Climate Change Is Threatening Many Species, But One Is Getting a Boost
By Lucy Goodchild van Hilten
A towering elm tree stands 30 meters (approximately 98 feet) tall, somewhere near the border between England and Scotland, defying the fate that so many of its cousins met when Dutch elm disease ravaged the species in the 1970s. One of relatively few elm trees left, it is a haven for wildlife. Look closely and you can see the erratic fluttering of a small brown butterfly, with a W-shaped white streak across its wing.
This butterfly is making history: It's crossed the border into Scotland, where it has settled happily in a native wych elm tree and been sighted in the country for the first time in 133 years. The white-letter hairstreak—Satyrium w-album—has been squeezed slowly out of its habitat over the last 40 years, but now it seems to be getting a helping hand from an unexpected source: climate change.
Although numbers were up slightly in 2017, the white-letter hairstreak isn't doing well in the UK—the population has fallen 93 percent in the last 42 years, according to the United Kingdom Butterfly Monitoring Scheme, with a 59 percent reduction in the last decade alone.
This is largely due to severe loss of habitat. Caterpillars feed on elm; when Dutch elm disease spread through the elm population in England in the 1970s and '80s, the caterpillars' source of food—the trees and their leaves—disappeared, and the butterfly declined. As a result, the white-letter hairstreak has made it onto various priority lists of species that need to be conserved. Volunteers across the country have been keeping an eye out for it.
Return to the Highlands
It was one such volunteer, butterfly recorder Iain Cowe, who made the exciting new discovery in the summer of 2017, in a field near Paxton, Berwickshire, about 100 meters from the English border.
"It is not every day that something as special as this is found when out and about on a regular butterfly foray," Cowe told The Guardian. "It was a very ragged and worn individual found feeding on ragwort in the grassy edge of an arable field."
"Iain is indefatigable—he had an eye to look for it, and he came across it by accident," said Paul Kirkland, director of Butterfly Conservation in Scotland. "A couple of other volunteers found some eggs in the autumn, and Iain's been back this year and found caterpillars, so we now have the full life cycle recorded in Scotland."
The white-letter hairstreak's northward journey is thought to be a response to the warming climate. It's one of about 15 different butterflies heading north; other species spotted for the first time in Scotland include the small and Essex skippers and the comma butterfly, which moved 220 kilometers (approximately 137 miles) from central England to Edinburgh in just 20 years.
"We assume this is related to a warming climate," said Kirkland. "It's hard to prove anything in relation to climate change, but the fact is that, certainly in the UK, Europe and North America, scientists are recording the northward movement of species that were formerly confined to southern areas. We don't know exactly which aspect is important—more sunshine, warmer winters, drier winters—but the core data shows us that many species in the UK are moving northward at different speeds."
We've seen this evidence for some time: In 2011, a team at the University of York in the UK analyzed data from previous studies about animal and plant species. They estimated that, on average, species have moved 12.2 meters (approximately 40 feet) higher in altitude and 17.6 kilometers (approximately 11 miles) northward every decade.
Chris Thomas, a professor of conservation biology at York, led the project. "These changes are equivalent to animals and plants shifting away from the Equator at around 20 cm per hour, for every hour of the day, for every day of the year," he commented. "This has been going on for the last 40 years and is set to continue for at least the rest of this century."
Climate Change: A Double-Edged Sword
The newly comfortable climate in Scotland opens up a whole new world for the butterfly: The country is full of healthy wych elm trees, which have evaded Dutch elm disease and are still prevalent there. According to Kirkland, this is good news for the white-letter hairstreak."They've only been spotted just over the border, but we're confident that there's so much elm in that area that they'll spread. The upshot is if the white-letter hairstreak can struggle north into Scotland, it'll be a very happy butterfly," he said.
Even though climate change now appears to be bringing at least one of the butterflies back, it's still bad news. "Although some of us are seeing a short-term benefit, the overall prognosis is pretty gloomy," said Kirkland. Climate change is threatening many species, but it seems to be giving the white-letter hairstreak a boost.
Species aren't just moving across the border, they're also moving north within Scotland—there is evidence that the northern species of butterfly are suffering due to climate change. Species like the orange-tip, peacock and ringlet have moved further and further north, away from the rising warmth and humidity.
"It's much harder to prove something's disappearing than appearing, but there are some hints that northern species are retreating northward," Kirkland said.
But there is hope for other species. Those struggling to survive in England because of intensive agriculture and development might now find a suitable climate—and unspoiled land—in Scotland. For Kirkland, there's one species, in particular, that might do well to move.
