Philippa Kaur

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In 1874, Nature published a book review by the biologist Alfred Russel Wallace of The Naturalist in Nicaragua, in which author Thomas Belt hypothesized that leafcutter ants cultivate fungi in their nests (A. R. Wallace Nature 9, 218–221; 1874). Later that year, it published a letter from German biologist Fritz Müller to Charles Darwin, confirming that leafcutter ants rely on fungal symbionts to digest the plant material they collect (F. Müller Nature 10, 102–103; 1874).
Competing Interests
The authors declare no competing interests. More

Before They Vanish: Saving Nature’s Populations — and Ourselves Paul R. Ehrlich et al. Johns Hopkins University Press (2024)Biologist Paul Ehrlich has a history of failed predictions. For example, his 1968 book The Population Bomb forecasted mass famine around the world owing to growth in human numbers outpacing food production. In Before They Vanish, however, it’s hard to see him being wrong. Ehrlich and his colleagues present powerful evidence of global wildlife decline and more extinctions to come. Yet, it’s a pessimistic portrayal, which undersells reasons to be optimistic about conservation. This matters because optimism has a contribution to make in slowing extinctions.Conservation policies must address an overlooked issue: how war affects the environmentThe book opens with the story of the Steller’s sea cow (Hydrodamalis gigas), an eight-metre-long mammal, which was described in 1741 by a German zoologist marooned in the Bering Strait. Within just 27 years, it was extinct. The authors use this well-known example to explain how extinctions can cascade through an ecosystem, by showing how the local extinction of sea otters (Enhydra lutris), which were hunted for the fur trade, contributed to the sea cows’ demise. The loss of the otters allowed a population explosion of their sea urchin prey, which overgrazed the kelp forests on which the sea cows depended.A reader new to the science of extinction will learn a lot from this book. Many underpinning concepts in conservation biology are expertly explored, and the authors take a novel angle by emphasizing the role of population extinction as a step to species extinction. They go on to present a compendium of extinctions, from birds to bivalves, pangolins to pandas, and marine fish to microorganisms.Grief for what has been lost permeates the book. And the authors, whose careers have spanned a period of dramatic wildlife decline, use personal anecdotes and rich imagery to powerful effect. Wholescale destruction across evolutionary relationships is described as “mutilation of the tree of life”. Individuals who remain in a landscape long after their population is doomed to extinction are “the living dead”.Yet, I found the book unsatisfying and, worse, it misses opportunities to inspire readers to support conservation action.‘Cocaine of the seas’ — how a luxury food is wreaking ecological mayhemIt is unsatisfying because it avoids tackling difficult questions about the extent to which human well-being really depends on the persistence of threatened species, and it fails to address trade-offs that must be made on a crowded planet. It misses opportunities because, despite the cover blurb promising insights into how species and ecosystems can be saved, it lacks a positive vision for the role of conservation and does little to showcase conservation successes.The authors shy away from addressing, or even acknowledging, the environmentalist paradox: that human well-being, by most measures, has increased even as we have destroyed natural ecosystems1. They argue that extinctions erode the conditions that make life on Earth possible, talking about “existential threats” and “a ghastly future”. However, it is difficult to argue that this is true for the extinction of the Bramble Cay melomys (Melomys rubicola), for example, a rodent found only on an uninhabited island off Australia. Do we really need to say that extinctions of populations threaten humanity’s existence to make a case that they matter?The authors don’t explore the difficult trade-offs that need to be negotiated to ensure the 8.2 billion humans that currently share this planet can thrive. When criticizing the Belt and Road Initiative, China’s massive infrastructure programme, they ignore why many leaders of low- and middle-income countries, desperate for better transport links and energy security, have embraced it. Similarly, biologist Edward Wilson’s controversial calls to protect half of Earth for nature, are presented as a solution to the pressures on remaining wildlife, with no discussion of what this means for people in rural areas who inhabit much of this land.Once the most endangered bird species, Mauritius kestrel (Falco punctatus) numbers are bouncing back through conservation projects.Credit: Fabrice Bettex Photography/AlamyThe authors mention that they themselves will find it difficult to make the behavioural changes needed to reduce their personal impacts on nature (the use of the future tense is interesting here), but how much more difficult is this for people living at the other end of the global income distribution?Across the environmental movement in general, and in conservation specifically, there are increasing calls for more optimism. Marine ecologist Nancy Knowlton has emphasized the value of sharing stories of conservation successes, rather than writing ever-more-sophisticated obituaries for nature2. Although bad news attracts attention, it does not tend to empower or inspire action3.Why repairing forests is not just about planting treesI would have liked to see the authors explore conservation success with the same narrative flair as the descriptions of extinction that make up the bulk of the book. There are so many examples of conservation efforts preventing extinction of populations and even species. To list just a few: the recovery of the saiga antelope (Saiga tatarica), resulting in it being downlisted from critically endangered to near threatened last year; the recovery of the Mauritius kestrel (Falco punctatus) from four individuals in 1974 to a thriving population today; or the rebuilding of breeding bird communities following rat eradication on numerous offshore islands around the world.Ehrlich and his co-authors rightly dismiss de-extinction efforts as being a costly distraction. But they seem overly negative about other approaches to conservation that they cover. Even the rare positive cases they mention are quickly turned around. For instance, the reintroduction of the extinct-in-the-wild Arabian oryx (Oryx leucoryx) ends with concerns over rising poaching and habitat destruction. The section on legal measures is largely a critique of the implementation of the US Endangered Species Act rather than summarizing where legal protection has contributed to the effective conservation of threatened species.Most frustratingly, despite a revolution in conservation evidence over the past 15 years, there’s