The Sixth Mass Extinction
The Sixth Mass Extinction
Earth is experiencing an unusually rapid decline in biological diversity. Species are disappearing, populations are shrinking, geographic ranges are contracting, ecological communities are being reorganized, and entire evolutionary lineages are being lost. A large body of scientific research describes these changes as evidence that humanity may be causing a mass extinction comparable in long-term significance to the five great extinction events identified in the fossil record.
The phrase Sixth Mass Extinction is powerful but scientifically contested. There is broad agreement that the planet is undergoing a severe, human-driven biodiversity crisis. The narrower question is whether the losses recorded so far have crossed the paleontological threshold normally used to define a mass extinction. Some researchers argue that the event is already underway because extinction rates greatly exceed natural background levels and because population losses precede final species extinction. Others argue that the term should be reserved for an event in which a very large proportion of Earth's species has actually disappeared.
The disagreement is therefore largely about how the present crisis should be classified, not about whether biodiversity is being seriously damaged.
Evidence for an Accelerating Extinction Crisis
Modern extinction rates are substantially higher than estimated natural background rates. Research on vertebrates has documented unusually rapid species losses, while studies of populations show an even broader pattern of decline. Animals may disappear from large portions of their historic ranges long before the species itself becomes globally extinct.
This distinction is important. A species does not have to vanish completely before its ecological role begins disappearing. Declining populations can eliminate predators, pollinators, grazers, seed dispersers, scavengers and other organisms from ecosystems where they once performed important functions.
Scientists have therefore increasingly emphasized concepts such as defaunation, population collapse, geographic range loss and functional diversity rather than relying only on officially recorded species extinctions.
Research also indicates that the disappearance of entire genera and evolutionarily distinct species can remove branches of the tree of life that developed over millions of years. Evolution cannot quickly replace these losses. Recovery following ancient mass extinctions often required millions of years.
Is It Really a Mass Extinction?
The Earth's geological record contains several periods when exceptionally large proportions of the planet's species disappeared. These events provide the reference point for evaluating the modern biodiversity crisis.
Traditionally, a mass extinction is associated with the disappearance of roughly three-quarters of species over a geologically short interval. Modern documented extinctions have not yet reached that level.
This has produced an important scientific distinction.
Researchers who describe the Sixth Mass Extinction as already underway emphasize the extraordinary rate of modern extinction, widespread population collapse, loss of evolutionary history and the trajectory toward much greater losses if current pressures continue.
More cautious researchers distinguish between an undeniable biodiversity crisis and a completed or fully developed mass extinction. They argue that comparisons with ancient events must account for differences between fossil evidence and modern ecological records.
Both perspectives nevertheless recognize that current biodiversity trends are serious. The debate concerns the scale, terminology and methods used to compare modern ecological change with events preserved in deep geological time.
Biodiversity Loss Beyond Species Extinction
Species extinction represents only the final stage of a much longer biological decline.
Before extinction occurs, populations may become smaller, fragmented and geographically isolated. Species may disappear from most of their former range. Genetic diversity can decline. Ecological interactions may weaken or vanish. Communities may become increasingly dominated by widespread species capable of surviving in human-altered environments.
This process can produce biological homogenization in which ecosystems in different places become increasingly similar.
There is also the problem of extinction debt. Habitat destruction can create conditions that ultimately make populations unsustainable even though the species may persist temporarily. Extinctions resulting from today's habitat changes may therefore continue for decades or centuries.
Conversely, local measurements of species richness do not always show immediate declines. New species may enter disturbed habitats while native or specialized species disappear. Local species counts can therefore remain relatively stable even while community composition, ecological function and global biodiversity deteriorate.
These complexities explain why scientists use multiple indicators—including abundance, population trends, geographic range, extinction risk, ecosystem condition and evolutionary diversity—to measure the biodiversity crisis.
Evidence Across Animals, Plants and Ecosystems
The extinction crisis is not confined to a single group of organisms.
Amphibian populations have experienced some of the most dramatic documented declines. Habitat destruction, emerging infectious diseases and climate change have contributed to losses among frogs, salamanders and other amphibians.
Many reptile species are also threatened, particularly by habitat conversion and exploitation.
Bird populations have declined across many regions. Even relatively common species can experience substantial losses without becoming globally endangered.
Large terrestrial mammals face pressure from habitat destruction, fragmentation, hunting and conflicts with human activities. Declines among large predators and herbivores can have disproportionately large ecological effects because these animals influence food webs, vegetation and ecosystem structure.
Marine biodiversity is also under growing pressure. Sharks, rays, large marine animals and reef-building corals face combinations of fishing pressure, warming oceans, pollution, habitat change and other threats.
Freshwater biodiversity is particularly vulnerable because rivers, lakes and wetlands are affected simultaneously by dams, water extraction, pollution, invasive species, habitat alteration and climate change.
Insects show complex regional patterns, but many studies have documented substantial declines in abundance, biomass or diversity. Because insects perform essential ecological roles such as pollination, decomposition and nutrient cycling, widespread losses can affect entire ecosystems.
Plants, fungi and trees face their own extinction pressures. Many species remain poorly documented, creating the possibility that organisms could disappear before science has fully described them.
Human Drivers of the Crisis
Unlike most ancient mass extinctions, the modern biodiversity crisis is primarily associated with the activities of a single species: humans.
Habitat loss is among the largest pressures. Forest clearing, agricultural expansion, urban development, mining, roads and other land-use changes remove or alter the places species require to survive.
Habitat fragmentation divides remaining ecosystems into smaller and more isolated patches. Populations trapped in fragmented habitats may become too small to remain viable and may lose the ability to move as environmental conditions change.
Direct exploitation includes hunting, fishing, wildlife trade and harvesting. Overexploitation has contributed to major declines among terrestrial animals, marine species and freshwater organisms.
Invasive species can transform ecosystems and have been especially destructive on islands, where native species frequently evolved without mammalian predators or other introduced competitors.
Climate change is becoming an increasingly important extinction pressure. Rising temperatures, changing rainfall, marine heatwaves, ocean warming and other climatic shifts can move suitable environmental conditions faster than some species can migrate or adapt.
Pollution affects terrestrial, freshwater and marine ecosystems through pesticides, nutrients, plastics, toxic chemicals and other contaminants.
These pressures rarely operate independently. Habitat loss can make populations more vulnerable to climate change, while invasive species, pollution, disease and exploitation can further reduce already stressed populations.
Agriculture, Consumption and Global Environmental Change
The biodiversity crisis is closely connected to the way human societies produce food, energy and material goods.
Agriculture occupies enormous areas of the planet and has converted forests, grasslands, wetlands and other natural ecosystems. Expanding agricultural production can increase habitat loss, fertilizer use, water consumption and chemical pollution.
International trade and consumption can separate the location where environmental impacts occur from the people who ultimately consume the products responsible for them. Biodiversity loss in tropical forests, oceans or other ecosystems can therefore be driven partly by demand originating thousands of kilometers away.
Food systems are also vulnerable to biodiversity loss. Wild relatives of crops, traditional varieties, pollinators and genetically diverse domesticated species can provide resilience against diseases, pests and changing climatic conditions.
Protecting biodiversity is therefore not simply an effort to preserve wildlife. It is also connected to the long-term stability of agriculture, fisheries, water systems and other ecological foundations of human societies.
Ecological and Human Consequences
The disappearance of species can alter ecosystem productivity, stability and resilience.
Different organisms perform different ecological functions. Plants capture energy, microorganisms recycle nutrients, insects pollinate flowers, predators regulate prey populations, herbivores shape vegetation and animals disperse seeds.
As biodiversity declines, these ecological networks can become simpler and potentially less resilient.
Species are also interconnected. The disappearance of one organism can sometimes threaten another species that depends upon it. Such co-extinctions mean that initial biodiversity losses can potentially trigger additional losses through disrupted ecological relationships.
The destruction of biodiversity also represents the loss of evolutionary history. When a highly distinctive species or an entire genus disappears, millions of years of biological evolution may vanish with it.
Human societies ultimately depend upon functioning ecosystems for food, freshwater, fisheries, soil fertility, pollination, climate regulation and many other services. Biodiversity loss is therefore both an ecological crisis and a long-term human welfare issue.
