15. M. L. Pace, J. A. Gephart, Ecosystems 20, 44–53 (2016).
16. A. R. Rissman, S. R. Carpenter, Daedalus 144, 35–47 (2015).
17. F. Berkes, Fish Fish. 13, 465–476 (2012).
18. D. Ludwig, Ecosystems 4, 758–764 (2001).
19. H. Rittel, M. M. Webber, Polity 4, 155–169 (1973).
20. B. W. Head, Public Policy 3, 101 (2008).
21. R. A. Heifetz, Leadership Without Easy Answers, vol. 465
(Harvard Univ. Press, 1994).
22. M. Roser, E. Ortiz-Espina, “Global extreme poverty” (Our World
in Data, 2017); https://ourworldindata.org/extreme-poverty/.
23. J. Liu et al., Ecol. Soc. 18, 26 (2013).
24. E. Ostrom, Governing the Commons (Cambridge Univ. Press,
25. L. Porter-Bolland et al., For. Ecol. Manage. 268, 6–17 (2012).
26. K. K. Davies, K. T. Fisher, M. E. Dickson, S. F. Thrush,
R. Le Heron, Ecol. Soc. 20, 37 (2015).
27. R. E. Grumbine, Conserv. Biol. 8, 27–38 (1994).
28. J. Sayer et al., Proc. Natl. Acad. Sci. U. S.A. 110, 8349–8356 (2013).
29. S. L. Postel, B. H. Thompson, in Natural Resources Forum,
vol. 29 (Wiley Online Library, 2005), pp. 98–108.
30. R. Nash, Am. Q. 22, 726–735 (1970).
31. R. DeFries, J. Foley, G. P. Asner, Front. Ecol. Environ 2,
32. B. Reyers, P. J. O’Farrell, J. L. Nel, K. Wilson, Landsc. Ecol. 27,
33. G. Rodríguez-Loinaz, J. G. Alday, M. Onaindia, J. Environ.
Manage. 147, 152–163 (2015).
34. M. E. Burton et al., Conserv. Lett. 10.1111/conl.12265 (2016).
35. H. Nagendra, E. Ostrom, Int. J. Commons 6, 104–133 (2012).
36. S. Koplitz et al., Environ. Res. Lett. 11, 094023 (2016).
37. F. Craighead, Track of the Grizzly (Sierra Club Books, 1979).
38. T. Dutta, S. Sharma, B. McRae, P. S. Roy, R. DeFries,
Reg. Environ. Change 16, 53–67 (2015).
39. M. D. Blum, H. H. Roberts, Nat. Geosci. 2, 488–491 (2009).
40. J. Dore, L. Lebel, Environ. Manage. 46, 60–80 (2010).
41. D. Heilmann, J. Curr. Southeast Asian Aff. 34, 95–121 (2015).
42. C. C. Chester, Environ. Sci. Policy 49, 75–84 (2015).
43. M. B. Holland, in Climate and Conservation, J. A. Hilty,
C. C. Chester, M. S. Cross, Eds. (Island Press, 2012), pp. 56–66.
44. D. R. Armitage et al., Front. Ecol. Environ 7, 95–102 (2009).
45. C. S. Holling, Adaptive Environmental Assessment and
Management (John Wiley and Sons, 1978).
46. National Research Council, Adaptive Management for Water
Resources Project Planning (National Research Council, 2004).
47. D. E. Schindler, R. Hilborn, Science 347, 953–954 (2015).
48. P. J. Balint, R. E. Stewart, A. Desai, Wicked Environmental
Problems: Managing Uncertainty and Conflict (Island Press, 2011).
49. C. J. Walters, Ambio 36, 304–307 (2007).
50. A. D. Guerry et al., Proc. Natl. Acad. Sci. U.S.A. 112, 7348–7355
51. Z. Ouyang et al., Science 352, 1455–1459 (2016).
52. University of the United Nations–International Human Dimensions
Programme on Global Environmental Change, UN Environment
Programme, Inclusive Wealth Report 2014: Measuring Progress
toward Sustainability (Cambridge Univ. Press, 2014).
53. J. C. Milder et al., Conserv. Biol. 29, 309–320 (2015).
54. P. M. Kareiva, B. W. McNally, S. McCormick, T. Miller, M. Ruckelshaus,
Proc. Natl. Acad. Sci. U.S.A. 112, 7375–7382 (2015).
55. E. Gómez-Baggethun, R. Muradian, Ecol. Econ. 117, 217– 224 (2015).
56. R. DeFries, in Science, Conservation, and National Parks,
S. Bessinger, D. Ackerly, H. Doremus, G. Machlis, Eds. (Univ. of
Chicago Press, 2017), pp. 227–246.
57. R. S. Reid et al., Proc. Natl. Acad. Sci. U.S.A. 113, 4579–4584
58. G. Epstein et al., Curr. Opin. Environ. Sustain. 14, 34–40 (2015).
59. T. Moss, in How Institutions Change (Springer, 2003), pp. 85–121.
60. E. S. Brondizio, E. Ostrom, O. R. Young, Annu. Rev. Environ.
Resour. 34, 253–278 (2009).
61. O. Young, Ecol. Soc. 11, 27 (2006).
62. R. DeFries et al., Science 349, 238–240 (2015).
63. E. Ostrom, M. A. Janssen, J. M. Anderies, Proc. Natl. Acad. Sci.
U.S.A. 104, 15176–15178 (2007).
