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US lost a fifth of its butterflies within two decades

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Thursday, March 6, 2025

US lost a fifth of its butterflies within two decades Maddie MolloyBBC Climate & ScienceJack CochranThe Danaus eresimus, commonly known as the soldier butterfly, is among the 20 butterfly species experiencing the steepest declineButterfly populations in the US shrank by more than a fifth within the space of two decades, according to a new study.Numbers fell by 22% between 2000 and 2020, according to research by Binghamton University in New York.A third of species saw serious decline, with some, like Julia's Skipper, losing more than 90% of their populations.However, the researchers say butterflies may be able to recover if urgent conservation measures are taken.The study published in the journal Science measured butterfly "abundance" - the number of individuals of a species within a specific area. It analysed 12.6 million butterfly sightings from 76,000 surveys across 35 monitoring programmes.This included data from citizen science programmes like the North American Butterfly Association's Fourth of July counts.Using statistical models, they estimated population trends for 342 species.The results showed that 33% were in significant decline, with many exhibiting extreme losses - 107 species declined by more than 50%."While the results aligned with global trends, seeing the extent of the decline at such a large spatial scale was sobering," said Prof Eliza Grames, an assistant professor of biological sciences at Binghamton University.Randy BodkinsThe West Virginia White (Pieris virginiensis) - a woodland butterfly - has declined in abundance by more than 98%Some of the most affected species include the Florida white, Hermes copper, tailed orange, Mitchell's satyr, and West Virginia white, all of which have declined in abundance by more than 98% within the US.The West Coast lady, once a common backyard butterfly, has declined by 80%, raising alarm as even this highly adaptable species struggled."That's alarming because it suggests even common butterflies aren't safe," Prof Grames said.Habitat loss, pesticides, and climate change are key causes of this decline, according to the researchers.Butterflies are crucial pollinators, supporting plants and crops. Experts say their decline could disrupt food production and entire ecosystems.They also serve as indicators of environmental health - when butterfly numbers fall, it signals trouble for other species.Southwest US most affectedSpecies are declining most severely in the US Southwest, one of the hottest and driest regions, researchers say. They believe drought may be a major contributor to these losses."Drought is a double threat - it harms butterflies directly and also affects their food and host plants," Prof Grames explained.The results could help drive important conservation efforts, such as prioritising species for the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and Endangered Species Act protection.Despite the decline, there is hope for recovery."Butterflies can recover quickly because they have short generation times. Small actions like planting wildflowers, reducing pesticide use, or even leaving part of a backyard unmowed can significantly improve their chances," Prof Grames said.She also stressed the need for government action."Insects are fundamental to life on earth, and we need conservation actions and policies that support insects."

However the researchers say butterflies may be able to recover if urgent conservation measures are taken.

US lost a fifth of its butterflies within two decades

Maddie Molloy

BBC Climate & Science

Jack Cochran A Danaus eresimus butterfly perched on a light purple flower. The butterfly has rich orange-brown wings with black veins and a black border adorned with white spots. Its body is black with small white speckles. The background is a lush green.Jack Cochran

The Danaus eresimus, commonly known as the soldier butterfly, is among the 20 butterfly species experiencing the steepest decline

Butterfly populations in the US shrank by more than a fifth within the space of two decades, according to a new study.

Numbers fell by 22% between 2000 and 2020, according to research by Binghamton University in New York.

A third of species saw serious decline, with some, like Julia's Skipper, losing more than 90% of their populations.

However, the researchers say butterflies may be able to recover if urgent conservation measures are taken.

The study published in the journal Science measured butterfly "abundance" - the number of individuals of a species within a specific area. It analysed 12.6 million butterfly sightings from 76,000 surveys across 35 monitoring programmes.

This included data from citizen science programmes like the North American Butterfly Association's Fourth of July counts.

Using statistical models, they estimated population trends for 342 species.

The results showed that 33% were in significant decline, with many exhibiting extreme losses - 107 species declined by more than 50%.

"While the results aligned with global trends, seeing the extent of the decline at such a large spatial scale was sobering," said Prof Eliza Grames, an assistant professor of biological sciences at Binghamton University.