little reference to evaluating the impact of different approaches or synthesizing such evidence4. Tools such as the Conservation Evidence database are making it easier for conservation practitioners to access information on the impact of interventions on ecological outcomes, and there is a rapidly expanding literature using causal-inference methods to evaluate the impact of conservation policies at scale5.The book dismisses out of hand many actions that, although not solving underlying drivers of extinction, can make an important local contribution to conservation. Certification schemes, such as those that charge a premium for coffee grown in ways that retain some natural tree cover, are apparently an “industry ploy”. Perhaps no coffee production would be better for biodiversity in these landscapes, but given that a lot of people really like coffee, might certification have a part to play?Fall of the wild: why pristine wilderness is a human-made mythComments about former US president Donald Trump will date the book and risk perpetuating unhelpful and untrue ideas that biodiversity conservation is associated with a particular political position. Perhaps more off-putting for many potential supporters of conservation is the undertone of environmental misanthropy. The authors sound almost ambivalent about a future collapse of human civilization. They acknowledge that collapse owing to climate change would be catastrophic for biodiversity as well as for humanity, but imply that such a collapse caused by the “crumbling of the debt pyramid”, would be welcome because it would take the pressure off of nature.The authors’ central thesis is that only economic and demographic transformation can ultimately prevent continued extinction. This is manifestly true. However, conservation science, policy and practice need to ensure that as much nature as possible makes it through to that time when human populations have stabilized, extreme poverty has been eradicated and technological and social changes have reduced pressures on the natural world6.Although I share the authors’ grief for the natural wonders that have been lost, I think that hope is a more powerful emotion. I want anyone interested in the extinction crisis to know about the successes that conservation is having, the increasingly sophisticated use of evidence to improve effectiveness, and the dedication of people from all walks of life and corners of the planet who are committing their energy to nature recovery. Because, ‘before they vanish’, there is still so much we can do. More

The last plenary session of the COP16 biodiversity summit in Cali, Colombia, wrapped up on 2 November.Credit: Joaquin Sarmiento/AFP via GettyTwo years ago, after more than 190 countries at a United Nations summit made a historic pledge to protect the world’s species, questions arose about whether they could afford to keep that promise. At the latest meeting — held in Cali, Colombia, over the past two weeks — fights about conservation funding took centre stage, with little resolution.Can the world save a million species from extinction?But there were some bright spots. One was that negotiators approved an agreement that paves the way for large companies to pay for the use of digital genetic information extracted from nature, if it generates profit. For instance, a highly profitable agribusiness in the United Kingdom might use a digital DNA sequence from a plant found in Brazil to improve a crop. Under the agreement, that business will be encouraged to pay 1% of its profits or 0.1% of its revenue into a fund that could help countries such as Brazil to pay for conservation. The agreement seemed far off before this year’s summit. Civil-society groups and researchers are calling it a crucial victory in the face of rapid decline in global biodiversity. “It is a voluntary mechanism, so there’s everything to be seen about how we get that to work and make sure companies are doing it,” says Yadvinder Malhi, an ecosystems researcher at the University of Oxford, UK. But “it is a big, big win, and we have to go further with it”.Species threatenedResearch released during the Cali summit, called the 16th Conference of the Parties to the Convention on Biological Diversity (COP16), highlighted the urgent need for action on biodiversity.For instance, the International Union for Conservation of Nature, based in Gland, Switzerland, reported that more than one in three tree species is now at risk of extinction, and the conservation organization WWF, also based in Gland, reported that the average size of the globe’s wildlife populations has declined by 73% in 50 years.10 startling images of nature in crisis — and the struggle to save it“We are already at a tipping point, and the change to these ecosystems will be irreversible” if action isn’t taken, says Manuel Pulgar-Vidal, the global leader of climate and energy at the WWF.Yet many researchers were frustrated by what they saw as a lack of progress at COP16. By the close of the summit, only 44 of the 190-plus countries that signed the biodiversity deal two years ago had submitted action plans. And although around US$163 million was pledged in Cali to protect and restore nature, that amount is well short of the $200 billion per year that nations agreed will be needed to attain the goal of protecting 30% of the world’s land and seas by 2030. With nations not yet spending the sums required, there is growing pressure to seek funding from the private sector.Paying for knowledgeFor example, in the agreement to pay for genetic information from nature, otherwise known as digital sequence information (DSI), highly profitable companies are asked to contribute to the conservation ‘Cali Fund’. To be tapped for money, these firms have to hit two of three criteria: they must have $20 million in assets per year, make $50 million in sales per year or make $5 million in profit annually, averaged over the preceding three years. “Conservation is mostly funded by governments and philanthropy,” says Amber Hartman Scholz, head of the science-policy department at Leibniz Institute DSMZ in Braunschweig, Germany. “Now businesses that profit from biodiversity will pay.”Members of Indigenous communities erupted in cheers at COP16 after a formal body representing their interests in biodiversity negotiations was created.Credit: Joaquin Sarmiento/AFP via GettyIf countries create strong legal frameworks to ensure that businesses comply, economic models show that the DSI agreement could bring in between $1 billion and $9 billion annually, Scholz adds. “It’s a step in the right direction,” says Nathalie Seddon, an evolutionary ecologist at the University of Oxford. She is concerned that the agreement doesn’t obligate businesses to pay into the fund and instead leaves it to governments to ensure compliance. But she points out a bright spot: half of the Cali Fund has been earmarked for Indigenous people and local communities, who are often the stewards of land rich in biodiversity. (Negotiators at COP16 also agreed