Abstract
On the sandy Swan Coastal Plain the distribution of the two most common emergent macrophytes, Baumea articulata and Typha angustifolia is similar along transects in different wetlands. Their biomass distribution is a reflection of measured productivity. Their response is similar to different stable water levels under controlled conditions, maximum productivity for both being achieved where the water level is at the sediment surface. The conclusion that water regime explains distribution is modified in the field, where different productivities were found in wetlands with the same water regimes, but different sediment nutrient concentrations and soil types. Typha fared better than Baumea when the two were grown in the same containers. In the field Typha replaced Baumea when Baumea had been eliminated by altered water levels.