Biodiversity
Biodiversity—the variety of all living things on Earth—sustains our food systems, regulates our climate, purifies our air and water, and supports human health and wellbeing. The UK's natural capital provides ecosystem services valued at £1.8 trillion, yet wildlife populations have declined by 19% since 1970, with one in six species now at risk of extinction. Understanding why biodiversity matters has never been more urgent, as the choices we make today will determine the natural world our children inherit.
When we speak of biodiversity, we're celebrating the extraordinary tapestry of life that makes our planet unique—from the ancient oak woodlands of Britain to the coral reefs of tropical seas, from the smallest soil microbes to the great whales that traverse our oceans. This remarkable diversity isn't merely beautiful to behold; it forms the foundation upon which all human civilisation depends.
Yet within this crisis lies opportunity. The UK's mandatory Biodiversity Net Gain policy, nature-based health initiatives, and remarkable species recovery programmes demonstrate that when we commit to protecting biodiversity, nature can recover. This guide explores why biodiversity matters—for our ecosystems, our economy, our health, and our future—and what we can all do to help reverse the decline.
Biodiversity encompasses the variety of life on Earth at every level—from genes to species to entire ecosystems. Scientists recognise three interconnected dimensions: genetic diversity (the variation within species that allows adaptation), species diversity (the number and variety of different species), and ecosystem diversity (the range of habitats and ecological communities).
The IUCN Red List has now assessed over 169,420 species globally, with 47,187 (28%) threatened with extinction. The scale of life on Earth remains breathtaking—scientists estimate between 8 and 10 million species exist, though only around 2 million have been formally described. In the UK alone, we're home to approximately 70,000 known species of animals, plants, fungi, and microorganisms.
Understanding biodiversity matters because each species plays a role in the intricate web of life. When we lose a species, we don't simply lose that organism—we lose its relationships with other species, its contributions to ecosystem function, and potentially vital resources we haven't yet discovered. The December 2024 IPBES Nexus Assessment emphasised that biodiversity, water, food, health, and climate are deeply interconnected, meaning that damage to one affects all others.
Biodiversity provides the essential services that make human life possible—scientists call these ecosystem services. From the oxygen we breathe to the food on our tables, from clean water to natural flood defences, nature works continuously to support us.
The UK's vegetation removes approximately 1.4 million tonnes of air pollutants annually, with broadleaf woodlands providing pollution removal services worth £1.1 billion each year. Urban vegetation alone saved £163 million in healthcare costs in 2017 through avoided deaths and hospital admissions. Wetlands and forests act as natural water filtration systems, though sadly only 14% of English rivers currently meet good ecological status.
Without pollinators, our food system would collapse. Globally, insect pollination is valued at €153 billion annually—representing 9.5% of world agricultural food production. In the UK, pollination services contribute £400–430 million to our economy each year. Yet we've seen an 18% decline in pollinator distribution since 1970, with bees, hoverflies, and moths all showing significant losses.
Healthy ecosystems provide critical flood defences. A single acre of wetland can store 1.5 million gallons of floodwater, while wetlands and natural floodplains reduce flood damages by 54–78%. As flooding events become more frequent with climate change, these natural solutions become ever more valuable—and far more cost-effective than engineered alternatives.
Over 80% of registered medicines come from or are inspired by natural products, with 70% of cancer drugs being natural or bio-inspired. The Convention on Biological Diversity notes that global trade in medicinal plants exceeds £2 billion annually. Every species lost potentially represents medicines we'll never discover—a sobering thought when current extinction rates run 100–1,000 times higher than natural background levels.
Far from being separate from the economy, biodiversity underpins it. The landmark Dasgupta Review, commissioned by HM Treasury, established that our economies are embedded within nature, not external to it. As Sir David Attenborough wrote in his foreword: "This comprehensive and immensely important report shows us how by bringing economics and ecology face to face, we can help to save the natural world and in doing so save ourselves."
| Ecosystem Service | Annual Value |
|---|---|
| Total UK natural capital asset value | £1.8 trillion |
| Annual ecosystem services value | £87 billion |
| Health benefits from nature recreation | £489 billion (asset) |
| Air pollution removal by vegetation | 1.4 million tonnes/year |
| People gaining health benefits from nature | 20 million |
Globally, the World Economic Forum estimates that $44–58 trillion (50–60% of global GDP) is moderately or highly dependent on nature. PwC's 2023 analysis found that 55% of global GDP—equivalent to $58 trillion—faces material risk without immediate action on nature loss. The IPBES Nexus Assessment revealed that $7 trillion is invested annually in activities harmful to biodiversity, while biodiversity finance stands at just $135–156 billion—a mere 0.25% of the global GDP that depends on nature.