to establish a subsidiary body for Indigenous communities to represent their interests in future biodiversity conservation decisions.)Putting a price on biodiversityThere was much more controversy over discussions of another way to coax businesses to financially support biodiversity conservation: the sale of biodiversity credits.The idea is that companies could purchase biodiversity credits to improve their reputation, to ensure their own survival if they rely on nature-based products and to offset any harm that they are doing to Earth’s species with their operations. The credits would, in turn, pay for conservation projects globally.How biodiversity credits could help to conserve and restore natureDuring COP16, the International Advisory Panel on Biodiversity Credits (IAPB) — a group of 25 specialists in business, conservation and finance from around the world — published its guidelines on how to establish and scale up the scheme. But the release was met with criticism.The plan has been compared with carbon credits, which companies can purchase to offset their release of greenhouse-gas emissions. Carbon credits have been derided for potential links to human-rights violations and for generating profits for intermediary businesses that sell the credits while failing to actually reduce emissions.“Government donations are the only thing that’s put significant amounts of money towards nature, and those efforts are getting diminished by talk of selling biodiversity credits, which are convoluted, unproven and have no demand,” says Brian O’Donnell, director of the environmental-advocacy organization Campaign for Nature, who is based in Durango, Colorado.According to a December 2023 report from the World Economic Forum, if biodiversity credits gain traction quickly like carbon credits, global demand for them could reach $2 billion per year by 2030 and $69 billion by 2050.IAPB member Simon Zadek, chief executive of NatureFinance — a non-profit organization in Geneva, Switzerland, that is working to increase the role of finance in conservation — argues that the “disgrace” of voluntary carbon markets provides lessons that will make it possible to design a biodiversity-credit market that works. For instance, says Zadek, the panel has recommended that there should be no secondary trading of biodiversity credits, as is done by intermediary companies in the carbon market. Instead, the panel proposes a national model in which businesses that damage nature are taxed by their government. The proceeds would buy national biodiversity credits to fund 20–25-year nature-restoration programmes.If the IAPB does not push the creation of a market for biodiversity credits, “there is a real risk” that private firms, including those already involved in the carbon market, will go it alone with no oversight, Zadek says. This would “generate a mess”. More

“The bird in my hand is a yellow-breasted chat (Icteria virens). This species breeds in North America — occurring in southern British Columbia and southwestern Ontario in Canada and in much of the United States — and then migrates to Mexico and Central America during the Northern Hemisphere’s autumn months. The chat is a declining species in North America, in part because it relies on habitat adjacent to bodies of water such as rivers and streams, much of which has been destroyed. In 2001, one population in the Okanagan valley in Canada had just 25 breeding pairs remaining. But conservation actions, including monitoring these birds and restoring their habitats, have helped their populations to recover. There are now more than 250 breeding pairs in the area.This photo was taken in February 2024 in Asunción Atoyaquillo, near Tlaxiaco, Mexico. We know that population declines in North America can be linked not only to what happens in Canada and the United States, but also to what happens during migration or at the wintering grounds. Two years ago, I started a project with Scott Wilson, my colleague at Environment and Climate Change Canada in Delta, British Columbia, and several collaborators in Mexico, to study these birds during the winter to better understand the threats that they face.Here, Sergio Gómez-Villaverde (left) and Adrián Cabrera-Valenzuela (right) are helping me to tag a chat with a radio transmitter so that we can track its movement. We tagged 30 chats this year. Sergio leads a bird-conservation organization in Oaxaca, Mexico, and Adrián is a field biologist at the Bird Observatory of Tlaxiaco.One thing I love about this photo is that it shows that I don’t work alone. Sergio is holding a radio transmitter in a pair of tweezers, while Adrián is recording data. Could I do this work by myself? Probably, but it’s a lot easier when you have partners.” More

Halloween, celebrated on 31 October, originated with the ancient Celtic festival of Samhain, during which people lit bonfires and wore costumes to ward off spirits. Today, it’s a holiday synonymous with not just witches and ghouls, but also crows, bats, owls, snakes and other ‘spooky’ creatures. Nature asked nine scientists what inspired them to study unorthodox animals and plants and what they want the world to know about their favourite organisms, and gave them the chance to correct misconceptions around the much-maligned reputations of these flora and fauna.IVO JACOBS: The ‘playful genius’ of crowsIvo Jacobs studies the evolution of cognition at Lund University in Sweden.Ivo Jacobs says that ravens compete to participate in his group’s research on cognition.Credit: Ivo JacobsCorvids, birds in the crow family, have quite the mythological status — from ominous tricksters to playful geniuses — across diverse cultures. I have always been fascinated by how creatures with walnut-sized brains and no hands have cognitive capacities similar to those of great apes1, despite the evolutionary gap of 320 million years. This suggests that complex cognition has evolved independently several times. Cognition is a solution to buffer against environmental changes that occur faster than evolution. I examine the problem-solving abilities that help corvids, such as the common raven (Corvus corax), to adjust to changing conditions.Misconceptions about corvids are rife: they are often viewed as unpleasant and dangerous birds, exhibiting behaviours such as pecking out of frustration. However, they are more likely to gently preen your eyebrows than to try plucking out your eyes. My chances of leaving the aviary with a peck mark are lower than the likelihood of them undoing my shoelaces, stealing my hat or stashing food in my pockets. I once had the surreal experience of explaining to airport security why a piece of rotten liver had fallen out of my jacket.Our corvids enjoy participating in research — essentially playtime for food rewards — so much that they compete to enter the testing room. Another widespread myth is that corvids have a proclivity to steal shiny things. Our research revealed that they prefer round objects that are not shiny2. Sometimes, they will even