)
Kristian Bell, Author provided

The above two photos show my study species: the mallee dragon and the mallee ctenotus. Despite one lizard being a skink and the other a dragon, both species are strongly associated with spinifex. The skink tends to forage within spinifex, whereas the dragon emerges into open patches adjacent to spinifex to eat and “signal” to other dragons.

Spinifex with a rainbow in the background

Kristian Bell, Author provided

Spinifex grass, pictured above, with its spiky, needle-like leaves, creates valuable habitat for numerous species of birds, mammals and invertebrates — not just reptiles. Its abundance and influence on many species make it a “foundation species”.

Burton's legless lizard
Burton’s legless lizard (Lialis burtonis)
Kristian Bell, Author provided

This photo above shows a Burton’s legless lizard (Lialis burtonis) — a predator of my study species. These snake-like reptiles are specialist lizard hunters and often use the dense cover of spinifex to their advantage to ambush passing lizards.

Legless lizards might look a bit like snakes, but they have different ancestries and subtle distinguishing features, such as the lizard’s eyelids and external ears, which snakes don’t have.

But many other animals live in or near spinifex, and would happily make a meal of small lizards, including those shown in the following photos. The ability of numerous predators to access the centre of spiky spinifex clumps throws some doubt on the idea spinifex is used as protection from predators.

slender-tailed dunnart
Slender-tailed dunnart (Sminthopsis murina)
Kristian Bell, Author provided
A soaring black shouldered kite
Black shouldered kite (Elanus axillaris)
Kristian Bell, Author provided
Dwyers snake, with a researcher in the background
Dwyers snake.
Kristian Bell, Author provided
Sand monitor
Sand monitor.
Kristian Bell, Author provided

We can’t claim to have cracked the case yet. But we’re a step closer to unravelling the secrets behind one of Australia’s remarkable, and under-appreciated, biodiversity stories.




Read more:
Scientists capture rare footage of mother skink fighting a deadly brown snake to protect her babies


The Conversation


Kristian Bell, PhD candidate, Deakin University

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

Photos from the field: capturing the grandeur and heartbreak of Tasmania’s giant trees



Steve Pearce/The Tree Projects, Author provided

Jennifer Sanger, University of Tasmania

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this new series, we’ve invited them to share their unique photos from the field.


Tasmania’s native forests are home to some of the tallest, most beautiful trees in the world. They provide a habitat for many species, from black cockatoos and masked owls to the critically endangered swift parrot.

But these old, giant trees are being logged at alarming rates, despite their enormous ecological and heritage value (and untapped tourism potential). Many were also destroyed in Tasmania’s early 2019 fires.




Read more:
Comic explainer: forest giants house thousands of animals (so why do we keep cutting them down?)


Former Greens leader Bob Brown recently launched a legal challenge to Tasmania’s native forest logging. And this year, Forestry Watch, a small group of citizen scientists, found five giant trees measuring more than five metres in diameter inside logging coupes. “Coupes” are areas of forest chopped down in one logging operation.

These trees are too important to be destroyed in the name of the forestry industry. This is why my husband Steve Pearce and I climb, explore and photograph these trees: to raise awareness and foster appreciation for the forests and their magnificent giants.

Climbing trees is not just for the young, but for the young at heart. Kevin is in his early 70’s and helps us with measuring giant trees.
Steve Pearce/The Tree Projects, Author provided

What makes these trees so special?

Eualypytus regnans, known more commonly as Mountain Ash or Swamp Gum, can grow to 100 metres tall and live for more than 500 years. For a long time this species held the record as the tallest flowering tree. But last year, a 100.8 m tall Yellow Meranti (Shorea faguetiana) in Borneo, claimed the title — surpassing our tallest Eucalypt, named Centrioun, by a mere 30 centimetres.

Centrioun still holds the record as the tallest tree in the southern hemisphere. But five species of Eucalypt also grow above 85 m tall, with many ranking among some of the tallest trees in the world.

It’s not only their height that make these trees special, they’re also the most carbon dense forests in the world, with a single hectare storing more than 1,867 tonnes of carbon.




Read more:
Money can’t buy me love, but you can put a price on a tree


Our giant trees and old growth forests provide a myriad of ecological services such as water supply, climate abatement and habitat for threatened species. A 2017 study from the Central Highlands forests in Victoria has shown they’re worth A$310 million for water supply, A$260 million for tourism and A$49 million for carbon storage.

