[See FA 45, 478-479] Felling crews provided information on the species and number of animals displaced during logging operations in 5010 ha of forest clear felled between May 1980 and Sept. 1981. Overall, 898 individuals of 8 species of glider and opossum were recorded. Geological data were also collected. The data were analysed together with published information on tree species within 22 recognizable communities and NPK concn. in Eucalptus foliage. The fauna tended to be concentrated in communities with Eucalyptus spp. with high nutrient concn. in their foliage. These communities occurred mostly on soils of one geological formation (Devonian intrusives) recognized in the district for the production of highly fertile soils.

The relationships were examined between measurements of forest habitat (10 explanatory variables: X) and densities of three species of arboreal marsupials (greater glider, feathertail glider and sugar glider); the sum of these three and an additional five species that occurred; species richness and diversity of all eight species present in the area (six response variables: Y). The habitat variables were: landform profile; elapsed time since a severe fire; degree of forest maturity (total basal area of wood); an index of den tree density; ratio of number of regeneration size trees to den trees; floristic diversity; basal area of peppermints; basal area of gums; basal area of eucalypts with a low level of nutrients in their foliage; and an index of potassium concentration in the foliage. The principal component transformation of the X set of variables (PCA) was used as an aid to interpret the individual response of Y to joint intercorrelated explanatory variables X. The regressions of Y on PCA-transformed X explained 76.2% of variation in density for the greater glider, 50.4% for the feathertail glider, 21.1% for the sugar glider, 68.3% for all arboreal marsupials, 49.7% for species richness and 30.1% for species diversity. The weak regressions obtained for densities for the sugar glider were attributed to probable non-measurement of important understorey habitat variables for this species, and those for species richness and diversity, to the presence of a curvilinear rather than linear relationship to foliage nutrients. The gradient in foliage nutrient concentration appears to be the major determinant of the density and species richness and diversity of arboreal marsupials in the Eden forests. Exceptions to the trend seem to occur where the forests include certain xeromorphic eucalypt species that are high in foliage nutrients yet poor in fauna, and, for the feathertail and sugar glider, in those sections of the Eden forests exhibiting fire successional stages and that are usually composed of eucalypts with low nutrient levels in their foliage.

The paper is the first of several to present the results of a study, over the last 12 years, of alpine vegetation of the Bogong High Plains (north-eastern Victoria, 5400–6200 ft elevation). Attention is focused on the grassland communities and the response of soils and vegetation to the exclusion of cattle grazing. The first paper outlines the problem, briefly describes the major grasslands, and discusses the climatic and biotic factors concerned.

A 10-year fencing experiment in the eroded grassland, type C, of the Bogong High Plains has established the value of the point analysis method for the quantitative study of continuing change in vegetation. The results show that the exclusion of cattle from this widespread type of subalpine grassland results in a gradual improvement in the amount of vegetative cover, especially in that provided by the herb Celmisia. Over the 10-year period there have been striking soil changes in the fenced plot, resulting in an increase in organic matter and in field capacity, and a significant decrease in bulk density. These findings enable one to make recommendations on catchment management in this area. They have also led to the hypothesis that the eroded grassland has been derived from a herb-field similar to that still existing in the higher parts of the area.

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