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    Wildfires launch microbes into the air. How big of a health risk is that?

    As climate change brings more wildfires to the western United States, a rare fungal infection has also been on the rise. Valley fever is up more than sixfold in Arizona and California from 1998 to 2018, according to the U.S. Centers for Disease Control and Prevention.

    Valley fever causes coughs, fevers and chest pain and can be deadly. The culprit fungi, members of the genus Coccidioides, thrive in soils in California and the desert Southwest. Firefighters are especially vulnerable to the disease. Wildfires appear to stir up and send the soil-loving fungi into the air, where they can enter people’s lungs.

    If the fires are helping these disease-causing fungi to get around, could they be sending other microorganisms aloft as well? Leda Kobziar, a fire ecologist at the University of Idaho in Moscow, decided in 2015 to see if she could find out if and how microorganisms like bacteria and fungi are transported by wildfire smoke — and what that might mean for human and ecological health.

    By 2018, Kobziar had launched a new research field she named “pyroaerobiology.” First, she asked if microorganisms can even survive the searing heat of a wildfire. The answer, she found, is yes. But how far bacteria and fungi can travel on the wind and in what numbers are two of the many big unknowns.

    With a recent push to spark new collaborations and investigations, Kobziar hopes that scientists will start to understand how important smoke transport of microbes may be.

    For Kobziar’s earliest studies in 2015, her students held up petri dishes on long poles to collect samples of the smoky air near a prescribed fire at the University of Florida experimental forest.L. Kobziar

    Today, Kobziar and colleagues use drones to collect samples at the University of Florida experimental forest.L. Kobziar

    Invisible but pervasive

    Air may look clear, but even in the cleanest air, “hundreds of different bacteria and fungi are blowing around,” says Noah Fierer, a microbiologist at the University of Colorado Boulder.

    Winds whisk bacteria and fungi off all kinds of surfaces — farm fields, deserts, lakes, oceans. Those microbes can rise into the atmosphere to travel the world. Scientists have found microorganisms from the Sahara in the Caribbean, for example.

    Many (if not most) of the airborne microorganisms, including bacteria, fungi and viruses, are not likely to cause disease, Fierer notes. But some can make people sick or cause allergic reactions, he says. Others cause diseases in crops and other plants.

    The billions of tons of dust that blow off of deserts and agricultural fields each year act as a microbial conveyor belt. In places like Arizona, people know to be alert for symptoms of airborne illnesses like Valley fever after dust storms, since infections increase downwind afterward. If dust can move living microorganisms around the globe, it makes sense that particulates in smoke would be microbe movers too, Kobziar says — assuming the microscopic life-forms can survive a fire and a spin in the atmosphere.

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    Tiny travelers

    Rising temperatures and worsening droughts have led to longer and more intense wildfire seasons across the West (SN: 9/26/20, p. 12). Breathing wildfire smoke makes people sick (SN Online: 9/18/20), even causing premature death from heart and lung illnesses. In the United States, wildfire smoke causes about 17,000 premature deaths per year — a number projected to double by 2100, according to a 2018 study in GeoHealth.

    In other parts of the world, the effects are far worse. In 2015, smoke from illegal land-clearing blazes plus wildfires in Indonesia killed an estimated 100,000 people across Southeast Asia, according to a 2016 report in Environmental Research Letters. Blame is usually attributed to particulate matter — organic and inorganic particles suspended in the air, including pollen, ash and pollutants. But scientists and health officials are increasingly realizing that there’s an awful lot we don’t know about what else in smoke is affecting human health.

    The most intense fires, the ones that burn the hottest and release the most energy, can create their own weather systems and send smoke all the way into the stratosphere, which extends about 50 kilometers above Earth’s surface (SN: 9/14/19, p. 12). Once there, smoke can travel around the world just as ash from explosive volcanoes does. Kobziar’s team and others provided compelling evidence in the February ISME Journal that live, viable microorganisms can be carried in smoke plumes — at least near Earth’s surface if not higher up.

    The Fire and Smoke Model Evaluation Experiment, or FASMEE, team set this high-intensity crown fire in the aspens of Fishlake National Forest, Utah, in 2019. The team used a drone to measure microbial concentrations in this smoke.L. Kobziar

    In 2015, while at the University of Florida in Gainesville, Kobziar and her students collected the first air samples for this line of research during a series of planned, or prescribed, burns that Kobziar set at the school’s experimental forest. The group arrived at the forest armed with 3-meter-long poles topped with petri dishes to collect samples from the air.

    Before any fires were set, the team held the petri dishes in the air for three minutes to collect air samples as a pre-fire baseline. Then Kobziar, a certified prescribed burn manager (or as she calls it, a “fire lighter”), lit the fires. Once flames were spreading at a steady rate and smoke was billowing, students hoisted new petri dishes into the smoke, almost as if aiming a marshmallow on a stick at a campfire. This allowed them to collect smoky air samples to compare to the “before” samples.

    Back in the lab, in a dark room held at a constant 23° Celsius, both the baseline and smoky petri dishes — covered and sealed from further contamination — were left for three days. Microbes began to grow. Far more bacterial and fungal species populated the smoky petri dishes than the baseline dishes, indicating that the fire aerosolized some species that weren’t in the air before the fire, Kobziar says.

    These petri dishes show bacterial and fungal colonies that grew after five minutes of exposure to smoke. The smoke came from pine needles collected from Florida then burned in Kobziar’s University of Idaho lab.L. Kobziar

    These petri dishes show bacterial and fungal colonies that grew after five minutes of exposure to smoke. The smoke came from pine needles collected from Florida then burned in Kobziar’s University of Idaho lab.L. Kobziar

    “We were stunned at how many different microbial colonies survived the combustion environment and grew in the smoke samples, compared to very few in the ambient air,” she says. Based on DNA tests, Kobziar’s team identified 10 types of bacteria and fungi; some are pathogenic to plants, one is an ant parasite and one helps plants absorb nutrients. “This was the moment when the way we thought about smoke was completely transformed,” she says.

    In 2017, after Kobziar had moved to Idaho, her team collected soil samples from the University of Idaho’s experimental forest and burned them — this time, in the lab. As smoke unfurled above the burning soils, the researchers collected air samples, and again, sealed them and put them in a dark, warm room to see what would grow. After a week, lots of different microbes, including fungi, had multiplied into colonies on the plates, the researchers reported in 2018 in Ecosphere.