Lessons From Earlier Mass Extinctions
The fossil record provides a deeper perspective on the present crisis.
Earth's earlier mass extinctions were associated with extraordinary planetary disruptions, including rapid climate change, massive volcanic activity, changes in ocean chemistry, oxygen depletion and asteroid impact.
The end-Permian extinction—the largest known mass extinction—is particularly important for understanding interactions among carbon emissions, warming, ocean acidification and oxygen loss.
The end-Cretaceous extinction demonstrates how rapidly a major environmental disturbance can reorganize life on Earth. The asteroid impact eliminated many biological groups, while survivors eventually gave rise to new evolutionary radiations.
These events also demonstrate that the survival of life itself does not mean that extinction is inconsequential. Earth eventually recovered from previous mass extinctions, but ecological and evolutionary recovery occurred over millions of years.
From a human perspective, such recovery times are effectively permanent.
Measuring a Changing Planet
Quantifying global biodiversity change is difficult.
Scientists must combine fossil evidence, modern species inventories, population monitoring, satellite observations, ecological surveys and conservation assessments. Each measures a different aspect of biological change.
Some studies find strong declines in abundance or extinction risk, while others find little average change in local species richness. These results are not necessarily contradictory. Local communities can gain some species while losing others, producing substantial ecological change without an immediate decline in the number of species counted at a particular site.
Many species also remain scientifically undescribed or poorly monitored. Invertebrates, fungi, microorganisms and organisms in remote terrestrial and marine ecosystems are particularly difficult to assess.
The fossil record has similar limitations. Many organisms fossilize poorly or not at all.
As a result, comparisons between modern biodiversity data and ancient extinction events inevitably contain uncertainty. Nevertheless, multiple independent indicators show extensive human-driven changes to populations, habitats, ecological communities and extinction risk.
Conservation and Preventing Future Extinction
The future scale of biodiversity loss is not predetermined.
Conservation programs have already prevented some species from becoming extinct. Protected areas, habitat restoration, control of invasive species, restrictions on exploitation, captive breeding and species recovery programs have produced measurable successes.
Conservation increasingly uses genetic information, artificial intelligence, satellite monitoring, ecological modeling and global databases to identify threatened species and prioritize areas for protection.
For species facing extremely small populations, more intensive measures may include conservation breeding, seed banks, genetic repositories and biobanking.
However, species-by-species conservation cannot by itself address a planetary biodiversity crisis. Large-scale protection requires preserving and reconnecting ecosystems while addressing the underlying drivers of habitat conversion, climate change, pollution, resource extraction and unsustainable consumption.
Proposals range from protecting large portions of Earth's remaining natural landscapes to transforming agricultural, energy and economic systems.
The evidence reviewed across the scientific literature suggests that conservation can work, but the scale and speed of action must match the scale of the pressures driving biodiversity decline.
Conclusion
The Sixth Mass Extinction is both a scientific concept and a warning about the direction of biological change on Earth.
Scientists continue to debate whether modern losses have already crossed the formal threshold required to call the present period a mass extinction. There is far less disagreement about the underlying biodiversity crisis. Species are disappearing faster than natural background rates, populations are declining, habitats are being transformed and ecological communities are being reorganized by human activity.
Perhaps the most important lesson is that extinction should not be understood only as the moment when the last individual of a species dies. Biological erosion begins much earlier through declining populations, shrinking ranges, fragmented habitats, disappearing ecological relationships and lost genetic diversity.
Whether future scientists ultimately classify the present era as Earth's sixth great mass extinction will depend partly upon what humanity does next. Previous mass extinctions demonstrate that life can eventually recover from enormous biological losses. They also demonstrate that recovery can require millions of years.
Preventing that outcome requires conserving not only endangered species but also the ecosystems, evolutionary processes and ecological relationships that sustain the diversity of life on Earth.
The Sixth Mass Extinction: Foundational Research and Scientific Debate
1. Are We in a Sixth Mass Extinction? The Challenges of Answering and Value of Asking | Multiple authors | British Journal for the Philosophy of Science | 2025-10-17
The authors examine difficulties involved in comparing the incomplete fossil record with modern conservation data and argue that the question remains scientifically and philosophically valuable even when a simple yes-or-no answer is elusive.
2. Questioning the Sixth Mass Extinction | John J. Wiens and Daniel Saban | Trends in Ecology & Evolution | 2025-02-14
This counterargument concludes that modern biodiversity loss is extremely serious but questions whether current species losses have yet approached the approximately 75% extinction threshold associated with the Big Five mass extinctions.
3. Mutilation of the Tree of Life via Mass Extinction of Animal Genera | Gerardo Ceballos and Paul R. Ehrlich | Proceedings of the National Academy of Sciences | 2023-09-18
The study estimated that at least 73 vertebrate genera have vanished since 1500, representing the destruction of entire evolutionary branches rather than merely individual species.
4. More Losers Than Winners: Investigating Anthropocene Defaunation Through the Diversity of Population Trends | Catherine Finn, Florencia Grattarola and Daniel Pincheira-Donoso | Biological Reviews | 2023-05-15
Analysis of more than 70,000 animal species found that declining populations greatly outnumber increasing ones, suggesting that extinction-risk classifications alone underestimate global biological erosion.
5. The Sixth Mass Extinction: Fact, Fiction or Speculation? | Robert H. Cowie, Philippe Bouchet and Benoît Fontaine | Biological Reviews | 2022-01-10
The authors argue that extinction estimates focusing primarily on vertebrates substantially underestimate losses among invertebrates and that evidence strongly supports an ongoing sixth mass extinction.
6. Biodiversity Crisis or Sixth Mass Extinction? | Valentí Rull | EMBO Reports | 2022
Rull distinguishes an indisputable modern biodiversity crisis from the stricter paleontological definition of mass extinction and cautions against treating the two concepts as automatically equivalent.
7. Witnessing Mass Extinction: What's Invisible, What's Visible, What's Possible | Eileen Crist | Biological Conservation | 2022
The article examines cultural and ethical dimensions of mass extinction and explores why gradual biological impoverishment can remain socially invisible despite its enormous consequences.
8. Macroevolutionary Perspectives on Anthropocene Extinction | Multiple authors | Biological Conservation | 2022
This paper uses evolutionary and paleontological perspectives to explain how current extinctions can eliminate disproportionate amounts of evolutionary history.
9. Underestimating the Challenges of Avoiding a Ghastly Future | Corey J. A. Bradshaw et al. | Frontiers in Conservation Science | 2021
Scientists review evidence for biodiversity decline, climate disruption and ecological degradation while warning that governments and societies systematically underestimate the scale of the environmental crisis.
10. Extinction of Threatened Vertebrates Will Lead to Idiosyncratic Changes in Functional Diversity Across the World | Multiple authors | Nature Communications | 2021
The research shows that future extinctions could remove important ecological functions unevenly across regions, meaning species counts alone cannot capture the full consequences of biodiversity loss.
11. Using the IUCN Red List to Map Threats to Terrestrial Vertebrates at Global Scale | Multiple authors | Nature Ecology & Evolution | 2021
Researchers mapped where major human pressures overlap with threatened vertebrate species, identifying geographic areas where conservation actions could address multiple extinction drivers.
12. Vertebrates on the Brink as Indicators of Biological Annihilation and the Sixth Mass Extinction | Gerardo Ceballos, Paul R. Ehrlich and Peter H. Raven | Proceedings of the National Academy of Sciences | 2020-06-01
The authors identified hundreds of terrestrial vertebrate species with fewer than 1,000 individuals remaining and warned that extinction cascades could accelerate as ecological interactions disappear.
13. Co-Extinctions Annihilate Planetary Life During Extreme Environmental Change | Giovanni Strona and Corey J. A. Bradshaw | Scientific Reports | 2018-11-13
Modeling suggests that ecological dependencies among species can cause secondary co-extinctions that greatly magnify biodiversity loss caused directly by extreme environmental change.
14. The Misunderstood Sixth Mass Extinction | Gerardo Ceballos and Paul R. Ehrlich | Science | 2018-06-08
The authors argue that concentrating only on complete species extinctions obscures the enormous ecological consequences of collapsing populations and shrinking geographic ranges.