This significantly dwarfs the A$12 million comparison for native forest timber production in the region.

Chopped wood in a logging coupe.
Chopping down old growth trees doesn’t make economic sense.
Steve Pearce/The Tree Projects, Author provided

Tasmania’s Big Tree Register

Logging organisation Sustainable Timber Tasmania’s giant tree policy recognises the national and international significance of giant trees. To qualify for protection, trees must be at least 85 m tall or at least an estimated 280 cubic metres in stem volume.




Read more:
The Leadbeater’s possum finally had its day in court. It may change the future of logging in Australia


While it’s a good place to start, this policy fails to consider the next generation of big, or truly exceptional trees that don’t quite reach these lofty heights.

That’s why we’ve created Tasmania’s Big Tree Register, an open-source public record of the location and measurements of more than 200 trees to help adventurers and tree-admirers locate and experience these giants for themselves. And, we hope, to protect them.

Last month, three giant trees measuring more than 5 m in diameter were added to the register. But these newly discovered trees are located in coupe TN034G, which is scheduled to be logged this year.

Logging is a very poor economic use for our forests. Native forest logging in Tasmania has struggled to make a profit due to declining demand for non-Forest Stewardship Council certified timber, which Sustainable Timber Tasmania recently failed. In fact, Sustainable Timber Tasmania sustained an eye watering cash loss of A$454 million over 20 years from 1997 to 2017.




Read more:
Summer bushfires: how are the plant and animal survivors 6 months on? We mapped their recovery


The following photos can help show why these trees, as one of the great wonders of the world, should be embraced as an important part of our environmental heritage, not turned to wood chips.

A portrait of an entire tree captured. Its canopy breaches the clouds.

Steve Pearce/The Tree Projects, Author provided

It’s not often you get to see the entirety of a tree in a single photo. This tree above is named Gandalf’s Staff and is a Eucalyptus regnans, measuring 84 m tall.

While Mountain Ash is the tallest species, others in Tasmania’s forests are also breathtakingly huge, such as the Tasmanian blue gum (Eucalyptus globulus) at 92 m, Manna gum (Eucalyptus viminalis) at 91 m, Alpine ash (Eucalyptus delegatensis) at 88 m and the Messmate Stringybark (Eucalyptus obliqua) at 86 m.

A woman appears tiny standing against an enormous felled tree.

Steve Pearce/The Tree Projects, Author provided

This giant tree, pictured above, was a Messmate Stringybark that was felled in coupe, but was left behind for unknown reasons. Its diameter is 4.4 metres. Other giant trees like this were cut down in this coupe, many of which provided excellent nesting habitat for the critically endangered swift parrot.

Nine people sit across the trunk of an enormous tree.
The citizen science group Forestry Watch helps search for and measure giant trees in Tasmania.
Steve Pearce/The Tree Projects, Author provided

Old-growth forests dominated by giant trees are excellent at storing large amounts of carbon. Large trees continue to grow over their lifetime and absorb more carbon than younger trees.

A man wraps a measuring tape around a huge tree trunk, covered in moss.

Steve Pearce/The Tree Projects, Author provided

The tree in the photo above is called Obolus, from Greek mythology, with a diameter of 5.1 m. Names are generally given to trees by the person who first records them, and usually reflect the characteristics of the tree or tie in with certain themes.

For example, several trees in a valley are all named after Lord of the Rings characters, such as Gandalf’s Staff (pictured above), Fangorn and Morannon.

The tops of the giant tree canopies are higher than the clouds.

Steve Pearce/The Tree Projects, Author provided

Giant trees are typically associated with Californian Redwoods or the Giant Sequoias in the US, where tall tree tourism is huge industry. The estimated revenue in 2012 from just four Coastal Redwood reserves is A$58 million dollars per year, providing more than 500 jobs to the local communities.

Few Australians are aware of our own impressive trees. We could easily boost tourism to regional communities in Tasmania if the money was invested into tall tree infrastructure.The Conversation

Jennifer Sanger, Research Associate, University of Tasmania

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

‘It is quite startling’: 4 photos from space that show Australia before and after the recent rain



National Map

Sunanda Creagh, The Conversation

Editor’s note: These before-and-after-images from several sources –NASA’s Worldview application, National Map by Geoscience Australia and Digital Earth Australia – show how the Australian landscape has responded to huge rainfall on the east coast over the last month. We asked academic experts to reflect on the story they tell:


Warragamba Dam, Sydney

Stuart Khan, water systems researcher and professor of civil and environmental engineering.

