Recognising the elephants when detecting and predicting species range change
Bruce L. Webber (1), Mohsen B. Mesgaran (2), Melinda S. Trudgen (3), David C. Le Maitre (4)
1 CSIRO Land & Water, 147 Underwood Ave, Floreat, WA 6014, Australia and School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia, bruce.webber@csiro.au, @DrBruceWebber
2 School of BioSciences, The University of Melbourne, VIC 3010, Australia, mohsenm@unimelb.edu.au, @MBMesgaran
3 CSIRO Land & Water, 147 Underwood Ave, Floreat, WA 6014, Australia and School of Plant Biology, The University of Western Australia, Crawley, WA 6009, Australia, meltrudgen@gmail.com, @MelTrudgen
4 Natural Resources and Environment, CSIR, Stellenbosch, 7599, South Africa, DlMaitre@csir.co.za
The modelling of species distributions is now commonly used to understand the future range of both native and non-native species. While many recognise that modelling is primarily either a first step in understanding possible range change or a useful way to formulate and test hypotheses, projections from these models are used to inform significant management decisions, to guide the investment of large amounts of funding, and to make bold claims about the risk of future species extinctions and invasions. Critically, however, there are several difficulties and limitations, both methodological and conceptual, with which users need to be familiar, but that remain frequently overlooked by both modellers and end-users alike. A particular concern has been the extent to which models are transferable to places or times different from those used for model calibration, and how this limitation influences the interpretation and reliability of model results. Here we explore a number of high priority issues for the projection of species distributions into the future, including conceptual underpinnings of the models and their assumptions, ways to identify and manage model extrapolation, and sources of uncertainty that should be accounted for in model parameterisation. In doing so, we detail methodological advances and practical guidelines in an effort to improve modelling practice and application. We caution that without careful consideration of these factors our understanding of moving species, and our ability to respond to and manage this change, will be limited.