Animals With White Winter Camouflage Could Struggle to Adapt to Climate Change
By Daisy Dunne
Animals that turn white in the winter to hide themselves in snowy landscapes could struggle to adapt to climate change, research suggests.
A new study finds that declining winter snowfall near the Arctic could have varying effects on the survival of eight mammal species that undergo a seasonal color molt from summer brown to winter white each year.
Species most at risk of standing out against the snow include mountain hares, snowshoe hares and short-tailed weasels. Without blending into the background, these animals could find it harder to hunt prey or hide from predators.
However, there are some parts of the northern hemisphere where color-changing mammals could have a better chance of adapting to climate change, the study finds.
These "rescue" hotspots, which include northern Scotland and parts of North America, should be protected by conservationists to give color-changing animals the best chance of adapting to future climate change, the lead author told Carbon Brief.
Visual camouflage is a vital tactic used by both predatory animals, who must hunt while avoiding detection, and their prey, who must hide to avoid being eaten.
But in parts of the northern hemisphere, the changing of the seasons offers a unique challenge to those trying to camouflage with their surroundings.
In winter, when the landscape is snowy and barren, animals with white coloring find it easiest to blend in. However, when spring arrives and snow is replaced with brown soils and growing vegetation, those with mottled brown coloring tend to find it easier to escape detection.
One solution to this problem, used by a range of animals, is to undergo a seasonal moult from brown to white each year.
Scientists have recorded 21 mammal and bird species using this color-changing tactic, including the Siberian hamster, the collared lemming and the willow ptarmigan.
The new study, published in Science, focuses on how climate change could alter the survival chances of eight of these species.
Climate change is causing a decline in winter snow cover in Arctic regions, along with the earlier onset of spring each year. This decline could be causing a "mismatch" between animals with white coats and the snowless ground, explains lead author Prof. Scott Mills, vice president of research for global change and sustainability at the University of Montana. He told Carbon Brief:
"All of these species literally live or die by the effectiveness of their camouflage, which evolution has exquisitely crafted to match the average duration of winter snow."
This mismatch could make some animals, such as hares, more vulnerable to predators, he said. It could also make it harder for predators, such as the arctic fox, to effectively hunt their prey. Mills said:
"One thing to realize is that all 21 of these species, including the carnivores, are prey: Arctic fox get clobbered by golden eagles, weasels are killed by foxes, coyotes, and raptors. For the hares and rodents, tasty snacks for multiple predators, camouflage is everything."
Arctic fox (Alopex lagopus) in snow, Churchill, Manitoba, Canada, North America. Robertharding / Alamy Stock Photo
Charting Color Change
For the study, the researchers first collected coat color and location data for more than 2,500 live animals and museum specimens spanning 60 countries.
They then analyzed this data using modeling to study the molting behavior of animals living in different parts of the world.
The researchers found that, within one species, not all individuals will molt in the winter.
The chances of an animal molting depend on the landscape in which they live. The more snowy the landscape, the higher the chance an animal will turn white in the winter.
This is shown on the chart below, where the number of snow-covered days per year is plotted against the likelihood of turning white in the winter for the Japanese hare (dark blue), the white-tailed jackrabbit (light blue), the least weasel (yellow) and the long-tailed weasel (red).
The probability of a colour-changing mammal having a white winter coat in regions with 0-320 days of snowfall per year. Results are shown for the Japanese hare (dark blue), the white-tailed jackrabbit (light blue), the least weasel (yellow) and the long-tailed weasel (red). Mills et al. (2018)
The chart also includes a "broad polymorphic zone." A "polymorphic zone" is a term used to describe regions where the probability of having either a brown or white winter coat is close to equal.
In these "zones," mammals could have the best chance of adapting to declining snowfall conditions, Mills said. That is because, in these areas, a proportion of each species do not turn white in the winter and are therefore more able to blend in with snowless environments.
These brown-coated animals will be more likely to survive winters with less snow cover and pass on their genes to their offspring. Over time, this would increase the proportion of animals with brown winter coats, allowing the population to adapt—and ultimately survive—in environments with less snow.
The maps below show where the polymorphic zone of two or more species overlap. On the charts, red shows where the zones of two species overlap, while brown shows areas where the zones of three species overlap.
Regions in North America (A) and Eurasia (B) with polymorphic zones in winter coat colour for more than two species (red) and more than three species (brown). Mills et al. (2018)
The charts show that parts of the U.S., Canada and Scotland show the largest overlap.
These regions could be considered "evolutionary rescue zones" where a number of color-changing mammal species could be able to adapt to declining snowfall, said Mills:
"Because areas with the most [coat color] variation evolve most quickly, these 'polymorphic' zones emerge as hotspots for rapid evolutionary response to climate change. Here in the polymorphic zones the populations are most likely to rapidly evolve towards winter brown, and to disperse the winter brown genes out into the adjacent winter white populations."
The species whose range most commonly fall into these zones include the arctic fox, the white-tailed jackrabbit and the long-tailed weasel, the research finds. These species may have the best chance of adapting to declining winter snowfall, Mills said, but it is still too soon to tell what their chances of survival could be:
"To really evaluate risk to various species will require a lot more fieldwork and genetic analyses for other species, like we've been doing with snowshoe hares. We're starting to work with weasels and Arctic fox, but I really hope that this paper initiates researchers around the world to start investigating coat color mismatch."
Picture of Change
The findings should provide "yet another push to policymakers" to reduce the "global carbon footprint," Mills said:
"I hope that the picture of white animals on brown snowless ground 'paints a thousand words' that shows that with continued human-caused climate change and reduction in snow duration, winter white animals on a brown snowless winter background will be in trouble."