This map from Digital Earth Australia shows a significant increase in water stored in Lake Burragorang. Lake Burragorang is the name of water body maintained behind the Warragamba Dam wall and the images show mainly the southern source to the lake, which is the Wollondilly River. A short section of the Coxs River source is also visible at the top of the images.

The Warragamba catchment received around 240mm of rain during the second week of February, which produced around 1,000 gigalitres (GL) of runoff to the lake. This took the water storage in the lake from 42% of capacity to more than 80%.

Unlike a typical swimming pool, the lake does not generally have vertical walls. Instead, the river valley runs deeper in the centre and more shallow around the edges. As water storage volumes increase, so does the surface area of water, which is the key feature visible in the images.

Leading up to this intense rainfall event, many smaller events occurred, but failed to produce any significant runoff. The catchment was just too dry. Dry soils act like a sponge and soak up rainfall, rather than allowing it to run off to produce flows in waterways.

The catchment is now in a much wetter state and we can expect to see smaller rainfall events effectively produce further runoff. So water storage levels should be maintained, at least in the short term.

However in the longer term, extended periods of low rainfall and warm temperatures will make this catchment drier.

In the absence of further very intense rainfall events, Sydney will lapse back into drought and diminishing water storages.

This pattern of decreasing storage, broken only by very intense rainfall, can be observed in Sydney’s water storage history.

It is a pattern likely to be exacerbated further in future.


Wivenhoe Dam, Brisbane

@media only screen and (max-width: 450px) {
iframe.juxtapose { height: 320px; width: 100%; }
}
@media only screen and (min-width: 451px) and (max-width: 1460px) {
iframe.juxtapose { height: 400px; width: 100%; }
}

Stuart Khan, water systems researcher and professor of civil and environmental engineering.

Lake Wivenhoe is the body of water maintained behind Wivenhoe Dam wall in southeast Queensland. It is the main water storage for Brisbane as well as much of surrounding southeast Queensland.

This image from National Map shows a visible change in colour from brown to green in the region around the lake. It is quite startling.

This is especially the case to the west of the lake, in mountain range areas such as Toowoomba, Warwick and Stanthorpe. Many of these areas were in very severe drought in January. Stanthorpe officially ran out of water. The February rain has begun to fill many important water storage areas and completely transformed the landscape.

Unfortunately, this part of Australia is highly prone to drought and we can expect to see this pattern recur over coming decades.

Much climate science research indicates more extreme weather events in future. That means more extreme high temperatures, more intense droughts and more severe wet weather.

There are many challenges ahead for Australian water managers as they seek to overcome the inevitable booms and busts of future water availability.




Read more:
Bushfires threaten drinking water safety. The consequences could last for decades


Australia-wide

@media only screen and (max-width: 450px) {
iframe.juxtapose { height: 320px; width: 100%; }
}
@media only screen and (min-width: 451px) and (max-width: 1460px) {
iframe.juxtapose { height: 400px; width: 100%; }
}

Grant Williamson, Research Fellow in Environmental Science, University of Tasmania

It’s clear from this map above, from NASA Worldview, the monsoon has finally arrived in northern Australia and there’s been quite a lot of rain.

On the whole, you can see how rapidly the Australian environment can respond to significant rainfall events.

It’s important to remember that most of that greening up will be the growth of grasses, which respond more rapidly after rain.

The forests that burned will not be responding that quickly. The recovery process will be ongoing and within six months to a year you’d expect to see significant regrowth in the eucalyptus forests.

Other more fire-sensitive vegetation, like rainforests, may not exhibit the same sort of recovery.




Read more:
‘This crisis has been unfolding for years’: 4 photos of Australia from space, before and after the bushfires


Grant Williamson, Research Fellow in Environmental Science, University of Tasmania

This slider from National Map shows both fire impact, and greening up after rain.

On the left – an area west of Cooma on December 24 – you can see the yellow treeless areas, indicating the extent of the drought, and the dark green forest vegetation. This image also shows quite a lot of smoke, as you’d expect.

On the right – the area on February 22 – a lot of those yellow areas are now significantly greener after the rain. However, some of those dark green forest areas are now brown or red, where they have been burnt.

