A foundational paradigm in biological and Earth sciences is that our planet is divided into distinct ecoregions and biomes demarking unique assemblages of species. This notion has profoundly influenced scientific research and environmental policy. Given recent advances in technology and data availability, however, we are now poised to ask whether ecoregions meaningfully delimit biological communities. Using over 200 million observations of plants, animals and fungi we show compelling evidence that ecoregions delineate terrestrial biodiversity patterns. We achieve this by testing two competing hypotheses: the sharp-transition hypothesis, positing that ecoregion borders divide differentiated biotic communities; and the gradual-transition hypothesis, proposing instead that species turnover is continuous and largely independent of ecoregion borders. We find strong support for the sharp-transition hypothesis across all taxa, although adherence to ecoregion boundaries varies across taxa. Although plant and vertebrate species are tightly linked to sharp ecoregion boundaries, arthropods and fungi show weaker affiliations to this set of ecoregion borders. Our results highlight the essential value of ecological data for setting conservation priorities and reinforce the importance of protecting habitats across as many ecoregions as possible. Specifically, we conclude that ecoregion-based conservation planning can guide investments that simultaneously protect species-, community- and ecosystem-level biodiversity, key for securing Earth’s life support systems into the future.
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Ebach, M. C. Origins of Biogeography (Springer, Dordrecht, 2015).
Gleason, H. A. On the relation between species and area. Ecology 3, 158–162 (1922).
Clements, F. E. Plant Succession. An Analysis of the Development of Vegetation (Carnegie Institution of Washington, Washington DC, 1916).
von Humboldt, A. & Bonpland, A. Essay on the Geography of Plants (University of Chicago Press, Chicago, 2013).
Tjørve, E., Calf Tjørve, K. M., Šizlingová, E. & Šizling, A. L. Great theories of species diversity in space and why they were forgotten: the beginnings of a spatial ecology and the Nordic early 20th-century botanists. J. Biogeogr. 45, 530–540 (2018).
Wallace, A. R. What are zoological regions? Nature 49, 610–613 (1894).
Wallace, A. R. The Geographical Distribution of Animals: With a Study of the Relations of Living and Extinct Faunas as Elucidating the Past Changes of the Earth’s Surface (Harper and Brothers, New York, 1876).
Holdridge, L. R. Determination of world plant formations from simple climatic data. Science 105, 367–368 (1947).
Whittaker, R. H. Classification of natural communities. Bot. Rev. 28, 1–239 (1962).
Carpenter, J. R. The biome. Am. Midl. Nat. 21, 75–91 (1939).
Hutchins, L. W. The bases for temperature zonation in geographical distribution. Ecol. Monogr. 17, 325–335 (1947).
Bailey, R. G. Identifying ecoregion boundaries. Environ. Manage. 34, S14–S26 (2004).
Ellis, E. C. & Ramankutty, N. Putting people in the map: anthropogenic biomes of the world. Front. Ecol. Environ. 6, 439–447 (2008).
Crowther, T. W. et al. Mapping tree density at a global scale. Nature 525, 201–205 (2015).
Snyder, P. K., Delire, C. & Foley, J. A. Evaluating the influence of different vegetation biomes on the global climate. Clim. Dynam. 23, 279–302 (2004).
Naidoo, R. et al. Global mapping of ecosystem services and conservation priorities. Proc. Natl Acad. Sci. USA 105, 9495–9500 (2008).
Sala, O. E. et al. Global biodiversity scenarios for the year 2100. Science 287, 1770–1774 (2000).
Holt, B. G. et al. An update of Wallace’s zoogeographic regions of the world. Science 339, 74–78 (2013).
Rueda, M., Rodríguez, M. Á. & Hawkins, B. A. Identifying global zoogeographical regions: lessons from Wallace. J. Biogeogr. 40, 2215–2225 (2013).
Di Marco, M., Watson, J. E. M., Currie, D. J., Possingham, H. P. & Venter, O. The extent and predictability of the biodiversity–carbon correlation. Ecol. Lett. 21, 365–375 (2018).
Kreft, H. & Jetz, W. Comment on ‘An update of Wallace’s zoogeographic regions of the world’. Science 341, 343 (2013).
Olson, D. M. et al. Terrestrial ecoregions of the world: a new map of life on Earth. Bioscience 51, 933–938 (2001).
Dinerstein, E. et al. An ecoregion-based approach to protecting half the terrestrial realm. Bioscience 67, 534–545 (2017).
Bailey, R. G. Ecoregions (Springer, New York, 2014).
Lamoreux, J. F. et al. Global tests of biodiversity concordance and the importance of endemism. Nature 440, 212–214 (2006).