Randy Bodkins A West Virginia White butterfly is perched on a cluster of small white flowers. The butterfly has delicate, white wings with a faint hint of veins visible. The plant has bright green, serrated leaves and a slender stem. The background is blurred, creating a soft contrast with the sharply focused butterfly and plant. Randy Bodkins

The West Virginia White (Pieris virginiensis) - a woodland butterfly - has declined in abundance by more than 98%

Some of the most affected species include the Florida white, Hermes copper, tailed orange, Mitchell's satyr, and West Virginia white, all of which have declined in abundance by more than 98% within the US.

The West Coast lady, once a common backyard butterfly, has declined by 80%, raising alarm as even this highly adaptable species struggled.

"That's alarming because it suggests even common butterflies aren't safe," Prof Grames said.

Habitat loss, pesticides, and climate change are key causes of this decline, according to the researchers.

Butterflies are crucial pollinators, supporting plants and crops. Experts say their decline could disrupt food production and entire ecosystems.

They also serve as indicators of environmental health - when butterfly numbers fall, it signals trouble for other species.

Southwest US most affected

Species are declining most severely in the US Southwest, one of the hottest and driest regions, researchers say. They believe drought may be a major contributor to these losses.

"Drought is a double threat - it harms butterflies directly and also affects their food and host plants," Prof Grames explained.

The results could help drive important conservation efforts, such as prioritising species for the International Union for Conservation of Nature (IUCN) Red List of Threatened Species and Endangered Species Act protection.

Despite the decline, there is hope for recovery.

"Butterflies can recover quickly because they have short generation times. Small actions like planting wildflowers, reducing pesticide use, or even leaving part of a backyard unmowed can significantly improve their chances," Prof Grames said.

She also stressed the need for government action.

"Insects are fundamental to life on earth, and we need conservation actions and policies that support insects."

Read the full story here.
Photos courtesy of

Reform of NZ’s protected lands is overdue – but the public should decide about economic activities

Changes to New Zealand’s conservation laws could delist up to 60% of protected areas. There are better ways to balance ecological values with economic gains.