It’s clear there is a long road ahead for recovery of these forests that were so badly burned in the recent fires but they will start resprouting in the coming months.

Grant Williamson is a Tasmania-based researcher with the NSW Bushfire Risk Management Research Hub.The Conversation


Sunanda Creagh, Head of Digital Storytelling, The Conversation

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

‘This crisis has been unfolding for years’: 4 photos of Australia from space, before and after the bushfires



Use the slider tool in the images below to see before and after NASA satellite images of Australia’s fire and drought effects.
NASA

Molly Glassey, The Conversation; Sunanda Creagh, The Conversation, and Wes Mountain, The Conversation

Editor’s note: We pulled four before-and-after-images from NASA’s Worldview application, and asked bushfire researcher Grant Williamson to reflect on the story they tell. Here’s what he told us:


I’ve been studying fires for more than a decade. I use satellite data to try to understand the global and regional patterns in fire – what drives it and how it will shift in the future as our climate and land use patterns change.

When I look at these images I think: this is a crisis we have seen coming for years. It’s something I have been watching unfold.

Look at the sheer scale of it. Seeing this much fire in the landscape in such a broad area, seeing so much severe fire at once, this quantity and concentration of smoke – it is astonishing. I haven’t seen it like this before.

November 1, 2019 and January 3, 2020

@media only screen and (max-width: 450px) {
iframe.juxtapose { height: 400px; width: 100%; }
}
@media only screen and (min-width: 451px) and (max-width: 1460px) {
iframe.juxtapose { height: 590px; width: 100%; }
}

In this comparison, you can see November last year versus now. In the present picture (on the right hand side) you can see a vast quantity of intense fires currently burning right down the eastern seaboard and a huge amount of smoke. It’s been blowing out across toward New Zealand for weeks now.

The scale of the current fires is definitely unusual. In a typical year, you might see, for example, a large fire in the alps (near Mount Kosciuszko) or in the Blue Mountains – but they would be isolated events.

What’s striking here is that there is so much going on at once. I have never seen it like this before.

Black Saturday smoke, Feburary 8, 2009 and the 2019-2020 bushfires smoke, January 3, 2020

This one is comparing two smoke events: one from Black Saturday and one from the current fires. In both cases, huge quantities of smoke was released. Both times, the sort of forest burning is very dense, there is a lot of wet eucalypt forest here which naturally has a high fuel load and that’s creating all that smoke. This type of forest only burns during extreme weather conditions.

Simply due to the scale of it and the fact that it’s been going on so long, I would say the current event is worse than Black Saturday, in terms of the quantity of smoke.

East Australia, 10 years ago vs today

In this image, we can the impact of drought. A decade ago, on the left hand side, it was clearly quite green along eastern Australia. That green shows there is a lot of growing vegetation there: pasture crops, grasses and a very wet environment.

If you compare that to the current year, on the right hand side, you can see it’s now extremely brown and extremely dry. There’s not much in the way of vegetation. That’s a result of drought and high temperatures.

Kangaroo Island, 2 months ago vs today

In this image, you can see Kangaroo Island two months ago on the left hand side, versus today.

The main thing I note here is the drying. The “before” image is so much greener than the “after” image. So there’s a real lack of rainfall that’s driving fire severity in this area. You can really see how much the island has dried out.


This has been an extraordinary year for climate and weather, and that’s manifesting now in these unprecedented bushfires. It’s not over yet.

But what’s important is the lessons we draw from this crisis and doing as much as we can to reduce the risk in future.


Grant Williamson is a Tasmania-based researcher with the NSW Bushfire Risk Management Research Hub.The Conversation

Molly Glassey, Digital Editor, The Conversation; Sunanda Creagh, Head of Digital Storytelling, The Conversation, and Wes Mountain, Multimedia Editor, The Conversation

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

#travelgram: live tourist snaps have turned solo adventures into social occasions



If you didn’t post it, did it even happen?
Shutterstock

Michael James Walsh, University of Canberra; Naomi F Dale, University of Canberra, and Raechel Johns, University of Canberra

In the years since selfie sticks went global, it has become clear that the mobile phone has changed the way we travel.
The ubiquity of social media means tourists can now produce content on the move for their networked audiences to view in close to real time.

Where once we shared slideshows post trip and saved prints and postcards as keepsakes, we now share holiday images and selfies from the road, sea or air — expanding the “tourist gaze” from the traveller to include remote audiences back home.




