Evidence for the Role of Salinity and Alkalinity in Plant Diversification in Australia

Australia is the world’s driest inhabited continent and has some of the world’s most stable landscapes and some of the oldest flora, dating back to Gondwana. Two-third of the island continent experiences arid and semiarid climate. Under these climatic conditions where seasonal water deficits occur regularly, salts and carbonates accumulate in soils. Plant distributions have shifted and plants have evolved to adapt to these conditions. This paper summarizes the evidence for the role of soil salinity and alkalinity as drivers in plant diversification in Australia; there is good evidence that both have played an important role for grasses and acacias. Moreover adaptation to salinity may have facilitated the evolution of C4 photosynthesis in Neurachne, an Australian endemic clade of grasses.