"There's a lovely butterfly called the Duke of Burgundy," he said. "In recent years, it's really been in trouble in England, but I think the climate might be suitable in Scotland now, and there's plenty of habitat here. It won't get here on its own—it's a fussy species, even though it breeds on primrose and pansies."
Kirkland might be "flying a kite" as he puts it, but it's possible that as the climate continues to change, conservation organizations like his could even have a role in relocating butterflies to give them a helping hand.
A Boost for Some Means a Bust for Others
Climate change is also giving some less desirable species a helping hand. In the U.S., the Asian needle ant (Pachycondyla chinensis) is causing mayhem—invading ecosystems, threatening native species and even damaging human health with its potentially deadly sting. In a study in PLOS ONE, researchers from France and Japan modeled the climate in 2020, 2050 and 2080 to work out where the ant could potentially spread to next. Their findings suggest that the ant's habitat could grow by almost 65 percent worldwide.
They wrote: "Our models suggest that the species currently has a far greater potential distribution than its current exotic range, including large parts of the world landmass, including Northeast America, Southeast Asia and Southeast America. ... The results of our study suggest P. chinensis deserves increased attention, especially in the light of on-going climate change."
There's something strange happening in the water, too. The proliferation of "rock snot"—a kind of algae—in eastern Canada was baffling (and angering) the local fishing community, and many thought it was an invasive species brought in by dirty fishing gear. But a 2014 study revealed that the algae had actually been there for decades, and was just growing more due to the changing climate.
The blooms, made up of the diatom Didymosphenia geminata, had been undetectable in the 1970s, but were likely there since the 1800s. "We suspect that climate change is favoring this species in several ways," said the study's lead author Michelle Lavery, currently a Ph.D. candidate in animal behavior at the University of Guelph. For example, warmer air means less ice and therefore less disruption to the flow of water in the rivers; the algal blooms survive better when the water moves less. "Instead of having to start over every summer, they can build on themselves and get bigger and bigger," she explained to Scientific American.
It's not just about warmer temperatures; climate change is also altering the ocean's pH balance, impacting different species in different ways. We know more acidic waters are bad news for coral, but the pH is having an indirect impact too, by favoring a predator.
Adult crown-of-thorns starfish (Acanthaster planci) eat coral—an increase in their number means a decrease in coral. Researchers in Australia wanted to know if the pH of the water affected how much of the coral the young of the starfish eat, determining how many of them survive into their coral-feeding adulthood. In a 2017 study, the team grew juvenile crown-of-thorns and their food, coralline algae, at three different pH levels, going down to 7.6, the level expected in the next few decades.
The results showed that the young starfish ate more in water with a lower pH, possibly because the pH altered the chemical composition and therefore the "taste" of the food. They wrote: "These results indicate that near future acidification will increase the success of early juvenile [starfish] and boost recruitment into the coral-eating life stage."
There's still a lot we don't yet understand about how climate change will impact ecosystems, and indirect effects like these could be surprising. The emergence of the field of climate change ecology is bringing many of these issues to light, but we must continue to monitor individual species and mitigate climate change in order to protect ecosystems.
For now, the white-letter hairstreak is enjoying its new home among Scotland's wych elms, as its cousins are being pushed further and further toward the northern Atlantic coast.
'Fish Fights' Could Erupt as Climate Change Drives Species Across Borders https://t.co/KytZvljuQ6 @foodandwater… https://t.co/rCu90n0tph— EcoWatch (@EcoWatch)1529074092.0
Lucy Goodchild van Hilten is a writing fellow for Earth | Food | Life, a project of the Independent Media Institute.
Republished with permission from our media associate Truthout.
By Melissa Gaskill
Two decades ago scientists and volunteers along the Virginia coast started tossing seagrass seeds into barren seaside lagoons. Disease and an intense hurricane had wiped out the plants in the 1930s, and no nearby meadows could serve as a naturally dispersing source of seeds to bring them back.