The cost of inaction is staggering. The World Bank projects that collapse of select ecosystem services could result in a $2.7 trillion annual decline in global GDP by 2030. Conversely, acting immediately to address biodiversity loss could generate $10 trillion in business opportunity value and create 395 million jobs by 2030, according to the December 2024 IPBES assessment.
The connection between nature and human wellbeing runs deeper than most people realise. Landmark research from the University of Exeter, studying nearly 20,000 people, found that spending at least 120 minutes per week in nature is significantly associated with good health and higher psychological wellbeing. Those spending less showed no significant benefits compared to those spending no time at all—suggesting there's a threshold dose of nature that we all need.
"It's well known that getting outdoors in nature can be good for people's health and wellbeing, but until now we've not been able to say how much is enough."
— Dr Mat White, University of Exeter
Research from King's College London in 2024 demonstrated that environments with higher biodiversity are associated with greater mental wellbeing, with nearly 25% of the positive impact of nature on mental health explained by the diversity of features present. Crucially, the benefits of exposure to biodiverse environments can last up to eight hours.
The NHS has embraced nature's healing power through its £5.77 million Green Social Prescribing programme. Running across seven Test and Learn sites from 2021–2025, the initiative has referred over 8,500 people to nature-based activities including conservation volunteering, community gardening, and open-water swimming. The results speak volumes: 85% uptake when green prescriptions are offered, with 57% of participants from the most economically underserved areas.
The economic case is compelling. For every £1 invested in green social prescribing, the social return reaches up to £2.42. The Wildlife Trusts estimate that scaling nature-based health projects nationally could save the NHS £635.6 million annually, while Public Health England suggests that improved green space access could deliver £2.1 billion in annual savings. Nature isn't just good for our souls—it's a cost-effective healthcare intervention.
The UK faces a biodiversity crisis that demands urgent attention. According to the State of Nature 2023 report—the most comprehensive assessment of British wildlife—species abundance has declined by 19% since monitoring began in 1970. One in six (16%) of over 10,000 species assessed are now at risk of extinction from Great Britain, with 1,500 species facing the prospect of being lost entirely.
Perhaps most concerning, the UK has only 50.3% of its biodiversity remaining—ranking us among the world's most nature-depleted countries and the worst among G7 nations. This decline began long before modern monitoring, with centuries of land-use change, industrialisation, and agricultural intensification taking their toll.
43%
of bird species at high extinction risk
62%
decline in farmland birds since 1970
98%
decline in Turtle Dove population
22m
House Sparrows lost over 57 years
The IPBES framework identifies five main drivers of biodiversity loss, all of which affect the UK. Agricultural intensification remains the biggest factor, with farming threatening over 85% of at-risk species globally. In the UK, agriculture contributes 70% of nitrogen entering our waterways, while only 14% of English rivers meet good ecological status.
Invasive species pose a growing threat, with 2,074 non-native species now established in Great Britain, of which 195 are classified as invasive. The economic cost to GB exceeds £1.9 billion annually, with Japanese knotweed alone costing £250 million. Meanwhile, pollution continues to devastate our waterways and wildlife—the UK has lost over 50% of its insects since 1970, and one-third of our bee population has disappeared in the last decade.
Climate change increasingly compounds these pressures. Research from the University of York predicts that climate change will become the primary driver of biodiversity loss by 2050. The UK's beloved puffin population, for example, is predicted to decline by 90% in the next 30 years as warming seas affect their food supply.
In a landmark policy shift, the UK introduced mandatory Biodiversity Net Gain (BNG) through the Environment Act 2021, making England the first country in the world to require developers to leave nature in a measurably better state than before. Since February 2024, most new developments must demonstrate that post-development biodiversity value exceeds pre-development value by at least 10%.
Developers must follow a clear hierarchy when addressing biodiversity impacts. First, they should avoid and minimise impacts on existing habitats wherever possible. Where impacts are unavoidable, they must provide on-site habitat enhancement within the development boundary. If this proves insufficient, off-site enhancement on other land is required. Only as a last resort can developers purchase statutory biodiversity credits from the government.
