*4.4. Community Assembly*

The diversity and composition patterns of the Sunshine Coast heaths are also intriguing against the background of contrasting theories of communities moving towards a climax assemblage [101], as opposed to random, temporary, and fluctuating assemblages of individual species responding to stochastic events [102]. Furthermore, this is a rejection of these two extreme views: ecosystem constraints and individual variability constantly interact, with the relative importance of each unsolved [103]. In the Sunshine Coast heaths this study found some distinct compositional communities as in the Glasshouse Mountains (RE 12.8.19), the montane heaths of the old volcanics (RE 12.12.10), and the dry sands (RE 12.2.9 and RE 12.2.13), with each of these communities also having their own unique species. However, this study also found the overlapping composition of the other five ecosystems, all found on the wetter sands, sediments, and alluviums. In this context, the observations of an early ecologist ring true—that the "wallum" vegetation of the coastal lowlands are a dynamic ecosystem with no climax and are subject to continual disturbance in the form of fire, wind, cyclones, periodic drought, storms, and flooding [36]. The vegeta-

tion was described as a continuum, as an oscillation of ecotones between floristic reservoirs, and consisting of flora of predominantly wide potential environment, with an infusion of species with much narrower environmental requirements [36]. Likewise, heaths of the Sydney sandstones have been described as dynamic "mosaics" over time [104] and that for Australian heathlands in general it is difficult to designate any one species as dominant, with proportions changing with microhabitat [105]. This mix of overlapping regional ecosystems in the wet and alluvial areas appears to be a dynamic system, where there is movement of species within the constantly changing environment, subject to extremes of moisture, fire, wind, and drainage. In terms of long-term conservation, it suggests the facilitation of this movement may be essential, and connectivity between these protected areas needs to be considered.
