Survival strategies of 34 species of lichens from a range of substrata, climates and growth forms were examined using the triangular ordination procedure of Grime. Triangular ordination is apparently an appropriate technique to apply to lichens, all available data falling within a triangle except for two foliicolous species which are probably partial leaf parasites. Statistically significant relationships between survival strategy and growth form, mode of asexual reproduction, substratum preference, family affiliation, and diversity of secondary chemical biosynthetic pathways have been demonstrated.

The germinable soil seed bank of a grassy Eucalyptus populnea F.Muell, open woodland was investigated in relationship to distance from water (away from a bore-drain) on North Yancho Station, near Bollon in southern semi-arid Queensland. The germinable soil seed bank was both diverse and abundant, 69 taxa of seedlings being identified to species and 2 more to genus. A mean density of 13 207 ± 4160 seeds m-2 was recorded, with over 80% of the seed being from the annual forbs Crassula sieberana (Schultes & J.H.Shultes) Druce, Wahlenbergia tumidifructa P.J.Smith and Dysphania gomulifera (Nees) Paul G.Wilson. Most common species showed spatial variation in their germinable seed density with relation to distance from water, resembling the patterns previously reported by other authors for standing vegetation under stocking pressure gradients.

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The plant components and chemical composition of litter fall and the litter layer in a forest growing on deep, nutrient-poor sands were examined on North Stradbroke Island, south-eastern Queensland. The seasonal distribution of litter fall was examined over a 26-month period. While the total litter fall was greatest during summer months, the dominant tree species differed in their individual patterns of litter fall. Eucalyptus signata showed a single summer peak for leaf fall while E. umbra exhibited one peak in early summer and another in autumn. The possibility is discussed that these and other temporal differences are evolutionary expressions of niche differentiatibn to reduce competition between species in the ecosystem. The total litter fall averaged 640 g m-1 yr-1 and the accumulated forest floor mass totalled 2700 g m-2. Total nutrient pools and nutrient inputs in litter fall are presented. A litter half-life of 2.9 years is estimated, a figure close to the half-life of most of the nutrients in the litter. Manganese appears to be markedly concentrated in eucalypt leaves before they fall. Only sodium, potassium, copper and chloride appear to be leached easily from leaves slashed from trees and left on the forest floor. Patterns of litter production and decay in this subtropical forest fit within trends extrapolated from temperate Eucalyptus-dominated communities studied to date.

The plant biomass of a Eucalyptus signata-dominated forest 15 m tall growing on infertile sands off the Queensland coast is characterized in detail. The forest has a biomass of 180 t/ha, 90% of which is found in the nine species achieving > 2.5 m height. Of the total biomass, 42.5 % is below ground. Pteridium esculentum occupies 41 % of the understorey biomass, with 50 shrub and herb species partitioning the remainder. Dimension analysis of 10-11 individuals of each of three tree species- Eucalyptus signata, E. umbra subsp. umbra and Banksia aemula-has served to characterize the above- and below-ground growth forms of each species, and provide regressions of the mass of tree components on easily measured plant parts. The size distribution of tree and shrub stems on the site suggests that the major species have evolved quite different reproductive strategies for main- taining a steady-state population in the face of recurrent fires.

The soil crust community from a sub-tropical grassland in southwest Queensland was found to include 34 taxa with cyanobacteria, other algae, lichens, fungi, mosses and liverworts represented. Cyanobacteria and liverworts were the major components of the cryptogamic cover. This is a significant component of the biodiversity of the region. Changes in the structure of this community were significantly correlated with distance firom a linear water supply (bore drain) and with dung density. It was concluded that hoof impact by grazing stock had measurably affected the cryptogamic community even under a moderate stocking policy. This research suggests that management for sustainable use of lownutrient rangelands should include consideration of soil crust condition.

SUMMARYThe distribution of Chondropsis semiviridis (FvM. ex Ny!.) Nyl. was mapped for Australia. Studies in gas exchange physiology demonstrated that length of drought is likely to limit distribution of the species. Similarly, it is shown that sensitivity to heat when wet is likely to prevent the species from establishing in arid areas with a summer rainfall seasons The surge of respiration upon wetting of lichen thalli noted by other workers was so short for C. semiviridis that it could not affect the limits of its distribution.

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