    Alive and on the move

    Since then, Kobziar’s team has collected more air samples during prescribed burns of varying intensities in Florida, Idaho, Montana and Utah, joining forces with the U.S. Forest Service Fire and Smoke Model Evaluation Experiment, or FASMEE, team. For her students’ safety, she’s replaced the poles and petri dishes with drones. She sends a single drone carrying a vacuum pump with a filter into smoke plumes at varying altitudes up to 120 meters, the team described in the journal Fire in 2019.

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    The FASMEE team set up a mobile research lab on the fire line at Fishlake National Forest. Drone operators sent the machines into the smoke to collect samples, back to the “lab” to return samples, then back up to collect more multiple times. They found about 1,000 different microbe types in the smoke.

    In every experiment, the researchers have found living bacteria and fungi, many of which were not found in any of the air samples taken before the fires. In Utah smoke samples, for example, the FASMEE team found more than 100 different fungi that were not in the air before the fire, Kobziar says. Findings included species of Aspergillus, which can cause fevers, coughs and chest pain, as well as Cladosporium, molds that can cause allergies and asthma.

    Whether any of these microorganisms pose a danger to people is unknown, Kobziar cautions. Her team has not tested whether the microbial species that survive the heat can cause disease, but the group plans to do so.

    The research in Utah revealed another crucial fact: These microbes are tough. Even in smoke from high-intensity, high-temperature fires, about 60 percent of bacterial and fungal cells are alive, Kobziar says. Roughly 80 percent seem to survive lower-intensity fires, which is “about the same percentage of cells we’d expect to see alive in ambient air conditions,” she says. Thus, these first studies show that fires are sending live bacteria and fungi into the air. And that they can travel at least 120 meters above the ground and close to a kilometer from a flame front.

    But many basic questions remain, Kobziar says. How do the microbes change — in quantity, type or viability — based on distance traveled away from the flames? How far can they actually go? How do different fuel sources — pine trees, grasslands, deciduous trees or crops, for example — affect microbial release? How does fire intensity affect what is released and how far it travels? Does the type of combustion — smoldering (like a wet log on a campfire) versus high-intensity flaming fires — affect what is released? How does temperature or humidity or weather affect microbial survival?

    Then, of course, Kobziar has plenty of questions about how to conduct this new field of research: What are the safest and best ways to sample the air in the dangerous environment of an unpredictable wildfire? How do you avoid contaminating the biological samples?

    She’s been learning as she goes, honing her methodology. The answers to many of those questions could come if one of Kobziar’s dream collaborations comes true: She wants to work with the researchers whose studies involve the NASA DC-8 “flying laboratory,” which explores Earth’s surface and atmosphere for studies ranging from archaeology to volcanology.

    Researchers have already tracked many different chemicals released by fires into the stratosphere from the Arctic to the South Pacific and everywhere in between, using the DC-8 for NASA’s Atmospheric Tomography Mission, says Christine Wiedinmyer, a fire emissions modeler at the Cooperative Institute for Research in Environmental Sciences in Boulder, Colo. Finding traceable signatures of fires everywhere in the atmosphere suggests that fires could also be sending bacteria and fungi around the world, she says.

    Nine kilometers above Earth’s surface, a camera on NASA’s DC-8 flying laboratory took this image of thunderclouds rising above columns of smoke from a fire in eastern Washington on August 8, 2019. Such storms, formed by intense fires, loft particulate matter, chemicals and maybe even microbes into the stratosphere.David Peterson/U.S. Naval Research Lab

    “Pyroaerobiology is so cool,” says Wiedinmyer, who tracks and simulates the movement of chemicals in wildfire smoke around the world. She sees no reason that such atmospheric chemistry models couldn’t also be used for tracking and forecasting the movement of microbes in smoke plumes — once researchers collect sufficient measurements. Those data might answer basic questions about the human health hazards of microorganisms in smoke.

    Microbiologist Fierer in Boulder and Wiedinmyer have collaborated on chemistry sampling and modeling. The two plan to move to bacterial and fungal modeling using data Fierer is gathering on microbial concentrations in wildfire smoke.

    Kobziar, meanwhile, is working with atmospheric modelers to figure out how to model microbes’ movements in smoke. The long-term aim is to develop models to supplement current air-quality forecasts with warnings of air-quality issues across the United States related to wildfire-released microorganisms in smoke.

    A U.S. map

    While Kobziar’s team focuses on measuring microbes in smoke, Fierer’s team is working to get a baseline of what microbes are in the air at different locations during normal times and then comparing the baseline to smoke. The group has been sampling indoor and outdoor air at hundreds of U.S. homes to “map out what microbes we’re breathing in as we’re walking around doing our daily business,” Fierer says. They are also sampling air across Colorado, which experienced record-breaking fires in 2020 (SN: 12/19/20 & 1/2/21, p. 32).

    Fierer’s team uses sampling stations with small, high-powered vacuums atop 2-meter-high poles to “sample air for a period of time without smoke. Then boom, smoke hits [the site], we sample for a few days when there’s smoke in the air, and then we also sample afterward,” Fierer says. Analyzing samples from before, during and after a fire is ideal, he says, as there’s tremendous variation in microbial and fungal populations in the air. Near a Midwestern city in winter, for example, microorganisms might include ones associated with local trees or, strangely, dog feces; near a Colorado cattle feedlot in summer, microbes might include those associated with cattle feces.

    Joanne Emerson, then a postdoctoral researcher at the University of Colorado Boulder, samples air atop a 300-meter-tall tower at the Boulder Atmospheric Observatory.N. Fierer

    When the team gets its results — data collection and analysis have been delayed by the pandemic — Fierer says, “we will know the amounts and types of microbes found in wildfire smoke compared with paired smoke-free air samples, and whether those microbes are viable.” At least in Colorado. Once scientists get the measurements of how many microbes can be carried in smoke, and to what altitudes, Fierer’s group can combine that information with global smoke production numbers to come up with “some back-of-the-envelope calculations” of the volume of microbes traveling in smoke plumes. Eventually, he says, scientists could figure out how many are alive, and whether that even matters for human health — still “an outstanding question.”

    Big leaps forward could be made if more scientists get involved in the research, Fierer and Kobziar both say. This research needs a truly multidisciplinary approach, with microbiologists, forest ecologists and atmospheric scientists collaborating, Fierer says. Going it alone would “be equivalent to a microbiologist studying microbes in the ocean and not knowing anything about oceanography,” he says. Fortunately, after Kobziar and infectious disease physician George Thompson of the University of California, Davis published a call-to-arms paper in Science last December, summing up their pyroaerobiology research and noting key questions, several researchers from different fields expressed interest in investigating the topic. “That’s exactly what we hoped would happen,” Kobziar says.

    Is there danger?