All habitat enhancements must be secured and maintained for at least 30 years, representing a significant long-term commitment to nature recovery. The government has deliberately priced statutory credits high—ranging from £42,000 for low-distinctiveness habitats like modified grassland up to £650,000 for high-distinctiveness features like lakes—to encourage private market solutions and genuine on-site improvements.
| Date | Milestone |
|---|---|
| 12 February 2024 | BNG mandatory for major developments |
| 2 April 2024 | BNG mandatory for small sites |
| May 2026 (expected) | BNG for Nationally Significant Infrastructure Projects |
While BNG represents a significant step forward, challenges remain. The National Audit Office found the policy was "launched before it was ready," with 60% of Local Planning Authorities lacking in-house ecological expertise. Natural England Chair Tony Juniper has acknowledged that the 10% requirement "will really only help us to stand still"—achieving no net loss rather than genuine gain. Some forward-thinking councils, including Lichfield, Kingston upon Thames, and Tower Hamlets, have adopted requirements of 20–30% to drive more meaningful improvements.
The climate and biodiversity crises are deeply intertwined—each making the other worse. The IPCC's AR6 Synthesis Report recognises "the interdependence of climate, ecosystems and biodiversity, and human societies," emphasising that we cannot solve one without addressing the other.
Rising temperatures are already forcing species to adapt, move, or perish. Local extinctions have been detected in 47% of the 976 species examined in one major study, while approximately half of all species have shifted polewards or to higher elevations. The stakes are stark: species extinction risk is roughly 10 times greater at 3°C warming compared to 1.5°C. For the UK, this means our iconic species face an uncertain future—climate projections suggest puffin populations could decline by 90% within 30 years.
Healthy ecosystems are vital carbon stores. When we degrade them, we release stored carbon and lose future sequestration capacity. UK peatlands, covering 12% of our land area, store an astonishing 3.2 billion tonnes of carbon—equivalent to all the carbon stored in the forests of the UK, France, and Germany combined. Yet 80% of UK peatlands are degraded, with damaged peat currently emitting 23 million tonnes of CO2 equivalent annually (3.5–5% of UK total emissions).
The UK's Peat Action Plan recognises this challenge, targeting restoration of 35,000 hectares by 2025 and 280,000 hectares by 2050. The economic case is strong: full restoration would cost £8–22 billion over 100 years but save an estimated £109 billion in reduced carbon emissions. Restoring bare peat saves approximately 19 tonnes of CO2 equivalent per hectare per year.
Protecting and restoring nature offers one of our most powerful tools for addressing climate change. UNEP analysis shows nature-based solutions can deliver at least 5 gigatonnes of CO2 reduction by 2030 and at least 10 gigatonnes by 2050—potentially contributing up to 40% of the mitigation needed to limit global warming. UK forests already sequester approximately 17–18 million tonnes of CO2 annually, while our seabed sediments store 205 million tonnes of carbon. Investing in nature isn't just about conservation—it's climate action.
Amid the sobering statistics, remarkable success stories prove that dedicated conservation effort can reverse decline. When we commit to protecting biodiversity, nature demonstrates an extraordinary capacity to recover—offering hope and a blueprint for wider action.
On 28 February 2025, the UK Government announced a historic commitment to wild beaver releases in England. The following month saw the first licensed wild beaver release at Purbeck Heath in Dorset—a milestone for nature recovery after an absence of over 400 years. Scotland now hosts approximately 2,000 beavers, while England has around 400 across 25+ enclosure projects and 30+ family groups in the River Otter catchment. These ecosystem engineers create wetland habitats that benefit countless other species while providing natural flood management.
The UK's largest bird of prey has returned to English skies after 243 years. Following the release of 45 young eagles between 2019 and 2025, the first breeding pair successfully raised a chick in 2023—and by 2025, six wild-born chicks had fledged. With 80% public support for the reintroduction, these magnificent birds symbolise what's possible when conservation ambition meets community backing.
Targeted conservation delivers results. The Bittern population has grown from just 11 booming males in 1997 to 234 in 2023—a 2,027% increase achieved through wetland creation and management. Marsh Harriers have risen from a single pair in the 1970s to 448 pairs by 2022. The Red Kite, extinct in England by the 1870s, has achieved a 2,464% increase since 1995 thanks to one of the world's most successful reintroduction programmes.
The Knepp Estate in Sussex has become the UK's flagship rewilding project, demonstrating that nature recovery and viable farming economics can coexist. Satellite research by ZSL and Imperial College documented a 40% increase in areas with trees and six times more shrubs than before the project began. The estate now hosts white stork chicks for the first time in 600 years and beavers for the first time in 400 years, while generating tourism turnover of approximately £800,000 annually with a 22% profit margin.
The scale of biodiversity loss can feel overwhelming, but individual and collective action makes a genuine difference. Every garden, every purchasing decision, every voice raised for nature contributes to the broader movement for change.
