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      How kelp forests off California are responding to an urchin takeover

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      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

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      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

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      A tour of ‘Four Lost Cities’ reveals modern ties to ancient people

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      Four Lost CitiesAnnalee NewitzW.W. Norton & Co., $26.95
      It’s a familiar trope in movies and books: A bright-eyed protagonist moves to the big city in search of fame and fortune. Amid the bustle and lights, all hopes and dreams come true. But why do we cling to this cliché? In Four Lost Cities: A Secret History of the Urban Age, author Annalee Newitz explores ancient settlements to find out why people flock to big cities — and why they leave.  
      The book is divided into four enjoyable, snack-sized sections, one for each city. Each section is accompanied by a handy map, drawn by artist Jason Thompson with engaging, cartoon-style flair.
      Rather than dry history, Newitz makes a special effort to highlight the oddities and innovations that made these cities unique. Take Çatalhöyük, the oldest city they feature, which thrived from 7500 to 5700 B.C. in what is now Turkey. This ancient city persisted for nearly 2,000 years despite lacking things that we might consider necessary to a city, such as roads, dedicated public spaces or shopping areas.
      Four Lost Cities includes illustrated maps, including this one of Çatalhöyük, to help guide readers, as well as offering a bit of insight into the art of ancient cultures.Jason Thompson
      Newitz’s also explores Pompeii (700 B.C to A.D. 79 in modern-day Italy). When paired with Çatalhöyük, it offers insights into how humans developed the distinction between public and private spaces and activities — ideas that would not have made sense before humans began living in large settled groups. The section on Cahokia (A.D. 1050 to 1350) — located in what is now Illinois, across the Mississippi River from St. Louis — offers an unexpected reason for a city’s emergence. Many people link cities with capitalism and trade. Cahokia’s 30-meter-tall pyramids, 20-hectare plazas and a population (at the time) bigger than Paris suggest that spiritual revival can also build a major metropolis. Cahokia and Angkor, which reached its peak from A.D. 800 to 1431 in what is now Cambodia, also show how cities can form when power gets concentrated in a few influential people. 
      Through touring such diverse cities, Newitz shows that the move to urban life isn’t just a setup for a hero of a story. It’s a common setup for many ancient cultures.

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      Each city, of course, eventually fell. Çatalhöyük and Angkor suffered from droughts and flooding (SN: 10/17/18). Pompeii felt the fury of a volcano (SN: 1/23/20). But Newitz also reveals something else: Collapsing infrastructure provided the final push that kept people away. Here we glimpse our potential future, as climate crises and political instability threaten our own urban networks. But Newitz’s vivid imaginings, bright prose and boundless enthusiasm manage to keep the tone optimistic. These cities did end, yes. Yet the people who built them and resided in them lived on. Even in Pompeii, many inhabitants made it out. Collectively, they went to new places and spurred new growth.
      Four Lost Cities is about how cities collapse. But it’s also about what makes a city succeed. It’s not glamour or Wall Street. It’s not good restaurants or big factories. It’s people and their infrastructure. It’s clean water, public spaces, decent roads and opportunities for residents to live with dignity and improve their lot, Newitz explains. And when infrastructure crumbles beyond repair, people inevitably move on. “Our forebears’ eroded palaces and villas warn us about how communities can go wrong,” they write. “But their streets and plazas testify to all the times we built something meaningful together.”
      Buy Four Lost Cities from Bookshop.org. Science News is a Bookshop.org affiliate and will earn a comission on purchases made from links in this article. More

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      The world wasted nearly 1 billion metric tons of food in 2019