forgo food to take a small wooden ball. Their extensive play with objects fuels their innovative tool use.LINFA WANG: Bats help to unravel infectious diseasesLinfa Wang studies zoonotic diseases and bat immunology at Duke-NUS Medical School in Singapore.Studying viruses in bats can help to better understand human disease, says Linfa Wang.Credit: Dr Feng Zhu/Duke-NUSI became interested in bats because the viruses that my research group studies, including Hendra virus, Nipah virus and SARS-CoV-1, are transmitted by them. The question of why bats can carry so many viruses without showing signs of disease propelled me to study bat genomics and immunology. The more I study these creatures, such as the cave nectar bat (Eonycteris spelaea), the more fascinated I am by their unique traits — from their relatively long lifespan to their resistance to cancer. We are motivated to discover bat-inspired therapeutics to treat disease in people.Many people mistakenly blame bats for viral outbreaks of severe acute respiratory syndrome and COVID-19. I try to emphasize that it is not the bats’ fault. They have co-existed with these viruses for millions of years, and it is human activities that have led to these spillover events.This field was very small 15–20 years ago, and it was hard to get funding and standard research tools. As a pioneering ‘batman’, I worked to expand the field. Here are some tips to do so for your favourite organism: first, focus on gathering essential tools and reagents, such as cell lines, a breeding colony, sequenced genomes and organism-specific antibodies. Second, share your resources with as many groups as possible. Third, actively promote and participate in activities in your organism’s research community, including workshops and symposiums. Fourth, convince funding bodies to expand this area of research. And finally, solicit commercial companies to support your efforts to develop products inspired by the organism.DAVID HU: Physics behind cat tongues and wombat pooDavid Hu is a biophysicist at the Georgia Institute of Technology in Atlanta.Cat tongues look creepy in a close-up, and inspire better brush designs.Credit: Alexis Noel and David HuI study the physics of animal form and movement, with the goal of designing bio-inspired robots and devices. I have studied how a cat’s tongue functions as a cleaning brush, how wombats produce cube-shaped poo and how elephants reach with their trunks. My work gathers inspiration from a variety of unconventional model organisms, and they have a key role in bio-inspired design of complex materials and soft adaptable robots.Many people think bio-inspiration is simply about searching for ideas by watching animal videos on the Internet. Long ago, biologists taught me to work with animals in person, filming them and collecting biological samples. I have since worked with zoos, aquariums, museums and field stations to find animal subjects. This process takes longer, but leads to so many discoveries.Animals do not usually do what you want. Studying each species requires techniques that I have learnt from animal specialists. An hour of networking can save days or months in the laboratory or field, turning seemingly impossible experiments into achievable ones.A big misperception about animals is that scientists already know everything about them. The simplest-looking movements, such as the leap of a cat or shake of a dog, cannot be robustly replicated by robots. Understanding how animals can move so well in unpredictable environments will help us to build devices that can do the same.MOYUAN CAO: Cacti offer a prickly way to collect waterMoyuan Cao is a materials scientist at Nankai University in Tianjin, China.After millions of years of evolution, plants and animals have developed superb abilities to manipulate and collect fluids. These processes are efficient, energy-saving and diverse — and offer numerous ideas to improve technology to collect water in arid environments. My work focuses on fluid-transport processes on bio-inspired interfaces that mimic cactus spines. In cactus clusters, a water droplet on the conical spine moves from the spine tip to its root. When the droplet reaches the root, the hydrophilic trichome — a fine outgrowth on the surface — rapidly absorbs it into the stem.My team has designed a fog collector, which acts like a cactus spine. These cactus-like devices are useful for collecting water in arid, foggy regions with no surface water, for example deserts near the sea, such as the Namib desert in southern Africa, and coastal mountain ranges, such as those near Antofagasta, Chile. Nature might have already found the best solution for unique environments, and my role is to identify the environmental conditions where those solutions can be best applied.DRIES KUIJPER: Debunking the false folklore about wolvesDries Kuijper is an ecologist at the Mammal Research Institute of the Polish Academy of Sciences in Białowieża.Centuries ago, the balance between humans and wolves was different — there was more wilderness, more wolves and fewer people. Back then, most wolf–human accidents involved wolves with rabies, whose behaviour is very unnatural, and this led to the folklore that wolves are dangerous. Interestingly, a review of all documented cases of wolves attacking humans from 2002 to 2020 shows that, despite large increases in wolf numbers in human-dominated landscapes of Europe, there has not been an increase in attacks (see go.nature.com/4iuop). No fatal attacks, and only a few bite incidents, have been documented in the past 20 years in Europe. Wolves are not dangerous to us, but people should respect the boundaries needed to keep wolves wild.From the archive: Halloween horrorsI study how grey wolves (Canis lupus) affect the functioning of ecosystems in the Białowieża forest in eastern Poland and in other places in Europe. I was inspired by the reintroduction of wolves in Yellowstone National Park in Montana, Idaho and Wyoming, and how it caused trophic cascading effects: the wolves decreased the density of prey species, such as deer, which reduced the deer’s feeding on young trees, and that facilitated tree regeneration. But I realized pretty quickly that the Białowieża forest is very different from Yellowstone’s vast wilderness. Outside the Białowieża National Park, the forest hosts plenty of human activities. People live and hunt in the forest, and many tourists visit it. This directly or indirectly influences the behaviour of deer, which the wolves prey on, and how wolves use the landscape to generally avoid humans.Wolves are not afraid of human-dominated landscapes in Europe and have recolonized many countries. That has resulted in more human–wolf conflicts — especially due to livestock predation — but it also raises the scientific question how the presence of wolves can reshape their environment. In human-dominated landscapes that have been modified and restructured, wolves often engage in interactions with other species in different ways, which can have different