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Cowie RH, Bouchet P, Fontaine B. The Sixth Mass Extinction: fact, fiction or speculation? Biol Rev Camb Philos Soc 2022; 97:640-663. [PMID: 35014169 PMCID: PMC9786292 DOI: 10.1111/brv.12816] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 11/04/2021] [Accepted: 11/08/2021] [Indexed: 12/30/2022]
Abstract
There have been five Mass Extinction events in the history of Earth's biodiversity, all caused by dramatic but natural phenomena. It has been claimed that the Sixth Mass Extinction may be underway, this time caused entirely by humans. Although considerable evidence indicates that there is a biodiversity crisis of increasing extinctions and plummeting abundances, some do not accept that this amounts to a Sixth Mass Extinction. Often, they use the IUCN Red List to support their stance, arguing that the rate of species loss does not differ from the background rate. However, the Red List is heavily biased: almost all birds and mammals but only a minute fraction of invertebrates have been evaluated against conservation criteria. Incorporating estimates of the true number of invertebrate extinctions leads to the conclusion that the rate vastly exceeds the background rate and that we may indeed be witnessing the start of the Sixth Mass Extinction. As an example, we focus on molluscs, the second largest phylum in numbers of known species, and, extrapolating boldly, estimate that, since around AD 1500, possibly as many as 7.5-13% (150,000-260,000) of all ~2 million known species have already gone extinct, orders of magnitude greater than the 882 (0.04%) on the Red List. We review differences in extinction rates according to realms: marine species face significant threats but, although previous mass extinctions were largely defined by marine invertebrates, there is no evidence that the marine biota has reached the same crisis as the non-marine biota. Island species have suffered far greater rates than continental ones. Plants face similar conservation biases as do invertebrates, although there are hints they may have suffered lower extinction rates. There are also those who do not deny an extinction crisis but accept it as a new trajectory of evolution, because humans are part of the natural world; some even embrace it, with a desire to manipulate it for human benefit. We take issue with these stances. Humans are the only species able to manipulate the Earth on a grand scale, and they have allowed the current crisis to happen. Despite multiple conservation initiatives at various levels, most are not species oriented (certain charismatic vertebrates excepted) and specific actions to protect every living species individually are simply unfeasible because of the tyranny of numbers. As systematic biologists, we encourage the nurturing of the innate human appreciation of biodiversity, but we reaffirm the message that the biodiversity that makes our world so fascinating, beautiful and functional is vanishing unnoticed at an unprecedented rate. In the face of a mounting crisis, scientists must adopt the practices of preventive archaeology, and collect and document as many species as possible before they disappear. All this depends on reviving the venerable study of natural history and taxonomy. Denying the crisis, simply accepting it and doing nothing, or even embracing it for the ostensible benefit of humanity, are not appropriate options and pave the way for the Earth to continue on its sad trajectory towards a Sixth Mass Extinction.
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Affiliation(s)
- Robert H. Cowie
- Pacific Biosciences Research CenterUniversity of HawaiiHonoluluHawaii96822U.S.A.
| | - Philippe Bouchet
- Institut Systématique Evolution Biodiversité (ISYEB), Muséum National d'Histoire Naturelle, CNRS, Sorbonne Université, EPHEUniversité des Antilles57 rue Cuvier CP 5175005 ParisFrance
| | - Benoît Fontaine
- UMS 2006 Patrinat (OFB, CNRS, MNHN), Centre d'Écologie et des Sciences de la Conservation (UMR 7204), Muséum National d'Histoire Naturelle43 rue Buffon CP 13575005 ParisFrance
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Peter A, Žlabur JŠ, Šurić J, Voća S, Purgar DD, Pezo L, Voća N. Invasive Plant Species Biomass-Evaluation of Functional Value. Molecules 2021; 26:3814. [PMID: 34206657 PMCID: PMC8270279 DOI: 10.3390/molecules26133814] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
Invasive plant species (IAS), with their numerous negative ecological, health, and economic impacts, represent one of the greatest conservation challenges in the world. Reducing the negative impacts and potentially exploiting the biomass of these plant species can significantly contribute to sustainable management, protect biodiversity, and create a healthy environment. Therefore, the main objective of this study was to evaluate the nutritional potential, phytochemical status, and antioxidant capacity of nine alien invasive plant species: Abutilon theophrasti, Amaranthus retroflexus, Ambrosia artemisiifolia, Datura stramonium, Erigeron annuus, Galinsoga ciliata, Reynoutria japonica, Solidago gigantea, and Sorghum halepense. Multivariate statistical methods such as cluster and PCA were performed to determine possible connections and correlations among selected IAS depending on the phytochemical content. According to the obtained results, R. japonica was notable with the highest content of vitamin C (38.46 mg/100 g FW); while E. annuus (1365.92 mg GAE/100 g FW) showed the highest values of total polyphenolic compounds. A. retroflexus was characterized by the highest content of total chlorophylls (0.26 mg/g) and antioxidant capacity (2221.97 µmol TE/kg). Therefore, it can be concluded that the selected IAS represent nutrient-rich plant material with significant potential for the recovering of bioactive compounds.