15. Biological Annihilation via the Ongoing Sixth Mass Extinction Signaled by Vertebrate Population Losses and Declines | Gerardo Ceballos, Paul R. Ehrlich and Rodolfo Dirzo | Proceedings of the National Academy of Sciences | 2017-07-10
Researchers found widespread population declines among terrestrial vertebrates, arguing that massive losses of populations and geographic ranges reveal an extinction crisis more severe than species-level statistics alone suggest.
16. Future Threats to Biodiversity and Pathways to Their Prevention | David Tilman et al. | Nature | 2017-05-31
The authors examine how agricultural expansion, population growth and development could intensify biodiversity losses while outlining pathways that could reduce future extinction risk.
17. Accelerated Modern Human-Induced Species Losses: Entering the Sixth Mass Extinction | Gerardo Ceballos et al. | Science Advances | 2015-06-19
Using highly conservative assumptions, the researchers estimated that modern vertebrate extinction rates are dramatically higher than natural background rates and concluded that a sixth mass extinction is already underway.
18. Defaunation in the Anthropocene | Rodolfo Dirzo et al. | Science | 2014-07-25
This influential review documents widespread declines in animal abundance and populations and introduces defaunation as a major dimension of human-driven global environmental change.
19. The Biodiversity of Species and Their Rates of Extinction, Distribution, and Protection | Stuart L. Pimm et al. | Science | 2014-05-30
The study estimated that contemporary species extinction rates may be roughly 1,000 times higher than natural background rates and identified geographic concentrations of threatened biodiversity.
20. Has the Earth's Sixth Mass Extinction Already Arrived? | Anthony D. Barnosky et al. | Nature | 2011-03-02
The study compared modern extinction rates with Earth's five previous mass extinctions and found that humanity could reach comparable levels of biodiversity loss within several centuries if threatened species disappear.
Evidence Across Species and Ecosystems
21. Potential Plant Extinctions With the Loss of the Pleistocene Mammoth Steppe | Multiple authors | Nature Communications | 2025
Deep-time analysis of vegetation loss provides context for understanding how major ecosystem transformations can eliminate plant lineages as well as conspicuous animal species.
22. Global Conservation Status of the Jawed Vertebrate Tree of Life | Multiple authors | Nature Communications | 2024
Researchers assess extinction risk across the vertebrate evolutionary tree and show that threatened species can represent disproportionately large amounts of unique evolutionary history.
23. Biodiversity Impacts of the 2019–2020 Australian Megafires | Multiple authors | Nature | 2024
A large-scale assessment examines how Australia's unprecedented megafires affected numerous animal and plant species and compounded existing extinction threats.
24. Preserving Earth's Flora in the 21st Century: Climate, Biodiversity, and Global Change Factors Since the Mid-1940s | Dasola A. Mosoh et al. | Frontiers in Conservation Science | 2024
The review examines how climate change and accelerating human pressures threaten global plant diversity and discusses strategies for preserving vulnerable flora.
25. Global Protected Areas as Refuges for Amphibians and Reptiles Under Climate Change | Multiple authors | Nature Communications | 2023
The study evaluates whether protected areas can continue sheltering amphibians and reptiles as climate conditions shift and species ranges reorganize.
26. Marine Biodiversity Discovery: The Metrics of New Species Descriptions | Multiple authors | Frontiers in Marine Science | 2023
The study shows that substantial portions of marine biodiversity remain undescribed, highlighting the possibility that species can disappear before science formally recognizes them.
27. Freshwater Biodiversity Crisis: Multidisciplinary Approaches as Tools for Conservation, Volume II | Multiple authors | Frontiers | 2023
A second collection expands research on freshwater biodiversity decline, monitoring, habitat degradation and practical conservation interventions.
28. Situating Defaunation in an Operational Framework to Advance Biodiversity Conservation | Multiple authors | BioScience | 2023
The authors propose a framework for measuring and addressing defaunation before declining animal populations reach the final stage of species extinction.
29. More Than Half of Data Deficient Species Predicted to Be Threatened by Extinction | Jan Borgelt, Martin Dorber, Marthe Alnes Høiberg et al. | Communications Biology | 2022-08-04
Modeling suggests that many poorly studied species currently classified as data deficient may actually be threatened, meaning documented extinction risk is likely an underestimate.
30. A Global Reptile Assessment Highlights Shared Conservation Needs of Tetrapods | Bruce E. Young et al. | Nature | 2022
A comprehensive global assessment found that about one-fifth of reptile species face extinction, demonstrating that the biodiversity crisis extends broadly across terrestrial vertebrates.
31. Freshwater Biodiversity Crisis: Multidisciplinary Approaches as Tools for Conservation | Multiple authors | Frontiers | 2022
This research collection examines the severe pressures on freshwater species and approaches for addressing one of the most threatened components of global biodiversity.
32. Local Awareness and Interpretations of Species Extinction in a Rural Chinese Biodiversity Hotspot | Heidi Ma et al. | Frontiers in Conservation Science | 2021-07-07
Interviews with local communities explore how people perceive declining wildlife and extinction, connecting global biodiversity statistics with lived ecological change.
33. Stable Soil Microbial Functional Structure Responding to Biodiversity Loss Based on Metagenomic Evidences | Multiple authors | Frontiers in Microbiology | 2021
The research investigates how biodiversity loss affects soil microbial communities, an often overlooked component of ecosystems essential to nutrient cycling and ecosystem function.
34. Are Insects Heading Toward Their First Mass Extinction? Distinguishing Turnover From Crises in Their Fossil Record | Multiple authors | Annals of the Entomological Society of America | 2020-12-31
The authors compare modern insect declines with fossil evidence to evaluate whether insects may be entering an extinction crisis without a direct historical analogue.
35. Global Dataset Shows Geography and Life Form Predict Modern Plant Extinction and Rediscovery | Aelys M. Humphreys et al. | Nature Ecology & Evolution | 2019-06-10
Researchers documented hundreds of plant extinctions since the eighteenth century and found that islands and particular plant forms are especially vulnerable.
36. Global Habitat Loss and Extinction Risk of Terrestrial Vertebrates Under Future Land-Use-Change Scenarios | Ryan P. Powers and Walter Jetz | Nature Climate Change | 2019-03-04
Projected land-use changes could cause major additional habitat losses for terrestrial vertebrates, particularly species already restricted to small geographic ranges.
37. Risk of Biodiversity Collapse Under Climate Change in the Afro-Arabian Region | Multiple authors | Scientific Reports | 2019
Modeling of endemic species indicates that rapid climate change could cause severe biodiversity losses across portions of Africa and Arabia during this century.
38. Extinction in Phylogenetics and Biogeography: From Timetrees to Patterns of Biotic Assemblage | Multiple authors | Frontiers in Genetics | 2016
This review explains how extinction influences evolutionary trees and geographic patterns, providing tools for reconstructing biodiversity loss over both ancient and modern times.
39. New Approaches Narrow Global Species Estimates for Beetles, Insects, and Terrestrial Arthropods | Nigel E. Stork et al. | Proceedings of the National Academy of Sciences | 2015
Improved estimates of arthropod diversity illustrate how enormous numbers of poorly documented species complicate attempts to calculate the true scale of modern extinction.
40. Are We in the Midst of the Sixth Mass Extinction? A View from the World of Amphibians | David B. Wake and Vance T. Vredenburg | Proceedings of the National Academy of Sciences | 2008-08-11
Amphibians provide some of the clearest evidence of a modern extinction crisis as habitat destruction, emerging diseases, climate change and other pressures eliminate populations around the world.
Drivers and Consequences of the Extinction Crisis
41. Tropical and Mediterranean Biodiversity Is Disproportionately Sensitive to Land-Use and Climate Change | Tim Newbold et al. | Nature Ecology & Evolution | 2020-09-14
Global data indicate that biodiversity in tropical and Mediterranean ecosystems is particularly vulnerable to the combined effects of land-use transformation and climate change.
42. Climate Change Contributes to Widespread Declines Among Bumble Bees Across Continents | Peter Soroye, Tim Newbold and Jeremy Kerr | Science | 2020
Increasingly frequent temperature extremes are associated with widespread bumblebee declines, illustrating how climate disruption can translate into rapid population losses.
