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Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0
Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0

Japanese Bears are Moving (and Conserving) Cherry Trees with Poop

Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0
Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0

We know Earth’s climate is changing rapidly, but we don’t fully know what those changes will mean for our planet and its inhabitants. Every organism interacts with those around it, making it hard to trace or predict the effects of pollution, species loss, and global warming. For example: a recent report published in the journal Current Biology shows that bears and their poop are slowly moving the cherry trees up mountains near Tokyo, Japan, and out of the damaging heat of lower altitudes. 

Plants, of course, don’t have legs (stick with us, this is going somewhere). Instead, they rely on the wind and on organisms with legs, wings, and fins to pollinate their flowers, eat their fruit, and carry the seeds to new locations

A team of Japanese researchers wondered how the behavior of these seed-dispersing animals might affect a plant’s ability to withstand climate change. They focused their study on the wild cherry tree (Prunus verecunda) for two reasons: first, botanists have predicted that the tree, which grows in temperate regions, will be especially vulnerable to rising temperatures; and second, the tree’s fruit are a favorite of local animals, especially the moon bear (Ursus thibetanus)

To track the plants’ movement, the scientists compared stable oxygen isotopes in their seeds. Every tree has these isotopes, which it gets from its parent tree while it’s still a seed. The isotope ratios vary by altitude, which makes them useful in geotagging. If a pooped-out seed on a mountain has a ratio associated with a lower altitude, it means the seed must have been carried up. (Unlike some species, P. verecunda seeds are exclusively dispersed by animals.) 

The researchers found that mountain-climbing bears brought cherry trees with them, often transporting seeds several hundred meters above their parent trees. The trees took root at new altitudes, in climates just slightly cooler than those down below. But this slight difference in temperature, around 3°F, might be enough to keep the trees safe. 

This is good news for the wild cherry; not all trees will be so lucky. P. verecunda happens to be a spring-fruiting tree, which means that bears stop and snack on its fruit on their journey up the mountain. The reverse would be true for autumn-fruiting trees: their seeds would be carried to lower, less tolerable altitudes. 

"The most important implication of our study on a warming planet is that seed dispersal direction can be asymmetric," lead author Shoji Naoe of the Forestry and Forest Products Research Institute said in a press statement. "Most previous studies have predicted future plant distributions under global warming based on the simple relationships between present plant distribution and environmental factors there, assuming that there are no seed dispersal limitations and no bias in dispersal direction. However, our study indicates that predicting future plant distributions can be very uncertain without considering the seed dispersal process that determines plant movement." 

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NUS Environmental Research Institute, Subnero
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Researchers in Singapore Deploy Robot Swans to Test Water Quality
NUS Environmental Research Institute, Subnero
NUS Environmental Research Institute, Subnero

There's something peculiar about the new swans floating around reservoirs in Singapore. They drift across the water like normal birds, but upon closer inspection, onlookers will find they're not birds at all: They're cleverly disguised robots designed to test the quality of the city's water.

As Dezeen reports, the high-tech waterfowl, dubbed NUSwan (New Smart Water Assessment Network), are the work of researchers at the National University of Singapore [PDF]. The team invented the devices as a way to tackle the challenges of maintaining an urban water source. "Water bodies are exposed to varying sources of pollutants from urban run-offs and industries," they write in a statement. "Several methods and protocols in monitoring pollutants are already in place. However, the boundaries of extensive assessment for the water bodies are limited by labor intensive and resource exhaustive methods."

By building water assessment technology into a plastic swan, they're able to analyze the quality of the reservoirs cheaply and discreetly. Sensors on the robots' undersides measure factors like dissolved oxygen and chlorophyll levels. The swans wirelessly transmit whatever data they collect to the command center on land, and based on what they send, human pilots can remotely tweak the robots' performance in real time. The hope is that the simple, adaptable technology will allow researchers to take smarter samples and better understand the impact of the reservoir's micro-ecosystem on water quality.

Man placing robotic swan in water.
NUS Environmental Research Institute, Subnero

This isn't the first time humans have used robots disguised as animals as tools for studying nature. Check out this clip from the BBC series Spy in the Wild for an idea of just how realistic these robots can get.

[h/t Dezeen]

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iStock
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science
There May Be an Ancient Reason Why Your Dog Eats Poop
iStock
iStock

Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]

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