Restored seagrass beds in Virginia now provide habitat for hundreds of thousands of scallops. Bob Orth, Virginia Institute of Marine Science / CC BY 2.0<p>The paper is part of a growing trend of evidence suggesting seagrass meadows can be easier to restore than other coastal habitats.</p><p>Successful seagrass-restoration methods include <a href="https://www.sciencedirect.com/science/article/abs/pii/S0304377099000078?via%3Dihub" target="_blank">transplanting shoots</a>, <a href="https://onlinelibrary.wiley.com/doi/10.1111/j.1061-2971.2004.00314.x" target="_blank" rel="noopener noreferrer">mechanized planting</a> and, more recently, <a href="https://www.nature.com/articles/s41467-020-17438-4" target="_blank" rel="noopener noreferrer">biodegradable mats</a>. Removing threats, proximity to donor seagrass beds, planting techniques, project size and site selection all play roles in a restoration effort's success.</p><p>Human assistance isn't always necessary, though. In areas where some beds remain, seagrass can even recover on its own when stressors are reduced or removed. For example, seagrass began to recover when Tampa Bay improved its water quality by reducing nitrogen loads from runoff by roughly 90%.</p><p>But more and more, seagrass meadows struggle to hang on.</p><p>The marine flowering plants have declined globally since the 1930s and currently disappear at a rate equivalent to a football field every 30 minutes, according to the <a href="https://www.unep.org/resources/report/out-blue-value-seagrasses-environment-and-people" target="_blank" rel="noopener noreferrer">United Nations Environment Programme</a>. And research published in 2018 found the rate of decline is <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GB005941" target="_blank" rel="noopener noreferrer">accelerating</a> in many regions.</p><p>The causes of decline vary and overlap, depending on the region. They include thermal stress from climate change; human activities such as dredging, anchoring and coastal infrastructure; and intentional removal in tourist areas. In addition, increased runoff from land carries sediment that clouds the water, blocking sunlight the plants need for photosynthesis. Runoff can also carry contaminants and nutrients from fertilizer that disrupt habitats and cause algal blooms.</p><p>All that damage comes with a cost.</p>
The Value of Seagrass<p>As with ecosystems like rainforests and <a href="https://therevelator.org/mangroves-climate-change/" target="_blank">mangroves</a>, loss of seagrass increases carbon dioxide emissions. And that spells trouble not just for certain habitats but for the whole planet.</p><p>Although seagrass covers at most 0.2% of the seabed, it <a href="https://www.unenvironment.org/news-and-stories/story/seagrass-secret-weapon-fight-against-global-heating" target="_blank">accounts for 10%</a> of the ocean's capacity to store carbon and soils, and these meadows store carbon dioxide an estimated 30 times faster than most terrestrial forests. Slow decomposition rates in seagrass sediments contribute to their <a href="https://www.researchgate.net/publication/238506081_Assessing_the_capacity_of_seagrass_meadows_for_carbon_burial_Current_limitations_and_future_strategies" target="_blank" rel="noopener noreferrer">high carbon burial rates</a>. In Australia, according to <a href="https://onlinelibrary.wiley.com/doi/10.1111/gcb.15204" target="_blank" rel="noopener noreferrer">research</a> by scientists at Edith Cowan University, loss of seagrass meadows since the 1950s has increased carbon dioxide emissions by an amount equivalent to 5 million cars a year. The United Nations Environment Programme reports that a 29% decline in seagrass in Chesapeake Bay between 1991 and 2006 resulted in an estimated loss of up to 1.8 million tons of carbon.</p>
Eelgrass in the river delta at Prince William Sound, Alaska. Alaska ShoreZone Program NOAA / NMFS / AKFSC; Courtesy of Mandy Lindeberg / NOAA / NMFS / AKFSC<p>Seagrasses also protect costal habitats. A healthy meadow slows wave energy, reduces erosion and lowers the risk of flooding. In Morro Bay, California, a 90% decline in the seagrass species known as eelgrass caused extensive erosion, according to a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0272771420303528?via%3Dihub" target="_blank" rel="noopener noreferrer">paper</a> from researchers at California Polytechnic State University.</p><p>"Right away, we noticed big patterns in sediment loss or erosion," said lead author Ryan Walter. "Many studies have shown this on individual eelgrass beds, but very few studies looked at it on a systemwide scale."</p><p>In the tropics, seagrass's natural protection can reduce the need for expensive and often-environmentally unfriendly <a href="https://www.nioz.nl/en/news/zeegras-spaart-stranden-en-geld" target="_blank" rel="noopener noreferrer">beach nourishments</a> regularly conducted in tourism areas.</p><p>Seagrass ecosystems improve water quality and clarity, filtering particles out of the water column and preventing resuspension of sediment. This role could be even more important in the future. By producing oxygen through photosynthesis, meadows could help offset decreased oxygen levels caused by warmer water temperatures (oxygen is less soluble in warm than in cold water).