scholarly journals Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines

2017 ◽  
Vol 114 (30) ◽  
pp. E6089-E6096 ◽  
Author(s):  
Gerardo Ceballos ◽  
Paul R. Ehrlich ◽  
Rodolfo Dirzo
Keyword(s):  
Mass Extinction ◽  
Vertebrate Species ◽  
Population Declines ◽  
Mammal Species ◽  
Geographic Ranges ◽  
Terrestrial Vertebrates ◽  
Population Extinction ◽  
Population Loss ◽  
Sixth Mass Extinction ◽  
Species Extinctions

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.

scholarly journals Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction

2020 ◽  
Vol 117 (24) ◽  
pp. 13596-13602 ◽  
Author(s):  
Gerardo Ceballos ◽  
Paul R. Ehrlich ◽  
Peter H. Raven
Keyword(s):  
Ecosystem Services ◽  
Endangered Species ◽  
Mass Extinction ◽  
Life Support ◽  
Human Impacts ◽  
Bird Species ◽  
Wildlife Trade ◽  
Ecological Interactions ◽  
Terrestrial Vertebrates ◽  
Sixth Mass Extinction

The ongoing sixth mass species extinction is the result of the destruction of component populations leading to eventual extirpation of entire species. Populations and species extinctions have severe implications for society through the degradation of ecosystem services. Here we assess the extinction crisis from a different perspective. We examine 29,400 species of terrestrial vertebrates, and determine which are on the brink of extinction because they have fewer than 1,000 individuals. There are 515 species on the brink (1.7% of the evaluated vertebrates). Around 94% of the populations of 77 mammal and bird species on the brink have been lost in the last century. Assuming all species on the brink have similar trends, more than 237,000 populations of those species have vanished since 1900. We conclude the human-caused sixth mass extinction is likely accelerating for several reasons. First, many of the species that have been driven to the brink will likely become extinct soon. Second, the distribution of those species highly coincides with hundreds of other endangered species, surviving in regions with high human impacts, suggesting ongoing regional biodiversity collapses. Third, close ecological interactions of species on the brink tend to move other species toward annihilation when they disappear—extinction breeds extinctions. Finally, human pressures on the biosphere are growing rapidly, and a recent example is the current coronavirus disease 2019 (Covid-19) pandemic, linked to wildlife trade. Our results reemphasize the extreme urgency of taking much-expanded worldwide actions to save wild species and humanity’s crucial life-support systems from this existential threat.

scholarly journals Mammal diversity will take millions of years to recover from the current biodiversity crisis

2018 ◽  
Vol 115 (44) ◽  
pp. 11262-11267 ◽  
Author(s):  
Matt Davis ◽  
Søren Faurby ◽  
Jens-Christian Svenning
Keyword(s):  
Time Scale ◽  
Mass Extinction ◽  
Evolutionary History ◽  
Phylogenetic Diversity ◽  
Global Scale ◽  
Mammal Species ◽  
Biodiversity Crisis ◽  
Extinction Rates ◽  
Sixth Mass Extinction ◽  
Mammal Diversity

The incipient sixth mass extinction that started in the Late Pleistocene has already erased over 300 mammal species and, with them, more than 2.5 billion y of unique evolutionary history. At the global scale, this lost phylogenetic diversity (PD) can only be restored with time as lineages evolve and create new evolutionary history. Given the increasing rate of extinctions however, can mammals evolve fast enough to recover their lost PD on a human time scale? We use a birth–death tree framework to show that even if extinction rates slow to preanthropogenic background levels, recovery of lost PD will likely take millions of years. These findings emphasize the severity of the potential sixth mass extinction and the need to avoid the loss of unique evolutionary history now.

scholarly journals Genome size versus geographic range size in birds

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10868
Author(s):  
Beata Grzywacz ◽  
Piotr Skórka
Keyword(s):  
Natural Selection ◽  
Chromosome Number ◽  
Genome Size ◽  
Body Mass ◽  
Generalized Least Squares ◽  
Geographic Range ◽  
Range Size ◽  
Geographic Ranges ◽  
Brain Mass ◽  
Terrestrial Vertebrates

Why do some species occur in small, restricted areas, while others are distributed globally? Environmental heterogeneity increases with area and so does the number of species. Hence, diverse biotic and abiotic conditions across large ranges may lead to specific adaptations that are often linked to a species’ genome size and chromosome number. Therefore, a positive association between genome size and geographic range is anticipated. Moreover, high cognitive ability in organisms would be favored by natural selection to cope with the dynamic conditions within large geographic ranges. Here, we tested these hypotheses in birds—the most mobile terrestrial vertebrates—and accounted for the effects of various confounding variables, such as body mass, relative brain mass, and geographic latitude. Using phylogenetic generalized least squares and phylogenetic confirmatory path analysis, we demonstrated that range size is positively associated with bird genome size but probably not with chromosome number. Moreover, relative brain mass had no effect on range size, whereas body mass had a possible weak and negative effect, and range size was larger at higher geographic latitudes. However, our models did not fully explain the overall variation in range size. Hence, natural selection may impose larger genomes in birds with larger geographic ranges, although there may be additional explanations for this phenomenon.

