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Xiong Y, Rozzi R, Zhang Y, Fan L, Zhao J, Li D, Yao Y, Xiao H, Liu J, Zeng X, Xu H, Jiang Y, Lei F. Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions. SCIENCE ADVANCES 2024; 10:eadm8240. [PMID: 38996028 PMCID: PMC11244536 DOI: 10.1126/sciadv.adm8240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 06/10/2024] [Indexed: 07/14/2024]
Abstract
Island vertebrates have evolved a number of morphological, physiological, and life history characteristics that set them apart from their mainland relatives. However, to date, the evolution of metabolism and its impact on the vulnerability to extinction of insular vertebrates remains poorly understood. This study used metabolic data from 2813 species of tetrapod vertebrates, including 695 ectothermic and 2118 endothermic species, to reveal that island mammals and birds evolved convergent metabolic strategies toward a slow pace of life. Insularity was associated with shifts toward slower metabolic rates and greater generation lengths in endotherms, while insularity just drove the evolution of longer generation lengths in ectotherms. Notably, a slow pace of life has exacerbated the extinction of insular endemic species in the face of anthropogenic threats. These findings have important implications for understanding physiological adaptations associated with the island syndrome and formulating conservation strategies across taxonomic groups with different metabolic modes.
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Affiliation(s)
- Ying Xiong
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Roberto Rozzi
- Zentralmagazin Naturwissenschaftlicher Sammlungen, Martin Luther University Halle-Wittenberg, 06108 Halle (Saale), Germany
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, 10115 Berlin, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, 04103 Leipzig, Germany
| | - Yizhou Zhang
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Liqing Fan
- Key Laboratory of Forest Ecology in Tibet Plateau, Tibet Agricultural & Animal Husbandry University, Ministry of Education, Nyingchi 860000, China
| | - Jidong Zhao
- Shaanxi Key Laboratory of Qinling Ecological Security, Shaanxi Institude of Zoology, Xi’an 710000, China
| | - Dongming Li
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
| | - Yongfang Yao
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Hongtao Xiao
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Jing Liu
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, China
| | - Xianyin Zeng
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Huailiang Xu
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Yanzhi Jiang
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Fumin Lei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Late quaternary biotic homogenization of North American mammalian faunas. Nat Commun 2022; 13:3940. [PMID: 35803946 PMCID: PMC9270452 DOI: 10.1038/s41467-022-31595-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 06/22/2022] [Indexed: 12/20/2022] Open
Abstract
Biotic homogenization—increasing similarity of species composition among ecological communities—has been linked to anthropogenic processes operating over the last century. Fossil evidence, however, suggests that humans have had impacts on ecosystems for millennia. We quantify biotic homogenization of North American mammalian assemblages during the late Pleistocene through Holocene (~30,000 ybp to recent), a timespan encompassing increased evidence of humans on the landscape (~20,000–14,000 ybp). From ~10,000 ybp to recent, assemblages became significantly more homogenous (>100% increase in Jaccard similarity), a pattern that cannot be explained by changes in fossil record sampling. Homogenization was most pronounced among mammals larger than 1 kg and occurred in two phases. The first followed the megafaunal extinction at ~10,000 ybp. The second, more rapid phase began during human population growth and early agricultural intensification (~2,000–1,000 ybp). We show that North American ecosystems were homogenizing for millennia, extending human impacts back ~10,000 years. Biotic homogenization, which is increased similarity in the composition of species among communities, is rising due to human activities. Using North American mammal fossil records from the past 30,000 years, this study shows that this phenomenon is ancient, beginning between 12,000 and 10,000 years ago with the extinction of the mammal megafauna.