    In recent years, Thompson has seen a substantial increase in patients getting Valley fever and other fungal infections after nearby wildfires. He was well aware that when particulate matter in smoke gets into the lungs, it can cause breathing difficulties, pneumonia and even heart attacks. In fact, scientists reported in the Journal of the American Heart Association in April 2020 that exposure to heavy smoke during 2015–2017 wildfires in California raised the risk of heart attacks by up to 70 percent.

    He began to wonder if California’s record-breaking infernos were stirring up other microbes along with the fungus that causes Valley fever. So he joined forces with Kobziar.

    The Valley fever link appears to be real, but so far, local. For example, after the 2003 Simi Fire burned through Ventura County, more than 70 people got sick with Valley fever. But whether the Coccidioides fungi can travel to make people sick at a distance from the fire, no one knows.

    There are ways to figure out if more people, either locally or farther away, are getting sick with bacterial or fungal infections after wildfires. One way, Thompson says, is to look at a community’s antibiotic prescriptions and hospitalizations in the month preceding and the month after a fire: More prescriptions or hospitalizations from bacterial or fungal infections after a fire could indicate a link.

    In 2019 at the American Transplant Congress meeting, for example, researchers linked California wildfires with increased hospitalizations related to Aspergillus mold and Coccidioides fungi infections.

    But until we know more about what microbes fires release and where they go, we won’t know how important such a link is for human health, Fierer says.

    There’s so much we don’t know yet, Thompson agrees. “We still have a lot of work to do. This is sort of the beginning of the beginning of the story.” More

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    Discarded COVID-19 PPE such as masks can be deadly to wildlife

    A Magellanic penguin in Brazil ingested a face mask. A hedgehog in England got itself entangled in a glove. An octopus off the coast of France was found seeking refuge under a mask.

    Wildlife and ecosystems around the world are suffering from the impact of discarded single-use COVID-19 protective gear, researchers warn March 22 in Animal Biology. Latex gloves and polypropylene masks which protect people from the coronavirus are exacerbating the plastic pollution problem when not disposed of properly and are causing wildlife deaths (SN:11/20/20). The study is the first global documentation of the impacts of COVID-19 litter on wildlife via entanglement, entrapment and ingestion (SN:12/15/20).

    In August 2020, volunteers cleaning canals in Leiden, Netherlands, chanced upon a perch — a type of freshwater fish — trapped inside a finger of a latex glove. The ensnared fish was the first recorded wildlife casualty caused by COVID-19 litter in the Netherlands. The find shocked two Leiden-based biologists — Auke-Florian Hiemstra and Liselotte Rambonnet — who wanted to know more about the extent of COVID-19 litter’s impact on wildlife. They embarked on an extensive search, online and in newspapers, to collate examples.

    A perch found trapped in a latex glove (pictured) in a Leiden canal inspired two Dutch biologists to look into how discarded single-use PPE is impacting animals around the world.Auke-Florian Hiemstra

    They found 28 such instances from all around the world, pointing to a larger, global problem.   The earliest reported victim was from April 2020: an American robin in Canada, which appears to have died after getting entangled in a face mask. Pets are at risk, too: In Philadelphia, a domestic cat ingested a glove, and a pet dog in Boston that had consumed a face mask. “Animals with plastic in their stomach could starve to death,” says Rambonnet, of Leiden University.

    “What this paper does is give us insight to the extent of the [COVID-19] litter’s impact on wildlife, so we can make efforts to minimize the consequences,” says Anna Schwarz, a sustainable plastics researcher at TNO, an independent organization for applied scientific research in Utrecht, Netherlands. That could be a tall order: A report published by Hong Kong–based marine conservation organization OceansAsia, for instance, estimates that 1.56 billion face masks would have entered the world’s ocean last year, part of the 8 million to 12 million metric tons of plastic that reaches the oceans annually.

    As the far-reaching impacts of COVID-19 litter on wildlife become more apparent over time, Hiemstra, of the Naturalis Biodiversity Center, and Rambonnet are relying on citizen scientists to help them continue monitoring the situation: At, people from around the world can submit their observations of affected wildlife. To curb the growing hazards, the study authors recommend switching to reusables wherever possible, as well as cutting up disposal gloves and snipping the straps off of single-use masks to prevent animals from getting entangled or trapped in them.

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    “The paper highlights the importance of proper waste management, especially the recycling or disposal of single-use materials,” says Schwarz.

    But the situation isn’t always so dire. Some animals have commandeered discarded PPE for their own uses. COVID-19 litter has become so pervasive that birds have been observed using face masks and gloves as building materials for their nests. “Bird nests from 2020 are so easy to recognize,” says Hiemstra. More

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    Corals’ hidden genetic diversity corresponds to distinct lifestyles

    Stony corals that build reefs have been hiding their diversity in plain sight. A genetic analysis of the most widespread reef coral in the Indo-Pacific revealed that rather than being a single species (Pachyseris speciosa), it was actually four distinct species of coral, researchers report April 2 in Current Biology.

    Coral reefs are the condominiums of ocean biodiversity, supporting more species per square meter than any other marine habitat. Understanding which coral species foster that biodiversity and how those corals behave is vital to taking care of them, especially as a warming climate threatens overall ocean biodiversity (SN: 5/6/20). “Just knowing what’s there is critical to tracking what we are losing,” says Rebecca Vega-Thurber, a marine microbiologist at Oregon State University in Corvallis, who was not involved in the new study. The results suggest other corals thought to be a single species may actually be much more diverse than researchers realized.

    Using a combination of scuba gear and remotely operated vehicles, marine biologist Pim Bongaerts of the California Academy of Sciences in San Francisco and colleagues sampled more than 1,400 P. speciosa corals from the ocean surface down to 80 meters. In the lab, the sampleslooked identical, and their internal structures were indistinguishable in scanning electron microscope images. Yet, their genomes — their full genetic instruction books — revealed the corals had diverged millions of years ago. That made sense for one of the species in the Red Sea’s Gulf of Aqaba, which was geographically separated from the others. But the other three newly identified species lived together on the same reefs in the waters off South Asia. If the corals were living together, why didn’t one overtake the other two, the team wondered.

    Examining habitat data from their dives, the researchers found the three distinct coral species favored different water depths, with one abundant in the top 10 meters and the other two flourishing deeper down. The three coral species also had different concentrations of photosynthetic algae and pigments, suggesting they had distinct strategies for hosting their algae partners that provide food. And spawning times of these three species were slightly spread out too. One released most of its gametes five days after the full moon, another seven days after, and the third at nine days and counting. The separation of spawning could help the eggs and sperm of each species hook up with its correct species match.