Getty ImagesThe government’s proposed reforms of the rules governing public conservation land aim to dismantle any potential obstacle to “unleashing economic growth” in protected areas. Currently, about a third of New Zealand’s land is under protection. This ranges from national parks (11.6%) to stewardship areas (9.4%) and conservation parks (5.7%). Twelve other designations make up the rest. Some commercial activities are permitted – including guided walks, aircraft-based sightseeing, ski fields and animal grazing – and approved by the Department of Conservation as “concessions”. The proposed changes to the Conservation Act include a review of land designation. The government could delist or swap up to 60% of the current area under protection. Conservation Minister Tama Potaka said he can’t indicate which designations or locations would be delisted. Nor can he say what percentage of conservation lands would be affected – and where – because changes will be driven by demand for land. The minister only committed to leaving untouched the designations that are difficult to change: national parks, wilderness areas, reserves and world heritage sites. The question of whether more economic benefits can be obtained from protected areas is legitimate. New Zealand does need a radical reform of its conservation areas and legislation. There is potential for better social and economic outcomes. But the proposal consolidates ministerial discretion to unprecedented levels and the government follows a misguided fast-track approach to permitting economic activities such as mining. This could take native biodiversity into dangerous territory. Outdated conservation laws New Zealand holds tight to an outdated approach known as “fortress conservation”. This limits commercial opportunities to specific areas, mostly concentrated around established facilities (roads, hotels) and the edges of designated lands. Even when regulating other activities such as energy generation or agriculture, the idea has been to “sacrifice” some spaces and keep as much land as possible “locked up”. A key reason was that people didn’t know enough about the ecological values of the land. As a proxy, lawmakers relied on the subjective concepts of wilderness values and intrinsic values to justify strict protections over most lands. Insufficient scientific input meant authorities have relied on “ecologically blind” zoning frameworks, such as a planning tool known as the recreation opportunity spectrum. This divides lands according to recreational opportunities and visitor needs. But there is a better path forward – one that allows public decision making and honours international commitments, while achieving better ecological and economic benefits. Towards regulations informed by science This alternative approach is grounded in three key principles. First, it uses gap analysis to identify which ecosystems and species are underprotected. Second, it relies on regulations shaped by ecological knowledge and conservation priorities. Third, it applies the principles of proportionality and precaution, meaning that regulatory responses should match the severity, reversibility and likelihood of environmental harm. Currently, New Zealand’s regulatory framework does not reflect this. New Zealand has signed the Kunming-Montreal Global Biodiversity Framework. This means at least 30% of conservation lands must be representative of most, if not all, native ecosystems by 2030. At present, coastal, lowland and dryland ecosystems are under-represented. In contrast, alpine and montane environments, are represented way above the recommended threshold (20% of the remaining cover for that ecosystem). If up to 60% of conservation lands were to be swapped or delisted without prioritising representativeness, vulnerability and rarity, the ecological losses may be immense and irreversible. Rethinking protection categories My research develops a broader reform approach. It also reflects growing international consensus on the need for science-informed conservation planning. I argue New Zealand should set up region-specific and nationwide fora, such as citizen assemblies or consensus conferences. Conversations should focus on specific topics, informed by scientists and iwi. Vulnerable or under-represented ecosystems currently require stronger protection. Deliberations should indicate which activities should be limited or excluded to better protect such areas. We must also consider vulnerability to climate change. Scientists expect that ecosystems may migrate outside protected areas. Consensus should be built around what qualifies as a “significantly over-represented” native ecosystem. Where ecosystems are already well protected and resilient, the public should discuss whether re-designation, land exchanges or even disposals may be appropriate. If lands are retained, consensus should be sought on the economic uses that can maintain ecological health. If the public doesn’t support land delisting or swaps, alternative strategies must be developed to improve ecological representativeness. Sustainable funding mechanisms should also be identified to support these efforts. The Department of Conservation should work with independent scientists and iwi to develop a new zoning framework to guide commercial concessions and recreational access. This framework should capture the principles highlighted above. When applied to each area, it should also enable the mapping of the ecological values feasible to protect. This would help select bespoke regulatory options. In turn, it would balance biodiversity and economic outcomes for each context. Guidance for these steps should be incorporated in a new national strategy, aligned with domestic goals such as the biodiversity strategy and international commitments. New Zealand has the expertise for smart reforms. New Zealanders have the passion for nature and patience required to engage in deliberations. But will politicians have the wisdom to avoid a totally unnecessary mutilation of conservation lands, for undefined biodiversity gains? Valentina Dinica does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

EPA to undergo layoffs amid shutdown fight

The Environmental Protection Agency (EPA) is among the agencies where federal workers will be laid off by the Trump administration in the ongoing federal government shutdown. Employees in the EPA’s Resource Conservation and Sustainability Division received an email indicating that the agency would be undertaking a reduction in force (RIF).  That division undertakes recycling initiatives and...

The Environmental Protection Agency (EPA) is among the agencies where federal workers will be laid off by the Trump administration in the ongoing federal government shutdown. Employees in the EPA’s Resource Conservation and Sustainability Division received an email indicating that the agency would be undertaking a reduction in force (RIF).  That division undertakes recycling initiatives and seeks to reduce food waste and plastic pollution. It’s not immediately clear how many people will be impacted and if any additional offices within EPA will also face layoffs.  “This notice is to inform you that the U.S. Environmental Protection Agency will be conducting a Reduction in Force,” said the email from Steven Cook, principal deputy assistant administrator for the Office of Land and Emergency Management.  “This action is necessary to align our workforce with the Agency’s current and future needs and to ensure the efficient and effective operation of our programs,” Cook wrote.  Asked about layoffs broadly, an EPA spokesperson told The Hill via email, "It’s unfortunate that Democrats have chosen to shut down the government and brought about this outcome. If they want to reopen the government, they can choose to do so at any time.”  The agency did not address questions from The Hill about which offices were facing cuts and how many people would be fired. It did not immediately respond to follow up questions about the resource conservation and sustainability division. Unions representing federal employees have been critical of the Trump administration’s moves.  “This is the latest way that the Trump administration is weaponizing this furlough against federal employees, stopping them from serving the American people to the best of their ability,” Nicole Cantello, president of the AFGE Local 704 union, which represents EPA staffers in the Midwest,  told The Hill. The notice comes after the Trump administration threatened to lay off federal workers if Democrats do not pass a bill to fund the government. Democrats are trying to get Republicans to pass legislation aimed at bringing down healthcare costs before they agree to fund the government. The administration has also more broadly sought to cut the federal workforce, including through earlier rounds of layoffs and buyouts. 