influences on ecosystems3.RIZMOON N. ZULKARNAEN: Ghost orchids ‘haunt’ the forestRizmoon N. Zulkarnaen is a plant conservationist at the National Research and Innovation Agency in Jakarta, Indonesia.The ghost orchid floats above the forest floor — a fragile sentinel of a healthy ecosystem.Credit: Rizmoon Nurul ZulkarnaenAs a plant conservationist, I am fascinated by the biodiversity of endemic and threatened plants, and recognize the urgent need for conservation, particularly in Indonesia. I study Didymoplexis pallens, known as the ghost orchid because of its pale, ethereal appearance, which makes it look as though it is floating. These orchids are entirely leafless, lack chlorophyll and often grow on decaying plant matter in dense forests.Ghost orchids are epiphytic plants, meaning they grow on the surface of other plants: they depend on relationships with mycorrhizae, or symbiotic fungi, for nutrients. In the past few years, bamboo litter in their habitat, an important source of organic material for mycorrhizae, has significantly decreased or even disappeared. This was due to land clearing in the Bogor Botanical Gardens in Indonesia, for beautification and land management. As a result, the population of ghost orchids has drastically declined.I found that ghost orchids have a significant role in their ecosystem, acting as indicators of environmental health owing to their reliance on specific conditions, such as soil type, humidity and the amount of light, to grow. I do fieldwork with students to foster a community centred on plant conservation. We have reframed ghost orchids from merely rare plants to fragile components of a larger ecosystem that are crucial for biodiversity conservation.JANE HILL: Corpse plants reflect nature’s clevernessJane Hill is a chemical engineer at the University of British Columbia in Vancouver, Canada.Jane Hill with a corpse plant, which can mimic odours produced during human and animal diseases.Credit: Jane E. HillThe rare flowering of the corpse plant is a wonderful example of the artistry and cleverness of nature. Plants must attract creatures to help them reproduce, and the corpse plant (Amorphophallus titanum) uses striking colours and odours to attract insect pollinators. My research team investigates molecules related to metabolism in human and animal disease, which we test as potential diagnostic biomarkers. We discovered that, during certain human infections, the odours that people emit are similar to those of corpse plants. We want to know how the plant evolved to mimic the smells of humans and other animals.Very few people study this rare plant, which grows in the tropical rainforest in Sumatra, Indonesia. Currently, my team studies the corpse plant as a hobby, using our tools to discover volatile molecules that give rise to odour. Although my team is not highly connected to the botanists studying corpse plants, our curiosity about which volatile molecules attract which insects, for example, has led to discussions with people studying insects, genetics and ecology. These fruitful exchanges stimulate our work, which helps us to better understand the smelly, odour-causing molecules produced during human disease. Those molecules might one day allow us to develop tools to diagnose diseases more quickly.DANIEL RABOSKY: Protect lizards to preserve ecosystem diversity Daniel Rabosky is an ecologist at the University of Michigan in Ann Arbor.Ecologist Daniel Rabosky, holding a yellow-spotted monitor (Varanus panoptes), says we understand very little about most lizard species.Credit: Alison Davis RaboskyI became obsessed with reptiles, especially snakes, as a child. My parents did not like snakes, but they took me to local swamps to catch them — and they even helped me to house my collection of live snakes and turtles. Just before graduate school, I read work by the late ecologist Eric Pianka on the spectacular diversity of lizards in Australian deserts. Those environments have more species of lizard than anywhere else on Earth, even tropical rainforests. This is a striking outlier, and I wanted to study what regulates species diversity in time and space — a very important issue now, given the fast pace of global ecological change.A common misunderstanding is that, because lizards are vertebrates, scientists have a good handle on their basic biology and ecology. But the truth is that we have an incredibly poor understanding of the natural history of most lizard species. We are wiping out populations around the world and losing crucial information needed to understand and preserve the biodiversity of these reptiles.One group that I lean on tremendously for support is the natural-history collection and museum community. Its members are passionate about building global knowledge infrastructure to support basic biodiversity science, including my group’s research on snakes and lizards. These folks inspired my choice to serve as a museum curator, and I hope I can continue mentoring the next generation of biodiversity scientists.YORAM GUTFREUND: Owls find their way in the darkYoram Gutfreund is a neuroscientist at the Technion — Israel Institute of Technology in Haifa.To truly understand the brain, we must learn how animals adapt their behaviours to natural settings. The barn owl (Tyto alba), a nocturnal predator, excels at detecting and capturing small prey in very-low-light environments, making it a great model to study sensory-based responses. Barn owls have been a focus of neuroscience research since the 1970s, but we still don’t know how they integrate information from several senses to guide their behaviour and filter out irrelevant sensory inputs.My group and others have shown that barn owls’ senses are surprisingly similar to people’s. Their stereo vision (the ability to perceive depth using two eyes), the auditory frequency range they can perceive and the way their brains interpret sound are more akin to traits of people than of most other mammals studied in neuroscience. Moreover, like humans, barn owls rely on vision as their dominant sense in cases of sensory conflict. Their sensory attention, like ours, is drawn to salient events and objects in their surroundings. While viewing an alert barn owl perched on a branch, scanning its environment with a human-like gaze, it is easy to imagine a ‘wise’ creature considering its next move.The barn owl research community is small but close-knit, with only about six labs worldwide. We all know each other well, and there is a strong spirit of collaboration. My work on the hippocampus brain region and spatial processing connects me to a much larger field, but being the only researcher focusing on this topic in barn owls allows me to offer a fresh, unique perspective. More

The European hedgehog (Erinaceus europaeus) is an ambassador wildlife species. In the United Kingdom, it topped a 2016 poll for favourite mammal organized by the Royal Society of Biology, and was chosen as the species most emblematic of Britain in a 2013 poll by UK broadcaster the BBC.
