The species richness (number of vascular-plant species per unit area) of sclerophyll (heathy) plant communities is examined from south-east Queensland to south-west Western Australia. The species richness
of communities of heathy open forest, heathy open scrub, dry heathland and wet heathland is consist-
ently similar throughout southern Australia and decreases from dry heathland (on laterite, coastal and
inland localities) to heathy open forest, heathy open scrub and wet heathland.
Investigation of related microcommunities at Cooloola, Stradbroke Island, Ku-ring-gai Chase and
Wilsons Promontory indicates that species richness decreases linearly as overstorey cover increases. In
post-fire succession on Stradbroke Island heathy woodland and Dark Island heathland, species richness
declines linearly as overstorey cover increases during the regeneration of the community. The appli-
cation of limiting fertiliser to Stradbroke Island heathy woodland and Dark Island heathland increases
the rate of development of overstorey cover, with a simultaneous decrease in species richness.
Species richness of the understorey strata of plant communities appears to be inversely related to the
rate of development of foliage projective cover in the overstorey. If an environmental or biotic factor
inhibits or retards the development of overstorey cover, the understorey increases in species richness.
Conversely, if any environmental or biotic factor accelerates the development of overstorey cover, the
understorey species show a reduction in species richness.
Nutrient enrichment of estuarine submersed vascular plant communities. 1. Algal growth and effects on production of plants and associated communities