Ricketts, T. H. et al. Terrestrial Ecoregions of North America: A Conservation Assessment (Island Press, Washington DC, 1999).
Groves, C., Valutis, L. & The Nature Conservancy (US) Guidelines for Representing Ecological Communities in Ecoregional Conservation Plans (The Nature Conservancy, Arlington, 1999).
Ricketts, T. & Imhoff, M. Biodiversity, urban areas, and agriculture: locating priority ecoregions for conservation. conservation. Conserv. Ecol. 8, 1 (2003).
Olson, D. M. & Dinerstein, E. The global 200: priority ecoregions for global conservation. Ann. Mo. Bot. Gard. 89, 199–224 (2002).
Ricklefs, R. E. Disintegration of the ecological community. Am. Nat. 172, 741–750 (2008).
McDonald, R. et al. Species compositional similarity and ecoregions: do ecoregion boundaries represent zones of high species turnover? Biol. Conserv. 126, 24–40 (2005).
Kerr, J. T. & Ostrovsky, M. From space to species: ecological applications for remote sensing. Trends Ecol. Evol. 18, 299–305 (2003).
Higgins, S. I., Buitenwerf, R. & Moncrieff, G. R. Defining functional biomes and monitoring their change globally. Glob. Change Biol. 22, 3583–3593 (2016).
Anderson, C. B. Biodiversity monitoring, Earth observations and the ecology of scale. Ecol. Lett. 21, 1572–1585 (2018).
Jetz, W., McPherson, J. M. & Guralnick, R. P. Integrating biodiversity distribution knowledge: toward a global map of life. Trends Ecol. Evol. 27, 151–159 (2012).
Hubbell, S. P. The Unified Neutral Theory of Biodiversity and Biogeography (Princeton Univ. Press, Princeton, 2001).
Davis, M. B. in Forest Succession (eds West, D. C., Shugart, H. H. & Botkin, D. B.) 132–153 (Springer, New York, 1981).
What is GBIF? (Global Biodiversity Information Facility, 2018); https://www.gbif.org/what-is-gbif
Codling, E. A., Plank, M. J. & Benhamou, S. Random walk models in biology. J. R. Soc. Interface 5, 813–834 (2008).
Soininen, J., McDonald, R. & Hillebrand, H. The distance decay of similarity in ecological communities. Ecography 30, 3–12 (2007).
Fortuna, M. A. et al. Nestedness versus modularity in ecological networks: two sides of the same coin? J. Anim. Ecol. 79, 811–817 (2010).
Report of the Task Group on GBIF Data Fitness for Use in Distribution Modelling (Global Biodiversity Information Facility, 2017); https://www.gbif.org/document/82612/report-of-the-task-group-on-gbif-data-fitnessfor-use-in-distribution-modelling.
Hoekstra, J. M., Boucher, T. M., Ricketts, T. H. & Roberts, C. Confronting a biome crisis: global disparities of habitat loss and protection. Ecol. Lett. 8, 23–29 (2005).
Watson, J. E. M. & Venter, O. Ecology: a global plan for nature conservation. Nature 550, 48–49 (2017).
Wilson, E. O. Half-Earth: Our Plant’s Fight for Life (Liveright, New York, 2017).
Noss, R. F. et al. Bolder thinking for conservation. Conserv. Biol. 26, 1–4 (2012).
Peay, K. G., Bidartondo, M. I. & Arnold, A. E. Not every fungus is everywhere: scaling to the biogeography of fungal–plant interactions across roots, shoots and ecosystems. New Phytol. 185, 878–882 (2010).
Peay, K. G., Kennedy, P. G. & Talbot, J. M. Dimensions of biodiversity in the Earth mycobiome. Nat. Rev. Microbiol. 14, 434–447 (2016).
Hendershot, J. N., Read, Q. D., Henning, J. A., Sanders, N. J. & Classen, A. T. Consistently inconsistent drivers of microbial diversity and abundance at macroecological scales. Ecology 98, 1757–1763 (2017).
Meyer, K. M. et al. Why do microbes exhibit weak biogeographic patterns? ISME J. 12, 1404–1413 (2018).
Troia, M. J. & McManamay, R. A. Filling in the GAPS: evaluating completeness and coverage of open-access biodiversity databases in the United States. Ecol. Evol. 6, 4654–4669 (2016).
Troudet, J., Grandcolas, P., Blin, A., Vignes-Lebbe, R. & Legendre, F. Taxonomic bias in biodiversity data and societal preferences. Sci. Rep. 7, 9132 (2017).