More than half of world’s bird species in decline, as leaders meet on extinction crisis

Biodiversity losses are growing, the IUCN reports as summit opens, but green turtle’s recovery ‘reminds us conservation works’More than half of all bird species are in decline, according to a new global assessment, with deforestation driving sharp falls in populations across the planet.On the eve of a key biodiversity summit in the UAE, scientists have issued a fresh warning about the health of bird populations, with 61% of assessed species now recording declines in their numbers. Continue reading...

More than half of all bird species are in decline, according to a new global assessment, with deforestation driving sharp falls in populations across the planet.On the eve of a key biodiversity summit in the UAE, scientists have issued a fresh warning about the health of bird populations, with 61% of assessed species now recording declines in their numbers.From Schlegel’s asity in Madagascar to the tail-bobbing northern nightingale-wren in Central America, many bird species have lost habitat to expanding agriculture and human development. Just nine years ago, 44% of assessed bird species had declining populations, according to the red list of endangered species from the International Union for Conservation of Nature (IUCN).Dr Ian Burfield, BirdLife’s global science coordinator, who helped oversee the assessment, said: “That three in five of the world’s bird species have declining populations shows how deep the biodiversity crisis has become and how urgent it is that governments take the actions they have committed to under multiple conventions and agreements.”It comes as hundreds of conservationists gather in Abu Dhabi on Friday for the IUCN’s congress, where the fate of many of the world’s most at-risk wildlife species will be discussed. In the face of global headwinds on environmental action, scientists are urging governments to deliver on recent pledges to better protect nature.Birds play an important role in ecosystems, helping to pollinate flowers, disperse seeds and control pests. Hornbills – which are found across the tropics – can spread up to 12,700 large seeds a day in a square kilometre.Dr Malin Rivers, head of conservation prioritisation at the Botanic Gardens Conservation International, said: “The fates of birds and trees are intertwined: trees depend on birds for regeneration and birds depend on trees for survival.”The green sea turtle’s recovery “reminds us that conservation works”, said the IUCN director general, Dr Grethel Aguilar. Once classified as endangered, it is now viewed as a species of least concern due to conservation efforts. The turtles’s numbers have grown by 28% since the 1970s thanks to greater protection for nest sites in Ascension Island, Brazil, Mexico and Hawaii.A Pacific green sea turtle cruising off Hawaii. The recovery of the species shows what global conservation efforts can achieve, experts say. Photograph: Chris Strickland/AlamyRoderic Mast, co-chair of IUCN’s species survival commission marine turtle specialist group, said the green turtle’s recovery was “a powerful example of what coordinated global conservation over decades can achieve to stabilise and even restore populations of long-lived marine species”.But there was bad news for Arctic seals, which scientists warn are drifting closer to extinction due to global heating. The loss of sea ice has seen population numbers for bearded and harp seals fall sharply. Thinning sea ice means that the Artic seals are finding it more difficult to find areas to rest and breed. They are a critical prey species for polar bears, which researchers fear will also be affected by the loss.Dr Kit Kovacs, Svalbard programme leader at the Norwegian Polar Institute, said: “Each year in Svalbard, the retreating sea ice reveals how threatened Arctic seals have become, making it harder for them to breed, rest and feed.“Their plight is a stark reminder that climate change is not a distant problem – it has been unfolding for decades and is having impacts here and now.”Find more age of extinction coverage here, and follow the biodiversity reporters Phoebe Weston and Patrick Greenfield in the Guardian app for more nature coverage.

Would a ban on genetic engineering of wildlife hamper conservation?

