Diversity and ecology of extant and Quaternary Australian charophytes (Charales)

The Australian charophyte flora (62 species recorded) is characterized by a high proportion of taxa which are endemic (62), dioecious (45), and that do not develop gyrogonites (84). In this study, charophytes (Charophyta, Charales) were collected from one hundred and fifty two localities and forty two species identified. Ecological factors were recorded, in particular, salinity and water depth because these are the main factors affecting charophyte distribution, and pertinent to increasing salinisation of some Australian water-bodies. The different species were recorded at salinities ranging between 0 g L-1 and 58 g L-1 and at depths between few cm of water up to 12 m. Data on salinity and water depth are summarized by salinity/species and water depth/species graphs. A temporal perspective is important to understand the modern species distribution and ecology, so available data from the Australian Quaternary record are incorporated, being two from the Late Pleistocene and one from the Holocene. The palaeolimnological methodology uses the modern environmental data to infer environmental changes.