Research Article

The geography of biodiversity change in marine and terrestrial assemblages

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Science  18 Oct 2019:
Vol. 366, Issue 6463, pp. 339-345
DOI: 10.1126/science.aaw1620

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  • Response to Cardinale and Loreau, and Baum et al. Letters to Science
    • Shane A. Blowes, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
    • Other Contributors:
      • Sarah R. Supp, Data Analytics Program, Denison University, Granville, OH, USA
      • Maria Dornelas, Centre for Biological Diversity, School of Biology, University of St. Andrews, St. Andrews, UK
      • Laura H. Antao, Research Centre for Ecological Change, Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki,
      • Amanda Bates, Department of Ocean Sciences, Memorial University of Newfoundland, Newfoundland, Canada
      • Helge Bruelheide, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
      • Jonathan M. Chase, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
      • Faye Moyes, Centre for Biological Diversity, School of Biology, University of St. Andrews, St. Andrews, UK
      • Anne Magurran, Centre for Biological Diversity, School of Biology, University of St. Andrews, St. Andrews, UK
      • Brian McGill, School of Biology and Ecology, University of Maine, Orono, ME, USA
      • Isla H. Myers-Smith, School of GeoSciences, University of Edinburgh, Edinburgh, UK
      • Marten Winter, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
      • Anne D. Bjorkman, Senckenberg Gesellschaft für Naturforschung, Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany
      • Diana E. Bowler, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
      • Jarrett E. K. Byrnes, Department of Biology, University of Massachusetts Boston, Boston, MA, USA
      • Andrew Gonzalez, Department of Biology, Quebec Centre for Biodiversity Science, McGill University, Montreal, Qc, Canada
      • Jes Hines, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
      • Holly P. Jones, Department of Biological Sciences and Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois
      • Laetitia M. Navarro, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig,
      • Patrick L. Thompson, Department of Zoology, University of British Columbia, Vancouver, BC, Canada
      • Mark Vellend, Département de biologie, Université de Sherbrooke, Sherbrooke, QC, Canada
      • Conor Waldock, Ocean and Earth Science, National Oceanography Centre, University of Southampton, UK
      • Gergana Daskalova, School of GeoSciences, University of Edinburgh, Edinburgh, UK

    In our paper (1), we quantified biodiversity change at 50,000 locations across the planet. We uncovered clear spatial variation in species richness and compositional change for local assemblages, with the oceans, and the marine tropics in particular, emerging as hotspots of change. Comments from Cardinale and Loreau and Baum et al. focus on two points: 1) global species richness change, which was not addressed by our work, and 2) the BioTIME database (2) that we analysed. First, we explain why our results describing local scale biodiversity change do not contradict observed and predicted losses at the global scale. Second, we provide evidence that the BioTIME database is appropriate for the analyses in our paper. We argue that progress towards understanding and managing biodiversity change will require many different data sources and analyses. The data and insights of researchers working collectively across approaches and systems will be needed to drive forward our understanding of biodiversity change.

    Local versus global biodiversity change

    Biodiversity change can occur in different ways over time at local, regional and global scales (3-5). Both comments suggest our work conflicts with evidence for increased rates of global species’ extinction, estimated either by comparing current and past extinction rates (6) or by extrapolating lists of threatened species (7). However, our work was focused on temporal shifts in measures of change at small spatial grains...

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    Competing Interests: None declared.
  • Underestimating global biodiversity loss: a comment on Blowes et al. “The geography of biodiversity change in marine and terrestrial assemblages”
    • Julia K. Baum, Department of Biology, University of Victoria, Victoria, BC, Canada
    • Other Contributors:
      • Kai M.A. Chan, Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, BC, Canada
      • Jedediah F. Brodie, Division of Biological Sciences and Wildlife Biology Program, University of Montana, Missoula, MT, USA
      • Tara G. Martin, Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, Canada
      • Joel Berger, Department of FWC Biology, Colorado State University, Fort Collins, CO, USA; Wildlife Conservation Society, Bronx, NY, USA
      • Ahimsa Campos-Arceiz, School of Environmental and Geographical Sciences, University of Nottingham Malaysia, Selangor, Malaysia
      • Mauro Galetti, Department of Biology, University of Miami, Coral Gables, USA
      • Alice C. Hughes, Centre for Integrative Conservation, Chinese Academy of Sciences, Yunnan, China
      • Erik Meijaard, Borneo Futures, Bandar Seri Begawan, Brunei Darussalam; Durrell Institute of Conservation and Ecology, University of Kent
      • Jayasilian Mohd-Azlan, Institute of Biodiversity and Environmental Conservation, Universiti Malaysia Sarawak, Sarawak, Malaysia
      • Margaretha Z. Pangua-Adam, Dept. of Conservation Biology, Georg-August-University of Göttingen, Germany; Cenderawasih University, Waena Papua, Indonesia