UK gardens collectively cover an area larger than all our nature reserves combined—making them a vital resource for wildlife. Let a corner grow wild, plant native species that support pollinators, create log piles for invertebrates, and install bird feeders and nest boxes. Even small ponds can support dozens of species. Consider joining local wildlife recording schemes—citizen science data powers the research that guides conservation priorities.
What we buy shapes what businesses produce. Choose sustainably sourced products—look for certifications like FSC for wood and paper, MSC for seafood, and organic for food. Reduce single-use plastics that pollute our waterways and oceans. Support businesses that take biodiversity seriously, and ask questions of those that don't.
Policy change requires public pressure. Write to your MP about nature protection, respond to local planning consultations, and support campaigns by organisations like the RSPB, Wildlife Trusts, and WWF. Share what you learn about biodiversity with friends and family—awareness is the first step toward action.
Conservation volunteering offers meaningful ways to contribute while gaining the health benefits of time in nature. Local Wildlife Trusts run practical conservation tasks, from hedgerow planting to pond creation. Beach cleans, river cleanups, and invasive species removal all need willing hands. If you're able to give financially, donations to conservation charities fund the land acquisition, research, and advocacy that protect wildlife at scale.
Biodiversity provides essential ecosystem services that sustain human life, including clean air and water, food production through pollination, natural medicines, climate regulation, and flood protection. The UK's natural capital delivers ecosystem services worth £87 billion annually, while nature-based recreation provides health benefits valued at £489 billion. Without biodiversity, these services would need to be artificially replaced at enormous cost—or would simply be lost.
The UK has experienced a 19% decline in species abundance since 1970, with one in six species now at risk of extinction. Only 50.3% of our original biodiversity remains, making us one of the world's most nature-depleted countries and the worst among G7 nations. Farmland birds have declined by 62%, and iconic species like the Turtle Dove have lost 98% of their population.
Biodiversity Net Gain is a UK policy requiring most new developments to leave nature in a measurably better state. Since February 2024, developers must demonstrate that biodiversity value increases by at least 10% compared to pre-development conditions. This is achieved through a hierarchy: first avoiding impacts, then enhancing on-site, then off-site enhancement, with government credits as a last resort. All improvements must be maintained for at least 30 years.
Healthy ecosystems store vast amounts of carbon—UK peatlands alone hold 3.2 billion tonnes. When ecosystems are degraded, they release stored carbon and lose capacity for future sequestration. Damaged UK peatlands currently emit 23 million tonnes of CO2 equivalent annually. Conversely, protecting and restoring nature provides powerful climate mitigation—nature-based solutions can deliver up to 40% of the emissions reductions needed to limit global warming.
The IPBES framework identifies five main drivers: land and sea use change (primarily agricultural expansion), direct exploitation of organisms (overfishing, overhunting), climate change, pollution (including pesticides and nutrient runoff), and invasive alien species. In the UK, agricultural intensification has had the greatest impact, threatening over 85% of at-risk species, while invasive species cost the economy nearly £2 billion annually.
Yes—conservation success stories demonstrate nature's remarkable resilience when given the chance. UK examples include the Bittern (11 males in 1997 to 234 in 2023), Red Kite (2,464% increase since 1995), and beaver reintroduction after 400 years. The Knepp Estate rewilding project shows what's possible at landscape scale. These successes prove that targeted conservation effort, policy support, and public engagement can reverse declines.
Research from the University of Exeter found that spending at least 120 minutes per week in nature is associated with significantly better health and psychological wellbeing. Those spending less showed no benefits compared to those spending no time at all—suggesting a threshold dose exists. The benefits are even greater in biodiverse environments, with positive effects lasting up to eight hours after exposure.
The UK's natural capital is valued at £1.8 trillion, providing ecosystem services worth £87 billion annually. Globally, 50–60% of GDP (£44–58 trillion) depends moderately or highly on nature. The cost of inaction is severe—the World Bank projects ecosystem collapse could cause $2.7 trillion in annual GDP losses by 2030. Conversely, addressing biodiversity loss could generate $10 trillion in business opportunities and 395 million jobs by 2030.
The data and findings in this guide are drawn from authoritative sources including government agencies, peer-reviewed research, and established conservation organisations. Click the links below to explore the original sources.
Biodiversity isn't an abstract concept—it's the living foundation of everything we depend upon. From the food on our tables to the medicines in our cabinets, from the air we breathe to the stability of our climate, nature's variety sustains us in ways we're only beginning to fully understand. The UK has committed to halting biodiversity decline by 2030, but meeting this target requires action from all of us—individuals, businesses, communities, and government working together. The success stories of beavers, eagles, and bitterns prove that when we commit to protecting nature, recovery is possible. The question isn't whether we can afford to act, but whether we can afford not to.