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      The world wasted about 931 million metric tons of food in 2019 — an average of 121 kilograms per person. That’s about 17 percent of all food that was available to consumers that year, a new United Nations report estimates.
      “Throwing away food de facto means throwing away the resources that went into its production,” said Martina Otto, who leads the U.N. Environment Program’s work on cities, during a news conference. “If food waste ends up in landfills, it does not feed people, but it does feed climate change.”
      Some 690 million people are impacted by hunger each year, and over 3 billion people can’t afford a healthy diet. Meanwhile, lost and wasted food accounts for 8 to 10 percent of global greenhouse gas emissions. Reducing food waste could ease both of those problems, according to the Food Waste Index Report 2021 published March 4 by the U.N. Environment Program and WRAP, an environmental charity based in the United Kingdom.
      Researchers analyzed food waste data from 54 countries. Most waste — 61 percent — came from homes. Food services such as restaurants accounted for 26 percent of global food waste while retail outlets such as supermarkets contributed just 13 percent. Surprisingly, food waste was a substantial problem for nearly all countries regardless of their income level, the team found. “We thought waste was predominantly a problem in rich countries,” Otto said.
      While the report is the most comprehensive analysis of global food waste to date, several knowledge gaps remain. The 54 countries account for just 75 percent of the world’s population, and only 23 countries provided waste estimates for their food service or retail sectors. The researchers accounted for these gaps by extrapolating values for the rest of the world from countries that did track these data. The report does not differentiate between potentially edible wasted food and inedible waste such as eggshells or bones.
      Otto recommends that countries begin addressing food waste by integrating reduction into their climate strategies and COVID-19 recovery plans. “Food waste has been largely overlooked in national climate strategies,” Otto said. “We know what to do, and we can take action quickly — collectively and individually.” More

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      A year after Australia’s wildfires, extinction threatens hundreds of species

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      When Isabel Hyman heads out in coming weeks to the wilds of northern New South Wales, she’s worried about what she won’t find. Fifteen years ago, the malacologist — or mollusk scientist — with the Australian Museum made an incredible discovery among the limestone outcrops there: a tiny, 3-millimeter-long snail, with a ribbed, dark golden-brown shell, that was new to science.
      Subsequently named after her husband, Hugh Palethorpe, Palethorpe’s pinwheel snail (Rophodon palethorpei) “is only known from a single location, at the Kunderang Brook limestone outcrops in Werrikimbe National Park,” she says. Now it may become known for a different, more devastating distinction: It is one of hundreds of species that experts fear have been pushed close to, or right over, the precipice of extinction by the wildfires that blazed across more than 10 million hectares of southeastern Australia in the summer of 2019–2020.
      “This location was completely burnt,” says Hyman, who is based in Sydney. “We expect the mortality at this site could be very high and … there is a possibility this species is extinct.”
      A year after the last of the fires were doused, their toll on species is becoming increasingly clear.  Flames devoured more than 20 percent of Australia’s entire forest cover, according to a February 2020 analysis in Nature Climate Change. Even if plants and animals survived the flames, their habitats may have been so changed that their survival is at risk (SN: 2/11/20). As a result of the scale of the disaster, experts say that more than 500 species of plants and animals may now be endangered — or even completely gone. 
      A wallaby licks its burnt paws after escaping a bushfire near Nana Glen in New South Wales on November 12, 2019.Wolter Peeters/The Sydney Morning Herald via Getty Image
      Australia’s iconic koala became the poster child of the crisis as images of rescuers carrying these singed marsupials out of the flames went global: As many as 60,000 of the nation’s estimated population of 330,000 koalas perished in the fires, ecologists concluded in December in a report for World Wildlife Fund Australia. While there’s no doubt that such charismatic megafauna suffered enormously, the greatest toll is likely to have been in other groups of species, such as invertebrates and plants, which often escape the public’s attention.
      As Kingsley Dixon, an ecologist at Curtin University in Perth told the Associated Press last year: “I don’t think we’ve seen a single event in Australia that has destroyed so much habitat and pushed so many creatures to the very brink of extinction.”

