Differential establishment potential of species predicts a shift in coral assemblage structure across a biogeographic barrier

have a unique assemblage structure. For these assemblages, an alternative explanation might be more appropriately sought at a smaller spatial scale to match the reduced geographical extent of these idiosyncratic reefs relative to a coherent province (Rahbek 2005, Fenberg et al. 2014). Coral assemblages located in marginal areas, such as those at higher latitudes, are of particular interest because of their potential to provide a refuge during climate change (Beger et al. 2014, Makino et al. 2014, Sommer et al. 2014): coral distributions have shifted towards the poles during both past and current periods of climate change (Precht and Aronson 2004, Greenstein and Pandolfi 2008, Yamano et al. 2011, Baird et al. 2012). Therefore, understanding the relative importance of different underlying processes, such as tolerance of environmental conditions and dispersal limitation, for influencing the assemblage composition of these reefs will help determine their potential suitability as a refuge in the future (Beger et al. 2014). For instance, a reef with an assemblage determined by environmental conditions could serve as a good candidate for protection as a future refuge, whilst Ecography 38: 1225–1234, 2015 doi: 10.1111/ecog.01437 © 2015 The Authors. Ecography © 2015 Nordic Society Oikos Subject Editor: Miguel Araújo. Editor-in-Chief: Miguel Araújo. Accepted 14 February 2015