</p><p>The meadows also provide vital habitat for a wide variety of marine life, including fish, sea turtles, birds, marine mammals such as manatees, invertebrates and algae. They provide nursery habitat for <a href="https://wedocs.unep.org/bitstream/handle/20.500.11822/32636/seagrass.pdf?sequence=1&isAllowed=y" target="_blank" rel="noopener noreferrer">roughly 20%</a> of the world's largest fisheries — an <a href="https://www.floridamuseum.ufl.edu/science/seagrass-meadows-harbor-wildlife-for-centuries/" target="_blank" rel="noopener noreferrer">estimated 70%</a> of fish habitats in Florida alone.</p><p>Conversely, their disappearance can contribute to die-offs of marine life. The loss of more than 20 square miles of seagrass in Florida's Biscayne Bay may have helped set the stage for a widespread <a href="https://www.wlrn.org/2020-08-14/the-seagrass-died-that-may-have-triggered-a-widespread-fish-kill-in-biscayne-bay" target="_blank">fish kill</a> in summer 2020. Lack of grasses to produce oxygen left the basin more vulnerable when temperatures rose and oxygen levels dropped as a result, says Florida International University professor Piero Gardinali.</p>
Damaged Systems, a Changing Climate<p>Governments and conservationists around the world have already put a lot of effort into coastal restoration efforts. And that's helped some seagrass populations.</p><p>Where stressors remain, though, restoration grows more complicated. <a href="https://www.rug.nl/research/portal/en/publications/the-future-of-seagrass-ecosystem-services-in-a-changing-world(3a8c56db-7bed-4c9e-ac7f-c72453e2a102).html" target="_blank">Research</a> published this September found that only 37% of seagrass restorations have survived. Newly restored meadows remain vulnerable to the original stressors that depleted them, as well as to storms — and <a href="https://www.ecowatch.com/tag/climate-crisis">climate change</a>.</p>
Seagrass in Dry Tortugas National Park, Florida. Alicia Wellman / Florida Fish and Wildlife / CC BY-NC-ND 2.0<p>In Chesapeake Bay a cold-water species of seagrass is currently hitting its heat limit, especially in summer, according to Alexander Challen Hyman of University of Florida's School of Natural Resources and Environment. As waters continue to warm due to climate change, the species likely will disappear there.</p><p>Climate-driven sea-level rise complicates the problem as well. Seagrasses thrive at specific depths — too shallow and they dry out or are eaten, too deep and there isn't enough light for photosynthesis.</p>
But There’s Good News, Too<p>Luckily, left to its own devices, a seagrass meadow can flourish for hundreds of years, according to a <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1861" target="_blank" rel="noopener noreferrer">paper</a> published last year by Hyman and other researchers from the University of Florida. The researchers arrived at their conclusion by looking at shells of living mollusks and fossil shells to estimate the ages of meadows in Florida's Big Bend region on the Gulf Coast.</p><p>That area has extensive, relatively pristine seagrass meadows. "Our motivation was to understand the past history of these systems, and shells store a lot of history," said co-author Michal Kowalewski.</p><p>A high degree of similarity between living and dead shells indicates a stable area, while a mismatch suggests an area shifted from seagrass to barren sand. The researchers found that long-term accumulations of shells resembled living ones, suggesting that the seagrass habitats have been stable over time.</p><p>That stability allows biodiversity to thrive, creating conditions where specialist species can survive and flourish, according to Hyman.</p><p>Discovering the long-term stability of seagrass meadows has implications for choosing restoration sites, Kowalewski notes.</p><p>"There must be reasons they thrive in one place, while a mile away they don't and fossil data says they probably never did," he said. "If we remove a seagrass patch, we cannot hope to plant it somewhere else. It's not just the seagrass that is special. The location at which it's found is special, too."</p><p>A better approach is conserving these habitats in the first place, but we're not doing enough of that right now. The UN reports that marine protected areas safeguard just 26% of recorded seagrass meadows, compared with 40% of coral reefs and 43% of mangroves.</p>
EcoWatch Daily Newsletter
Carbon dioxide levels in the atmosphere hit a new record in 2019 and have continued climbing this year, despite lockdowns and other measures to curb the pandemic, the World Meteorological Organization (WMO) said on Monday, citing preliminary data.
- 13 Must-Read Climate Change Reports for 2020 - EcoWatch ›
- Large Methane Leaks Soar 32% Despite Lockdowns and Green ... ›
These black-and-white lizards could be the punchline of a joke, except the situation is no laughing matter.
By Isabella Garcia
September in Portland, Oregon, usually brings a slight chill to the air and an orange tinge to the leaves. This year, it brought smoke so thick it burned your throat and made your eyes strain to see more than 20 feet in front of you.
- 16 Essential Books About Environmental Justice, Racism and Activism ›
- 7 Devastating Photos of Wildfires in California, Oregon and ... ›
- Several West Coast Cities Have the World's Worst Air - EcoWatch ›
- Extremely Rare Leopard Cubs Born in Connecticut Zoo - EcoWatch ›
- Small Wild Cats Face Big Threats Including Lack of Conservation ... ›
- 5 Species Bouncing Back From the Brink of Extinction - EcoWatch ›