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      Koala charisma
      Even before the fires, many vertebrate species were already on downward trends, says John Woinarski, an ecologist at Charles Darwin University in Darwin. The blazes have “exacerbated the threats that were driving the declines,” he says.
      For example, fluffy arboreal marsupials called greater gliders (Petauroides volans) had already experienced a 50 percent population decline in recent decades. The fires then burned a third of their remaining habitat along Australia’s eastern coastline. An ongoing assessment may lead to the gliders being recategorized from vulnerable to endangered.
      Overall, 49 vertebrates that previously were not endangered now qualify for being listed as threatened under Australia’s guidelines for that designation, researchers reported in July in Nature Ecology and Evolution. That shift alone would increase the tally of nationally protected nonmarine vertebrate species by about 15 percent, from 324 to 373.
      Another 21 already threatened vertebrates had more than 30 percent of their ranges burned, and some may now qualify for being reassessed to higher categories of threat, the authors found. One species that may need to be recategorized is the koala (Phascolarctos cinereas), with some state’s populations that were hardest hit under consideration to be upgraded from vulnerable to endangered. 
      A koala named Paul recovers from his burns at an ICU in November 2019 after being rescued by volunteers following weeks of bushfires across New South Wales and Queensland.Edwards/Getty Image
      Besides the impact on koalas, the WWF Australia report suggests that as many as 3 billion individual mammals, birds, reptiles and frogs died or were displaced during the crisis. Though those figures are astounding, the impacts on lesser-studied groups such as invertebrates and plants may have been even greater.
      “Many of those have much smaller ranges [than vertebrates], which means they are going to be even more impacted when a big fire goes through,” says James Watson, a conservation scientist at the University of Queensland in Brisbane and an author of the Nature Ecology and Evolution paper on vertebrates. “I am willing to bet that there’s many species … that may disappear forever.”
      Invertebrate impact
      In February, more than 100 biologists convened the first of several online workshops to assess whether 234 Australian invertebrates now need to be added to the International Union for the Conservation of Nature’s Red List — a global who’s who of threatened species. 
      Snails, similar to many invertebrates, are particularly susceptible to wildfires, as they are unable to outrun flames and can’t survive intense heat, Hyman notes. Many also have small ranges that were completely incinerated, leaving no survivors that can recolonize the burned area.
      “A snail can’t do much to escape,” she says. “You could expect more than 90 percent mortality in a high-intensity bushfire.” In October, Hyman’s team published one of the first papers quantifying the impacts on invertebrates in New South Wales in the Technical Reports of the Australian Museum Online.
      The Palethorpe’s pinwheel snail (Rophodon palethorpei) has not yet turned up in searches following the wildfires, but other snail species did survive.Vince Railton, Queensland Museum
      Their surveys showed that 29 species in the state — including dung beetles, freshwater crayfish, flies, snails and spiders — had their entire ranges burned. Another 46 species had at least half their known habitat within the fire zones. These 75 species were among the 234 under consideration for adding to the IUCN Red List during the biologists’ first online workshop.
      “We’ve gathered together 230-odd species that are believed to now be of concern. These include a range of different taxa from land snails to millipedes to arachnids to insects, and this 230 is growing rapidly,” says Jess Marsh, an arachnologist at Charles Darwin University who was one of the conveners of the workshop. “I expect it will massively increase.”
      Some of the spiders she studies were the first to be added to that list. She’s already spent several months on South Australia’s Kangaroo Island hunting without luck for the Kangaroo Island assassin spider (Zephyrarchaea austini). Dependent on leaf litter suspended in the understory, and restricted to just a few locations that were razed in early 2020, she suspects that the species may be extinct.
      Spiders on Kangaroo Island such as this assassin spider (Zephyrarchaea austini) may now be extinct after most of their habitat was razed in early 2020.M.G. Rix and M.S. Harvey/ZooKeys 2012
      “There’s no understory vegetation left, let alone any leaf litter suspended in it, so that species is really hanging in the balance,” says Marsh.
      Generally, the species being considered for recognition as endangered had more than 50 percent of their ranges burned, lived in flammable parts of the habitat and have little ability to disperse to other areas. More than 150 of the 234 species being urgently assessed had their entire range burned. And it’s not just the flames themselves that are problematic; so is the reshaped environment following fires. Millipedes, for example, are very vulnerable not only to fire but also to drying out in the reduced shade and shelter of the post-fire environment.
      “A lot of invertebrates are very susceptible to desiccation, and need cover and humidity to survive a hot summer, which are obviously lacking following the fire,” Marsh says. “Taking into account all of the threats … we could be looking at significant numbers going extinct.”
      Rooted in place
      Lost vegetation hasn’t just put animals in danger. Many plants themselves may also be at risk, though experts have yet to compile an official list.
      Rachael Gallagher, a plant ecologist at Macquarie University in Sydney, has been prioritizing endemic plant species — those found nowhere else on Earth — that are in most urgent need of conservation for the Australian government. Perhaps surprisingly, she’s particularly worried about some trees that actually depend on fire to survive. Eucalypts known as alpine ash (Eucalyptus delegatensis) and mountain ash (E. regnans), for instance, are typically killed by fire and then regenerate from surviving seeds in the aftermath. Australia has many trees that must complete their entire life cycle from germination through to reproductively mature adult before the next major bushfire passes through (SN: 2/11/20). For some species, this may take 15 to 20 years.
      Some trees in Australia, such as this mountain ash (Eucalyptus regnans), depend on fire for their lifecycle, but recent wildfires may have been too much too soon.station96/iStock/Getty Images Plus
      The problem now is that climate change has increased the frequency of fires to the degree that many of these plants are unable to reach adulthood and set seed before the next fire passes through, meaning they may be lost from these ecosystems (SN: 3/4/20).
      The fires burned 25–100 percent of the ranges of 257 species of plants for which “the historical intervals between fire events across their range are likely to be too short to allow them to effectively regenerate,” Gallagher says. These species, which have some degree of fire tolerance, are at “increased risk of extinction.” These include shrubs and trees such as the granite boronia (Boronia granitica), Forrester’s bottlebrush (Callistemon forresterae), dwarf cypress pine (Callitris oblonga) and the Wolgan snow gum (Eucalyptus gregsoniana).
      Found, not lost
      Nevertheless, as researchers head out into the field to assess what’s lost, what they are sometimes finding are glimmers of hope. “Australian plants are remarkably resilient and there’s been regeneration in places where nobody thought there would be,” Gallagher says.
      One species that survived against all the odds is the Gibraltar Range waratah (Telopea aspera), a drought-resistant shrub with leathery leaves and bright red flowers. “This species has a very small range, being specialized to granite outcrops in one mountain range, which was burnt during the fires,” she says. “However, it has been noted as resprouting after the fires by park rangers and, in the absence of another fire in coming years, is likely to be able to recover.”
      Several animal species that were thought to be in grave peril following the fires that burned nearly half of the 4,400-square-kilometer Kangaroo Island have survived better than expected too (SN: 1/13/20). In the particularly badly burned reserves of the western end of the island, tiny marsupial carnivores called Kangaroo Island dunnarts (Sminthopsis aitkeni) are frequently appearing on camera traps. Swiftly erected predator-exclusion fences now protect survivors from feral cats.
      Tiny marsupials known as Kangaroo Island dunnarts (Sminthopsis aitkeni) have fared much better than other animals, appearing frequently on camera traps.Australian Wildlife Conservancy
      Similarly, large flocks of the glossy black-cockatoo (Calyptorhynchus lathami) have adapted by moving to unburned areas with food trees, says Karleah Berris of Natural Resources Kangaroo Island, who heads the crew that manages the endangered birds. Better news yet, a surprising number of birds bred and fledged young in mid-2020. “The important thing now is to protect what is left from fire until the burnt areas regenerate,” she says. “But I think, at present, all signs are that they are coping.”
      Hyman says that, hearteningly, her team found handfuls of survivors of some snail species during several surveys in New South Wales in late 2020. The snails turned up in small patches of unburned habitat, sometimes at the bottom of gullies or in deep leaf litter around the bases of large trees. And that gives her hope that other snail species may have held on in other, larger unburned patches with greater numbers of survivors.
      “But the question then becomes, what sort of recovery can they make from that?” she says. “Whether they can recover and breed up and start to move back into surviving areas again perhaps depends on how dry the weather is in coming years and if there are more fires.”
      She’s still hoping that a handful of Palethorpe’s pinwheel snails may have clung on against all the odds. “My husband is on tenterhooks wondering if his snail is still there or not,” she says. More

