FLORISTICS AND SOIL RELATIONS OF UPLAND SWAMP VEGETATION NEAR SYDNEY

We examined relations between vegetation and soils, using multivariate methods, in hitherto poorly-known upland swamps on the Woronora Plate au, south of Sydney. A major trend in floristic composition was relate d to the height and cover of the herbaceous stratum and reflected a gr adient in soil moisture and nutrients. A second trend in floristic com position was related to the height and cover of the shrub stratum, and may reflect the influence of recurring fires on certain dominant shru b species. Five plant communities were recognized on the basis of flor istic composition and were distinguishable by their different soil hab itats and/or structural characteristics. We report some of the highest species-richness values in the world (at scales of 1-15 m2) for shrub /sedge-dominated vegetation, with up to 70 vascular plant species in 1 5 m2. Variation in species richness is inversely related to the resour ce gradient and positively related to the penetration of light through the vegetation canopy. This pattern is consistent with resource-compe tition models and warrants further investigation.