Eucalypt Dieback on the Northern Tablelands of New South Wales

This study was initiated in order to attempt to describe the nature and extent of eucalypt dieback on the Northern Tablelands. It was found that the typical symptoms of eucalypts exhibiting dieback involved general deterioration of the crown with thinning of foliage and progressive death of twigs and branches. Most of the declining trees were severely defoliated by a variety of native insects, in particular paropsine and scarabaeid beetles. Partial recovery usually occurred in the form of bursts of epicormic shoots, but the new growth was also liable to deterioration. The trees usually died, with a few intact leaves remaining, but occasionally trees wilted while still bearing a significant portion of their leafy crown. Wood decay was common in the affected eucalypts, but the rotting of live sapwood was only occasionally evident. Semi-quantitative scales were constructed to facilitate the assessment of tree vigour and foliage cover. A broadscale road survey of the Northern Tablelands was undertaken during 1980 to ascertain the extent of eucalypt dieback and which species were involved; 48 species of naturally occurring eucalypts were encountered. The stretch of country in which most dieback had occurred runs from Bendemeer and Yarrowitch in the south to Tenterfield in the north. ... It is argued that lignotuberous advanced growth is critical for the survival of eucalypt populations during periods of intense dieback

Ecological studies of 'Hyparrhenia hirta' (L.) Stapf in northern New South Wales

'Hyparrhenia hirta' (L.) Stapf (Coolatai grass) is a summer active, C4 perennial grass, native to southern Africa and the Mediterranean region. In recent years its range has expanded rapidly and there are now populations of H. hirta in all states and Territories of Australia except Tasmania. It invades native grassy and open woodland communities, including roadsides and travelling stock routes, national parks and pastures. There is little published information on the biology and ecology of 'H. hirta' in the summer rainfall environment of northern New South Wales. This study aimed to increase our understanding of key aspects of the ecophysiology, population dynamics and community ecology of 'H. hirta' to assist in control and management

Tree clearing in Australia : the dilemma of rural tree clearing. by Christopher Nadolny

The loss of trees from rural Australia has been identified as one of the major environmental problems facing this country, the root cause of such problems as salinization, soil erosion and the loss of species

Effects of recent changes in grazing and fertiliser management on the species richness of native ground-storey vegetation, Northern Tablelands, New South Wales

Despite major land use changes, much of the ground-layer vegetation on the Northern Tablelands of New South Wales is still dominated by native grasses. The native grassy ecosystems of the region were studied to determine the impacts of grazing, fertilising and cultivation history on vascular plant species richness. Sampling was stratified on the basis of management. The incidence of all plant species in 30 m² quadrats was recorded at 373 sites within a 60 km radius of Armidale. Sites with a history of cultivation were found not to contribute any additional native species to the total number of native species found in uncultivated sites. In sites with no history of cultivation or fertiliser, the never grazed and infrequently grazed sites had significantly higher native species richness than grazed sites. The combined effects of increasing grazing intensity and fertiliser inputs significantly reduced native species richness and increased exotic species richness

Testimonial: Wool production & biodiversity working together for Gordon & Jan Edmonds - 'Ponds Creek'

Gordon Edmonds grew up at 'Ponds Creek' and he and his wife Jan took over management from Gordon's parents in the late 1980s. The Edmonds have revegetated 15% of 'Ponds Creek; and intend to increase this to 20-25% as part of their farm re-development plan. They have established 34 revegetation sites, planted more than 20 000 seedlings and direct seeded 50 km of trees and shrubs. This testimonial describes how they restore biodiversity, repair gully erosion, drought-proof their property, subdivide their country for better grazing management, ensure there is adequate shelter and water in each new paddock, and achieve market premiums for their livestock

The Effects of Fungal Volatile Organic Compounds on Bone Marrow Stromal Cells

Evidence has shown that individuals exposed to indoor toxic molds for extended periods of time have elevated risk of developing numerous respiratory illnesses. It is not clear at the cellular level what impact mold exposure has on the immune system. Herein, we show that 2 fungal volatiles (E)-2-octenal and oct-1-en-3-ol have cytotoxic effects on murine bone marrow stromal cells. To further analyze alterations to the cell, we evaluated the impact these volatile organic compounds have on membrane composition and hence fluidity. Both (E)-2-octenal and oct-1-en-3-ol exposure caused a shift to unsaturated fatty acids and lower cholesterol levels in the membrane. This indicates that the volatile organic compounds under investigation increased membrane fluidity. These vast changes to the cell membrane are known to contribute to the breakdown of normal cell function and possibly lead to death. Since bone marrow stromal cells are vital for the appropriate development and activation of immune cells, this study provides the foundation for understanding the mechanism at a cellular level for how mold exposure can lead to immune-related disease conditions

Grazing management and environmental determinants of the diversity and composition of ground-story vegetation on the Northern Tablelands, NSW

