Flora of Tasmania - Overview

Overview

The marine fauna of the period, separate from that of the southwest Pacific, was distinguished as the "Maori province". Gondwana began its fragmentation in the middle and upper Jurassic, and the arrival of benthic invertebrate fauna is visible in fossil deposits. The Cretaceous marked the appearance of marine invertebrate fauna of southern origin. It was then that angiosperm flora such as Nothofagus and Proteaceae colonized New Zealand and New Caledonia, from South America, along the Antarctic margin of Gondwana: Antarctica, Australia and Tasmania. At the beginning of the Tertiary the area moved to north to a warmer climate.

This led to long periods of evolution in near complete isolation. The isolation of the Island was not absolute, given the rise and fall of sea level caused by the ebb and flow of ice ages. Land bridges or islands formed between Tasmania and its neighbour, Australia. Thus new species came to Tasmania while Gondwanan species were able to penetrate the Pacific Islands region. Plants have limited seed dispersal mobility away from the parent plant and consequently rely upon a variety of dispersal vectors to transport their propagules, including both abiotic and biotic vectors. Seeds can be dispersed away from the parent plant individually or collectively, as well as dispersed in both space and time. Birds and bats swallow seeds, then regurgitate them or pass them in their faeces. Such ornithochory has been a major mechanism of seed dispersal across ocean barriers. Other seeds may stick to the feet or feathers of birds, particularly migratory or aquatic birds, and in this way may travel long distances. Seeds of grasses, spores of algae, and the eggs of molluscs and other invertebrates commonly establish in remote areas after long journeys of such types.