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Messing with Mother Nature: The Macquarie Island Ecosystem

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The story of the Macquarie Island ecosystem may remind you of the song about the woman who swallowed a fly. The island was exploited mercilessly, but various plans to repair the damage had their own unintended consequences. Introducing a non-native species to control another invasive species can backfire and escalate the situation to ridiculous and tragic levels.

Macquarie Island, part of the Australian state of Tasmania, is a UNESCO World Heritage Site. The island lies in a spot where tectonic plates meet, about halfway between New Zealand and Antarctica, and has unique geological significance. Macquarie is a breeding ground for aquatic life, particularly elephant seals and royal penguins. It is also home to other seals and penguins, several species of albatross and other sea birds, plus a few dozen wildlife scientists and park rangers who work there on a temporary basis. The seals and penguins had no natural enemies on the island until Europeans arrived in 1810. Since then, humans have hatched schemes to either exploit or repair the Macquarie Island ecosystem. Most of these schemes caused further problems.

Polynesians may have inhabited the island in the distant past, but there were no people there when it was discovered by Captain Frederick Hasselborough of the ship Perseverance in 1810. He was looking for seals, and Macquarie Island proved to be a bounty. Fur seals and then elephant seals were hunted almost to extinction on the island. When the seal supply ebbed, penguins were hunted for their oil. Photograph by Wikipedia user Hullwarren.

Meanwhile, any place on earth that was visited by exploring ships ran the risk of introducing rats to the ecosystem. Macquarie Island had no rodents before the seal hunting began, but mice and rats began to flourish soon afterward. Photograph by Wikipedia user Kilessan.

Seafarers knew how to control rats. Most ships had a cat or two just for this purpose. Within ten years of the commencement of sealing, there were feral cats on the island. While rats are omnivores, they only become predators when the easier food is in short supply. Some species of fur seals eat penguins, but the cats were the first land-based true predators on the island. In addition to rodents, the cats ate seabirds.

William Elder of the Otago Whaling Company brought rabbits to the island as a food source in 1870. They, of course, bred like rabbits. Despite being eaten by both cats and people, the wild rabbit population soared to 130,000 on the tiny island within 100 years. Rabbits ate the grass, which allowed erosion to damage the island, and subsequent storms and tremors destroyed erosion-damaged penguin breeding grounds.

look out for dangers

Stoats, a species of weasel, were brought in to control the rabbits on Macquarie Island and in New Zealand soon after the feral population of rabbits became established. Soon the stoat population was helping itself to seabirds and their eggs. Photograph by Flickr user Markus Hoppe.

Possums

As possums were introduced to New Zealand to raise for fur, they made their way to Macquarie Island as well. The cats weren't all that interested in possums, so they bred to the point of becoming pests along with the other introduced species. Photograph by Flickr user Peter Firminger.

As the populations of non-native species grew on Macquarie Island, a time bomb was ticking. When the balance of predators and food supplies reaches a certain point, predators will turn to different species to eat. The Macquarie parakeet flourished on the island until around 1880, when the rabbit supply allowed the number of feral cats to explode, and the cats branched out to eat parakeets. The last Macquarie parakeet was sighted in 1891, and the species became extinct. Of course, the feral cats, while still eating rabbits, went after other native birds. Shown is the red-crowned parakeet of New Zealand, which is similar in appearance to the Macquarie parakeet. Photograph by Thomas Mattern.

Skeleton of sea-elephant & Harold Hamilton

When Macquarie Island began to be used as a science station in the 20th century, seal hunting met its end. Antarctic explorer Douglas Mawson spearheaded the drive to declare the island a nature reserve, and it was his efforts that forced the end of sealing. The last load of oil was taken off the island in 1919. In 1933, Macquarie Island became an official wildlife preserve.