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      ‘Green’ burials are slowly gaining ground among environmentalists

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      Despite “green” burials becoming increasingly available in North America, some older eco-conscious adults remain unaware of the option when planning for their deaths, a small study hints.
      Green burials do not use concrete vaults, embalm bodies or use pesticides or fertilizers at gravesites. Bodies are buried in a biodegradable container like a pinewood or wicker casket, or a cotton or silk shroud. Proponents of the small but growing trend argue it is more environmentally friendly and in line with how burials were done before the invention of the modern funeral home industry.
      But when researchers asked 20 residents of Lawrence, Kan., over the age of 60 who identify as environmentalists if they had considered green burial, most hadn’t heard of the practice. That’s despite the fact that green burial had been available in Lawrence for nearly a decade at the time. More than half of the survey participants planned on cremation, because they viewed it as the eco-friendliest option, the team reported online January 26 in Mortality.
      In 2008, Lawrence became the first U.S. city to allow green burials in a publicly owned cemetery. Several years later, at a meeting of an interfaith ecological community organization in the city, sociologist Paul Stock of the University of Kansas in Lawrence and his colleague Mary Kate Dennis noticed that most of the attendees were older adults. These people “live and breathe their environmentalism,” says Dennis, now a social work researcher at the University of Manitoba in Canada. “We were curious if it followed them all the way through to their burials.”