Reducing the sixth mass extinction: Understanding the value of human-altered landscapes to the conservation of the world's largest terrestrial mammals

2020 ◽  
Vol 249 ◽  
pp. 108706 ◽  
Author(s):  
Erik Joaquín Torres-Romero ◽  
Anthony J. Giordano ◽  
Gerardo Ceballos ◽  
José Vicente López-Bao
Keyword(s):  
Mass Extinction ◽  
Terrestrial Mammals ◽  
Sixth Mass Extinction

scholarly journals Large-Scale Hybridisation as an Extinction Threat to the Suweon Treefrog (Hylidae: Dryophytes suweonensis)

Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 764 ◽  
Author(s):  
Amaël Borzée ◽  
Jonathan J. Fong ◽  
Hoa Quynh Nguyen ◽  
Yikweon Jang
Keyword(s):  
Mitochondrial Dna ◽  
Species Distribution ◽  
Dna Sequences ◽  
Mass Extinction ◽  
Large Scale ◽  
Natural Habitats ◽  
Commensal Species ◽  
Polymorphic Microsatellites ◽  
Sixth Mass Extinction ◽  
Threaten Species

Amphibians are in the midst of a sixth mass extinction, and human activities play a major role in pushing species towards extinction. Landscape anthropisation has impacts that indirectly threaten species, in addition to the obvious destruction of natural habitats. For instance, land modification may bring human-commensal species in contact with sister-clades from which they were previously isolated. The species in these new contact zones are then able to hybridise to the point of reaching lineage fusion, through which the gene pool of the two species merges and one of the parental lineages becomes extirpated. Here, we documented the patterns of hybridisation between the spatially restricted D. suweonensis and the widespread D. japonicus. On the basis of the analysis of Cytochrome c oxidase subunit I mitochondrial DNA sequences (404 individuals from 35 sites) and six polymorphic microsatellites (381 individuals from 34 sites), we revealed a generalised, bi-directional, and geographically widespread hybridisation between the two species. Evidence of fertile back-crosses is provided by relatively high numbers of individuals in cyto-nuclear disequilibrium, as well as the presence of hybrid individuals further south than the species distribution limit, determined on the basis of call properties. Hybridisation is an additional threat to the endangered D. suweonensis.

Ecology in the Sixth Mass Extinction: Detecting and Understanding Rare Biotic Interactions

2019 ◽  
Vol 112 (3) ◽  
pp. 119-121 ◽  
Author(s):  
Elsa Youngsteadt ◽  
Margarita M López-Uribe ◽  
Clyde E Sorenson
Keyword(s):  
Mass Extinction ◽  
Biotic Interactions ◽  
Sixth Mass Extinction

Population extinction risks of three Neotropical small mammal species

Oecologia ◽  
1998 ◽  
Vol 115 (1-2) ◽  
pp. 120-126 ◽  
Author(s):  
Mauricio Lima ◽  
Pablo A. Marquet ◽  
Fabian M. Jaksic
Keyword(s):  
Small Mammal ◽  
Mammal Species ◽  
Population Extinction ◽  
Small Mammal Species

scholarly journals The geography of high-value biodiversity areas for terrestrial vertebrates in Western Europe and their coverage by protected area networks

Web Ecology ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 65-73 ◽  
Author(s):  
M. J. T. Assunção-Albuquerque ◽  
J. M. Rey Benayas ◽  
F. S. Albuquerque ◽  
M. Á. Rodríguez
Keyword(s):  
Protected Areas ◽  
Protected Area ◽  
Western Europe ◽  
Natura 2000 ◽  
Area Network ◽  
Vertebrate Species ◽  
Natura 2000 Network ◽  
Study Region ◽  
Terrestrial Vertebrates ◽  
Major Taxon

Abstract. We identified high-value biodiversity areas (HVBAs) of terrestrial vertebrates according to a combined index of biodiversity (CBI) for each major taxon and a standardized biodiversity index (SBI) for all taxa in 2195 cells of 50 × 50 km in Western Europe to evaluate whether these areas are included in the current protected area networks. The World Database on Protected Areas (WDPA) and NATURA 2000 protected area network were used to assess the protected area cover in HVBAs. WDPA and NATURA 2000 were geographically quite complementary as WDPA is more densely represented in Central and Northern Europe and NATURA 2000 in the Mediterranean basin. A total of 729 cells were identified as HVBAs. From the total of these HVBA areas, NATURA 2000 network was present in more cells (660) than the WDPA network (584 cells). The sum of protected land percentages across all the HVBA cells was 28.8%. The identified HVBA cells according to the SBI included 603 or 78.2% of all vertebrate species in the study region, whereas the identified HVBA cells according to the SBI for individual taxa included 47 (90.4%) species of amphibians, 79 (74.5%) of reptiles, 417 (88.5%) of birds, and 130 (91.5%) of mammals. However, neither network was present in 7 or 3% of the identified HVBA cells. Thus, we recommend expanding protected areas in Europe to fill this gap and improve coverage of vertebrate species to strengthen biodiversity conservation.

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