    Marine biologists Pim Bongaerts and Norbert Englebert collect coral samples during a dive at Holmes Reef in the Coral Sea north of Australia.David Whillas

    This study is the first to show how a set of cryptic reef corals are splitting up their shared ecological space — by depth, physiology and spawning time, Bongaerts says. “There are all these cryptic lineages occurring, but they’ve largely been ignored from an ecological point of view.”

    The results open the door to the possibility that many other doppelgänger corals may be multiple species that coexist thanks to ecological differences, says reef genomicist Christian Voolstra at the University of Konstanz in Germany. “There is a minimal chance that they picked the unicorn, but I highly doubt it. This paper shows that in all likelihood there is a huge diversity of reef corals with distinct ecologies.” More

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    A trek under Thwaites Glacier’s ice shelf reveals specific risks of warm water

    The under-ice trek of an autonomous underwater vehicle is giving scientists their first direct evidence for how and where warm ocean waters are threatening the stability of Antarctica’s vulnerable Thwaites Glacier. These new data will ultimately help scientists more accurately project the fate of the glacier — how quickly it is melting and retreating inland, and how far it might be from complete collapse, the team reports April 9 in Science Advances.

    “We know there’s a sick patient out there, and it’s not able to tell us where it hurts,” says Eric Rignot, a glaciologist at the University of California, Irvine who was not involved in the new study. “So this is the first diagnosis.”

    Scientists have eyed the Florida-sized Thwaites Glacier with mounting concern for two decades. Satellite images reveal it has been retreating at an alarming rate of somewhere between 0.6 to 0.8 kilometers per year on average since 2001, prompting some to dub it the “doomsday glacier.” But estimates of how quickly the glacier is retreating, based on computer simulations, vary widely from place to place on the glacier, Rignot and other researchers reported in Science Advances in 2019. Such uncertainty is the biggest difficulty when it comes to future projections of sea level rise (SN: 1/7/20).

    The primary culprit for the rapid retreat of Thwaites and other Antarctic glaciers is known: Relatively warm ocean waters sneak beneath the floating ice shelves, the fringes of the glaciers that jut out into the ocean (SN: 9/9/20). This water eats away at the ice shelves’ underpinnings, points where the ice is anchored to the seafloor that buttress the rest of the glacier against sliding into the sea.

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    Scientists have used satellite data to roughly map out what lies beneath the Thwaites ice shelf. Three deep channels carved into the seafloor snake beneath a vast water-filled cavity 120 kilometers across. But without direct measurements of the chemistry and paths the water takes to reach Thwaites’ underbelly, it’s been impossible to know where the threatening water is really coming from, how warm it is, and where it’s attacking the ice, says Anna Wåhlin, a physical oceanographer at the University of Gothenburg in Sweden.

    In February and March 2019, Wåhlin and her colleagues sent the AUV Ran to traverse two of the deep channels. Gliding about 50 meters above the seafloor, the AUV collected the first direct measurements of temperature, salinity and oxygen levels in the water. From those measurements, the team was able to trace the origins of different parcels of water mixing beneath Thwaites.

    Based on its chemical makeup, some of the warm water came from neighboring Pine Island Bay. “We were very surprised,” because Pine Island Bay wasn’t previously thought to be a major player in the future of Thwaites, Wåhlin says. The water mass from there was near the bottom of the cavity, about 500 meters deep, and was both less salty than the surrounding seawater and several degrees Celsius warmer than the freezing point. That’s an unstable situation, likely to create turbulence, and increasing the potential for erosion of the ice, Wåhlin says.

    The find also suggests that what happens in Pine Island Bay doesn’t necessarily stay in Pine Island Bay — and that the fate of Thwaites may be closely intertwined with that of the Pine Island Glacier, another rapidly-melting river of ice, Wåhlin says. Together, the two glaciers are responsible for most of the ice and water that Antarctica is currently shedding. But while Thwaites is still pinned to the seafloor in some places, which slows its slide into the sea, those underpinnings are long gone for Pine Island, she says.

    In April, scientists identified three tipping points for the precarious Pine Island glacier, thresholds it might cross as climate conditions evolve that would lead to phases of rapid, irreversible retreat. The third and final threshold, prompted by a roughly 1.2 degree Celsius increase in the temperature of ocean waters compared with current ocean temperatures, would drive the glacier to complete collapse, the team found.

    An upcoming expedition Wåhlin and others are planning for January 2022 will use two AUVs to explore much farther into the cavity beneath Thwaites. Ideally, the AUVS will get several hundred kilometers closer to the shore, all the way to the grounding line, where the base of the glacier rests on land.

    “That’s the key down the line,” Rignot says. Observing how water masses are interacting with the glacier’s grounding line will be crucial to understanding the future of the glacier, he says. “That’s the place where melting makes the most difference to the glacier’s stability.”

    And there’s a lot that researchers still don’t know about the vast water cavity beneath Thwaites ice shelf, including its precise dimensions and the best places for AUVs to explore, he adds. “We are only just at the beginning.” More

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    A spike in Arctic lightning strikes may be linked to climate change

    Climate change may be sparking more lightning in the Arctic.

    Data from a worldwide network of lightning sensors suggest that the frequency of lightning strikes in the region has shot up over the last decade, researchers report online March 22 in Geophysical Research Letters. That may be because the Arctic, historically too cold to fuel many thunderstorms, is heating up twice as fast as the rest of the world (SN: 8/2/19).

    The new analysis used observations from the World Wide Lightning Location Network, which has sensors across the globe that detect radio waves emitted by lightning bolts. Researchers tallied lightning strikes in the Arctic during the stormiest months of June, July and August from 2010 to 2020. The team counted everywhere above 65° N latitude, which cuts through the middle of Alaska, as the Arctic.

    The number of lightning strikes that the detection network precisely located in the Arctic spiked from about 35,000 in 2010 to about 240,000 in 2020. Part of that uptick in detections may have resulted from the sensor network expanding from about 40 stations to more than 60 stations over the decade.

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    And just looking at the 2010 and 2020 values alone may overstate the increase in lightning, because “there’s such variability, year to year,” and 2020 was a particularly stormy year, says Robert Holzworth, an atmospheric and space scientist at the University of Washington in Seattle. In estimating the increase in average annual lightning strikes, “I would argue that we have really good evidence that the number of strokes in the Arctic has increased by, say, 300 percent,” Holzworth says.

    That increase happened while global summertime temperatures rose from about 0.7 degrees Celsius above the 20th century average to about 0.9 degrees C above — hinting that global warming may create more favorable conditions for lightning in the Arctic.