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      That the majority of participants in the new survey leaned towards cremation aligns with national trends. Cremation recently surpassed traditional burial as the most popular death care choice in the United States. In July 2020, the National Funeral Directors Association projected the cremation rate that year would be 56 percent compared to 38 percent for casket burials. By 2040, the cremation rate is projected to grow to about 78 percent while the burial rate is estimated to shrink to about 16 percent.
      Cremation’s growing popularity can be traced to a number of factors, including affordability and concerns about traditional burial’s environmental impacts. But cremation comes with its own environmental cost, releasing hundreds of kilograms of carbon dioxide into the air per body.
      The preference for green burial, meanwhile, is small but growing. The Green Burial Council was founded in 2005 to establish green burial standards by certifying green burial sites. Now 14 percent of Americans over age 40 say they would choose green burial, the NFDA reports, and around 62 percent are open to exploring it.
      For those who go the green burial route, there now are a variety of commercially available choices. More adventurous options include a burial suit designed to sprout mushrooms as the body decomposes, an egg-shaped burial pod that eventually grows into a tree and human composting (SN: 2/16/20) — a one- to two-month process that turns the body into soil. In 2019, Washington became the first and only U.S. state to legalize human composting. 
      Conservation burial cemeteries take the green burial concept a step further by doubling as protected nature preserves. To date, the Green Burial Council has certified over 200 green burial sites and eight conservation burial sites in North America.
      Such initiatives showcase a growing awareness that death care choices can have a positive impact on ecosystems, says Lynne Carpenter-Boggs, a soil scientist at Washington State University in Pullman and a research advisor for the Seattle-based human composting company Recompose. But, she cautions, there is still little formal research comparing the environmental impacts of different death care choices.
      Stock and Dennis think this lack of research, coupled with a general lack of awareness of green burial as an available choice, could be the reason why many of the environmentalists they spoke with weren’t yet considering it. But as the option becomes more widely available, Dennis says, “it will be interesting to see how that shifts.” More

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      Climate change helped some dinosaurs migrate to Greenland

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      A drop in carbon dioxide levels may have helped sauropodomorphs, early relatives of the largest animal to ever walk the earth, migrate thousands of kilometers north past once-forbidding deserts around 214 million years ago.
      Scientists pinpointed the timing of the dinosaurs’ journey from South America to Greenland by correlating rock layers with sauropodomorph fossils to changes in Earth’s magnetic field. Using that timeline, the team found that the creatures’ northward push coincides with a dramatic decrease in CO2, which may have removed climate-related barriers, the team reports February 15 in Proceedings of the National Academy of Sciences.
      The sauropodomorphs were a group of long-necked, plant-eating dinosaurs that included massive sauropods such as Seismosaurus as well as their smaller ancestors (SN: 11/17/20). About 230 million years ago, sauropodomorphs lived mainly in what is now northern Argentina and southern Brazil. But at some point, these early dinosaurs picked up and moved as far north as Greenland.
      Exactly when they could have made that journey has been a puzzle, though. “In principle, you could’ve walked from where they were to the other hemisphere, which was something like 10,000 kilometers away,” says Dennis Kent, a geologist at Columbia University. Back then, Greenland and the Americas were smooshed together into the supercontinent Pangea. There were no oceans blocking the way, and mountains were easy to get around, he says. If the dinosaurs had walked at the slow pace of one to two kilometers per day, it would have taken them approximately 20 years to reach Greenland.