    In their Research Article “The geography of biodiversity change in marine and terrestrial assemblages”, Blowes et al. (1) claim to have provided a “global map of current rates of biodiversity change” that can help to “inform conservation prioritization”. While we see some value in the analysis of local richness and species composition, limitations in their underlying dataset (2) seriously undermine their claims.

    First, species richness is not generally conservation-relevant. Because it ignores declines in population abundance, the most prevalent form of biodiversity change, and enables species introductions to mask the loss of native endemics, resource managers focus on conservation of populations, not just species numbers (3-5).

    Second, Blowes et al.’s analysis fails to capture the massive biodiversity losses that accompany habitat loss (6), the world’s primary driver of terrestrial biodiversity change (4). This limitation arises because monitoring programs are seldom initiated in places slated for clear cutting, farming or urbanization. Yet, three-quarters of the planet’s terrestrial environment have been severely altered by such human activities (4).

    Finally, with little terrestrial, marine or freshwater data coming from the tropics where the vast majority of the world’s biodiversity resides (virtually no time series are included from Asia, Africa, or South America), the authors’ assertion that their work can inform global conservation prioritizat...

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    Competing Interests: None declared.
  • RE: Biologists don’t monitor biodiversity in cornfields
    • Bradley Cardinale, Professor, University of Michigan
    • Other Contributors:
      • Michel Loreau, Director, Theoretical and Experimental Ecology Station - National Centre for Scientific Research (CNRS), Moulis

    Blowes et al. (1) analyzed 51,932 ecological time-series from the ‘BioTIME’ database to assess how biodiversity is changing at individual locations around the globe. They concluded that while changes in species composition are pervasive, species richness is not changing on average. The accompanying Perspectives article (2) summarized the study by writing “… the global biodiversity crisis, at least for now, is not primarily about decline but, rather, about large-scale reorganization [of biota].”

    These conclusions are unfounded for three reasons:

    First, the BioTIME dataset does not account for habitat loss, the world’s primary driver of biodiversity loss. Since 1700, 75% of land has been transformed by human activities (3), including 57-million km2 of natural habitat that has been converted to agriculture and urban environments (4). Yet, because biologists do not typically monitor biodiversity before and after conversion of natural habitats to cornfields, clear-cut forests, or parking lots, BioTIME fails to capture the pervasive impacts of habitat loss on biodiversity.

    Second, the BioTIME dataset is heavily biased towards monitoring programs in rich nations in North America and Europe, with sparse data from developing nations and tropical locations where the majority of biodiversity exists.

    Third, because most of the analyzed time series are of short duration (< 16 years) and limited to the last few decades, the time spans under-represent huma...

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    Competing Interests: None declared.
  • Changing biodiversity in terrestrial assemblages without insects: a comment on Blowes et al “The geography of biodiversity change in marine and terrestrial assemblages”
    • M. Alex Smith, Associate Professor, Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada

    Blowes et al (1) recently reported a global and rapid re-organisation of biological diversity and abundance. Their conclusions were reached using a collection of long-term monitoring studies (BioTIME - 2). However, the BioTIME dataset is fundamentally influenced (as is much of ecology) by a sampling bias towards plants and vertebrates (two taxa comprising more than 70% of BioTIME), while the terrestrial world’s most diverse group – the insects (3) –represent only 5% of the data. Moreover, BioTIME studies tend to occur in northern-hemisphere temperate systems (only ~16% are tropical). These qualities are more than nuances – they fundamentally change what conclusions can be derived from the dataset and furthermore these characteristics could be used to call attention to those missing taxa and regions. This is not to criticise BioTIME itself because there is currently no better resource. Yet we must use extreme caution when we extrapolate trends derived from a dataset containing such biased characteristics. Blowes et al found that, on average, assemblage richness is not changing, but the dataset from which they derived this conclusion is not richly filled in the terrestrial environment as long-term datasets involving insects (and in particular from the tropics) remain underrepresented. The use of datasets such as BioTIME ought to be accompanied by a call to better understand where fundamental gaps exist. Such absences are a glaring concern and ought to be of growing impor...

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    Competing Interests: None declared.

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