43. Increasing Impacts of Land Use on Biodiversity and Carbon Sequestration Driven by Population and Economic Growth | Multiple authors | Nature Ecology & Evolution | 2019
The study links growing consumption and international trade to biodiversity impacts far from consumer markets, especially in tropical regions.
44. Climate and Land-Use Change Homogenise Terrestrial Biodiversity, With Consequences for Ecosystem Functioning and Human Well-Being | Tim Newbold et al. | Emerging Topics in Life Sciences | 2019
The review describes how environmental change increasingly favors similar human-tolerant species while eliminating specialized species, making biological communities more alike.
45. More Than 75 Percent Decline Over 27 Years in Total Flying Insect Biomass in Protected Areas | Caspar A. Hallmann et al. | PLOS ONE | 2017-10-18
Long-term monitoring in German protected areas revealed a dramatic decline in flying-insect biomass, helping trigger international concern about widespread insect losses.
46. Global Forest Loss Disproportionately Erodes Biodiversity in Intact Landscapes | Matthew G. Betts et al. | Nature | 2017
The researchers found that even relatively small amounts of forest loss can sharply increase extinction risk when they occur in previously intact landscapes.
47. Biodiversity: The Ravages of Guns, Nets and Bulldozers | Sean L. Maxwell et al. | Nature | 2016-08-10
Analysis of threatened species shows that habitat destruction and direct exploitation remain dominant causes of biodiversity loss despite increasing attention to newer threats such as climate change.
48. Land-Use Intensification Causes Multitrophic Homogenization of Grassland Communities | Martin M. Gossner et al. | Nature | 2016
Intensive management made grassland communities more biologically similar across sites, reducing ecological variation among plants, microbes and animals.
49. On the Decline of Biodiversity Due to Area Loss | Petr Keil, David Storch and Walter Jetz | Nature Communications | 2015-11-17
The study demonstrates that the geographic pattern of habitat destruction influences how rapidly species, functional diversity and evolutionary history disappear.
50. Global Effects of Land Use on Local Terrestrial Biodiversity | Tim Newbold et al. | Nature | 2015-04-01
A worldwide analysis found that land use and related human pressures have already reduced average local species richness and abundance, with substantially larger losses in heavily altered habitats.
51. Land Use Matters | Brian McGill | Nature | 2015-04-01
This commentary explains why land conversion is a major global biodiversity pressure and discusses evidence that human land use has already reduced local species richness.
52. Accelerating Extinction Risk From Climate Change | Mark C. Urban | Science | 2015
A meta-analysis concluded that extinction risks rise as global temperatures increase, with the greatest risks occurring under higher-warming scenarios.
53. Habitat Fragmentation and Its Lasting Impact on Earth's Ecosystems | Nick M. Haddad et al. | Science Advances | 2015
Long-running fragmentation experiments show that breaking continuous habitat into isolated pieces causes persistent reductions in biodiversity and ecosystem function.
54. Biodiversity Loss and Its Impact on Humanity | Bradley J. Cardinale et al. | Nature | 2012-06-06
This major synthesis concludes that biodiversity supports ecosystem productivity, stability and services on which human societies depend, making extinction a human welfare issue as well as a conservation concern.
55. A Global Synthesis Reveals Biodiversity Loss as a Major Driver of Ecosystem Change | David U. Hooper et al. | Nature | 2012
Experimental evidence shows that losing species can impair ecosystem productivity and decomposition at magnitudes comparable to several major forms of environmental change.
56. Rapid Range Shifts of Species Associated With High Levels of Climate Warming | I-Ching Chen et al. | Science | 2011
Species around the world are shifting toward higher elevations and latitudes as temperatures rise, demonstrating the rapidly changing conditions confronting ecological communities.
57. Population and Species Extinction Exacerbated by Climate Change | Chris D. Thomas et al. | Nature | 2004
Modeling across multiple regions projected substantial extinction risks from climate-driven range changes, helping establish climate change as a major biodiversity threat.
58. Global Biodiversity Scenarios for the Year 2100 | Osvaldo E. Sala et al. | Science | 2000
Researchers projected how land-use change, climate change, invasive species, nitrogen deposition and atmospheric carbon dioxide could reshape biodiversity during the twenty-first century.
59. The Global Decline of Reptiles, Déjà Vu Amphibians | J. Whitfield Gibbons et al. | BioScience | 2000
The authors identify habitat loss, exploitation, pollution, invasive species and climate change as interacting drivers placing reptiles on trajectories resembling amphibian declines.
60. Human Domination of Earth's Ecosystems | Peter M. Vitousek et al. | Science | 1997
This landmark paper documents how extensively humans have altered land, oceans, atmospheric chemistry and biological communities, establishing the environmental context for modern extinction.
Conservation, Monitoring and Preventing Extinction
61. Biodiversity Conservation Has an Evidence Problem — It's Time to Fix It | Nature Editorial | Nature | 2026-02-04
This editorial argues that conservation needs stronger systems for measuring which interventions actually prevent biodiversity decline and extinction.
62. Professor David Tilman Awarded National Medal of Science for Revealing the Importance of Biodiversity | Harrison Tasoff | UC Santa Barbara The Current | 2025-01-27
The profile reviews decades of ecological research demonstrating that diverse ecosystems tend to be more productive and resilient than biologically simplified ones.
63. Conserving Biodiversity and Halting Extinction: From Ambition to Action on Conservation Imperatives and How to Pay for It | Emma Duncan and Charles V. Barber | Frontiers Policy Labs | 2024-06-25
The policy analysis examines the financing and institutional changes needed to move global biodiversity commitments from promises to effective conservation.
64. Global Shortfalls in Documented Actions to Conserve Biodiversity | Multiple authors | Nature | 2024
Researchers found major gaps between recognition of threatened biodiversity and documented conservation interventions, highlighting the need to translate assessments into concrete action.
65. What Is the Sixth Mass Extinction and What Can We Do About It? | World Wildlife Fund | WWF | 2024
This explainer outlines the meaning of mass extinction, major human causes of current biodiversity decline and actions that could slow species losses.
66. The Sixth Mass Extinction and Amphibian Species Sustainability Through Reproduction and Advanced Biotechnologies, Biobanking of Germplasm and Somatic Cells, and Conservation Breeding Programs | Multiple authors | Animals / PubMed Central | 2024
The review examines reproductive technologies, biobanking and captive breeding as tools for preventing amphibian extinctions when wild populations can no longer be protected through habitat conservation alone.
67. Improving Biodiversity Protection Through Artificial Intelligence | Daniele Silvestro et al. | Nature Sustainability | 2022-03-24
The study demonstrates how machine learning can help identify species and regions most in need of protection when conventional conservation data are incomplete.
68. Integrating Deep-Time Palaeontology in Conservation Prioritisation | Multiple authors | Frontiers in Ecology and Evolution | 2022
The article explains how fossil evidence and evolutionary history can inform decisions about protecting lineages during the current biodiversity crisis.
69. Biodiversity Imperiled | Harrison Tasoff | UC Santa Barbara The Current | 2021-06-17
The article explores accelerating biodiversity loss and research examining how conservation can preserve both species and ecosystem function.
70. Loss of Land-Based Vertebrates Is Accelerating | Stanford Report | Stanford University | 2020-06-01
Scientists warn that hundreds of vertebrates with very small remaining populations could vanish soon, potentially triggering ecological cascades involving other species.
71. Breaching a Carbon Threshold Could Lead to Mass Extinction | MIT News | Massachusetts Institute of Technology | 2019
Research into Earth's carbon cycle identifies thresholds beyond which relatively gradual environmental disruption could transition toward catastrophic biological change.
72. Biological Extinction | Multiple authors | IUCN Library | 2019
This conservation resource examines biological extinction and the international scientific and policy frameworks developed to understand and counter species loss.
73. Mathematics Predicts a Sixth Mass Extinction | Jennifer Chu | MIT News | 2017-09-20
Mathematical analysis of past ocean-carbon disruptions suggests that sufficiently large changes to the carbon cycle could push Earth toward another major extinction event.
74. World's Food and Energy Systems Key to Tackling Global Biodiversity Decline | World Wildlife Fund | WWF | 2016
WWF argues that transforming food production, energy and resource consumption is essential to reversing global wildlife and habitat decline.