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      But during much of the Late Triassic Epoch, which spans 233 million to 215 million years ago, Earth’s carbon dioxide levels were incredibly high — as much as 4,000 parts per million. (In comparison, CO2 levels currently are about 415 parts per million.) Climate simulations have suggested that level of CO2 would have created hyper-arid deserts and severe climate fluctuations, which could have acted as a barrier to the giant beasts. With vast deserts stretching north and south of the equator, Kent says, there would have been few plants available for the herbivores to survive the journey north for much of that time period.
      Previous estimates suggested that these dinosaurs migrated to Greenland around 225 million to 205 million years ago. To get a more precise date, Kent and his colleagues measured magnetic patterns in ancient rocks in South America, Arizona, New Jersey, Europe and Greenland — all locales where sauropodomorphs fossils have been discovered. These patterns record the orientation of Earth’s magnetic field at the time of the rock’s formation. By comparing those patterns with previously excavated rocks whose ages are known, the team found that sauropodomorphs showed up in Greenland around 214 million years ago.
      Vertebrate fossils from the Late Triassic have been found at a number of sites around the world, some of which are marked (black dots) on this map showing how the continents were arranged about 220 million years ago. New dating of rocks at sites in South America and Greenland pinpoint when long-necked dinosaurs known as sauropodomorphs migrated north.Dennis Kent and Lars Clemmensen
      That more precise date for the sauropodomorphs’ migration may explain why it took them so long to start the trek north — and how they survived journey: Earth’s climate was changing rapidly at that time.
      Around the time that sauropodomorphs appeared in Greenland, carbon dioxide levels plummeted within a few million years to 2,000 parts per million, making the climate more travel-friendly to herbivores, the team reports. The reason for this drop in carbon dioxide — which appears in climate records from South America and Greenland — is unknown, but it allowed for an eventual migration northward.
      “We have evidence for all of these events, but the confluence in timing is what is remarkable here,” says Morgan Schaller, a geochemist at Rensselaer Polytechnic Institute in Troy, N.Y., who was not involved with this study. These new findings, he says, also help solve the mystery of why plant eaters stayed put during a time that meat eaters roamed freely.
      “This study reminds us that we can’t understand evolution without understanding climate and environment,” says Steve Brusatte, a vertebrate paleontologist and evolutionary biologist at the University of Edinburgh, also not involved with the study. “Even the biggest and most awesome creatures that ever lived were still kept in check by the whims of climate change.” More

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      A drop in CFC emissions puts the hole in the ozone layer back on track to closing

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      Good news for the ozone layer: After a recent spike in CFC-11 pollution, emissions of this ozone-destroying chemical are on the decline.
      Emissions of trichlorofluoromethane, or CFC-11, were supposed to taper off after the Montreal Protocol banned CFC-11 production in 2010 (SN: 7/7/90). But 2014 to 2017 saw an unexpected bump. About half of that illegal pollution was pegged to eastern China (SN: 5/22/19). Now, atmospheric data show that global CFC-11 emissions in 2019 were back down to the average levels seen from 2008 to 2012, and about 60 percent of that decline was due to reduced emissions in eastern China, two teams report online February 10 in Nature. 
      These findings suggest that the hole in Earth’s ozone layer is still on track to close up within the next 50 years — rather than being delayed, as it would have been if CFC-11 emissions had remained at the levels seen from 2014 to 2017 (SN: 12/14/16).
      One group analyzed the concentration of CFC-11, used to make insulating foams for buildings and household appliances, in the air above atmospheric monitoring stations around the globe. The team found that the world emitted about 52,000 metric tons of CFC-11 in 2019 — a major drop from the annual average of 69,000 metric tons from 2014 to 2018. The 2019 emissions were comparable to the average annual emissions from 2008 to 2012, Stephen Montzka, an atmospheric chemist at the U.S. National Oceanic and Atmospheric Administration in Boulder, Colo., and colleagues report.

      The new measurements imply that there has been a significant decrease in illicit CFC-11 production within the last couple of years, the researchers say, probably thanks to more rigorous regulation enforcement in China and elsewhere.
      Another group confirmed that emissions from eastern China have diminished since 2018 by analyzing air samples from Hateruma, Japan and Gosan, South Korea. The region emitted about 5,000 metric tons of CFC-11 in 2019, which was about 10,000 metric tons less than its average annual emissions from 2014 to 2017 and was similar to the 2008 to 2012 average. That analysis was led by Sunyoung Park, a geochemist at Kyungpook National University in Daegu, South Korea.

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      The recent downturn in CFC-11 pollution shows that “the Montreal Protocol is working,” says A.R. “Ravi” Ravishankara, an atmospheric scientist at Colorado State University in Fort Collins not involved in either study. When someone violates the treaty, “atmospheric sleuthing” can uncover the culprits and spur countries to take action, he says. “China clearly took action, because you can see the result of that action in the atmosphere.” 
      Montzka cautions that it might not always be so easy to point the finger at rogue emitters. “I think we got lucky this time,” he says, because atmospheric monitoring sites in Asia were able to trace the bulk of illegal emissions to eastern China and monitor the situation over several years. Many places around the world, such as in Africa and South America, lack atmospheric monitoring stations — so it’s still a mystery which countries besides China were responsible for the recent rise and fall of CFC-11 emissions. More