Sea elephants and royal penguins, Macquarie Island, c. 1950s

Meanwhile, as the seal and penguin population slowly began to recover, the island was still overrun with rabbits. Australian scientists hatched a plan to control rabbits (which were out of control in all of Australia) by introducing the virus Myxoma which causes Myxomatosis, a disease fatal to rabbits. First, rabbit fleas were brought to the island in 1968 (yet another invasive species) as a future carrier of the virus. The environment being what it was, the establishment of fleas wasn't as successful as had been hoped. The virus itself was introduced on the island in 1978. The rabbit population plunged from 130,000 to around 10,000, which is the good news. The bad news is that the remaining rabbits were the ones that were immune to the disease.

With most of the rabbits gone, the estimated 500 feral cats on Macquarie Island knew what to do. They ate the native seabirds -up to 60,000 of them every year. The government of Australia decided the only thing to do at that point was to eliminate the feral cats. Cat hunting was encouraged beginning in 1985. The Tasmanian government intensified the program in 1997, using traps and dogs to catch the cats. The last feral cat was caught in 2000. No more cats on Macquarie Island.

Problem solved? Oh no! With the cats gone, those 10,000 rabbits who were immune to the Myxoma virus began to multiply again. The Tasmanian government came to the conclusion that all non-native species had to be eradicated at the same time. That would be the only way to restore the nature preserve to its intended use for the original sea animals. The current eradication program began in 2010. But even that has its problems. The poison bait used to eliminate invasive mammals is working its way through the ecosystem. Just last year, we learned of the death of thousands of seabirds that ate the carcasses of the poisoned mammals. Albatross photograph by Wikipedia user Hullwarren.

Will Macquarie Island ever return to its 18th-century ecological state? Let's hope. Photograph by Wikipedia user Hullwarren.

See also: Messing with Mother Nature: 5 Cautionary Tales

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iStock // Ekaterina Minaeva
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technology
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Health
200 Health Experts Call for Ban on Two Antibacterial Chemicals
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iStock

In September 2016, the U.S. Food and Drug Administration (FDA) issued a ban on antibacterial soap and body wash. But a large collective of scientists and medical professionals says the agency should have done more to stop the spread of harmful chemicals into our bodies and environment, most notably the antimicrobials triclosan and triclocarban. They published their recommendations in the journal Environmental Health Perspectives.

The 2016 report from the FDA concluded that 19 of the most commonly used antimicrobial ingredients are no more effective than ordinary soap and water, and forbade their use in soap and body wash.

"Customers may think added antimicrobials are a way to reduce infections, but in most products there is no evidence that they do," Ted Schettler, science director of the Science and Environmental Health Network, said in a statement.

Studies have shown that these chemicals may actually do more harm than good. They don't keep us from getting sick, but they can contribute to the development of antibiotic-resistant bacteria, also known as superbugs. Triclosan and triclocarban can also damage our hormones and immune systems.

And while they may no longer be appearing on our bathroom sinks or shower shelves, they're still all around us. They've leached into the environment from years of use. They're also still being added to a staggering array of consumer products, as companies create "antibacterial" clothing, toys, yoga mats, paint, food storage containers, electronics, doorknobs, and countertops.

The authors of the new consensus statement say it's time for that to stop.

"We must develop better alternatives and prevent unneeded exposures to antimicrobial chemicals," Rolf Haden of the University of Arizona said in the statement. Haden researches where mass-produced chemicals wind up in the environment.

The statement notes that many manufacturers have simply replaced the banned chemicals with others. "I was happy that the FDA finally acted to remove these chemicals from soaps," said Arlene Blum, executive director of the Green Science Policy Institute. "But I was dismayed to discover at my local drugstore that most products now contain substitutes that may be worse."

Blum, Haden, Schettler, and their colleagues "urge scientists, governments, chemical and product manufacturers, purchasing organizations, retailers, and consumers" to avoid antimicrobial chemicals outside of medical settings. "Where antimicrobials are necessary," they write, we should "use safer alternatives that are not persistent and pose no risk to humans or ecosystems."

They recommend that manufacturers label any products containing antimicrobial chemicals so that consumers can avoid them, and they call for further research into the impacts of these compounds on us and our planet.

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