Life histories of charophytes from permanent and temporary wetlands in eastern Australia

The results of an experiment on the demography of charophytes in permanent and temporary sites in two wetlands are outlined and the charophytes that germinated and established are described in relation to their life histories. Three life-history patterns are represented. First, Monoecious annual species germinate easily and rapidly aft er inundation, they grow quickly and initiate sexual reproduction at the expense of vegetative expansion, produce relatively few, large oospores and die in winter. Second, Dioecious annual species are slower to germinate than Monoecious annuals, they grow more slowly, but also initiate sexual reproduction early in life. They usually produce large numbers of small oospores and die in unfavourable seasons. Both winter-growing and summer-growing Dioecious annuals were represented in experiments. Third, Dioecious perennials germinate after a lag time and establishment; vegetative growth and expansion takes place early in spring. Reproduction in Dioecious perennials is stimulated by increasing water temperatures and other environmental cues. Vegetative reproductive organs are produced in autumn and individual shoots can be very long-lived. Life-history parameters such as germination requirements, establishment requirements and timing of vegetative growth and reproduction can be important in determining the distribution patterns in charophytes.