A survey of 20 km'^ of species-rich kwongan (sclerophyllous shrubland or sandplain vegetation) is reported, A total of 429 vascular plant species were found, of which 338 were recorded at the eighty-seven systematically located 0,1 ha releves, Eive vegetation units were deflned following analysis ofthe site-floristics data. Small but distinctive suites of species (totalling 26% of recorded species) characterized a gradient in soils from the sands and gravels ofthe lateritic uplands, through the deep sands of the dune sequence, to the clays ofthe winter-wet depressions. However the soils-related axis in the ordinations accounted for only ca. 6% of the variability in the data, indicating the complexity of the vegetationenvironment interactions. Species richness was greatest in a zone of apparent overlap between the lateritic group of species and those of the deep sand areas. The winter-wet areas were poorest in species. The distributions of the floristicallydeflned vegetation units did not closely parallel those of physiognomic units deflned by interpretation of air photos. Structural dominance was negligible in all but the winter-wet areas and the few dominants appeared poorly correlated with other species and with the physical environment. Comparisons are made with areas of similar vegetation elsewhere in Australia and in South Africa,
Kwongan vegetation (sclerophyllous shrublands) growing on a single soil type was surveyed over a 5 000 km 2 area centered about Eneabba, Western Australia. All samples were on laterite, a deeply weathered, infertile soil developed since the Tertiary over much of the ancient, subdued landscape of south-western Australia. The vegetation was rich in angiosperm plant species and, although quite uniform in structure, highly variable floristically, suggesting the existence of a complex mosaic of species distributions. Of the four floristic groups defined using both ordination and classification techniques, the group including the Mt Lesueur area was the most distinctive. Site groupings were predominantly regional although the influence of climatic factors, particularly potential evaporation, was significant. Biogeographic patterns of each of the major plant families were not coincident. The geographic arrangement of the floristic groups does not correspond with existing vegetation maps compiled primarily on the basis of physiognomy.
Long term effects of a single flre on eucalypt woodland vegetation in south-western Australia are reported. The flre, which was about 40 years ago, converted the woodland to a mallee-heath. Edaphic and floristic continuity across the clearly deflned structural boundaries, established through sampling, supports the contention that the structural disjunction is the result of this flre. Regeneration is estimated to take up to 100 years, during which time the shrub stratum thins out and herbs and grasses become more abundant. Further episodes of flre are likely to reinforce the structural changes in the vegetation. This example of mallee-heath is described as a pyric discUmax. It is suggested that some other Australian heath and mallee-heath formations may be of similar successional status.
Kwongan is an important vegetation type in southwestern Australia. It occurs in small patches throughout Ttitanning Nature Reserve. Eleven patches, totalling 64 ha, were found to contain 315 vascular plant species: over half the total species recorded for the whole reserve. The patches were floristically heterotoneous (cf. Westhoff & van der Maarel 1973) but could be grouped according to three major soil types. The richest kwongan was on pockets of shallow duplex soil occurring midway down the landscape profile. Species richness appears to decline only slightly with increasing time since fire. Presence of emergent Banksia attenuata at one site did not influence the overall speciesrichness of that area.
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