Read more:
#MeTourism: the hidden costs of selfie tourism


Instagram-worthy

Travelling has gone from a solitary quest to a “social occasion”. As such, gazing is becoming inseparably linked with photography. Taking photos has become habitual, rendering the camera as a way of seeing and experiencing new places.

Travellers take selfies that present both locations and people in aesthetically pleasing and positive ways.

Indeed, the “instagrammability” of a destination is a key motivation for younger people to travel there – even if filters and mirrors have been used to create a less than realistic image.

This transforms the relationship between travellers and their social networks in three important ways: between tourists and destination hosts; between fellow tourists; and lastly, between tourists and those that stay home.

The urge to share travel imagery is not without risk. An Australian couple were released from detention in Iran in October, following their arrest for ostensibly flying a drone without a permit.

Other tourists earned derision for scrambling to post selfies at Uluru before it was closed to climbers.

Meanwhile, there is a sad story behind the newly popular travelgram destination Rainbow Mountain in the Peruvian Andes. It has reportedly only recently emerged due to climate change melting its once snowy peaks.

Testing the effects

To understand the way social media photography impacts travelling, we undertook an exploratory study of overnight visitors at zoological accommodation in lavish surrounds.

We divided 12 participants into two groups. One group was directed to abstain from posting on social media but were still able to take photos. The second group had no restrictions on sharing photos. Though the numbers were small, we gathered qualitative information about engagement and attitudes.

Participants were invited to book at Jamala Wildlife Lodge in Canberra. The visit was funded by the researchers — Jamala Wildlife Lodge did not sponsor the research and the interviewees’ stay at the Lodge was a standard visit. We then conducted interviews immediately after their departure from the zoo, critically exploring the full experience of their stay.

The study confirmed that the desire to share travel pictures in close to real time is strongly scripted into the role of the tourist; altering the way travellers engage with sites they are visiting, but also their sense of urgency to communicate this with remote audiences.

Pics or it didn’t happen

Participants Mandy and Amy were among those instructed to refrain from posting pictures to social media while at the zoo. They described having to refrain from social media use as a disappointment, even though it seemed to further their engagement.

Interviewer: Did you look at your social media throughout your stay or did you refrain?

Mandy: A bit yeah. But even then, probably not reading it as much as I often would. I don’t think I commented on anything yeah.

Amy: Even today when we put something up [after staying at the Zoo] about the things we’d done today and only a few people had liked it, there was that little bit of disappointment that ‘Oh more people haven’t liked my post.’ Where we didn’t have that for the previous 24 hours [because of the experiment] … because nobody knew about it.

The tension between capturing and experiencing travel is ever-present.
Shutterstock

The desire for social media recognition resumed after leaving the zoo. For Michelle, posting after the experience presented new concerns:

Interviewer: How did you feel about not being able to post?

Michelle: Spanner in the works! For me personally not being able to post was a negative experience because I wanted to show people what we’re doing, when we’re doing it.

And I also feel, like a couple of people knew we were going to the zoo, right, and knew that we couldn’t use social media. So, when I eventually post it, they’re going to go, ‘She’s been hanging on to those and now she’s posting them and that’s just a bit weird.’ Like, to post it after the event. Everyone normally posts it in real time.

Later, Michelle commented that withholding content from posting to social media also diminished a part of the experience itself:

I sort of feel like if we don’t share the photos it’s like a tree fell down in the forest and no one heard it, like, we’ve had this amazing experience and if I don’t share them, then no one’s going to know that we had this experience, you know, apart from us.

Tips garnered from travelgrammers fill lots of online video tutorials.

Centre Stage

Digital photography and social media transform the relationship between the travelling self and its audience, as individuals have an expanded — and potentially diversified — audience.

Selfies in tourist contexts reflect the tourist gaze back at the tourist, rather than outward.

The perfect digital postcard now incorporates the self centrestage. As one participant suggested:

Shannon: It almost feels like it’s kind of an expected behaviour when you are doing something touristy … We’ve actually had tour guides before … kind of a bit disappointed if you don’t take a photograph.

The purpose of photography has shifted from a memory aid to a way of sharing experience in the moment. There is tension now between the need to capture tourist experiences for digital sharing and individual engagement in the tourist activity. Decrying the desire to use photography as a way of communicating experience will not constructively address this tension.