75. Stanford Researcher Declares That the Sixth Mass Extinction Is Here | Stanford Report | Stanford University | 2015-06-19
The article explains research concluding that vertebrate extinction rates are far above natural background levels even when researchers make conservative assumptions.
76. Has the Earth's Sixth Mass Extinction Already Arrived? | Robert Sanders | Berkeley News | 2011-03-02
This accessible account explains the Barnosky study comparing current extinction trends with the five great mass extinctions preserved in the fossil record.
77. Conservation of Biodiversity | Multiple authors | Nature Education Knowledge | 2010
This overview explains why biodiversity is declining, how extinction affects ecosystem processes and which conservation approaches can protect species and habitats.
78. Current Mass Extinction Spurs Major Study of Which Plants to Save | Gail Gallessich | UC Santa Barbara The Current | 2008-10-20
Researchers examined evolutionary relationships among plants to improve conservation prioritization when limited resources make it impossible to protect every threatened species equally.
79. Scientists Warn That Species Extinction Could Reduce Productivity of Plants on Earth by as Much as Half | Gail Gallessich | UC Santa Barbara The Current | 2007-11-05
Experimental research suggests that substantial species loss can sharply reduce plant productivity, demonstrating that extinction can alter fundamental ecosystem processes.
80. Wilson Urges Alliance to Save Species | Harvard Gazette | Harvard University | 2007-02
Biologist E. O. Wilson calls for large-scale conservation action to prevent humanity from eliminating a major share of Earth's species.
Journalism, Explanations and Public Debate
81. 'Mutilating the Tree of Life': Wildlife Loss Accelerating, Scientists Warn | Patrick Greenfield | The Guardian | 2023-09-19
This report explains research showing that entire animal genera are disappearing, eliminating evolutionary history accumulated over millions of years.
82. Anthropocene 'Sixth Mass Extinction' Event Predicted to Be Worse Than Previously Thought | Bob Yirka | Phys.org | 2023-05-24
New population-trend research suggests the number of species experiencing substantial decline is much larger than indicated by recorded species extinctions alone.
83. Biodiversity Is Nearing an 'Extinction Crisis,' Animal Researchers Say | TIME | TIME | 2023-05-23
The article reports research showing that population declines occur across far more animal species than formal threatened-species lists alone reveal.
84. Are We Really in a Sixth Mass Extinction? | Jessica Colarossi / Boston University | Phys.org | 2023-04-10
Scientists discuss what qualifies as a mass extinction, how current extinction rates compare with deep time and why disagreement about terminology does not lessen the seriousness of biodiversity decline.
85. Biodiversity Needs to Be a Climate Priority | TIME | TIME | 2022-12
This article argues that biodiversity loss and climate change must be treated as interconnected global crises rather than addressed through separate policy systems.
86. Strong Evidence Shows Sixth Mass Extinction of Global Biodiversity in Progress | Marcie Grabowski / University of Hawai‘i at Mānoa | Phys.org | 2022-01-14
The article reports research arguing that extinction assessments biased toward mammals and birds fail to capture extensive losses among invertebrates.
87. Sixth Mass Extinction of Wildlife Accelerating, Scientists Warn | Damian Carrington | The Guardian | 2020-06-01
Reporting on research into extremely rare vertebrates, the article describes warnings that hundreds of species could disappear within decades and accelerate wider ecological collapse.
88. UN Draft Plan Sets 2030 Target to Avert Earth's Sixth Mass Extinction | Patrick Greenfield | The Guardian | 2020-01-13
Reporting on international biodiversity negotiations, the article examines proposals for protecting ecosystems and reducing extinction pressures by 2030.
89. Mammals Cannot Evolve Fast Enough to Escape Current Extinction Crisis | ScienceDaily | ScienceDaily | 2018-10-15
Researchers estimate that evolutionary diversification would require millions of years to replace the unique mammal lineages humanity could eliminate during the present century.
90. Sixth Mass Extinction of Wildlife Also Threatens Global Food Supplies | Damian Carrington | The Guardian | 2017-09-26
Loss of crop varieties, wild relatives and domesticated genetic diversity could make the global food system increasingly vulnerable to disease, pests and climate change.
91. Chips, Chocolate and Coffee — Our Food Crops Face Mass Extinction Too | M. Ann Tutwiler | The Guardian | 2017-09-26
The article explains why protecting crop diversity and wild relatives is an important but often overlooked component of preventing the broader biodiversity crisis.
92. You Don't Need a Scientist to Know What's Causing the Sixth Mass Extinction | Paul R. Ehrlich | The Guardian | 2017-07-11
Ehrlich argues that habitat destruction, overconsumption and human population pressures are driving the widespread disappearance of wildlife populations.
93. Earth's Sixth Mass Extinction Event Under Way, Scientists Warn | Damian Carrington | The Guardian | 2017-07-10
The article reports evidence of widespread vertebrate population and range losses that scientists describe as biological annihilation.
94. What the 'Sixth Extinction' Will Look Like in the Oceans: The Largest Species Die Off First | Chris Mooney | The Washington Post | 2016-09-14
Research into marine extinction patterns suggests human exploitation is disproportionately eliminating large ocean animals, reversing patterns associated with some ancient extinctions.
95. Many Species Now Going Extinct May Vanish Without a Fossil Trace | ScienceDaily | ScienceDaily | 2016-03-21
Research shows that many threatened modern species have little or no known fossil record, making today's biodiversity crisis potentially difficult for future paleontologists to reconstruct.
96. How Humans Are Driving the Sixth Mass Extinction | Jeremy Hance | The Guardian | 2015-10-20
The article examines several interconnected human pressures—including habitat destruction, hunting, invasive species and climate change—that are pushing species toward extinction.
97. Earth Is on Brink of a Sixth Mass Extinction, Scientists Say, and It's Humans' Fault | Sarah Kaplan | The Washington Post | 2015-06-22
The report explains the influential 2015 study estimating exceptionally high modern vertebrate extinction rates even under conservative assumptions.
98. The Earth Stands on the Brink of Its Sixth Mass Extinction and the Fault Is Ours | Jan Zalasiewicz | The Guardian | 2015-06-21
The article places contemporary species losses within Earth's geological history and emphasizes the exceptional role of human activity in the present crisis.
99. Our Planet May Be on the Verge of Its Sixth Mass Extinction | Chris Mooney | The Washington Post | 2014-11-28
The article reviews evidence that modern extinction rates greatly exceed background levels and considers whether current losses justify comparison with Earth's previous mass extinctions.
100. Biologists Warn of Early Stages of Earth's Sixth Mass Extinction Event | ScienceDaily | ScienceDaily | 2014-07-24
Reporting on the concept of Anthropocene defaunation, the article describes widespread declines among animal populations and the ecological consequences of losing animals even before species become globally extinct.
The Sixth Mass Extinction: Deep-Time Context and Mass-Extinction Science
101. Mental Models of the Sixth Mass Extinction Reveal Pathways for Transformative Sustainability Action | Ganga Shreedhar | Scientific Reports | 2026-02-20
A representative UK survey examines public awareness of the sixth mass extinction and finds that understanding human causes is strongly associated with support for transformative environmental action.
102. Extinction Magnitude of Animals in the Near Future | Kunio Kaiho | Scientific Reports | 2022-11-23
This study models possible future animal losses and distinguishes between a major mass extinction and smaller but still severe extinction events under different environmental trajectories.
103. Early Evolution of Modern Birds Structured by Global Forest Collapse at the End-Cretaceous Mass Extinction | Daniel J. Field et al. | Current Biology | 2018
Evidence suggests that worldwide forest destruction after the asteroid impact strongly shaped which bird lineages survived and diversified.
104. Temperature-Dependent Hypoxia Explains Biogeography and Severity of End-Permian Marine Mass Extinction | Justin L. Penn et al. | Science | 2018
Modeling indicates that ocean warming and oxygen loss can explain much of the geographic pattern and magnitude of the end-Permian marine extinction.
105. The Pliocene Marine Megafauna Extinction and Its Impact on Functional Diversity | Catalina Pimiento et al. | Nature Ecology & Evolution | 2017
Fossil evidence reveals a previously underappreciated extinction of marine megafauna that substantially reduced ecological functional diversity.