Sato, H., Tsujino, R., Kurita, K., Yokoyama, K. & Agata, K. Modelling the global distribution of fungal species: new insights into microbial cosmopolitanism. Mol. Ecol. 21, 5599–5612 (2012).
Tedersoo, L. et al. Global diversity and geography of soil fungi. Science 346, 1256688 (2014).
Hortal, J., Roura-Pascual, N., Sanders, N. J. & Rahbek, C. Understanding (insect) species distributions across spatial scales. Ecography 33, 51–53 (2010).
Lobo, J. M. The use of occurrence data to predict the effects of climate change on insects. Curr. Opin. Insect Sci. 17, 62–68 (2016).
Lightfoot, D. C., Brantley, S. L. & Allen, C. D. Geographic patterns of ground-dwelling arthropods across an ecoegional transition in the North American southwest. West. N. Am. Naturalist 68, 83–102 (2008).
González-Reyes, A. X., Corronca, J. A. & Rodriguez-Artigas, S. M. Changes of arthropod diversity across an altitudinal ecoregional zonation in northwestern Argentina. PeerJ 5, e4117 (2017).
González-Reyes, A. X., Corronca, J. A. & Arroyo, N. C. Differences in alpha and beta diversities of epigeous arthropod assemblages in two ecoregions of northwestern Argentina. Zool. Stud. 51, 1367–1379 (2012).
Anderson, D. J. & Vondracek, B. Insects as indicators of land use in three ecoregions in the Prairie Pothole Region. Wetlands 19, 648–664 (1999).
Melo, A. S., Rangel, T. F. L. V. B. & Diniz‐Filho, J. A. F. Environmental drivers of beta-diversity patterns in New-World birds and mammals. Ecography 32, 226–236 (2009).
Van Rensburg, B. J., Koleff, P., Gaston, K. J. & Chown, S. L. Spatial congruence of ecological transition at the regional scale in South Africa. J. Biogeogr. 31, 843–854 (2004).
Beaumont, L. J. et al. Impacts of climate change on the world’s most exceptional ecoregions. Proc. Natl Acad. Sci. USA 108, 2306–2311 (2011).
Karp, D. S. et al. Intensive agriculture erodes β-diversity at large scales. Ecol. Lett. 15, 963–970 (2012).
Ecoregions (US Environmental Protection Agency, 2015); https://www.epa.gov/eco-research/ecoregions
Digital Map of European Ecological Regions (European Environment Agency, 2003); https://www.eea.europa.eu/data-and-maps/data/digital-map-of-european-ecological-regions
The Nature Conservancy Ecoregional Priorities (LandScope America, 2018); http://www.landscope.org/focus/understand/tnc_portfolio/
Ecoregions (World Wildlife Fund, 2018); https://www.worldwildlife.org/biomes
Beck, J., Böller, M., Erhardt, A. & Schwanghart, W. Spatial bias in the GBIF database and its effect on modeling species’ geographic distributions. Ecol. Inform. 19, 10–15 (2014).
Plants: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.uhenlf
Arthropods: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.uhumps
Reptiles: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.pn1aw9
Amphibians: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.as6uug
Mammals: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.diqarx
Birds: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.61rqcy
Fungi: GBIF.org (GBIF, 2018); https://doi.org/10.15468/dl.akftay
EPSG:3410 NSIDC EASE-Grid Global (National Snow and Ice Data Center, 2018); https://epsg.io/3410
Yesson, C. et al. How global is the Global Biodiversity Information Facility? PLoS ONE 2, e1124 (2007).
GBIF replacing coordinateAccuracy w/ coordinateUncertaintyInMeters & coordinatePrecision, Issue #206 (GitHub, 2018); https://github.com/ropensci/rgbif/issues/206
Maldonado, C. et al. Estimating species diversity and distribution in the era of Big Data: to what extent can we trust public databases. Glob. Ecol. Biogeogr 24, 973–984 (2015).
This work was supported financially by the National Science Foundation’s Graduate Research Fellowship Program Division of Graduate Education No. 1656518, the Stanford Department of Biology and the Ward Wilson Woods Jr Environmental Studies Fund (to J.R.S.). Some of the computing for this project was performed on the Sherlock cluster. We would like to thank Stanford University and the Stanford Research Computing Center for providing computational resources and support that contributed to these research results. We thank K. Peay, T. Fukami, B. Brosi and B. Bryant for discussions that increased the quality of the manuscript.
The authors declare no competing interests.
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Smith, J.R., Letten, A.D., Ke, P. et al. A global test of ecoregions. Nat Ecol Evol 2, 1889–1896 (2018). https://doi.org/10.1038/s41559-018-0709-x
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