Climate velocity and the future global redistribution of marine biodiversity

Jorge García Molinos (1), Benjamin S. Halpern (2), David S. Schoeman (3), Christopher J. Brown (4), Wolfgang Kiessling (5), Pippa J. Moore (6), John M. Pandolfi (7), Elvira S. Poloczanska (8), Anthony J. Richardson (9), Michael T. Burrows (10)

1 Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan;

2 Bren School of Environmental Science and Management, University of California, Santa Barbara, California 93106, USA;

3 School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia;

4 The Global Change Institute, The University of Queensland, Brisbane, Queensland 4072, Australia;

5 GeoZentrum Nordbayern, Paläoumwelt, Universität Erlangen-Nürnberg, Loewenichstrasse 28, 91054 Erlangen, Germany;

6 Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3DA, UK;

7 School of Biological Sciences, Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, Queensland 4072, Australia;

8 CSIRO Oceans and Atmosphere Flagship, Ecosciences Precinct, Boggo Road, Brisbane, Queensland 4001, Australia;

9 CSIRO Oceans and Atmosphere Flagship, Ecosciences Precinct, Boggo Road, Brisbane, Queensland 4001, Australia;

10 Scottish Association for Marine Science, Oban, Argyll PA37 1QA, UK;

Anticipating the effect of climate change on biodiversity, in particular on changes in community composition, is crucial for adaptive ecosystem management but remains a critical knowledge gap. Here, we present the results of a recent study were we used climate velocity trajectories, together with information on thermal tolerances and habitat preferences, to project changes in global patterns of marine species richness and community composition under IPCC Representative Concentration Pathways4 (RCPs) 4.5 and 8.5. Our simple, intuitive approach emphasizes climate connectivity, and enabled us to model over 12 times as many species as previous studies. We find that range expansions prevail over contractions for both RCPs up to 2100, producing a net local increase in richness globally, and temporal changes in composition, driven by the redistribution rather than the loss of diversity. Conversely, widespread invasions homogenize present-day communities across multiple regions. High extirpation rates are expected regionally (for example, Indo-Pacific), particularly under RCP8.5, leading to strong decreases in richness and theanticipated formation of no-analogue communities where invasions are common. The spatial congruence of these patterns with contemporary human impacts highlights potential areas of future conservation concern. These results strongly suggest that the millennial stability of current global marine diversity patterns, against which conservation plans are assessed, will change rapidly over the course of the century in response to ocean warming.