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Male mastodon landscape use changed with maturation (late Pleistocene, North America). Proc Natl Acad Sci U S A 2022; 119:e2118329119. [PMID: 35696566 PMCID: PMC9231495 DOI: 10.1073/pnas.2118329119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Fossil remains usually reveal little about lifetime landscape use beyond place of death, but ever-growing tusks of American mastodons (Mammut americanum) record this fundamental aspect of paleobiology. Using oxygen and strontium isotopes from a serially sampled male mastodon tusk, we reconstruct changing patterns of landscape use during his life. We find clear shifts in landscape use during adolescence and following maturation to adulthood, including increased monthly movements and development of a summer-only range and mating ground. The mastodon died in his inferred summer mating ground, far from landscapes used during other seasons. Mastodons had long gestation times, and late Pleistocene populations lived in harsh, rapidly changing environments. Seasonal landscape use and migration were likely critical for maximizing mastodon reproductive success. Under harsh Pleistocene climates, migration and other forms of seasonally patterned landscape use were likely critical for reproductive success of mastodons (Mammut americanum) and other megafauna. However, little is known about how their geographic ranges and mobility fluctuated seasonally or changed with sexual maturity. We used a spatially explicit movement model that coupled strontium and oxygen isotopes from two serially sampled intervals (5+ adolescent years and 3+ adult years) in a male mastodon tusk to test for changes in landscape use associated with maturation and reproductive phenology. The mastodon’s early adolescent home range was geographically restricted, with no evidence of seasonal preferences. Following inferred separation from the matriarchal herd (starting age 12 y), the adolescent male’s mobility increased as landscape use expanded away from his natal home range (likely central Indiana). As an adult, the mastodon’s monthly movements increased further. Landscape use also became seasonally structured, with some areas, including northeast Indiana, used only during the inferred mastodon mating season (spring/summer). The mastodon died in this area (>150 km from his core, nonsummer range) after sustaining a craniofacial injury consistent with a fatal blow from a competing male’s tusk during a battle over access to mates. Northeast Indiana was likely a preferred mating area for this individual and may have been regionally significant for late Pleistocene mastodons. Similarities between mammutids and elephantids in herd structure, tusk dimorphism, tusk function, and the geographic component of male maturation indicate that these traits were likely inherited from a common ancestor.
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Small brains predisposed Late Quaternary mammals to extinction. Sci Rep 2022; 12:3453. [PMID: 35361771 PMCID: PMC8971383 DOI: 10.1038/s41598-022-07327-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/11/2022] [Indexed: 11/17/2022] Open
Abstract
The Late Quaternary witnessed a dramatic wave of large mammal extinctions, that are usually attributed to either human hunting or climatic change. We hypothesized that the large mammals that survived the extinctions might have been endowed with larger brain sizes than their relatives, which could have conferred enhanced behavioral plasticity and the ability to cope with the rapidly changing Late Quaternary environmental conditions. We assembled data on brain sizes of 291 extant mammal species plus 50 more that went extinct during the Late Quaternary. Using logistic, and mixed effect models, and controlling for phylogeny and body mass, we found that large brains were associated with higher probability to survive the Late Quaternary extinctions, and that extant species have brains that are, on average, 53% larger when accounting for order as a random effect, and 83% when fitting a single regression line. Moreover, we found that models that used brain size in addition to body size predicted extinction status better than models that used only body size. We propose that possessing a large brain was an important, yet so far neglected characteristic of surviving megafauna species.
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Mychajliw AM, Almonte JN, Martinez PA, Hadly EA. Stable isotopes reveal seasonal dietary responses to agroforestry in a venomous mammal, the Hispaniolan solenodon ( Solenodon paradoxus). Ecol Evol 2022; 12:e8761. [PMID: 35356572 PMCID: PMC8948124 DOI: 10.1002/ece3.8761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 12/18/2022] Open
Abstract
While trends in tropical deforestation are alarming, conservation biologists are increasingly recognizing the potential for species survival in human-modified landscapes. Identifying the factors underlying such persistence, however, requires basic ecological knowledge of a species' resource use. Here, we generate such data to guide conservation of an understudied venomous mammal, the Hispaniolan solenodon (Solenodon paradoxus), that occupies a mosaic landscape of agriculture and forest fragments in the western Dominican Republic. Using feces collected in both wet and dry seasons, we found significant differences in the stable isotope values of carbon (δ13C) between pasture (-24.63 ± 2.31‰, Las Mercedes) and agroforestry (-28.07 ± 2.10‰, Mencia). Solenodon populations in agricultural areas occupied wider isotopic niche spaces, which may be explained by more diverse resource within these patches or individuals combining resources across habitats. We detected elevated δ15N values in the dry season of pasture areas (8.22 ± 2.30‰) as compared to the wet season (5.26 ± 2.44‰) and overall narrower isotopic niche widths in the dry season, suggestive of the impacts of aridity on foraging behavior. Our work highlights the importance of considering a more nuanced view of variations in 'modified' or "agricultural" landscapes as compared with strictly protected national parks. We suggest that seasonal differences in foraging should be considered as they intersect with landscape modification by landowners for maintaining resources for focal consumers. This work adds to a growing body of literature highlighting that fecal stable isotopes are a non-invasive and cost-effective monitoring tool that is particularly well-suited for cryptic small mammal species, ensuring actionable and evidenced-based conservation practices in the tropic's rapidly changing landscapes.
