Introduction Although the latitudinal diversity gradient (LDG) is recognised as one of ecology's oldest patterns (Hawkins 2001), unravelling the mechanisms that underpin it remains a core ecological challenge (Hawkins 2001, Nekola and White 2004). LDGs have been attributed to speciation, extinction and species dispersal processes, combined with environmental filtering, operating at a range of spatial and temporal scales (Lamanna et al. 2014, Mannion et al. 2014).
