||The Lancet Planetary Health. A sixth mass extinction? Why planetary health matters. Lancet Planet Health. 2017 Aug1(5):e163. doi: 10.1016/S2542-5196(17)30083-9 p.e163 left column top paragraphPubMed ID29851630
||Ceballos G, Ehrlich PR, Dirzo R. Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines. Proc Natl Acad Sci U S A. 2017 Jul 25 114(30):E6089-E6096. doi: 10.1073/pnas.1704949114PubMed ID28696295
||Primary source abstract: "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."
||P.e163 left column top paragraph: "According to an article published in July by Gerardo Ceballos and colleagues [primary source], the Earth is experiencing a huge decline in species' populations and a great reduction in their range that could have profound effects on the ecosystems on which human civilisation depends. They found that about 30% of land vertebrates including reptiles, birds, and amphibians are experiencing a decline and losses in local population." Primary source abstract: "In [investigators'] 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 [they] 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)."