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Affiliation(s)
- Alexis M. Mychajliw
- Departments of Biology and Environmental StudiesMiddlebury CollegeMiddleburyVermontUSA
- Department of BiologyStanford UniversityStanfordCaliforniaUSA
| | - Juan N. Almonte
- Museo Nacional de Historia Natural “Prof. Eugenio de Jesús Marcano”Santo DomingoDominican Republic
| | - Pedro A. Martinez
- Escuela de BiologíaUniversidad Autónoma de Santo DomingoSanto DomingoDominican Republic
| | - Elizabeth A. Hadly
- Department of BiologyStanford UniversityStanfordCaliforniaUSA
- Woods Institute of the EnvironmentStanford UniversityStanfordCaliforniaUSA
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6
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Louys J, Braje TJ, Chang CH, Cosgrove R, Fitzpatrick SM, Fujita M, Hawkins S, Ingicco T, Kawamura A, MacPhee RDE, McDowell MC, Meijer HJM, Piper PJ, Roberts P, Simmons AH, van den Bergh G, van der Geer A, Kealy S, O'Connor S. No evidence for widespread island extinctions after Pleistocene hominin arrival. Proc Natl Acad Sci U S A 2021; 118:e2023005118. [PMID: 33941645 PMCID: PMC8157961 DOI: 10.1073/pnas.2023005118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The arrival of modern humans into previously unoccupied island ecosystems is closely linked to widespread extinction, and a key reason cited for Pleistocene megafauna extinction is anthropogenic overhunting. A common assumption based on late Holocene records is that humans always negatively impact insular biotas, which requires an extrapolation of recent human behavior and technology into the archaeological past. Hominins have been on islands since at least the early Pleistocene and Homo sapiens for at least 50 thousand y (ka). Over such lengthy intervals it is scarcely surprising that significant evolutionary, behavioral, and cultural changes occurred. However, the deep-time link between human arrival and island extinctions has never been explored globally. Here, we examine archaeological and paleontological records of all Pleistocene islands with a documented hominin presence to examine whether humans have always been destructive agents. We show that extinctions at a global level cannot be associated with Pleistocene hominin arrival based on current data and are difficult to disentangle from records of environmental change. It is not until the Holocene that large-scale changes in technology, dispersal, demography, and human behavior visibly affect island ecosystems. The extinction acceleration we are currently experiencing is thus not inherent but rather part of a more recent cultural complex.