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Affiliation(s)
- Anamarija Peter
- Department of Agricultural Technology, Storage and Transport, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia; (A.P.); (J.Š.); (S.V.); (N.V.)
| | - Jana Šic Žlabur
- Department of Agricultural Technology, Storage and Transport, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia; (A.P.); (J.Š.); (S.V.); (N.V.)
| | - Jona Šurić
- Department of Agricultural Technology, Storage and Transport, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia; (A.P.); (J.Š.); (S.V.); (N.V.)
| | - Sandra Voća
- Department of Agricultural Technology, Storage and Transport, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia; (A.P.); (J.Š.); (S.V.); (N.V.)
| | - Dubravka Dujmović Purgar
- Department of Agricultural Botany, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia;
| | - Lato Pezo
- Engineering Department, Institute of General and Physical Chemistry, University of Belgrade, Studentski trg 12/V, 11000 Belgrade, Serbia;
| | - Neven Voća
- Department of Agricultural Technology, Storage and Transport, Faculty of Agriculture, University of Zagreb, Svetošimunska cesta 25, 10000 Zagreb, Croatia; (A.P.); (J.Š.); (S.V.); (N.V.)
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Razafindratsima OH, Brown KA, Carvalho F, Johnson SE, Wright PC, Dunham AE. Edge effects on components of diversity and above-ground biomass in a tropical rainforest. J Appl Ecol 2017. [DOI: 10.1111/1365-2664.12985] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Kerry A. Brown
- Department of Geography and Geology; Kingston University; Kingston Upon Thames Surrey UK
| | - Fabio Carvalho
- Department of Geography and Geology; Kingston University; Kingston Upon Thames Surrey UK
| | - Steig E. Johnson
- Department of Anthropology and Archaeology; University of Calgary; Calgary AB Canada
- Centre ValBio; Ifanadiana Fianarantsoa Madagascar
| | - Patricia C. Wright
- Centre ValBio; Ifanadiana Fianarantsoa Madagascar
- Department of Anthropology; Stony Brook University; Stony Brook NY USA
| | - Amy E. Dunham
- Centre ValBio; Ifanadiana Fianarantsoa Madagascar
- Department of BioSciences; Rice University; Houston TX USA
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Esposito LA, Bloom T, Caicedo-Quiroga L, Alicea-Serrano AM, Sánchez-Ruíz JA, May-Collado LJ, Binford GJ, Agnarsson I. Islands within islands: Diversification of tailless whip spiders (Amblypygi, Phrynus) in Caribbean caves. Mol Phylogenet Evol 2015. [DOI: 10.1016/j.ympev.2015.07.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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In the light of evolution VIII: Darwinian thinking in the social sciences. Introduction. Proc Natl Acad Sci U S A 2014; 111 Suppl 3:10781-4. [PMID: 25202765 DOI: 10.1073/pnas.1411483111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Freed LA, Cann RL. Females lead population collapse of the endangered Hawaii creeper. PLoS One 2013; 8:e67914. [PMID: 23861831 PMCID: PMC3701621 DOI: 10.1371/journal.pone.0067914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/22/2013] [Indexed: 11/19/2022] Open
Abstract
Population collapses result from drastic environmental changes, but the sexes may differ in vulnerability. Collapse of the endangered Hawaii creeper (Oreomystis mana) at Hakalau Forest National Wildlife Refuge resulted from food limitation associated with increased numbers of an introduced bird (Japanese white-eye, Zosterops japonicus), which competes with the creeper for food. Both creeper sexes had stunted bill growth and the greatest change in molt of native species in the community. With a surge in numbers of white-eyes, a recent cohort of adult females had very low survival after breeding, while adult males from the same cohort, and older females and males, continued to have high survival. Lower female survival resulted in a significantly more male-biased adult sex ratio. Recent low female survival was based on a great cost of reproduction, indicated by molt-breeding overlap that was previously avoided, and lower fat during the lengthy fledgling period. The difference in female survival between cohorts was associated with stunted bills from being reared in and then breeding in an increasingly poor food environment. Trend analysis of survey data indicate that the bird is declining throughout the refuge, with males being 72-80% of adults left six years after the white-eye increased. Competition over time was consistent with that previously documented over space on the Island of Hawaii. Adaptive management to recover the bird in this protected area needs to focus on improving both adult female survival and the adult sex ratio.