The research also shows that conserving "evolutionary rescue zones" could help wildlife to survive future climate change, Mills said:
"I hope it also helps [policymakers] see that other short-term, yet effective, options are available for protecting wildlife in the face of climate change."
The new study provides striking evidence of how climate change could drive the evolution of new characteristics in animals, said Prof. Innes Cuthill, a behavioral ecologist with specialist knowledge of camouflage from the University of Bristol, who was not involved in the study. He told Carbon Brief:
"We have long known that evolution can be rapid, from detailed case studies of particular species in particular locations, but the new research is a great example of how to capture the 'big picture' of evolution of colouration in time and space."
Reposted with permission from our media associate Carbon Brief.
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By Gwen Ranniger
In the midst of a pandemic, sales of cleaning products have skyrocketed, and many feel a need to clean more often. Knowing what to look for when purchasing cleaning supplies can help prevent unwanted and dangerous toxics from entering your home.
1. Fragrance – Avoid It<p>One of the fastest ways to narrow down your product options is immediately eliminating any product that promotes a fragrance, or parfum. That scent of "fresh breeze" or lemon might initially smell good, but the fragrance does not last. What does last? The concoction of various undisclosed and unregulated chemicals that created that fragrance.</p><p>Many fragrances contain phthalates, which are linked to many health risks including reproductive problems and cancer.</p>
2. With Bleach? Do Without<p>Going scent-free should have narrowed down your options substantially – now, check the front of the remaining packaging. Any that include ammonia or chlorine bleach ought to go, as these substances are irritating and corrosive to your body. While bleach is commonly known as a powerful disinfectant, there are safer alternatives that you can use in your home, such as sodium borate or hydrogen peroxide.</p><p>While you're at it, check if there are any warnings on the label – "flammable," "use in ventilated area," etc. – if the product is hazardous, that's a red flag and should be avoided.</p>
3. Check the Back Label<p>Flip to the back of the remaining contenders and check out that ingredient list. Less is more, here. Opt for a shorter ingredient list with words you recognize and/or can pronounce.</p><p>You may notice many products do not have ingredient lists – while this doesn't necessarily mean they contain toxic ingredients, transparency is key. Feel free to look up a list online, or stick to products that are open about their ingredients.</p>
4. Ingredients to Avoid<p>We already mentioned that cleaners containing fragrance or parfum, and bleach or ammonia should be avoided, but there are other ingredients to look out for as well.</p><ul><li>Quaternary ammonium "quats" – lung irritants that contribute to asthma and other breathing problems. Also linger on surfaces long after they've been cleaned.</li><li>Parabens – Known hormone disruptor; can contribute to ailments such as cancer</li><li>Triclosan – triclosan and other antibacterial chemicals are registered with the EPA as pesticides. Triclosan is a known hormone disruptor and can also impact your immune system.</li><li>Formaldehyde – Causes irritation of eyes, nose, and throat; studies suggest formaldehyde exposure is linked with certain varieties of cancer. Can be found in products or become a byproduct of chemical reactions in the air.</li></ul>
Cleaning Products and Toxics: The Bottom Line<p>Do your research. There are many cleaning products available, but taking these steps will drastically reduce your options and help keep your home toxic-free. Protecting your home from bacteria and viruses is important, but make sure you do so in a way that doesn't introduce other health risks into the home.</p><p><em>Reposted with permission from </em><em><a href="https://www.ehn.org/how-to-shop-for-cleaning-products-while-avoiding-toxics-2648130273.html" target="_blank">Environmental Health News</a>. </em><a href="https://www.ecowatch.com/r/entryeditor/2649054624#/" target="_self"></a></p>
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Returning the ‘Three Sisters’ – Corn, Beans and Squash – to Native American Farms Nourishes People, Land and Cultures
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Historians know that turkey and corn were part of the first Thanksgiving, when Wampanoag peoples shared a harvest meal with the pilgrims of Plymouth plantation in Massachusetts. And traditional Native American farming practices tell us that squash and beans likely were part of that 1621 dinner too.
Abundant Harvests<p>Historically, Native people throughout the Americas bred indigenous plant varieties specific to the growing conditions of their homelands. They selected seeds for many different traits, such as <a href="https://emergencemagazine.org/story/corn-tastes-better/" target="_blank" rel="noopener noreferrer">flavor, texture and color</a>.</p><p>Native growers knew that planting corn, beans, squash and sunflowers together produced mutual benefits. Corn stalks created a trellis for beans to climb, and beans' twining vines secured the corn in high winds. They also certainly observed that corn and bean plants growing together tended to be healthier than when raised separately. Today we know the reason: Bacteria living on bean plant roots pull nitrogen – an essential plant nutrient – from the air and <a href="http://www.tilthalliance.org/learn/resources-1/almanac/october/octobermngg" target="_blank" rel="noopener noreferrer">convert it to a form that both beans and corn can use</a>.</p><p>Squash plants contributed by shading the ground with their broad leaves, preventing weeds from growing and retaining water in the soil. Heritage squash varieties also had spines that discouraged deer and raccoons from visiting the garden for a snack. And sunflowers planted around the edges of the garden created a natural fence, protecting other plants from wind and animals and attracting pollinators.</p><p>Interplanting these agricultural sisters produced bountiful harvests that sustained large Native communities and <a href="http://dx.doi.org/10.1353/eam.2015.0016" target="_blank">spurred fruitful trade economies</a>. The first Europeans who reached the Americas were shocked at the abundant food crops they found. My research is exploring how, 200 years ago, Native American agriculturalists around the Great Lakes and along the Missouri and Red rivers fed fur traders with their diverse vegetable products.</p>
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