    It makes sense that a warmer climate could generate more lightning in historically colder climes, says Sander Veraverbeke, an earth systems scientist at VU University Amsterdam who was not involved in the work. If it does, that could potentially ignite more wildfires (SN: 4/11/19). But the apparent trend in Arctic lightning strikes should be taken with a grain of salt because it covers such a short period of time and the detection network includes few observing stations at high latitudes, Veraverbeke says. “We need more stations in the high north to really accurately monitor the lightning there.” More

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    Dazzling underwater photos capture new views and scientific detail of fish larvae

    The open ocean is a veritable soup of tiny critters, including newborn fishes. It’s hard to learn about them, though, because they are mere millimeters long and semitransparent. When netted from research vessels, their delicate body parts may get mashed or removed. Now, a partnership between scientists and scuba divers is giving researchers fresh perspectives on the secrets of larval fishes.

    Underwater photos taken at night — when larval fishes migrate to within 200 meters of the ocean surface — reveal colors, body structures and behaviors that could never be seen in preserved specimens. Examining those same fishes back in the lab lets ichthyologists match the photographed larval fishes to known species, researchers report March 30 in Ichthyology & Herpetology.

    Scientists at the Smithsonian Institution and the National Oceanic and Atmospheric Administration hatched a collaboration in 2016 with blackwater divers — who enter the ocean in the dark of night — to photograph larval fishes and collect them as specimens. With lights in hand, divers Jeff Milisen and Sarah Mayte snapped up-close photos of nearly 80 larval fishes, then gingerly captured and shipped them to scientists to be studied alongside their mugshots.

    “Fish larvae that looked utterly drab as specimens have turned out to have brilliantly colored markings and fantastic structures,” says Ai Nonaka, a larval fish expert at the Smithsonian’s National Museum of Natural History in Washington, D.C.

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    Fragile appendages

    Specialists like Nonaka sort out larval fish identities by looking at body shapes and minuscule features through microscopes and by analyzing DNA of larval tissue. Unlike their swimming parents, fish larvae drift on currents, and their strange body parts — adaptations for a drifting lifestyle — make larvae look nothing like adults. 

    “Larval fishes are extremely difficult to identify,” says Dave Johnson, an ichthyologist also at the Smithsonian. Scientists have mistakenly given larval fishes new scientific names, not recognizing them as early life stages of known species.

    Because larval fishes are soft and fragile, they don’t travel well. Larvae lose fins and other delicate structures that evoke their behavior. The scalloped ribbonfish (Zu cristatus) larva, for example, has spaghetti-like ornamental fins sprinkled with white spots that get broken off on specimens. The way these ornamental structures appear to flow out like tentacles in the images of wild larvae suggests the larvae could be jellyfish mimics, say the study authors.

    Scalloped ribbonfish (Zu cristatus) larva in the oceanJ. Milisen

    Scalloped ribbonfish (Z. cristatus) larva specimenA. Nonaka/Smithsonian NMNH

    The trailing guts of a barbeled dragonfish (Aristostomias sp.) larva get mashed or broken off altogether, but the undersea photo reveals it coiled up into a tight corkscrew. Nonaka and Johnson confess that scientists don’t yet understand the function of the trailing guts seen in some larval fishes. One theory is that exposed innards might somehow increase digestion efficiency, while another suggests they could confuse predators.

    Barbeled dragonfish (Aristostomias sp.) larva in the oceanJ. Milisen

    Barbeled dragonfish (Aristostomias sp.) larva specimenA. Nonaka/Smithsonian NMNH

    Hidden colors

    Ethanol preservation of specimens repels bacteria and fungi, but leaches out colors. The three-spot righteye flounder (Samariscus triocellatus) larva, bone white as a specimen, is bright blue. Its dorsal and anal fins are fringed with white, and rows of yellow spots dot the base of the fin rays. While their function has yet to be studied, it’s possible that these borders create a flickering visual effect to help the fish escape from predators, suggests Geoff Moser, a retired NOAA fisheries biologist not involved with the study. Called “flicker fusion,” it’s been examined in other animals such as striped snakes as a form of camouflage on the go.

    Three-spot righteye flounder (Samariscus triocellatus) larva in the oceanJ. Milisen

    Three-spot righteye flounder (S. triocellatus) larva specimenA. Nonaka/Smithsonian NMNH

    The deep-sea tripodfish (Bathymicrops sp.) is plain and pale when prepared as a specimen and uniform brown as an adult fish — not exactly a looker. But the larva appears to have donned a clown costume with large white and orange polka dots flecked on its otherwise blue-hued body. In an ethanol specimen, its pectoral fins look soft and ghostly, whereas the living larva sports flamboyant, spiky and spotted fins. The function of the coloration is unknown. says Nonaka, but it could also be a flicker fusion trick.

    Deep-sea tripodfish (Bathymicrops sp.) larva in the oceanJ. Milisen

    Deep-sea tripodfish (Bathymicrops sp.) larva specimenA. Nonaka/Smithsonian NMNH

    Fishy behavior

    In larval specimens, scientists can observe some structures as evidence of behaviors. But undersea observations of wild larval fishes can show what they’re really up to when they are alive. The larva of the barred conger (Ariosoma fasciatum) is super flat, quite unlike the cylindrical adult. Yet a photo shows that it swims like an adult barred conger, by undulating its long body laterally. So, while it’s more svelte as a larva, it’s got some of the adult movements down.

    Barred conger (Ariosoma fasciatum) larva in the oceanJ. Milisen

    Barred conger (A. fasciatum) larva specimenA. Nonaka/Smithsonian NMNH

    Undersea observations can also reveal associations larvae have with other marine animals, including other tiny critters that also ride the currents. For example, a petite Pacific pomfret (Brama japonica) larva was caught on camera riding on a jellyfish. That’s a discovery that the study authors were unwilling to even speculate about. Although larval fishes have been seen taking shelter in the tentacles of jellies, hitching a ride on top of a jellyfish seems like an odd twist on that behavior.

    A pacific pomfret (Brama japonica) larva (pictured from three angles) in the ocean, riding a jellyfishJ. Milisen (photos); E. Otwell/Science News (collage)

    Pacific pomfret (Brama japonica) larva specimenA. Nonaka/Smithsonian NMNH

    Each larval fish that gets identified by scientists sets the stage for conservation. By knowing where larval fishes of particular species live, researchers can better advise on how to manage the ocean ecosystems the fishes depend on for survival.

    Conservation planning also requires knowledge of behavior (SN: 12/30/10). So photographing larval fishes and making their specimens available for identification means researchers get a handle on fishes’ behavioral adaptations for survival in the wild.