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Affiliation(s)
- Julien Louys
- Australian Research Centre for Human Evolution, Griffith University, Brisbane, QLD 4111, Australia;
- Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT 2601, Australia
| | - Todd J Braje
- Department of Anthropology, San Diego State University, San Diego, CA 5500
| | - Chun-Hsiang Chang
- Department of Geology, National Museum of Natural Science, 404 Taichung City, Taiwan
| | - Richard Cosgrove
- Department of Archaeology and History, La Trobe University, Melbourne, VIC 3086, Australia
| | - Scott M Fitzpatrick
- Department of Anthropology, University of Oregon, Eugene, OR 97403
- Museum of Natural and Cultural History, University of Oregon, Eugene, OR 97403
| | - Masaki Fujita
- Department of Zoology, National Museum of Nature and Science, 110-8718 Tokyo, Japan
| | - Stuart Hawkins
- Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Australian National University, Canberra, ACT 2601, Australia
| | - Thomas Ingicco
- Muséum national d'Histoire naturelle de Paris, UMR 7194, Département Homme et Environnement, Sorbonne Universités, 75005 Paris, France
| | - Ai Kawamura
- Faculty of Education, University of Toyama, 930-8555 Toyama, Japan
| | - Ross D E MacPhee
- Division of Vertebrate Zoology/Mammalogy, American Museum of Natural History, New York, NY 10024
| | - Matthew C McDowell
- College of Sciences and Engineering, University of Tasmania, Hobart, TAS 7005, Australia
- Field Museum of Natural History, Science and Education, Earth Sciences, Chicago, IL 60605
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Tasmania, Hobart, TAS 7001, Australia
| | - Hanneke J M Meijer
- University Museum of Bergen, Department of Natural History, University of Bergen, 5007 Bergen Norway
- Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20002
| | - Philip J Piper
- School of Archaeology and Anthropology, The Australian National University, Canberra, ACT 0200, Australia
| | - Patrick Roberts
- Department of Archaeology, Max Planck Institute for the Science of Human History, 07745 Jena, Germany
- School of Social Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Alan H Simmons
- Department of Anthropology, University of Nevada and Desert Research Institute, Reno, NV 89512
| | - Gerrit van den Bergh
- Centre for Archaeological Science, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Alexandra van der Geer
- Vertebrate Evolution, Development and Ecology, Naturalis Biodiversity Center, 2333 CR Leiden, the Netherlands
| | - Shimona Kealy
- Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Australian National University, Canberra, ACT 2601, Australia
| | - Sue O'Connor
- Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT 2601, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Australian National University, Canberra, ACT 2601, Australia
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7
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Bradshaw CJ, Johnson CN, Llewelyn J, Weisbecker V, Strona G, Saltré F. Relative demographic susceptibility does not explain the extinction chronology of Sahul's megafauna. eLife 2021; 10:63870. [PMID: 33783356 PMCID: PMC8043753 DOI: 10.7554/elife.63870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/29/2021] [Indexed: 11/17/2022] Open
Abstract
The causes of Sahul’s megafauna extinctions remain uncertain, although several interacting factors were likely responsible. To examine the relative support for hypotheses regarding plausible ecological mechanisms underlying these extinctions, we constructed the first stochastic, age-structured models for 13 extinct megafauna species from five functional/taxonomic groups, as well as 8 extant species within these groups for comparison. Perturbing specific demographic rates individually, we tested which species were more demographically susceptible to extinction, and then compared these relative sensitivities to the fossil-derived extinction chronology. Our models show that the macropodiformes were the least demographically susceptible to extinction, followed by carnivores, monotremes, vombatiform herbivores, and large birds. Five of the eight extant species were as or more susceptible than the extinct species. There was no clear relationship between extinction susceptibility and the extinction chronology for any perturbation scenario, while body mass and generation length explained much of the variation in relative risk. Our results reveal that the actual mechanisms leading to the observed extinction chronology were unlikely related to variation in demographic susceptibility per se, but were possibly driven instead by finer-scale variation in climate change and/or human prey choice and relative hunting success.
