Biological annihilation via the ongoing sixth mass extinction signaled by
vertebrate population losses and declines
Significance
The strong focus on species extinctions, a critical aspect of the
contemporary pulse of biological extinction, leads to a common
misimpression that Earth’s biota is not immediately threatened, just slowly
entering an episode of major biodiversity loss. This view overlooks the
current trends of population declines and extinctions. Using a sample of
27,600 terrestrial vertebrate species, and a more detailed analysis of 177
mammal species, we show the extremely high degree of population decay in
vertebrates, even in common “species of low concern.” Dwindling population
sizes and range shrinkages amount to a massive anthropogenic erosion of
biodiversity and of the ecosystem services essential to civilization. This
“biological annihilation” underlines the seriousness for humanity of
Earth’s ongoing sixth mass extinction event.
Abstract
The population extinction pulse we describe here shows, from a quantitative
viewpoint, that Earth’s sixth mass extinction is more severe than perceived
when looking exclusively at species extinctions. Therefore, humanity needs
to address anthropogenic population extirpation and decimation immediately.
That conclusion is based on analyses of the numbers and degrees of range
contraction (indicative of population shrinkage and/or population
extinctions according to the International Union for Conservation of
Nature) using a sample of 27,600 vertebrate species, and on a more detailed
analysis documenting the population extinctions between 1900 and 2015 in
177 mammal species. We find that the rate of population loss in terrestrial
vertebrates is extremely high—even in “species of low concern.” In our
sample, comprising nearly half of known vertebrate species, 32%
(8,851/27,600) are decreasing; that is, they have decreased in population
size and range. In the 177 mammals for which we have detailed data, all
have lost 30% or more of their geographic ranges and more than 40% of the
species have experienced severe population declines (>80% range shrinkage).
Our data indicate that beyond global species extinctions Earth is
experiencing a huge episode of population declines and extirpations, which
will have negative cascading consequences on ecosystem functioning and
services vital to sustaining civilization. We describe this as a
“biological annihilation” to highlight the current magnitude of Earth’s
ongoing sixth major extinction event.
- 1To whom correspondence may be addressed. Email:
gceballo@ecologia.unam.mx or pre@stanford.edu.
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Author contributions: G.C., P.R.E., and R.D. designed research; G.C. and
P.R.E. performed research; G.C., P.R.E., and R.D. contributed new
reagents/analytic tools; G.C. analyzed data; and G.C., P.R.E., and R.D.
wrote the paper.
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Reviewers: T.E.L., George Mason University; and P.H.R., Missouri
Botanical Garden.
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The authors declare no conflict of interest.
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This article contains supporting information online at
www.pnas.org/lookup/suppl/doi:10.1073/pnas.1704949114/-/DCSupplemental.
Freely available online through the PNAS open access option.
[permaculture] Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines,
Lawrence London, 07/12/2017