Competing Interests
The authors declare no competing interests. More

Workers plant trees in the outskirts of Bogotá as part of a reforestation project.Credit: Florian Kopp/imageBroker/ShutterstockThis year’s Global Risks Report from the World Economic Forum ranked ‘biodiversity loss and ecosystem collapse’ as one of the three most severe risks that societies face over the next ten years, alongside ‘extreme weather’ and ‘critical change to Earth systems’ caused by climate change1.There is a plan to address this threat. In 2022, 196 countries adopted the Kunming–Montreal Global Biodiversity Framework, agreeing to halt and reverse biodiversity loss by 2030 and ensure that natural resources are used sustainably by 2050. Yet, an estimated funding gap of US$598 billion–$824 billion exists between current annual spending on conservation and restoration and what is needed to achieve the goals of the framework2. Public finance and policies can help to close this gap — for example, governments could lower taxes for green technologies and redirect subsidies from activities that are environmentally harmful to those that are more sustainable. But a new source of finance is also needed.Biodiversity credits are one mechanism, highlighted by the Global Biodiversity Framework, that could help to generate private-sector funds and ensure that those funds pay for demonstrable conservation and restoration achievements. By buying these credits, which would be used to fund certain projects, companies could achieve any one of three goals. First, to boost their profile and marketing, organizations could make contributions to improving the world’s biodiversity independent of their own activities. Second, after assessing their impact on the environment and doing all they can to avoid or minimize harm, companies could compensate for any residual harm in a like-for-like way — meaning the credits they purchase would need to fund remediation efforts in the same location and ecosystem type as wherever the harm is being done3. Last, organizations could invest in efforts that enhance biodiversity and resilience in their supply chains.Analysis: the biodiversity footprint of the University of OxfordSome corporations are already making promises not just to minimize their impact on nature but also to enhance ecosystems and enrich biodiversity — in other words, to become ‘nature positive’. And mandatory biodiversity-credit markets (in which companies that are harming the environment are required by law to purchase credits) are emerging in several countries, including Colombia, Germany, India, France and England. But — as the failures of carbon-credit markets, designed to reduce greenhouse-gas emissions, have made plain — for biodiversity-credit markets to grow and achieve what’s needed, they must be built in the right way, and they must operate in the right way.As members of the International Advisory Panel on Biodiversity Credits, we have been developing a road map for biodiversity credits for about a year. Our panel consists of scientists, Indigenous Peoples and representatives from local communities, non-governmental organizations (NGOs), finance and industry. Together, we have analysed 31 initiatives that are trialling the use of biodiversity credits in 21 countries. We have organized events at international meetings and held hundreds of discussions and numerous workshops in multiple languages. We have also conducted two global surveys to assess people’s interest and understanding, and to better understand how potential sellers and buyers imagine using biodiversity credits in practice.Drawing on this work and taking lessons from other markets, including carbon-credit and finance markets, here we lay out what we think is needed to establish trustworthy, impactful biodiversity-credit markets. We will present our recommendations in full (which we have developed in collaboration with the World Economic Forum and the Biodiversity Credit Alliance, an international organization that aims to support the implementation of the Global Biodiversity Framework) at this month’s United Nations biodiversity summit COP16 in Cali, Colombia.Carbon-credit conundrumFor most people working on issues tied to the environment, mentioning the word ‘credits’ brings to mind carbon credits. It probably also raises misgivings.Carbon-credit markets generally involve carbon-offsetting projects, which promise reductions in emissions in one place (often through the planting of trees to absorb carbon dioxide, or through the protection of existing forests that act as carbon sinks) to compensate for the emission of CO2 in another location. Despite their promise in helping to reduce greenhouse-gas emissions, however, carbon-credit markets have hit problems4.The non-profit organization Environmental Conservation Trust of Uganda is helping to restore forested land in the northern Albertine Rift in Uganda.Credit: Martin Zwick/AvalonThere has been a lack of transparency about how many offsetting projects have achieved or will achieve their long-term goals5,6, and a lack of clarity for buyers about how they can use the credits they purchase, and what claims they can make about them. Some schemes that focus only on the removal of CO2 from the atmosphere, such as the planting of eucalyptus trees in African savannahs, can harm biodiversity and the communities that depend on it. Because most projects have focused on forested ecosystems, other important carbon sinks, such as salt marshes, have been overlooked. It has been unclear how the costs and benefits of carbon-offset projects will be shared among those involved, and who gets to decide this. Also, few efforts have engaged Indigenous Peoples or local communities — or engaged them enough.But carbon-credit markets are evolving and many of these problems could be resolved in the future. Also, well-designed biodiversity-credit markets — that help to strengthen the rights and voices of Indigenous Peoples and local communities — wouldn’t operate in the same way as today’s carbon-credit markets do. In fact, for biodiversity credits to drive the flow of money towards conservation and restoration that is needed — and for the work on the ground to be effective — governments and companies establishing biodiversity-credit markets must ensure that the problems that have arisen with carbon-credit markets are avoided. They will also need to ensure that the necessary conditions for biodiversity-credit markets to operate effectively are in place.Carbon offsets aren’t helping the planet — four ways to fix themCompanies buying biodiversity credits should view them as a way to channel funds into long-term conservation and restoration