Research ArticleENVIRONMENTAL SCIENCES

Accelerated modern human–induced species losses: Entering the sixth mass extinction

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Science Advances  19 Jun 2015:
Vol. 1, no. 5, e1400253
DOI: 10.1126/sciadv.1400253
  • Fig. 1 Cumulative vertebrate species recorded as extinct or extinct in the wild by the IUCN (2012).

    Graphs show the percentage of the number of species evaluated among mammals (5513; 100% of those described), birds (10,425; 100%), reptiles (4414; 44%), amphibians (6414; 88%), fishes (12,457; 38%), and all vertebrates combined (39,223; 59%). Dashed black curve represents the number of extinctions expected under a constant standard background rate of 2 E/MSY. (A) Highly conservative estimate. (B) Conservative estimate.

  • Fig. 2 Number of years that would have been required for the observed vertebrate species extinctions in the last 114 years to occur under a background rate of 2 E/MSY.

    Red markers, highly conservative scenario; blue markers, conservative scenario. Note that for all vertebrates, the observed extinctions would have taken between 800 to 10,000 years to disappear, assuming 2 E/MSY. Different classes of vertebrates all show qualitatively similar trends.

  • Table 1 Numbers of species used in the Table 2 calculations of “highly conservative” and “conservative” modern extinction rates based on the IUCN Red List (17).

    For the highly conservative rates, only species verified as “extinct” (EX) were included; for the conservative extinction rates, species in the categories “extinct in the wild” (EW) and “possibly extinct” (PE) were also included.

    Vertebrate taxonNo. of species, IUCN 2014.3
    Highly conservative
    rates (EX)
    Conservative rates
    (EX + EW + PE)
    No. of species
    evaluated by IUCN
    Since 1500Since 1900Since 1500Since 1900
    Vertebrates33819861747759% (39,223)
    Mammals773511169100% (5,513)
    Birds1405716380100% (10,425)
    Reptiles218372444% (4,414)
    Amphibians343214814688% (6,414)
    Fishes666615815838% (12,457)
  • Table 2 Elevation of “highly conservative” and “conservative” modern vertebrate extinction rates above background rate of 2 E/MSY (see table S2 for calculations).

    For each assessment category, two periods are shown: extinction rates computed from 1500 to the present, and from 1900 to the present.

    Animal groupElevation of modern rates with
    respect to expected rates
    Highly conservativeConservative
    Since 1500Since 1900Since 1500Since 1900
    Vertebrates8221553
    Mammals14282055
    Birds13241534
    Reptiles58824
    Amphibians52222100
    Fishes5231256

Supplementary Materials

  • Supplementary Materials

    This PDF file includes:

    • Table S1. Definitions of IUCN categories (17) used to assess modern extinction rates.
    • Table S2. Estimation of modern extinction rates since 1500 and 1900.

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