    “I’ve been working with fish larvae for over 40 years,” says Moser. “The chance to see these larvae in their environment was a wonderful advance in our scientific endeavors.” More

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    How kelp forests off California are responding to an urchin takeover

    Joshua Smith has been diving in kelp forests in Monterey Bay along the central coast of California since 2012. Back then, he says, things looked very different. Being underwater was like being in a redwood forest, where the kelp was like “towering tall cathedrals,” says Smith, an ecologist at the University of California, Santa Cruz. Their tops were so lush that it was hard to maneuver a boat across them.

    No longer. The once expansive kelp forests are now a mosaic of thinner thickets interspersed with barrens colonized by sea urchins. And those sea urchins have so little to eat, they aren’t even worth the effort of hungry sea otters — which usually keep urchins in check and help keep kelp forests healthy, Smith and his colleagues report March 8 in the Proceedings of the National Academy of Sciences.

    A similar scene is playing out farther north. A thick kelp forest once stretched 350 kilometers along the northern California coast. More than 95 percent of it has vanished since 2014, satellite imagery shows. Once covering about 210 hectares on average, those forests have been reduced to a mere 10 hectares scattered among a few small patches, Meredith McPherson, a marine biologist also at UC Santa Cruz, and her colleagues report March 5 in Communications Biology. Like the barrens farther south, the remaining forests are now covered by purple sea urchins.

    Satellite images in 2008 (left) and 2019 (right) of a section of the northern California coastline reveal a 95 percent reduction in the area covered by underwater kelp forests (yellow).Meredith McPherson

    Satellite images in 2008 (left) and 2019 (right) of a section of the northern California coastline reveal a 95 percent reduction in the area covered by underwater kelp forests (yellow).Meredith McPherson

    Together, the two studies reveal the devastation of these once resilient ecosystems. But a deeper dive into the cascading effects of this loss may also provide clues to how at least some of these forests can bounce back.

    California’s kelp forests, which provide a rich habitat for marine organisms, got hit by a double whammy of ecological disasters in the past decade, says UC Santa Cruz ecologist Mark Carr. He is a coauthor on the Communications Biology paper who has mentored both McPherson and Smith.

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    First, sea star wasting syndrome wiped out local populations of sunflower sea stars (Pycnopodia helianthoides), which typically feed on urchins (SN: 1/20/21). Without sea stars, purple sea urchins (Strongylocentrotus purpuratus) proliferated.

    The second wallop was a marine heat wave so big and persistent it was nicknamed “The Blob” (SN: 12/14/17). While kelp forests have been resilient to warming events before, this one was so extreme it spiked temperatures in many parts of the Pacific to 2 to 3 degrees Celsius above normal (SN: 1/15/20).

    Kelp thrives in cold and nutrient rich water. As its growth slowed in the warmer water, less kelp drifted into the crevices of the reefs where sea urchins typically lurk. With a key predator gone and a newfound need to forage for food rather than waiting for it to come to them, urchins emerged and turned the remaining kelp into a giant buffet.

    For the northern California kelp forests, the shift could spell doom for two reasons. The dominant species growing there is bull kelp (Nereocystis leutkeana). It dies each winter to return again in the spring, and the changes are making it more difficult to bounce back year after year.  In comparison, one of the main kelp species in Monterey Bay is giant kelp (Macrocystis pyrifera), which lives for many years, making it a bit more resilient.

    Bull kelp (Nereocystis leutkeana), seen here growing at Pescadero Point near Carmel-by-the-Sea, Calif., becomes the dominant species of kelp growing along the northern California coast. A marine heat wave and loss of a sea urchin predator has led to a massive loss of bull kelp in that region.Steve Lonhart/NOAA, MBNMS

    The kelp forests in the north also lack an urchin predator common farther south: sea otters. Those sea otters are what’s providing a glimmer of hope in Monterey Bay. Smith and his colleagues wondered how the bonanza of sea urchins was affecting the otters. They found that sea otters were eating three times as many sea urchins as they were before 2014, but they were being picky. They avoided the more populous urchin barrens, instead feasting only on urchins in the remaining patches of kelp. That’s because the barrens offer only a poor diet of scraps, leaving the urchins there essentially hollow on the inside. “Zombies,” Smith calls them.

    The nutrient-rich urchins in the healthy kelp make a far better sea otter snack. And by zeroing in on those urchins, the otters keep the population in check, preventing urchins from scarfing up the remaining kelp.

    Simply transplanting sea otters to new locations may create new challenges. That’s what happened off the Pacific Coast of Canada. Kelp forests there rebounded, but the otters competed with humans, especially Indigenous communities, that rely on the same food sources (SN: 6/11/20).

    “The community on the North Coast is a very natural resource–dependent community, and this will impact them,” says Marissa Baskett, an ecologist at the University of California, Davis.

    And there’s a lot of work to do to figure out how to bring back sunflower sea stars, now a critically endangered species. Nailing down the cause of the wasting syndrome, which is still unknown, will be crucial to recovery efforts.

    Even so, understanding these interactions can provide clues to how to help restore the lost kelp forests, Baskett says. “These findings can inform restoration efforts aimed at recovering kelp forests and anticipating the effects of future marine heat waves.” More

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    Simple hand-built structures can help streams survive wildfires and drought

    Wearing waders and work gloves, three dozen employees from the U.S. Department of Agriculture’s Natural Resources Conservation Service stood at a small creek amid the dry sagebrush of southeastern Idaho. The group was eager to learn how to repair a stream the old­-fashioned way.

    Tipping back his white cowboy hat, 73-year-old rancher Jay Wilde told the group that he grew up swimming and fishing at this place, Birch Creek, all summer long. But when he took over the family farm from his parents in 1995, the stream was dry by mid-June.

    Wilde realized this was partly because his family and neighbors, like generations of American settlers before them, had trapped and removed most of the dam-building beavers. The settlers also built roads, cut trees, mined streams, overgrazed livestock and created flood-control and irrigation structures, all of which changed the plumbing of watersheds like Birch Creek’s.

    Many of the wetlands in the western United States have disappeared since the 1700s. California has lost an astonishing 90 percent of its wetlands, which includes streamsides, wet meadows and ponds. In Nevada, Idaho and Colorado, more than 50 percent of wetlands have vanished. Precious wet habitats now make up just 2 percent of the arid West — and those remaining wet places are struggling.

