A study of the quaternary vegetation history in the volcanic lakes region of Western Victoria

Abstract

The Newer Volcanic Plains of Westem Victoria are Pleistocene in age and have many Zakes of voicanic and tectonic origin, which encompass an entire range of saZinity from fresh-brackish-saline-brine.The general vegetation is an open grassiand, deficient in vascular plant species and tree cover. The dryland vegetation reflects the influence of both adaphic and biotic factors. The basaltic soil is largely responsible for the general paucity of the flora of these plains. However, the aquatic flora, especially in the freshwater lakes, is rich both in species and number of individuals. This study presents an outline of the extant aquatic micro and macrofiora of the volcanic lakes region of Western Victoria. The distribution of aquatic macrophytes is presented in vegetation maps of seven volcanic lakes and descriptions of six tectonic lakes. The composition of the phytoplankton communities of the Westem Victorian lakes and rivers, estuaries and a lagoon of Wilson s Promontory is given with particular emphasis on the members of the Chlorococcales. Various phytoplankton indices are used to present a tentative classification of the trophic status of the volcanic lakes. These indices show that most of the freshwater lakes are oligotrophic, and the saline Zlkes are eutrophic[...]