To ensure tourism sustainability, and engagement with their target market, tourism providers need to explore better ways to manage travellers’ face-to-face and digital engagement.

Digital engagements have become a defining part of travel, and organisations should be encouraged to promote online sharing of experiences — phone charging stations and photo competitions were two suggestions offered by our interviewees.

In contrast, device-free days or activities could be another way to encourage face-to-face engagement and prompt tourists to be more considered with their online sharing.The Conversation

Michael James Walsh, Assistant Professor Social Science, University of Canberra; Naomi F Dale, Associate Professor of Management, University of Canberra, and Raechel Johns, Head of the Canberra Business School and Professor of Marketing and Service Management, University of Canberra

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

Here’s how your holiday photos could help save endangered species



Zephyr_p/Shutterstock

Kasim Rafiq, Liverpool John Moores University

Animal populations have declined on average by 60% since 1970, and it’s predicted that around a million species are at risk of extinction. As more of the Earth’s biodiversity disappears and the human population grows, protected landscapes that are set aside to conserve biodiversity are increasingly important. Sadly, many are underfunded – some of Africa’s most treasured wildlife reserves operate in funding deficits of hundreds of millions of dollars.

In unfenced wilderness, scientists rarely have an inventory on the exact numbers of species in an area at a particular time. Instead they make inferences using one of many different survey approaches, including camera traps, track surveys, and drones. These methods can estimate how much and what kind of wildlife is present, but often require large amounts of effort, time and money.

Camera traps are placed in remote locations and activated by movement. They can collect vast quantities of data by taking photographs and videos of passing animals. But this can cost tens of thousands of dollars to run and once in the wild, cameras are at the mercy of curious wildlife.

Track surveys rely on specialist trackers, who aren’t always available and drones, while promising, have restricted access to many tourism areas in Africa. All of this makes wildlife monitoring difficult to carry out and repeat over large areas. Without knowing what’s out there, making conservation decisions based on evidence becomes almost impossible.

Citizen science on Safari

Tourism is one of the fastest growing industries in the world – 42m people visited sub-Saharan Africa in 2018 alone. Many come for the unique wildlife and unknowingly collect valuable conservation data with their phones and cameras. Photographs on social media are already being used to help track the illegal wildlife trade and how often areas of wilderness are visited by tourists.

Despite this, tourists and their guides are still an overlooked source of information. Could your holidays snaps help monitor endangered wildlife? In a recent study, we tested exactly this.

Partnering with a tour operator in Botswana, we approached all guests passing through a safari lodge over three months in the Okavango Delta and asked them if they were interested in contributing their photographs to help with conservation. We provided those interested with a small GPS logger – the type commonly used for tracking pet cats – so that we could see where the images were being taken.

We then collected, processed, and passed the images through computer models to estimate the densities of five large African carnivore species – lions, spotted hyaenas, leopards, African wild dogs and cheetahs. We compared these densities to those from three of the most popular carnivore survey approaches in Africa – camera trapping, track surveys, and call-in stations, which play sounds through a loudspeaker to attract wildlife so they can be counted.

The tourist photographs provided similar estimates to the other approaches and were, in total, cheaper to collect and process. Relying on tourists to help survey wildlife saved up to US$840 per survey season. Even better, it was the only method to detect cheetahs in the area – though so few were sighted that their total density couldn’t be confirmed.

Thousands of wildlife photographs are taken every day, and the study showed that we can use statistical models to cut through the noise and get valuable data for conservation. Still, relying on researchers to visit tourist groups and coordinate their photograph collection would be difficult to replicate across many areas. Luckily, that’s where wildlife tour operators could come in.

Tour operators could help collect tourist images to share with researchers. If the efforts of tourists were paired with AI that could process millions of images quickly, conservationists could have a simple and low-cost method for monitoring wildlife.

Tourist photographs are best suited for monitoring large species that live in areas often visited by tourists – species that tend to have high economic and ecological value. While this method perhaps isn’t as well suited to smaller species, it can still indirectly support their conservation by helping protect the landscapes they live in.

The line between true wilderness and landscapes modified by humans is becoming increasingly blurred, and more people are visiting wildlife in their natural habitats. This isn’t always a good thing, but maybe conservationists can use these travels to their advantage and help conserve some of the most iconic species on our planet.The Conversation

Kasim Rafiq, Postdoctoral Researcher in Wildlife Ecology and Conservation, Liverpool John Moores University

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