106. Paleontological Baselines for Evaluating Extinction Risk in the Modern Oceans | Seth Finnegan et al. | Science | 2015-05-01
Fossil records spanning millions of years identify biological traits associated with extinction vulnerability and help establish a pre-human baseline against which modern marine risks can be measured.
107. Rarity in Mass Extinctions and the Future of Ecosystems | Pincelli M. Hull, Simon A. F. Darroch and Douglas H. Erwin | Nature | 2015
The authors argue that widespread declines of formerly abundant species may provide an important early warning of mass extinction before large numbers of species disappear entirely.
108. Global Late Quaternary Megafauna Extinctions Linked to Humans, Not Climate Change | Christopher J. Sandom et al. | Proceedings of the Royal Society B | 2014
Global patterns of prehistoric megafaunal extinction are more strongly associated with human expansion than with climate change alone.
109. Extinctions in Ancient and Modern Seas | Paul G. Harnik et al. | Trends in Ecology & Evolution | 2012
The review compares extinction patterns in ancient oceans with threats facing modern marine organisms, including warming, acidification, exploitation and habitat disruption.
110. End-Permian Mass Extinction in the Oceans: An Ancient Analog for the Twenty-First Century? | Jonathan L. Payne and Matthew E. Clapham | Annual Review of Earth and Planetary Sciences | 2012
The authors examine Earth's largest known mass extinction and its connections to rapid carbon release, warming, ocean acidification and oxygen loss.
111. Mass Extinction of Birds at the Cretaceous-Paleogene Boundary | Nicholas R. Longrich, Tim Tokaryk and Daniel J. Field | Proceedings of the National Academy of Sciences | 2011
Fossil evidence indicates that the asteroid-driven extinction eliminated many bird lineages while a smaller surviving group eventually produced modern avian diversity.
112. The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary | Peter Schulte et al. | Science | 2010
A major interdisciplinary synthesis concludes that the Chicxulub asteroid impact was the principal trigger of the end-Cretaceous mass extinction.
113. Dynamics of Origination and Extinction in the Marine Fossil Record | John Alroy | Proceedings of the National Academy of Sciences | 2008-08-11
Fossil data suggest that recovery from a severe modern mass extinction could require millions to tens of millions of years even after the environmental causes were removed.
114. Phanerozoic Biodiversity Mass Extinctions | Richard K. Bambach | Annual Review of Earth and Planetary Sciences | 2006-05-30
This review examines extinction intensity throughout the Phanerozoic and shows that mass extinctions differ substantially in magnitude, duration and biological consequences.
115. Late Quaternary Extinctions: State of the Debate | Paul L. Koch and Anthony D. Barnosky | Annual Review of Ecology, Evolution, and Systematics | 2006
This broad review analyzes how human expansion and rapid environmental change contributed to the disappearance of mammoths, giant ground sloths and other large animals.
116. Assessing the Causes of Late Pleistocene Extinctions on the Continents | Anthony D. Barnosky et al. | Science | 2004
The study evaluates climate change and human activity as causes of prehistoric megafaunal extinctions and shows that their relative importance varied geographically.
117. How to Kill (Almost) All Life: The End-Permian Extinction Event | Michael J. Benton and Richard J. Twitchett | Trends in Ecology & Evolution | 2003
This review explores environmental mechanisms behind the Permian mass extinction, offering deep-time comparisons for modern climate and biodiversity disruption.
118. Extinctions: A Paleontological Perspective | David Jablonski | Science | 1991-08-16
Jablonski explains how the fossil record reveals differences between ordinary background extinction and mass extinction, providing an important framework for evaluating today's biodiversity crisis.
119. Mass Extinctions in the Marine Fossil Record | David M. Raup and J. John Sepkoski Jr. | Science | 1982-03-19
A landmark quantitative analysis of the marine fossil record identified unusually severe extinction episodes that helped establish the modern concept of the "Big Five" mass extinctions.
120. Extraterrestrial Cause for the Cretaceous-Tertiary Extinction | Luis W. Alvarez, Walter Alvarez, Frank Asaro and Helen V. Michel | Science | 1980
The famous asteroid-impact hypothesis transformed scientific understanding of catastrophic extinction and demonstrated how rapidly planetary disturbances can reorganize life.
Measuring the Modern Biodiversity Crisis
121. Living Planet Report 2024: A System in Peril | WWF and Zoological Society of London | WWF | 2024
The report compiles wildlife-population and ecosystem indicators showing severe ongoing biological decline while emphasizing approaching ecological tipping points.
122. Half-Millennium Evidence Suggests That Extinction Debts of Global Vertebrates Started in the Second Industrial Revolution | Ziyan Liao, Shushi Peng and Youhua Chen | Communications Biology | 2022-12-13
Historical forest data indicate that delayed extinction pressures on forest vertebrates began accumulating rapidly during nineteenth-century industrialization.
123. Widespread Extinction Debts and Colonization Credits in United States Breeding Bird Communities | Yacob Haddou et al. | Nature Ecology & Evolution | 2022-02-10
Current bird diversity across much of the United States still reflects past landscapes, suggesting substantial future losses may already be embedded in today's altered habitats.
124. Clustered Versus Catastrophic Global Vertebrate Declines | Brian Leung et al. | Nature | 2020-11-18
The authors show that global population averages can be strongly influenced by clusters of extremely severe declines, illustrating the importance of carefully interpreting biodiversity indicators.
125. Global Biodiversity Outlook 5 | Secretariat of the Convention on Biological Diversity | Convention on Biological Diversity | 2020
The report assesses global progress on biodiversity protection and identifies systemic transformations needed in food, land, freshwater, cities, fisheries and climate policy.
126. Pervasive Human-Driven Decline of Life on Earth Points to the Need for Transformative Change | Sandra Díaz et al. | Science | 2019-12-13
Drawing on the IPBES global assessment, the authors document widespread human-driven degradation of biodiversity and argue that incremental reforms will not be sufficient.
127. The Geography of Biodiversity Change in Marine and Terrestrial Assemblages | Shane A. Blowes et al. | Science | 2019-10-18
More than 50,000 ecological time series reveal strong geographic variation in biodiversity change, with particularly rapid community restructuring in marine ecosystems.
128. Global Assessment Report on Biodiversity and Ecosystem Services | IPBES | Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services | 2019
This major international assessment concludes that nature is declining globally at unprecedented rates and that roughly one million species could face extinction.
129. Extinction Debt and Colonization Credit Delay Range Shifts of Eastern North American Trees | Lauren Talluto et al. | Nature Ecology & Evolution | 2017-06-12
Tree distributions can lag behind rapid environmental change, creating both delayed disappearances and delayed expansions.
130. Evidence and Mapping of Extinction Debts for Global Forest-Dwelling Reptiles, Amphibians and Mammals | Youhua Chen and Shushi Peng | Scientific Reports | 2017-03-16
Global mapping indicates that historical deforestation may have created substantial delayed extinction risks that are not fully reflected by current threat maps.
131. Dynamics of Extinction Debt Across Five Taxonomic Groups | John M. Halley et al. | Nature Communications | 2016-07-25
Extinction often occurs decades or centuries after habitat destruction, meaning present-day biodiversity can conceal losses that have already been ecologically committed.
132. Estimating Local Biodiversity Change: A Critique of Papers Claiming No Net Loss of Local Diversity | Andrew Gonzalez et al. | Ecology | 2016
The authors examine methodological limitations in studies suggesting little average local biodiversity loss and warn against using local richness trends to dismiss global decline.
133. Estimating the Normal Background Rate of Species Extinction | Jurriaan M. De Vos et al. | Conservation Biology | 2015
The researchers develop improved estimates of natural background extinction rates, providing a baseline essential for judging how exceptional modern human-driven losses are.
134. A Mid-Term Analysis of Progress Toward International Biodiversity Targets | Derek P. Tittensor et al. | Science | 2014-10-10
The analysis found that global conservation responses were increasing but remained insufficient to reverse negative biodiversity trends.
135. Assemblage Time Series Reveal Biodiversity Change but Not Systematic Loss | Maria Dornelas et al. | Science | 2014-04-18
Local ecological communities did not show a uniform decline in species richness, but their composition changed substantially, demonstrating that biodiversity change involves more than simple species counts.