    Nearly half of U.S. streams are in poor condition, unable to fully sustain wildlife and people, says Jeremy Maestas, a sagebrush ecosystem specialist with the NRCS who organized that workshop on Wilde’s ranch in 2016. As communities in the American West face increasing water shortages, more frequent and larger wildfires (SN: 9/26/20, p. 12) and unpredictable floods, restoring ailing waterways is becoming a necessity.

    Staff from the USDA Natural Resources Conservation Service pound posts to build a beaver dam analog across Birch Creek in Idaho in 2016. The effort gave nine relocated beavers a head start to create their own dam complexes.J. Maestas/USDA NRCS

    Landowners and conservation groups are bringing in teams of volunteers and workers, like the NRCS group, to build low-cost solutions from sticks and stones. And the work is making a difference. Streams are running longer into the summer, beavers and other animals are returning, and a study last December confirmed that landscapes irrigated by beaver activity can resist wildfires.

    Filling the sponge

    Think of a floodplain as a sponge: Each spring, floodplains in the West soak up snow melting from the mountains. The sponge is then wrung out during summer and fall, when the snow is gone and rainfall is scarce. The more water that stays in the sponge, the longer streams can flow and plants can thrive. A full sponge makes the landscape better equipped to handle natural disasters, since wet places full of green vegetation can slow floods, tolerate droughts or stall flames.

    Typical modern-day stream and river restoration methods can cost about $500,000 per mile, says Joseph Wheaton, a geomorphologist at Utah State University in Logan. Projects are often complex, and involve excavators and bulldozers to shore up streambanks using giant boulders or to construct brand-new channels.

    “Even though we spend at least $15 billion per year repairing waterways in the U.S., we’re hardly scratching the surface of what needs fixing,” Wheaton says.

    Big yellow machines are certainly necessary for restoring big rivers. But 90 percent of all U.S. waterways are small streams, the kind you can hop over or wade across.

    For smaller streams, hand-built restoration solutions work well, often at one-tenth the cost, Wheaton says, and can be self-sustaining once nature takes over. These low-tech approaches include building beaver dam analogs to entice beavers to stay and get to work, erecting small rock dams or strategically mounding mud and branches in a stream. The goal of these simple structures is to slow the flow of water and spread it across the floodplain to help plants grow and to fill the underground sponge.

    Less than a year after workers installed this hand-built rock structure, called a Zuni bowl, in an intermittent stream in southwestern Montana, erosion stopped moving upstream, keeping the grass above the structure green and lush.Sean Claffey/Southwest Montana Sagebrush Partnership

    Fixes like these help cure a common ailment that afflicts most streams out West, including Birch Creek, Wheaton says: Human activities have altered these waterways into straightened channels largely devoid of debris. As a result, most riverscapes flow too straight and too fast.

    “They should be messy and inefficient,” he says. “They need more structure, whether it’s wood, rock, roots or dirt. That’s what slows down the water.” Wheaton prefers the term “riverscape” over stream or river because he “can’t imagine a healthy river without including the land around it.”

    Natural structures “feed the stream a healthy diet” of natural materials, allowing soil and water to accumulate again in the floodplain, he says.

    Since as much as 75 percent of water resources in the West are on private land, conservation groups and government agencies like the NRCS are helping ranchers and farmers improve the streams, springs or wet meadows on their property.

    “In the West, water is life,” Maestas says. “But it’s a very time-limited resource. We’re trying to keep what we have on the landscape as long as possible.”

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    Beaver benefits

    In watersheds across the West, beavers can be a big part of filling the floodplain’s sponge. The rodents gnaw down trees to create lodges and dams, and dig channels for transporting their logs to the dams. All this work slows down and spreads out the water.

    On two creeks in northeastern Nevada, streamsides near beaver dams were up to 88 percent greener than undammed stream sections when measured from 2013 to 2016. Even better, beaver ponds helped maintain lush vegetation during the hottest summer months, even during a multiyear drought, Emily Fairfax, an ecohydrologist at California State University Channel Islands, and geologist Eric Small of University of Colorado Boulder reported in 2018 in Ecohydrology.

    Satellite images show that when beavers settled into one part of Nevada’s Maggie Creek (bottom), digging channels to ferry in logs to build dams, the floodplain was wider, wetter and greener than an area of the creek with no dams (top).E. Fairfax/CSU Channel Islands

    Satellite images show that when beavers settled into one part of Nevada’s Maggie Creek (bottom), digging channels to ferry in logs to build dams, the floodplain was wider, wetter and greener than an area of the creek with no dams (top).E. Fairfax/CSU Channel Islands

    “Bringing beavers back just makes good common sense when you get down to the science of it,” Wilde says. He did it on his ranch.

    Using beavers to restore watersheds is not a new idea. In 1948, for instance, Idaho Fish and Game biologists parachuted beavers out of airplanes, partly to improve trout habitat on public lands.

    Wilde used trucks instead of parachutes. In 2015 and 2016, he partnered with the U.S. Forest Service and Idaho Fish and Game to livetrap and relocate nine beavers to Birch Creek from public lands about 120 kilometers away. To ensure the released rodents had a few initial ponds where they could escape from predators, Wilde worked with Anabranch Solutions, a riverscape restoration company cofounded by Wheaton and colleagues, to construct 26 beaver dam analogs. Would these simple branch-and-post structures entice the beavers to stay in Birch Creek?

    It worked like a charm. In just three years, those beavers built 149 dams, transforming the once-narrow strip of green along the stream into a wide, vibrant floodplain. Birch Creek flowed 42 days longer, through the hottest part of the summer. Fish rebounded quickly too: Native Bonneville cutthroat trout populations were up to 50 times as abundant in the ponded sections in 2019 as they were when surveyed by the U.S. Forest Service in 2000, before beavers went to work.

    “When you see the results, it’s almost like magic,” Wilde says. Even more magical, the transformation cost Wilde only “a couple hundred bucks in fence posts” and a few days of sweat equity, thanks in part to those NRCS staffers who came in 2016 and a host of volunteers.

    Rock dams in the desert

    Beaver-powered restoration isn’t the answer everywhere, especially in the desert where creeks are ephemeral, flowing only intermittently. In Colorado’s Gunnison River basin, ranchers were looking for ways to boost water availability to ensure their cattle had enough drinking water and green grass in the face of climate change. Meanwhile, the area’s public land managers wanted to restore streams to help at-risk wildlife species like the Gunnison sage grouse, once prolific across sagebrush country.

    In 2012, a group of private landowners, public agencies and nonprofit organizations launched the Gunnison Basin Wet Meadow and Riparian Restoration and Resilience-building Project to revive streams and keep meadows green. The group hired Bill Zeedyk to instruct on how to build simple, low-profile dams by stacking rocks, known widely as Zeedyk structures, to slow down the water.