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Affiliation(s)
- Corey Ja Bradshaw
- Global Ecology Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Tarndanya (Adelaide), Australia.,ARC Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, Australia
| | - Christopher N Johnson
- ARC Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, Australia.,Dynamics of Eco-Evolutionary Pattern, University of Tasmania, Hobart, Australia
| | - John Llewelyn
- Global Ecology Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Tarndanya (Adelaide), Australia.,ARC Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, Australia
| | - Vera Weisbecker
- ARC Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, Australia.,College of Science and Engineering, Flinders University, Adelaide, Australia
| | - Giovanni Strona
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Frédérik Saltré
- Global Ecology Partuyarta Ngadluku Wardli Kuu, College of Science and Engineering, Flinders University, Tarndanya (Adelaide), Australia.,ARC Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, Australia
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8
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Darroch SAF, Fraser D, Casey MM. The preservation potential of terrestrial biogeographic patterns. Proc Biol Sci 2021; 288:20202927. [PMID: 33622123 PMCID: PMC7935024 DOI: 10.1098/rspb.2020.2927] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Extinction events in the geological past are similar to the present-day biodiversity crisis in that they have a pronounced biogeography, producing dramatic changes in the spatial distributions of species. Reconstructing palaeobiogeographic patterns from fossils therefore allows us to examine the long-term processes governing the formation of regional biotas, and potentially helps build spatially explicit models for future biodiversity loss. However, the extent to which biogeographic patterns can be preserved in the fossil record is not well understood. Here, we perform a suite of simulations based on the present-day distribution of North American mammals, aimed at quantifying the preservation potential of beta diversity and spatial richness patterns over extinction events of varying intensities, and after applying a stepped series of taphonomic filters. We show that taphonomic biases related to body size are the biggest barrier to reconstructing biogeographic patterns over extinction events, but that these may be compensated for by both the small mammal record preserved in bird castings, as well as range expansion in surviving species. Overall, our results suggest that the preservation potential of biogeographic patterns is surprisingly high, and thus that the fossil record represents an invaluable dataset recording the changing spatial distribution of biota over key intervals in Earth History.
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Affiliation(s)
- Simon A F Darroch
- Department of Earth and Environmental Sciences, Vanderbilt University, 5726 Stevenson Center, Nashville, TN 37240, USA.,Senckenberg Museum of Natural History, Frankfurt 60325, Germany
| | - Danielle Fraser
- Department of Palaeobiology, Canadian Museum of Nature, 240 McLeod Street, Ottawa, Ontario, Canada K2P 2R1.,Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.,Department of Earth Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.,Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, 10th and Constitution NW, Washington, DC 20560-0121, USA
| | - Michelle M Casey
- Department of Physics, Astronomy and Geosciences, Towson University, 8000 York Road, Towson, MD 21252, USA
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9
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Biogeographic problem-solving reveals the Late Pleistocene translocation of a short-faced bear to the California Channel Islands. Sci Rep 2020; 10:15172. [PMID: 32938967 PMCID: PMC7494929 DOI: 10.1038/s41598-020-71572-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 08/14/2020] [Indexed: 11/08/2022] Open
Abstract
An accurate understanding of biodiversity of the past is critical for contextualizing biodiversity patterns and trends in the present. Emerging techniques are refining our ability to decipher otherwise cryptic human-mediated species translocations across the Quaternary, yet these techniques are often used in isolation, rather than part of an interdisciplinary hypothesis-testing toolkit, limiting their scope and application. Here we illustrate the use of such an integrative approach and report the occurrence of North America's largest terrestrial mammalian carnivore, the short-faced bear, Arctodus simus, from Daisy Cave (CA-SMI-261), an important early human occupation site on the California Channel Islands. We identified the specimen by corroborating morphological, protein, and mitogenomic lines of evidence, and evaluated the potential natural and anthropogenic mechanisms of its transport and deposition. While representing just a single specimen, our combination of techniques opened a window into the behavior of an enigmatic species, suggesting that A. simus was a wide-ranging scavenger utilizing terrestrial and marine carcasses. This discovery highlights the utility of bridging archaeological and paleontological datasets to disentangle complex biogeographic scenarios and reveal unexpected biodiversity for island systems worldwide.
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10
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Abstract
AbstractHuman-mediated species invasion and climate change are leading to global extinctions and are predicted to result in the loss of important axes of phylogenetic and functional diversity. However, the long-term robustness of modern communities to invasion is unknown, given the limited timescales over which they can be studied. Using the fossil record of the Paleocene-Eocene thermal maximum (PETM; ∼56 Ma) in North America, we evaluate mammalian community-level response to a rapid global warming event (5°-8°C) and invasion by three Eurasian mammalian orders and by species undergoing northward range shifts. We assembled a database of 144 species body sizes and created a time-scaled composite phylogeny. We calculated the phylogenetic and functional diversity of all communities before, during, and after the PETM. Despite increases in the phylogenetic diversity of the regional species pool, phylogenetic diversity of mammalian communities remained relatively unchanged, a pattern that is invariant to the tree dating method, uncertainty in tree topology, and resolution. Similarly, body size dispersion and the degree of spatial taxonomic turnover of communities remained similar across the PETM. We suggest that invasion by new taxa had little impact on Paleocene-Eocene mammal communities because niches were not saturated. Our findings are consistent with the numerous studies of modern communities that record little change in community-scale richness despite turnover in taxonomic composition during invasion. What remains unknown is whether long-term robustness to biotic and abiotic perturbation are retained by modern communities given global anthropogenic landscape modification.