136. Global Meta-Analysis Reveals No Net Change in Local-Scale Plant Biodiversity Over Time | Mark Vellend et al. | Proceedings of the National Academy of Sciences | 2013
The study finds that local plant richness does not universally decline even while global extinction proceeds, highlighting differences between local and planetary biodiversity measures.
137. Species-Area Relationships Always Overestimate Extinction Rates From Habitat Loss | Fangliang He and Stephen P. Hubbell | Nature | 2011-05-18
This influential critique argues that one common method can overpredict immediate extinctions after habitat loss, generating an important methodological debate about extinction estimates.
138. Global Biodiversity: Indicators of Recent Declines | Stuart H. M. Butchart et al. | Science | 2010-05-28
A large collection of biodiversity indicators showed continuing deterioration in species populations, extinction risk, habitat condition and ecological communities.
139. Scenarios for Global Biodiversity in the 21st Century | Henrique M. Pereira et al. | Science | 2010
Researchers compare global biodiversity scenarios and show that future outcomes depend heavily on land use, climate, pollution, exploitation and conservation choices.
140. Extinction Debt: A Challenge for Biodiversity Conservation | Mikko Kuussaari et al. | Trends in Ecology & Evolution | 2009
The review explains why species may persist temporarily after habitat destruction even when remaining habitat can no longer support them over the long term.
Amphibians, Birds, Mammals and Marine Vertebrates
141. Ongoing Declines for the World's Amphibians in the Face of Emerging Threats | Jennifer A. Luedtke et al. | Nature | 2023-10-04
The second Global Amphibian Assessment finds amphibians remain the most threatened vertebrate class, with climate change becoming an increasingly important driver.
142. State of the World's Birds 2022 Paints Most Concerning Picture for Nature Yet | BirdLife International | BirdLife International | 2022-09-28
This accessible overview summarizes worldwide bird declines while emphasizing that targeted conservation has already prevented numerous extinctions.
143. State of the World's Birds | Alexander C. Lees et al. | Annual Review of Environment and Resources | 2022
This comprehensive review concludes that numerous indicators of global bird diversity, abundance and extinction risk are deteriorating.
144. State of the World's Birds 2022: Insights and Solutions for the Biodiversity Crisis | BirdLife International | BirdLife International | 2022
BirdLife's global assessment reports that nearly half of bird species are declining and more than one in eight is threatened with extinction.
145. Overfishing Drives Over One-Third of All Sharks and Rays Toward a Global Extinction Crisis | Nicholas K. Dulvy et al. | Current Biology | 2021-09-06
A comprehensive reassessment finds more than one-third of shark and ray species threatened with extinction, with overfishing overwhelmingly responsible.
146. Tracking the Rising Extinction Risk of Sharks and Rays in the Northeast Atlantic Ocean and Mediterranean Sea | Rachel H. L. Walls and Nicholas K. Dulvy | Scientific Reports | 2021-07-28
Regional Red List trends demonstrate increasing extinction risk among sharks and rays subjected to sustained fishing pressure.
147. Half a Century of Global Decline in Oceanic Sharks and Rays | Nathan Pacoureau et al. | Nature | 2021-01-27
Global abundance of oceanic sharks and rays declined sharply during the previous half-century as fishing pressure increased.
148. Amphibian Fungal Panzootic Causes Catastrophic and Ongoing Loss of Biodiversity | Ben C. Scheele et al. | Science | 2019
The chytrid fungus pandemic has driven declines in hundreds of amphibian species and represents one of the greatest recorded losses of biodiversity caused by a disease.
149. Decline of the North American Avifauna | Kenneth V. Rosenberg et al. | Science | 2019
Long-term monitoring indicates that North America lost billions of breeding birds within roughly half a century, including many species not formally classified as endangered.
150. Collapse of the World's Largest Herbivores | William J. Ripple et al. | Science Advances | 2015
Many of Earth's largest herbivores face extinction from hunting, livestock competition and habitat loss, threatening ecological functions such as seed dispersal and vegetation management.
151. Marine Defaunation: Animal Loss in the Global Ocean | Douglas J. McCauley et al. | Science | 2015
The authors compare modern ocean wildlife losses with terrestrial defaunation and warn that industrial exploitation could accelerate marine extinctions dramatically.
152. Global Patterns of Extinction Risk in Marine and Non-Marine Systems | Thomas J. Webb and Bethan L. Mindel | Current Biology | 2015
Comparisons across marine and terrestrial species show how geography, body size and ecological characteristics influence extinction vulnerability.
153. Status and Ecological Effects of the World's Largest Carnivores | William J. Ripple et al. | Science | 2014
Declines of large carnivores such as lions, wolves and big cats can restructure entire ecosystems through trophic cascades.
154. Extinction Risk and Conservation of the World's Sharks and Rays | Nicholas K. Dulvy et al. | eLife | 2014
The first global assessment of sharks and rays revealed widespread extinction risk, particularly among large-bodied species exposed to fisheries.
155. The Conservation Status of the World's Reptiles | Monika Böhm et al. | Biological Conservation | 2013
A global sample-based assessment showed substantial extinction risk among reptiles and identified habitat loss and exploitation as major threats.
156. Seabird Conservation Status, Threats and Priority Actions: A Global Assessment | John P. Croxall et al. | Bird Conservation International | 2012
The global assessment documents unusually high levels of threat among seabirds from fisheries, invasive species, habitat disturbance and pollution.
157. The Changing Fates of the World's Mammals | Michael Hoffmann et al. | Philosophical Transactions of the Royal Society B | 2011
Tracking changes in mammal conservation status identifies both continuing deterioration and cases where direct conservation action improved species prospects.
158. The Status of the World's Land and Marine Mammals: Diversity, Threat and Knowledge | Jan Schipper et al. | Science | 2008
A comprehensive mammal assessment found large numbers of species threatened by habitat loss, exploitation and other human pressures.
159. One-Third of Reef-Building Corals Face Elevated Extinction Risk From Climate Change and Local Impacts | Kent E. Carpenter et al. | Science | 2008
A worldwide coral assessment revealed widespread extinction risk from warming, disease, coastal development, pollution and destructive fishing.
160. Status and Trends of Amphibian Declines and Extinctions Worldwide | Simon N. Stuart et al. | Science | 2004
The first comprehensive global amphibian assessment revealed widespread population declines and unusually high extinction risk across frogs, salamanders and caecilians.
Freshwater, Insects, Plants and Other Vulnerable Biodiversity
161. Linking Species Local Trends From Assemblage Monitoring to Global Extinction Risk | Laura H. Antão et al. | Nature Communications | 2026-06-23
More than 60,000 monitored populations are used to investigate how local population changes correspond with species-level global extinction assessments.
162. State of the World's Plants and Fungi 2023 | Royal Botanic Gardens, Kew | Royal Botanic Gardens, Kew | 2023
Hundreds of scientists synthesize evidence on newly discovered species, extinction risk and threats to global plant and fungal diversity.
163. The World's Forgotten Fishes | WWF et al. | World Wildlife Fund | 2021-03-30
This international report highlights the ecological and human importance of freshwater fishes and warns that roughly one-third face extinction.
164. Insect Decline in the Anthropocene: Death by a Thousand Cuts | David L. Wagner et al. | Proceedings of the National Academy of Sciences | 2021
This synthesis argues that insect declines result from numerous interacting pressures rather than a single global cause.
165. State of the World's Trees | Botanic Gardens Conservation International | BGCI | 2021
The Global Tree Assessment concludes that roughly one-third of known tree species face extinction, principally from habitat destruction and direct exploitation.
166. Extinction Risk and Threats to Plants and Fungi | Eimear Nic Lughadha et al. | Plants, People, Planet | 2020-09-29
The review assesses the poorly documented extinction risk facing plants and fungi and emphasizes large gaps in global conservation assessments.
167. Loss of Dominant Caterpillar Genera in a Protected Tropical Forest | Danielle M. Salcido et al. | Scientific Reports | 2020-01-16
More than two decades of tropical forest monitoring found declines in caterpillar diversity and density even inside protected habitat.
168. Bending the Curve of Global Freshwater Biodiversity Loss: An Emergency Recovery Plan | David Tickner et al. | BioScience | 2020
Scientists propose an emergency recovery framework addressing river flows, water pollution, habitat connectivity, exploitation, invasive species and wetland protection.
