Christopher J. Brown(1), Mary I.O’Connor(2), Elvira S.Poloczanska (3), David S. Schoeman (4), Lauren B.Buckley (5), Michael T. Burrows (6), Carlos M. Duarte (7), Ben S.Halpern (8), John M. Pandolfi (9),Camille Parmesan (10) Anthony J. Richardson (11)
1 Australian Rivers Institute, Griffith University, 170 Kessels Road, Nathan, Queensland, Australia chris.brown@griffith.edu.au,
2 Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada V6T1Z4
3 CSIRO Oceans and Atmosphere Flagship, EcoSciences Precinct, Dutton Park, Brisbane, QLD 4102, Australia
4 Faculty of Science, Health, Education and Engineering, University of Sunshine Coast, Maroochydore, DC, Qld, Australia
5 Department of Biology, University of Washington, Seattle, WA 98115-1800.
6 Department of Ecology, Scottish Association for Marine Science, Marine Institute, Oban, Argyll, UK
7 King Abdullah University of Science and Technology (KAUST), Red Sea Research Center (RSRC), Thuwal, 23955-6900, Saudi Arabia
8 National Center for Ecological Analysis and Synthesis, 735 State St. Suite 300, Santa Barbara, CA, 93101 USA
9 ARC Centre of Excellence for Coral Reef Studies and School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia
10 Marine Institute, Plymouth University, Drakes Circus, Plymouth, Devon PL4 8AA
11 Centre for Applications in Natural Resource Mathematics, School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland, 4072, Australia
Studies of climate-driven range-shifts have evaluated how well ecological traits, such as mobility or reproductive mode, explain variation in observed rates of shift. However, these estimates could also be influenced by methodological attributes. We compiled a global dataset of marine species’ distribution (n=359) responses to climate change to assess the relative importance of ecological traits and methods in measurements of change. We found methodological attributes explained 42% of the variation in range shifts compared to 53% that could be attributed to ecological traits. For ecological traits, we found strong variation in the magnitude of range change among taxa, that changes were greater for pelagic and demersal (vs coastal) species, and greater for studies measuring populations at range centres and leading (rather than trailing) edges. For methodological approaches, greater range shifts were observed when single occurrences were used to define range shifts (rather than abundances or multiple occurrences over a large portion of a range boundary), and for time series with lower than annual frequency. Our analyses indicate that methodological approaches should be explicitly considered when designing, analysing and comparing results among studies. We recommend (1) re-analyses of existing data-sets acknowledge how the methods of data collection have limited their inferences; (2) comparisons of range shifts be made across similar methodologies and; (3) meta-analyses of range shifts include methodological approaches as covariates. Accounting for the influence of methodological approaches in analyses of range change will lead to more representative estimates of the rate of species range change.