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11
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Large-scale mitogenomic analysis of the phylogeography of the Late Pleistocene cave bear. Sci Rep 2019; 9:10700. [PMID: 31417104 PMCID: PMC6695494 DOI: 10.1038/s41598-019-47073-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 07/10/2019] [Indexed: 12/04/2022] Open
Abstract
The cave bear (Ursus spelaeus) is one of the Late Pleistocene megafauna species that faced extinction at the end of the last ice age. Although it is represented by one of the largest fossil records in Europe and has been subject to several interdisciplinary studies including palaeogenetic research, its fate remains highly controversial. Here, we used a combination of hybridisation capture and next generation sequencing to reconstruct 59 new complete cave bear mitochondrial genomes (mtDNA) from 14 sites in Western, Central and Eastern Europe. In a Bayesian phylogenetic analysis, we compared them to 64 published cave bear mtDNA sequences to reconstruct the population dynamics and phylogeography during the Late Pleistocene. We found five major mitochondrial DNA lineages resulting in a noticeably more complex biogeography of the European lineages during the last 50,000 years than previously assumed. Furthermore, our calculated effective female population sizes suggest a drastic cave bear population decline starting around 40,000 years ago at the onset of the Aurignacian, coinciding with the spread of anatomically modern humans in Europe. Thus, our study supports a potential significant human role in the general extinction and local extirpation of the European cave bear and illuminates the fate of this megafauna species.
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12
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Lyons SK, Smith FA, Ernest SKM. Macroecological patterns of mammals across taxonomic, spatial, and temporal scales. J Mammal 2019. [DOI: 10.1093/jmammal/gyy171] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- S Kathleen Lyons
- University of Nebraska–Lincoln, School of Biological Sciences, St. Lincoln, NE
| | - Felisa A Smith
- University of New Mexico, Department of Biology, Albuquerque, NM
| | - S K Morgan Ernest
- University of Florida, Department of Wildlife Ecology and Conservation, Gainesville, FL
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13
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Mann DH, Groves P, Gaglioti BV, Shapiro BA. Climate-driven ecological stability as a globally shared cause of Late Quaternary megafaunal extinctions: the Plaids and Stripes Hypothesis. Biol Rev Camb Philos Soc 2019; 94:328-352. [PMID: 30136433 PMCID: PMC7379602 DOI: 10.1111/brv.12456] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 07/14/2018] [Accepted: 07/19/2018] [Indexed: 01/24/2023]
Abstract
Controversy persists about why so many large-bodied mammal species went extinct around the end of the last ice age. Resolving this is important for understanding extinction processes in general, for assessing the ecological roles of humans, and for conserving remaining megafaunal species, many of which are endangered today. Here we explore an integrative hypothesis that asserts that an underlying cause of Late Quaternary megafaunal extinctions was a fundamental shift in the spatio-temporal fabric of ecosystems worldwide. This shift was triggered by the loss of the millennial-scale climate fluctuations that were characteristic of the ice age but ceased approximately 11700 years ago on most continents. Under ice-age conditions, which prevailed for much of the preceding 2.6 Ma, these radical and rapid climate changes prevented many ecosystems from fully equilibrating with their contemporary climates. Instead of today's 'striped' world in which species' ranges have equilibrated with gradients of temperature, moisture, and seasonality, the ice-age world was a disequilibrial 'plaid' in which species' ranges shifted rapidly and repeatedly over time and space, rarely catching up with contemporary climate. In the transient ecosystems that resulted, certain physiological, anatomical, and ecological attributes shared by megafaunal species pre-adapted them for success. These traits included greater metabolic and locomotory efficiency, increased resistance to starvation, longer life spans, greater sensory ranges, and the ability to be nomadic or migratory. When the plaid world of the ice age ended, many of the advantages of being large were either lost or became disadvantages. For instance in a striped world, the low population densities and slow reproductive rates associated with large body size reduced the resiliency of megafaunal species to population bottlenecks. As the ice age ended, the downsides of being large in striped environments lowered the extinction thresholds of megafauna worldwide, which then increased the vulnerability of individual species to a variety of proximate threats they had previously tolerated, such as human predation, competition with other species, and habitat loss. For many megafaunal species, the plaid-to-stripes transition may have been near the base of a hierarchy of extinction causes whose relative importances varied geographically, temporally, and taxonomically.
