Water regimes, seedling recruitment and establishment in three wetland plant species

Abstract

The regeneration niche of three wetland species that co-occur at Bool Lagoon, South Australia, was investigated under nine hydrologic conditions. Typha domingensis grown from seed had the broadest niche requirements; seeds germinated and seedlings were established in all 9 hydrologic regimes, and asexual reproduction occurred in 5 of the 9 regimes. Whether asexual reproduction occurred was dependent upon an interaction between the rate of leaf elongation, the rate of drawdown and whether the leaf was able to broach the water surface. The buoyant nature of seeds and seedlings ofTriglochin procerum allowed it to avoid unfavourable regeneration niches. Melaleuca halmaturorum had a narrow regeneration niche that was confined to wet mud flats. The results are consistent with the changes in the floristic composition of the lagoon.