initiatives, rather than as something they can quickly sell to another firm to make a profit — as can happen, for example, in cap-and-trade schemes in which a limited supply of carbon credits can make for valuable commodities in their own right. Also, one tonne of CO2 will have the same impact wherever it is released, whereas the effects of damage to biodiversity are hugely variable depending on the precise location. If a company negatively affects a rainforest in Borneo, for instance, any biodiversity credits that the company buys to compensate for that harm will need to fund equivalent conservation and restoration in the same ecosystem.Five aspects in particular need addressing.Measuring the state of nature. One of the most commonly asked questions in our discussions was, ‘How do you measure actual improvements to biodiversity (or the amount of biodiversity loss that will be avoided thanks to an initiative) in a consistent, reliable and credible way?’Biodiversity is much more complicated to measure than are carbon emissions7. It encompasses genetic, taxonomic, functional, evolutionary and ecosystem diversity — all of which can be assessed in different ways8. For instance, when assessing taxonomic diversity, biologists might count the number of species in an area, or they might just count the number of genera. More than 570 biodiversity metrics have been proposed so far, and standards for monitoring biodiversity continue to be debated at international and national levels9. Also, how people value biodiversity will vary depending on the species or ecosystem in question, and the geographical and cultural context. Adding to these difficulties, the restoration of habitats can take decades, making it hard to measure a project’s actual or potential impact.But a balance can be found between technical rigour and practicability.Even relatively simple metrics, such as the probable impact of land-use changes on the risk of certain species going extinct (which can be readily estimated10), can provide clues about an ecosystem’s integrity and, crucially, about how this changes over time. And an array of metrics, such as the number of individuals in easily identifiable and ecologically important species groups, can be used to support assertions about improvements made to biodiversity and enable biologists to detect positive change in a relatively short time frame.Through our consultations and analyses, we have identified six key criteria for biodiversity measurements and reporting standards. First, with the objectives and rights of Indigenous Peoples and local communities and of those buying the biodiversity credits in mind, a project’s goals — meaning what aspects of biodiversity are to be conserved or restored and to what degree — should be made clear at the outset. Second, measurements should be verifiable, appropriate for that ecosystem and based on robust science11. Third, measurements should be confirmed and assured by individuals or organizations working independently of the project. Fourth, all data should be made publicly available. Fifth, measurements should be made before the conservation or restoration work begins, while the project is under way, and after the project has been completed. Last, results should show that, thanks to the project, more biodiversity conservation or restoration is enabled than what would have happened anyway.Driving up demand. Many of the people we consulted questioned why companies would want to buy biodiversity credits. Certainly, outside the mandatory schemes, such as those established in Colombia and England, few companies are buying them today12. This is because companies are unsure of what biodiversity credits are, what makes a biodiversity credit high quality and how biodiversity credits should be used13. Companies are also wary because it can take years for substantial benefits of conservation and restoration projects to be detected — which in turn affects what statements an organization can make about what their purchases of biodiversity credits are achieving.Technologies, such as camera traps, are making it easier to monitor changes to biodiversity.Credit: Ann & Steve Toon/Nature Picture LibraryYet, our discussions have convinced us that all sorts of organizations recognize humanity’s dependence on nature and are committed to addressing the biodiversity crisis as well as the climate crisis. Also, many of these obstacles listed can be tackled.National and regional legislation should aid the development of ethical and trustworthy projects and transactions. This could entail requirements for companies to compensate for their harms to biodiversity. In February, the English government introduced a scheme called biodiversity net gain, a requirement that all new building projects achieve a 10% net gain in biodiversity (measured by the size, type, condition and strategic significance of the habitats being affected, on the basis of information such as species richness and rarity).More governments should establish rules on what counts as like-for-like habitat and lay out what principles should underlie accepted methodologies and assertions — just as we are doing here. Also, more governments should provide publicly available lists of independently approved approaches that involve the use of biodiversity credits, and registries of conservation and restoration projects that need funding. Colombia’s government is doing exactly this in association with the environmental-investment company Terrasos in Bogotá.Meanwhile, philanthropic organizations and impact-fund providers — which channel funds into investments that generate a measurable and beneficial social or environmental impact alongside a financial return — could provide the seed money needed to get projects up and running. This would in turn lower the risks of investment for private companies.Stimulating supply. Most of the conservation and restoration projects being funded by biodiversity credits today are at an early stage, in which the suppliers of the credits (that is, those developing the conservation or restoration projects) are still refining their methodologies for measuring biodiversity, setting the prices of the credits, assessing demand, identifying buyers and so on.To increase the number of biodiversity credits available for sale, governments, impact-fund providers and philanthropic organizations should invest in the people, training and technology needed for measuring, conserving and restoring biodiversity. In other words, seed investment from these organizations would help to bolster both the demand for and the supply of biodiversity credits.Environmentalists are trying to protect endangered