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Affiliation(s)
- Daniel H. Mann
- Department of Geosciences and Institute of Arctic BiologyUniversity of AlaskaFairbanksAK 99775USA
| | - Pamela Groves
- Institute of Arctic BiologyUniversity of AlaskaFairbanksAK 99775USA
| | | | - Beth A. Shapiro
- Department of Ecology and Evolutionary BiologyUniversity of CaliforniaSanta CruzCA 95064USA
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Brook BW, Alroy J. Pattern, process, inference and prediction in extinction biology. Biol Lett 2017; 13:rsbl.2016.0828. [PMID: 28077688 DOI: 10.1098/rsbl.2016.0828] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/08/2016] [Indexed: 11/12/2022] Open
Abstract
Extinction is a key feature of the evolutionary history of life, and assessments of extinction risk are essential for the effective protection of biodiversity. The goal in assembling this special issue of Biology Letters was to highlight problems and questions at the research frontier of extinction biology, with an emphasis on recent developments in the methodology of inferring the patterns and processes of extinction from a background of often noisy and sparse data. In selecting topics, we sought to illustrate how extinction is not simply a self-evident phenomenon, but the subject of a dynamic and quantitatively rigorous field of natural science, with practical applications to conservation.
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Affiliation(s)
- Barry W Brook
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart 7001, Australia
| | - John Alroy
- Department of Biological Sciences, Macquarie University, New South Wales 2109, Australia
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15
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Greenberg DA, Mooers AØ. Linking speciation to extinction: Diversification raises contemporary extinction risk in amphibians. Evol Lett 2017; 1:40-48. [PMID: 30283637 PMCID: PMC6121784 DOI: 10.1002/evl3.4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/14/2017] [Accepted: 03/21/2017] [Indexed: 11/08/2022] Open
Abstract
Many of the traits associated with elevated rates of speciation, including niche specialization and having small and isolated populations, are similarly linked with an elevated risk of extinction. This suggests that rapidly speciating lineages may also be more extinction prone. Empirical tests of a speciation-extinction correlation are rare because assessing paleontological extinction rates is difficult. However, the modern biodiversity crisis allows us to observe patterns of extinction in real time, and if this hypothesis is true then we would expect young clades that have recently diversified to have high contemporary extinction risk. Here, we examine evolutionary patterns of modern extinction risk across over 300 genera within one of the most threatened vertebrate classes, the Amphibia. Consistent with predictions, rapidly diversifying amphibian clades also had a greater share of threatened species. Curiously, this pattern is not reflected in other tetrapod classes and may reflect a greater propensity to speciate through peripheral isolation in amphibians, which is partly supported by a negative correlation between diversification rate and mean geographic range size. This clustered threat in rapidly diversifying amphibian genera means that protecting a small number of species can achieve large gains in preserving amphibian phylogenetic diversity. Nonindependence between speciation and extinction rates has many consequences for patterns of biodiversity and how we may choose to conserve it.
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Affiliation(s)
- Dan A Greenberg
- Department of Biological Sciences Simon Fraser University Burnaby British Columbia V5A 1S6 Canada.,Earth-to-Ocean Research Group Simon Fraser University Burnaby British Columbia V5A 1S6 Canada.,Crawford Lab for Evolutionary Studies Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
| | - Arne Ø Mooers
- Department of Biological Sciences Simon Fraser University Burnaby British Columbia V5A 1S6 Canada.,Crawford Lab for Evolutionary Studies Simon Fraser University Burnaby British Columbia V5A 1S6 Canada
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