Patterns of plant diversity in ironstone ranges in arid south western Australia

► The isolated ironstone ranges of arid south western Australia showed high beta diversity both within and between ranges. ► The high beta diversity between ranges was largely due to high species turnover between ranges. ► Species richness patterns were most strongly correlated with broad scale spatial and climate gradients. ► Compositional patterns were correlated with environmental and spatial pattern across a number of different scales. ► Areas of highest conservation concern occur along the arid zone boundary with two hotspots of specialist ironstone taxa.