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Affiliation(s)
- Leonard A Freed
- Department of Biology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America.
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Oro D, Jiménez J, Curcó A. Some clouds have a silver lining: paradoxes of anthropogenic perturbations from study cases on long-lived social birds. PLoS One 2012; 7:e42753. [PMID: 22936988 PMCID: PMC3425592 DOI: 10.1371/journal.pone.0042753] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/11/2012] [Indexed: 11/19/2022] Open
Abstract
In recent centuries and above all over the last few decades, human activities have generated perturbations (from mild to very severe or catastrophes) that, when added to those of natural origin, constitute a global threat to biodiversity. Predicting the effects of anthropogenic perturbations on species and communities is a great scientific challenge given the complexity of ecosystems and the need for detailed population data from both before and after the perturbations. Here we present three cases of well-documented anthropogenic severe perturbations (different forms of habitat loss and deterioration influencing fertility and survival) that have affected three species of birds (a raptor, a scavenger and a waterbird) for which we possess long-term population time series. We tested whether the perturbations caused serious population decline or whether the study species were resilient, that is, its population dynamics were relatively unaffected. Two of the species did decline, although to a relatively small extent with no shift to a state of lower population numbers. Subsequently, these populations recovered rapidly and numbers reached similar levels to before the perturbations. Strikingly, in the third species a strong breakpoint took place towards greater population sizes, probably due to the colonization of new areas by recruits that were queuing at the destroyed habitat. Even though it is difficult to draw patterns of resilience from only three cases, the study species were all long-lived, social species with excellent dispersal and colonization abilities, capable of skipping reproduction and undergoing a phase of significant long-term population increase. The search for such patterns is crucial for optimizing the limited resources allocated to conservation and for predicting the future impact of planned anthropogenic activities on ecosystems.
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Affiliation(s)
- Daniel Oro
- Institut Mediterrani d'Estudis Avançats IMEDEA, CSIC-UIB, Esporles, Spain
| | - Juan Jiménez
- Conselleria de Medio Ambiente, Generalitat Valenciana, Valencia, Spain
| | - Antoni Curcó
- Parc Natural del Delta de l'Ebre, Deltebre, Spain
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In the light of evolution V: cooperation and conflict. Proc Natl Acad Sci U S A 2011; 108 Suppl 2:10787-91. [PMID: 21690379 DOI: 10.1073/pnas.1100289108] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Krams I, Cīrule D, Krama T, Hukkanen M, Rytkönen S, Orell M, Iezhova T, Rantala MJ, Tummeleht L. Effects of Forest Management on Haematological Parameters, Blood Parasites, and Reproductive Success of the Siberian Tit (Poecile cinctus) in Northern Finland. ANN ZOOL FENN 2010. [DOI: 10.5735/086.047.0504] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Colloquium paper: in the light of evolution IV: the human condition. Proc Natl Acad Sci U S A 2010; 107 Suppl 2:8897-901. [PMID: 20460311 DOI: 10.1073/pnas.1003214107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Douglas ME, Douglas MR, Schuett GW, Beck DD, Sullivan BK. Conservation phylogenetics of helodermatid lizards using multiple molecular markers and a supertree approach. Mol Phylogenet Evol 2009; 55:153-167. [PMID: 20006722 DOI: 10.1016/j.ympev.2009.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Revised: 12/06/2009] [Accepted: 12/07/2009] [Indexed: 11/13/2022]
Abstract
We analyzed both mitochondrial (mt-) and nuclear (n) DNAs in a conservation phylogenetic framework to examine deep and shallow histories of the Beaded Lizard (Heloderma horridum) and Gila Monster (H. suspectum) throughout their geographic ranges in North and Central America. Both mtDNA and intron markers clearly partitioned each species. One intron and mtDNA further subdivided H. horridum into its four recognized subspecies (H. n. alvarezi, charlesbogerti,exasperatum, and horridum). However, the two subspecies of H. suspectum (H. s. suspectum and H. s. cinctum) were undefined. A supertree approach sustained these relationships. Overall, the Helodermatidae is reaffirmed as an ancient and conserved group. Its most recent common ancestor (MRCA) was Lower Eocene [35.4 million