Some conservation groups are calling for an effective ban on genetic modification, but others say these technologies are crucial for preserving biodiversity

The idea of genetically modifying wild lions divides opinionAndrewfel/Shutterstock Should we genetically modify wild lions? Of course not, might be your instant response. But what if lions were being wiped out by a devastating disease introduced by people? What if the genetic change was a tiny tweak that makes them immune to this disease, of the sort that might evolve naturally given enough time and enough dead lions? These kinds of questions are dividing conservationists, and matters are about to come to a head. In the coming week, at a meeting of the International Union for Conservation of Nature (IUCN) – the world’s leading conservation organisation – delegates will vote on a motion that would “pause” any form of genetic engineering of wildlife, including the introduction of modified microbes. “I have no idea how the vote will go,” says Piero Genovesi at the Institute for Environmental Protection and Research in Italy, who helped draft an open letter opposing the proposed motion. An IUCN moratorium on synthetic biology would have no legal force, but it could still have far-reaching effects. For instance, many conservation organisations might stop funding work involving genetic engineering, and some countries could make such a ban part of national laws. “The moratorium would certainly be problematic on many levels,” says Ben Novak at Revive & Restore, a US-based non-profit that aims to use biotechnologies to rescue endangered and extinct species. Why is this happening now? In a word, CRISPR. In 2014, it was shown that CRISPR gene-editing technology can be used to create gene drives – basically, a piece of DNA that gets passed down to all offspring, rather than the usual half. This means a gene drive can spread even if it is harmful and could, in theory, be used to wipe out invasive species. Gene drives could also be used to spread beneficial traits, such as disease resistance. At a conference in Hawaii in 2016, there was talk of using gene drives to get rid of the invasive mosquitoes that have wiped out half of Hawaii’s native bird species, says Genovesi. Some conservationists were enthusiastic; others were horrified. That triggered the events leading to the proposed moratorium. “Gene drives are being pushed quite strongly by some as the panacea for dealing with all sorts of environmental problems,” says Ricarda Steinbrecher at EcoNexus, a research organisation that is among those backing a moratorium. But the broad wording of the proposed motion applies to far more than gene drives. It would rule out most de-extinction efforts, for instance, and could also be seen as banning live vaccines. Steinbrecher says a moratorium is a pause, not a permanent block, and that there could be another vote to end it “when we have more data”. But some of those backing the ban are campaign groups opposed to any genetic engineering, so it is hard to see what would change their minds. “I am afraid it could be a very long ban,” says Genovesi. Take the idea of using gene editing to make wild animals resistant to diseases. Steinbrecher says gene editing could have unintended side effects. But the evidence we have suggests the risks are low – which is why several gene-edited foods are already being eaten, and why the first CRISPR treatment for people got approved last year. The same benefits-versus-risks considerations apply with conservation. Is it really better to stand by and watch coral reefs being wiped out by global warming than to, say, release genetically engineered algal symbionts that give corals more heat tolerance? A key issue is scalability, says Novak. Divers transplanting corals by hand are never going to save reefs. “This is where synthetic biology tools are vital,” he says. “The overall goals of restoring 30 per cent of land to nature, of saving species, etc, will not be attainable without synthetic biology.” Ultimately, this is about competing visions of nature. Some see nature as pristine and sacrosanct, and are appalled by the idea of any genetic meddling. But humans have been transforming nature ever since we wiped out most megafauna. We are already unintentionally meddling genetically by imposing all kinds of selection pressures. Hunting, pollution, pesticides, invasive species and introduced diseases are forcing many plants and animals to change to survive. Some elephant populations are nearly tuskless, for instance. Of course, this doesn’t mean that more meddling will make things better. There are indeed serious risks to releasing gene drives – for instance, gene drives designed to wipe out invasive species might spread to the native range of the target species. But researchers are very aware of the risks. And there are ways to reduce them, for instance by making gene drives self-limiting so they cannot just spread indefinitely. “We are facing a dramatic crisis of biodiversity,” says Genovesi. “We shouldn’t close the door to new tools that could help us combat some of the major threats.” Conservation and rewilding in the Central Apennines: Italy Journey into Italy’s Central Apennines region for a fascinating introduction to the concept and practicalities of rewilding.

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