169. Meta-Analysis Reveals Declines in Terrestrial but Increases in Freshwater Insect Abundances | Roel van Klink et al. | Science | 2020
Long-term datasets reveal significant average declines among terrestrial insects while showing that insect trends vary greatly among ecosystems and regions.
170. Scientists' Warning to Humanity on Insect Extinctions | Pedro Cardoso et al. | Biological Conservation | 2020
Scientists warn that insect extinctions threaten pollination, nutrient cycling, decomposition and food webs and call for major changes in land and chemical management.
171. Rare and Common Vertebrates Span a Wide Spectrum of Population Trends | Gergana N. Daskalova, Isla H. Myers-Smith and John L. Godlee | Nature Communications | 2020
Global vertebrate time series demonstrate enormous variation among populations and reinforce the need to distinguish broad biodiversity trends from local trajectories.
172. Emerging Threats and Persistent Conservation Challenges for Freshwater Biodiversity | Andrea J. Reid et al. | Biological Reviews | 2019
The authors identify multiple interacting threats to freshwater biodiversity, including pollution, dams, overharvesting, invasive species and climate change.
173. Worldwide Decline of the Entomofauna: A Review of Its Drivers | Francisco Sánchez-Bayo and Kris A. G. Wyckhuys | Biological Conservation | 2019
This widely discussed review compiles evidence of insect declines and examines habitat loss, pesticides, pollution, invasive species and climate change as potential causes.
174. Arthropod Decline in Grasslands and Forests Is Associated With Landscape-Level Drivers | Sebastian Seibold et al. | Nature | 2019
A decade of monitoring in Germany documented strong declines in arthropod abundance, biomass and species numbers across grasslands and forests.
175. Global Warming Transforms Coral Reef Assemblages | Terry P. Hughes et al. | Nature | 2018
Extreme heat can permanently restructure coral communities, replacing complex reef assemblages with biologically simplified systems.
176. Global Warming and Recurrent Mass Bleaching of Corals | Terry P. Hughes et al. | Nature | 2017
Repeated marine heatwaves are causing mass coral bleaching too frequently for many reefs to recover fully between events.
177. Green Plants in the Red: A Baseline Global Assessment for the IUCN Sampled Red List Index for Plants | Neil Brummitt et al. | PLOS ONE | 2015
A representative global plant assessment demonstrates that extinction risk is widespread across major plant groups and provides a baseline for measuring future changes.
178. Can We Name Earth's Species Before They Go Extinct? | Mark J. Costello, Robert M. May and Nigel E. Stork | Science | 2013
The authors investigate whether science can describe the planet's remaining unknown species quickly enough to assess and conserve them before they disappear.
Human Drivers, Conservation and Avoiding Future Extinction
179. Has Life on Earth Survived More Than Five Mass Extinctions? | Riley Black | Smithsonian Magazine | 2024-07-12
This accessible review explores ongoing scientific debate over how many ancient events qualify as mass extinctions and places the modern biodiversity crisis within that changing paleontological framework.
180. The Minimum Land Area Requiring Conservation Attention to Safeguard Biodiversity | James R. Allan et al. | Science | 2022
Researchers map areas requiring conservation management to protect threatened species, key biodiversity areas and ecologically intact landscapes.
181. How Many Bird and Mammal Extinctions Has Recent Conservation Action Prevented? | Friederike C. Bolam et al. | Conservation Letters | 2021
Expert assessment suggests that targeted conservation prevented numerous bird and mammal extinctions, providing evidence that extinction trajectories can be changed.
182. Recent Responses to Climate Change Reveal the Drivers of Species Extinction and Survival | Cristian Román-Palacios and John J. Wiens | Proceedings of the National Academy of Sciences | 2020
Local extinction records suggest that exposure to unusually high maximum temperatures is particularly important in determining climate-related species losses.
183. The Projected Timing of Abrupt Ecological Disruption From Climate Change | Christopher H. Trisos, Cory Merow and Alex L. Pigot | Nature | 2020
Climate models indicate that ecological communities could experience abrupt exposure to unprecedented temperatures rather than gradual biological change.
184. A Global Deal for Nature: Guiding Principles, Milestones, and Targets | Eric Dinerstein et al. | Science Advances | 2019
The authors propose large-scale habitat protection and restoration targets intended to address both biodiversity loss and climate change.
185. The Projected Effect on Insects, Vertebrates, and Plants of Limiting Global Warming to 1.5°C Rather Than 2°C | Rachel Warren et al. | Nature Climate Change | 2018
Modeling shows that limiting warming substantially reduces the number of species projected to lose large portions of their climatic ranges.
186. How to Protect Half of Earth to Ensure It Protects Sufficient Biodiversity | Stuart L. Pimm et al. | Science Advances | 2018
The study evaluates how large conservation targets could be designed so that protected lands encompass species with small geographic ranges and high extinction risk.
187. Quantification of Habitat Fragmentation Reveals Extinction Risk in Terrestrial Mammals | Kevin R. Crooks et al. | Proceedings of the National Academy of Sciences | 2017
Global analysis demonstrates that mammal extinction risk rises substantially where habitats become highly fragmented.
188. Why Should Humans Care if We're Entering the Sixth Mass Extinction? | Smithsonianmag.com | Smithsonian Magazine | 2016-11-21
Paleontologists and ecologists explain what previous mass extinctions reveal about ecological collapse and why today's loss of animals can ultimately affect human societies.
189. Saving Half the Planet for Nature Isn't As Crazy As It Seems | Simon Worrall | National Geographic | 2016-03-27
E. O. Wilson discusses the Half-Earth proposal and argues that protecting roughly half the planet's surface could preserve most remaining species.
190. Alien Species as a Driver of Recent Extinctions | Céline Bellard, Phillip Cassey and Tim M. Blackburn | Biology Letters | 2016
Analysis of recent extinction records shows that invasive alien species have contributed to a substantial fraction of documented animal and plant extinctions.
191. Invasive Predators and Global Biodiversity Loss | Tim S. Doherty et al. | Proceedings of the National Academy of Sciences | 2016
Introduced cats, rats, foxes and other mammalian predators have contributed disproportionately to vertebrate extinctions, particularly on islands.
192. Spatially Explicit Trends in the Global Conservation Status of Vertebrates | Ana S. L. Rodrigues et al. | PLOS ONE | 2014
Mapping changes in vertebrate conservation status identifies regions where extinction risk has worsened most rapidly and where conservation has produced measurable benefits.
193. Impacts of Climate Change on the Future of Biodiversity | Céline Bellard et al. | Ecology Letters | 2012
The authors synthesize projected climate impacts on species distributions, communities and extinction risk while emphasizing major uncertainties in forecasting.
194. Anthropogenic Transformation of the Biomes, 1700 to 2000 | Erle C. Ellis et al. | Global Ecology and Biogeography | 2010
Historical reconstruction shows how human settlement and agriculture transformed much of Earth's terrestrial environment long before modern industrialization.
195. The Impact of Conservation on the Status of the World's Vertebrates | Michael Hoffmann et al. | Science | 2010
Global Red List trends show continued deterioration but also demonstrate that conservation programs have prevented some species from moving closer to extinction.
196. Global Consequences of Land Use | Jonathan A. Foley et al. | Science | 2005
Land conversion for agriculture, forestry and development profoundly alters biodiversity, climate, water systems and ecosystem services.
197. Invasive Species Are a Leading Cause of Animal Extinctions | Miguel Clavero and Emili García-Berthou | Trends in Ecology & Evolution | 2005
Analysis of extinction records demonstrates the major role played by introduced species in historical animal extinctions.
198. Avian Extinction and Mammalian Introductions on Oceanic Islands | Tim M. Blackburn et al. | Science | 2004
Introduced mammals are strongly associated with bird extinctions on islands where native species evolved in the absence of terrestrial predators.
199. Effects of Habitat Fragmentation on Biodiversity | Lenore Fahrig | Annual Review of Ecology, Evolution, and Systematics | 2003
This influential review examines how habitat loss and fragmentation alter species populations, movement, ecological interactions and extinction risk.
200. Forecasting Agriculturally Driven Global Environmental Change | David Tilman et al. | Science | 2001
Growing demand for food could greatly expand agriculture, fertilizer use and environmental degradation unless production systems become substantially more sustainable.