years ago (mya)], with a approximately 25 my period of stasis before the MRCA of H. horridum diversified in Lower Miocene. Another approximately 5 my passed before H. h. exasperatum and H. h. horridum diverged, followed by approximately 1.5 my before H. h. alvarezi and H. h. charlesbogerti separated. Heloderma suspectum reflects an even longer period of stasis (approximately 30 my) before diversifying from its MRCA. Both H. suspectum (México) and H. h. alvarezi also revealed evidence of historic range expansion following a recent bottleneck. Our conservation phylogenetic approach emphasizes the origin and diversification of this group, yields information on the manner by which past environmental variance may have impacted its populations and, in turn, allows us to disentangle historic from contemporary impacts that might threaten its long-term persistence. The value of helodermatid conservation resides in natural services and medicinal products, particularly venom constituents, and these are only now being realized.
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Affiliation(s)
- Michael E Douglas
- Illinois Natural History Survey, Institute for Natural Resource Sustainability, University of Illinois, Champaign, IL 61820, USA.
| | - Marlis R Douglas
- Illinois Natural History Survey, Institute for Natural Resource Sustainability, University of Illinois, Champaign, IL 61820, USA
| | - Gordon W Schuett
- Department of Biology and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30303-3088, USA
| | - Daniel D Beck
- Department of Biological Sciences, Central Washington University, Ellensburg, WA 98926, USA
| | - Brian K Sullivan
- Division of Mathematics & Natural Sciences, Arizona State University, Phoenix, AZ 85069, USA
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Avise JC, Ayala FJ. In the light of evolution III: two centuries of Darwin. Proc Natl Acad Sci U S A 2009; 106 Suppl 1:9933-8. [PMID: 19528649 PMCID: PMC2702790 DOI: 10.1073/pnas.0903381106] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- John C. Avise
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
| | - Francisco J. Ayala
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697
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Reply to Couée: Biodiversity conservation by any other name. Proc Natl Acad Sci U S A 2008. [DOI: 10.1073/pnas.0809261105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Evaluating the links between climate, disease spread, and amphibian declines. Proc Natl Acad Sci U S A 2008; 105:17436-41. [PMID: 18987318 DOI: 10.1073/pnas.0806368105] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human alteration of the environment has arguably propelled the Earth into its sixth mass extinction event and amphibians, the most threatened of all vertebrate taxa, are at the forefront. Many of the worldwide amphibian declines have been caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), and two contrasting hypotheses have been proposed to explain these declines. Positive correlations between global warming and Bd-related declines sparked the chytrid-thermal-optimum hypothesis, which proposes that global warming increased cloud cover in warm years that drove the convergence of daytime and nighttime temperatures toward the thermal optimum for Bd growth. In contrast, the spatiotemporal-spread hypothesis states that Bd-related declines are caused by the introduction and spread of Bd, independent of climate change. We provide a rigorous test of these hypotheses by evaluating (i) whether cloud cover, temperature convergence, and predicted temperature-dependent Bd growth are significant positive predictors of amphibian extinctions in the genus Atelopus and (ii) whether spatial structure in the timing of these extinctions can be detected without making assumptions about the location, timing, or number of Bd emergences. We show that there is spatial structure to the timing of Atelopus spp. extinctions but that the cause of this structure remains equivocal, emphasizing the need for further molecular characterization of Bd. We also show that the reported positive multi-decade correlation between Atelopus spp. extinctions and mean tropical air temperature in the previous year is indeed robust, but the evidence that it is causal is weak because numerous other variables, including regional banana and beer production, were better predictors of these extinctions. Finally, almost all of our findings were opposite to the predictions of the chytrid-thermal-optimum hypothesis. Although climate change is likely to play an important role in worldwide amphibian declines, more convincing evidence is needed of a causal link.
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