marine species in the Colombian Pacific.Credit: Luis Acosta/AFP via GettyInitially, the use of biodiversity credits will work better for some projects and regions than others. A current difficulty is the complexity of people’s rights to ownership of land, seas and natural resources. Such rights might not be officially registered, but might align with the customary laws, values and traditions of Indigenous Peoples or local communities. Also, the rules and customs around who owns what vary in and between countries, and in the case of international waters, multiple countries are involved in governance14. Longer term, these challenges can and must be addressed.Setting the rules. The main lesson from carbon-credit markets is that governments should develop and enforce clear rules — about how biodiversity credits can be used, what needs to be reported by those selling them, what can be said about them and so on. Establishing and enforcing these rules will require governments and international oversight bodies to work together with organizations that set standards (such as those establishing certification schemes), Indigenous Peoples, local communities and international and national NGOs.Governments should require, for example, project developers selling biodiversity credits to make project information publicly available — from the impact of projects on biodiversity to the benefits they provide to local communities. In principle, a new or existing body at the international level could support the development of ethical and trustworthy biodiversity markets by developing standards, and sharing information and lessons from biodiversity-credit funded projects.Certification schemes could also help to ensure that biodiversity credits are ethical and trustworthy. Various media reports suggest that some certification systems have failed to protect either biodiversity or Indigenous Peoples. But emerging schemes are tackling these issues — such as the Global Biodiversity Standard for habitat restoration, which aims to provide assurance that tree planting, habitat restoration and agroforestry practices are protecting, restoring and enhancing biodiversity.Making projects work on the ground. One of the most common criticisms that we have heard environmentalists and others make about carbon-offset projects is that those involved fail to sufficiently engage the local stewards and custodians of land and seas in the design, planning and running of projects.In many carbon-offset projects, if Indigenous Peoples and local communities are considered at all, they are consulted only in the final stages of the project. Or they might be asked to sign forms to give their ‘free, prior and informed consent’. Such forms are a crucial tool. But in many cases, if they are given to people at all, they are given too late or without sufficient discussion. Also, often the forms are not legally binding.A project in Uganda is trialling the use of biodiversity credits to help the conservation of the chimpanzee.Credit: Godong/Universal Images Group via GettyFormally recognizing the importance of Indigenous and local knowledge, and the rights of Indigenous Peoples and local communities to govern and manage their lands according to traditional practices, when designing biodiversity-credit markets would be a game-changer. Securing and protecting the rights of these communities is ultimately the duty of governments. Yet, to ensure that biodiversity-credit markets do not worsen current inequities, no biodiversity credits should be bought or sold without a seller first certifying to the buyer how people’s rights are being (or will be) observed and protected in the projects tied to the credits.In practice, this means companies enabling Indigenous Peoples and local communities to drive projects forwards from the outset. It means ensuring that individuals get the conservation or restoration training they need; that Indigenous Peoples and local communities receive fair compensation for their stewardship of biodiversity; that benefit-sharing mechanisms are integrated into contracts and so on.As an example, in one of the 31 projects that we have analysed, the non-profit Environmental Conservation Trust of Uganda is building on its 25 years of experience and working with nearly 42,000 smallholder farming households. Project goals include: restoring 12,000 hectares of forested land to provide connectivity for wildlife between currently protected but fragmented blocks of forest in the northern Albertine Rift in Uganda; supporting the conservation of several threatened species, such as the chimpanzee; and creating income opportunities for more than 15,000 households. Crucially, the project has been designed by rural communities, and it will be owned and led by them.One year onWhen we were invited to develop a road map for biodiversity credits in 2023, we recognized the importance of the task, but were also concerned about the risks. We knew about the problems with carbon offsets and we were daunted by the ecological, social, financial, ethical and legal challenges that biodiversity-credit markets present.One year on, we still think that unregulated markets could lead to a poor use of public and private funds just when those funds are needed the most. These markets could even worsen the situation if investors are unable to recognize greenwashing claims; if companies use biodiversity credits to sustain or increase their negative impacts on biodiversity; and if efforts to protect and restore biodiversity fail to embrace the rights and needs of Indigenous Peoples and local communities.But all of us that have worked on this project are now convinced that — designed in the right way and used alongside other approaches, including those using high-quality carbon credits or payments for ecosystem services15,16 — biodiversity-credit markets could become one of the most important funding sources for implementing the Global Biodiversity Framework.Governments shape economies, champion innovation and enable markets through the signals they send and the rules they set. We therefore urge all governments to introduce policy measures and legislation that encourages — or preferably requires — companies to assess, disclose and address their impacts on biodiversity (as outlined in target 15 of the Global Biodiversity Framework). As part of this process, we recommend that the regulation, certification and enforcement of biodiversity credits be based on the framework laid out here and in our full report.Over time, success will be measured, not so much by the total market value, but by the long-term benefits that such credits bring — to biodiversity and to people. More