64. C. Wyborn, Glob. Environ. Change 30, 56–67 (2015).
65. Yellowstone to Yukon Conservation Initiative, The Yellowstone
to Yukon Vision: Progress & Possibility (Yellowstone to Yukon
Conservation Initiative, 2014); https://y2y.net/publications/
66. D. E. Calkin, J. D. Cohen, M. A. Finney, M. P. Thompson, Proc.
Natl. Acad. Sci. U.S.A. 111, 746–751 (2014).
67. A. H. Toomey, A. T. Knight, J. Barlow, Conserv. Lett. 10.1111/
Biodiversity losses and conservation
responses in the Anthropocene
Christopher N. Johnson,1 Andrew Balmford,2 Barry W. Brook,1 Jessie C. Buettel,1
Mauro Galetti,3 Lei Guangchun,4 Janet M. Wilmshurst5,6
Biodiversity is essential to human well-being, but people have been reducing biodiversity
throughout human history. Loss of species and degradation of ecosystems are likely to
further accelerate in the coming years. Our understanding of this crisis is now clear, and
world leaders have pledged to avert it. Nonetheless, global goals to reduce the rate of
biodiversity loss have mostly not been achieved. However, many examples of conservation
success show that losses can be halted and even reversed. Building on these lessons to
turn the tide of biodiversity loss will require bold and innovative action to transform
historical relationships between human populations and nature.
Extinction has always been a feature of life on Earth, but the domination of global eco- systems by people has caused a sharp rise in the rate of extinctions to far above pre- human levels. Loss of biodiversity affects
the functioning of natural ecosystems and threatens
human well-being. In this Review, we place the
current extinction crisis in the context of long-term impacts of humanity and assess current trends
in biodiversity loss. We identify successes as well
as failures in our response to this crisis and draw
lessons on what is needed to turn the tide of biodiversity loss.
A brief history of human-caused extinction
The imprint of humanity on biodiversity reaches
back 2 million years, when our ancestors in the
genus Homo began to use the large-carnivore niche
in Africa. This was associated with a two-thirds
decline in other large carnivores, as species such
as sabretooth cats and long-legged hyenas disappeared (1). Diversity of large herbivores also
declined. For example, the 12 species of elephants
and their relatives living in Africa around 3 million
years ago were reduced to two (2). Similar disappearances began elsewhere as species of Homo spread
beyond Africa (3), then accelerated in step with
the global expansion of H. sapiens through the
past 60,000 years (Fig. 1A).
Even before the dawn of the modern era of
extinctions in 1500 CE, the wave of extinctions
that followed our species around the world had
large impacts on biodiversity. At least 140 genera
of mammals, more than 10% of the global total,
were lost over the 100,000 years to 1500 CE (table
S1), a pace of extinction that far exceeds back-
ground rates estimated from the fossil record (4).
Similarly, 23% of the world’s turtle and tortoise
species have disappeared over approximately the
past 300,000 years (5). Prehistoric occupation of
Pacific islands alone was associated with extinc-
tion of at least 1000 bird species, which is around
10% of all birds (6). In New Zealand, 36% (44 of
the original 117) of land bird species have gone
extinct since human settlement began 750 years
ago, most of them in the prehistoric period be-
tween Polynesian and European arrival (Fig. 1B).
Most prehistoric extinctions were of terrestrial
animal species, but marine biodiversity also de-
clined because of local extirpations and loss of abun-
dance as human use of the oceans expanded (7).
Prehistoric extinctions are predominantly associated with human arrival rather than climate
change (8) and are best explained by the impacts
of hunting (9). Habitat modification and predation by alien species were additional factors in
some places, especially islands. Throughout the
Pacific and Indian Oceans, human-lit fires transformed island ecosystems with unprecedented
speed (10); in New Zealand, anthropogenic fire
saw the loss of over 40% of forest cover in the drier
lowland regions within 10 to 70 years of human
arrival (11). The main causes of recent extinctions
and declines continue to be overexploitation and
conversion of habitat, along with invasive species, disease, and urban development (12). Global
climate change is already causing large disruptions to ecosystems (13) and is likely to grow in
importance as a cause of extinction.
Estimates of the recent rate of extinction are
limited by poor knowledge of most species. Our
best information is for vertebrates: At least 363
vertebrate species have gone extinct since 1500 CE,
according to the International Union for the Conservation of Nature (IUCN) Red List (14). The rate
of extinction of vertebrates rose through the past
two centuries as human populations industrialized and grew (Fig. 1C and fig. S1). Levels of current threat of extinction in those groups of plants
and invertebrates that have been systematically assessed cover a similar range to vertebrates (Fig. 1D),
1School of Biological Sciences and Australian Research
Council Centre of Excellence for Australian Biodiversity and
Heritage, University of Tasmania, Private Bag 55, Hobart,
Tasmania 7001, Australia. 2Conservation Science Group,
Department of Zoology, University of Cambridge, Downing
Street, Cambridge CB2 3EJ, UK. 3Instituto de Biociências,
Universidade Estadual Paulista (UNESP), Departamento de
Ecologia, 13506-900 Rio Claro, São Paulo, Brazil. 4School of
Nature Conservation, Beijing Forestry University, 100083
Beijing, People’s Republic of China. 5Long-Term Ecology
Laboratory, Landcare Research, Post Office Box 69040, Lincoln
7640, New Zealand. 6School of Environment, University of
Auckland, Private Bag 92019, Auckland, New Zealand.
*Corresponding author. Email: email@example.com (C.N.J.)