    Zeedyk, now 85, runs his own wetland and stream restoration firm in New Mexico, after 34 years as a wildlife biologist at the U.S. Forest Service. His 2014 book Let the Water Do the Work has inspired people across the West — including Maestas and Wheaton — to turn to simple, nature-based stream restoration solutions.

    Over the last nine years, Zeedyk has helped the Gunnison collaborative build nearly 2,000 rock structures throughout the roughly 10,000-square-kilometer upper Gunnison watershed. The group has restored 43 kilometers of stream and improved nearly 500 hectares of wet habitat for people and wildlife. A typical project involves a dozen volunteers working for a day or two in one creek bottom where they build dozens of rock structures.

    In 2017, Maestas asked Zeedyk to show more than 100 people involved in the NRCS-led Sage Grouse Initiative how to install rock structures. The white-bearded Zeedyk led them along an eroding gully near Gunnison that June.

    Conservation professionals gathered in Gunnison, Colo., in 2017 to learn how to build Zeedyk structures, simple rock dams that slow the flow of water in small creeks to increase surrounding plant growth.B. Randall

    Lifting his wooden walking staff, Zeedyk pointed out how the adjacent dirt road originally created by horses and wagons cut off the creek from its historic floodplain. The road made the channel shorter, straighter and steeper over time. “There’s less growing space, and the whole system is less productive,” he explained.

    As participants decided where to stack rocks to spread water across the dusty sagebrush flat, Zeedyk encouraged them to “read the landscape” and “think like water.” After three hours of work, participants could already see ponds forming behind their rock creations.

    Watching the teams work and laugh together, Maestas called it the aha moment for the crew. “When you get your hands dirty, there’s a degree of buy-in that can’t come from sitting in a classroom or reading about it.”

    The grass is greener

    The hope is that, like the beaver dam analogs, these hand-built rock structures will halt erosion, capture sediment, fill the floodplain sponge and grow more water-loving plants.

    Patience, Zeedyk says, is crucial. “After we put natural processes into play in a positive direction, we have to wait for the water to do its work.”

    The wait isn’t necessarily long. At four of the sites in the Gunnison basin restored with Zeedyk structures, wetland plant cover (including sedges, rushes, willows and wetland forbs) increased an average of 160 percent four years post-treatment, compared with a 15 percent average increase at untreated areas near each study site, according to a 2017 report by The Nature Conservancy.

    “As of 2019, we had increased the wetland species cover by 200 percent in six years,” says Renee Rondeau, an ecologist at the Colorado Natural Heritage Program, based in Hesperus. “So great to see this success.”

    Animals seem to enjoy all that fresh green growth too. Colorado Parks and Wildlife set up remote cameras to monitor whether wildlife use the restored floodplain. Since 2016, the cameras have captured more than 1.5 million images, most of which show a host of animals — from cattle and elk to sage grouse and voles — munching away in the now-lush meadows. A graduate student at Western Colorado University is classifying photos to determine whether there’s a significant difference in the number of Gunnison sage grouse at the restored sites compared with adjacent untreated areas.

    “Sage grouse chicks chase the green line as the desert dries up,” Maestas explains. After hatching in June, hens and their broods seek out wet areas where chicks stock up on protein-rich insects and wildflowers to grow and survive the winter.

    A remote camera spies Gunnison sage grouse feasting on insects and plants in a wet meadow. The area stays green long into the summer because of hand-built rock dams that spread water across the land.Courtesy of Nathan Seward/Colorado Parks and Wildlife

    Water in the bank

    The Gunnison basin is not the only place where sticks-and-stones restoration is paying dividends for people and wildlife. Nick Silverman, a hydroclimatologist and geospatial data scientist, and his colleagues at the University of Montana in Missoula used satellite imagery to evaluate changes in “greenness” at three sites that used different simple stream restoration treatments: Zeedyk’s rock structures in Gunnison, beaver dam analogs in Oregon’s Bridge Creek and fencing projects that kept livestock away from streambanks in northeastern Nevada’s Maggie Creek.

    Late summer greenness increased up to 25 percent after streams were restored compared with before, the researchers reported in 2018 in Restoration Ecology. Plus, the streams showed greater resilience to climate variability as time went on: Along Maggie Creek, restored more than two decades before the study, the plants stayed green even when rainfall was low, and the area had substantial increases in plant production during late summer, when vegetation usually dries out.

    “It’s like putting water in a piggy bank when it’s wet, so plants and animals can withdraw it later when it’s dry,” Silverman says. Even more exciting, he adds, is that the impact of the low-cost options is large enough to see from space.

    Water doesn’t burn

    The Sharps Fire that scorched south-central Idaho in July 2018 burned a wide swath of a watershed where Idaho Fish and Game had relocated beavers to restore a floodplain. A strip of wet, green vegetation stood untouched along the beavers’ ponds. Wheaton sent a drone to take photos, tweeting out an image on September 5, 2018: “Why is there an impressive patch of green in the middle of 65,000 acres of charcoal? Turns out water doesn’t burn. Thank you beaver!”

    The green strip of vegetation along beaver-made ponds in Baugh Creek near Hailey, Idaho, resisted flames when a wildfire scorched the region in 2018, as shown in this drone image.J. Wheaton/Utah State Univ.

    Fairfax, the ecohydrologist who reported that beaver dams increase streamside greenness, had been searching for evidence that beavers could help keep flames at bay. Wheaton’s tweet was a “kick in the pants to push my own research on beavers and fire forward,” she says.

    With undergraduate student Andrew Whittle, now at the Colorado School of Mines, Fairfax got to work analyzing satellite imagery from recent wildfires. The two mapped thousands of beaver dams within wildfire-burned areas in several western states. Choosing five fires of varying severity in both shrubland and forested areas, the pair analyzed the data to see if creeks with beaver activity stayed greener than creeks without beavers during wildfires.

    [embedded content]
    Emily Fairfax produced this stop-motion video to show how beavers and their dams and channels keep water in an area, supporting the surrounding vegetation and helping the area resist wildfires.

    “Across the board, beaver-dammed areas didn’t burn,” Fairfax says. The study was published last December in Ecological Applications during one of the West’s worst fire seasons. It garnered plenty of attention from land managers asking for more specifics, like how many beavers are needed to buffer a fire.

    Fairfax plans to study several more burned sites with beaver ponds. She hopes to eventually create a statistical model that can help people plan nature-powered stream restoration projects.

    “When we’re seeing hotter, more unpredictable fires that are breaking all the rules we know of,” Fairfax says, “we have to figure out how to preserve critical wet habitats.” More