Agricultural management influences the species richness and composition of ground-storey vegetation in Australia and elsewhere. This thesis investigates the influence of grazing management and environmental determinants on the diversity of native ground-storey vegetation on the Northern Tablelands of New South Wales. The predominant land use is livestock grazing in a variegated landscape in which pastures dominated by native ground-storey species are more extensive than sown pastures dominated by exotic ground-storey species. Vascular plants were floristically surveyed in 6 x 5 m plots at 373 sites within a 60 km radius of Armidale from January to April in 2001 and 2002. Sampling was concentrated in commercially grazed paddocks (81 %), remnant vegetation managed for conservation on private land (7%), and public land grazed intermittently or not at all (12%). Management history and environmental variables were recorded at each site. Confounding of management influences was addressed by stratified sampling in relation to grazing, cultivation, fertiliser management and lithology. Over the period of the study, some 321 species and sub-species of vascular plants were recorded, 70% of them native taxa. Seasonal fluctuations in native, exotic and total species richness were determined, with maxima recorded in late spring to autumn, thereby identifying this period as the optimal time for sampling the diversity of native ground-storey vegetation on the Northern Tablelands. ... Information from this study was used to develop a state and transition model for native ground-storey species. Transitions were based upon changes due to agricultural management (grazing, fertiliser application and cultivation). The assemblages of ground-storey species associated with particular agricultural management practices were used to define states for each lithology. The identity and species richness of native ground-storey vegetation in commercially grazed areas, public reserves, and on-farm remnants were determined. The data are useful for determining the importance of these areas in the conservation and management of ground-storey vegetation on the Northern Tablelands. While production areas are floristically less diverse than public reserves and on-farm remnants, they provide an extensive matrix of predominantly native vegetation, which is vital for the long-term conservation of the regional biota

Impacts of 'Hyparrhenia hirta' (L.) Stapf (Coolatai grass) on native vegetation in a travelling stock route in northern New South Wales

'Hyparrhenia hirta' (L.) Stapf (Coolatai grass, tambookie grass) is an invasive grass from Africa and the Middle East that has infested large areas of northern New South Wales (NSW) and also occurs in other Australian states. Ten plots were set up for this monitoring study in white box/yellow box/Blakely's red gum woodland, an endangered ecological community, on a travelling stock route near Manilla. Five plots were in an area infested by 'H. hirta' and the rest were in an area where infestations had previously been controlled by spot spraying with glyphosate. Vegetation surveys were conducted in these plots in autumn 2003 and spring 2005. In both surveys 'H. hirta' dominated ground cover in all infested sites and greatly reduced the species richness of native flora, but was absent from the controlled sites. The presence of 'H. hirta' reduced native species richness by about 48% in 20 x 20 m plots and 59% in 6 x 5 m plots in 2003. Results were similar in 2005. Projected cover of 'H. hirta' greatly exceeded that of all native ground-cover species combined in the infested plots. The results are consistent with those of McArdle et al. (2004) from Kwiambal National Park and demonstrate that the impact of this weed on species richness in travelling stock routes, which are intermittently grazed, may be as severe as those in conservation reserves, where domestic livestock grazing is excluded

Seed-bank and seedling dynamics in 'Hyparrhenia hirta' are influenced by herbicide application and mowing management

'Hyparrhenia hirta' (L.) Stapf (Coolatai grass) is a summer-active, C₄ perennial tussock grass native to southern Africa and the Mediterranean region, which has invaded areas of native flora in Australia in recent decades. Understanding its seed and seedling dynamics and how various management treatments (e.g. mowing, herbicide and no management) affect these may assist in identifying the conditions and management strategies required to limit its invasion. The population dynamics of 'H. hirta' have not been comprehensively studied previously. A 2 year field experiment (December 2005-December 2007) was conducted to determine the seed-bank size, pattern of seedling emergence and survival of 'H. hirta' seedlings at three sites in northern New South Wales, Australia, under three treatments: unmanaged (control), mowing and herbicide treatments. The density of 'H. hirta' seeds in the soil at each experimental site under different treatments was measured in December 2005 at the start of the experiment, in December 2006 before the application of the second round of treatments and again at the end of the experiment in December 2007. 'Hyparrhenia hirta' seedlings were assessed at monthly intervals in permanent quadrats (0.5) to determine seedling emergence and survival. Seedling emergence occurred on many occasions during the 2 year period of the experiment in each treatment and at all sites but the main seedling flushes were observed from mid summer to early autumn. In 2007 at all sites seedling emergence declined by more than 90% on the mowing and herbicide treatments compared with the control treatment. Seedling survival was greater in the mowing and herbicide treatments than in the control treatment. The seedling cohorts emerging in winter had a lower survival. This study showed that 'H. hirta' infestations have a large viable seed bank (~3000m-²) dependent on the level of infestation and climatic conditions but that the seed-bank declines rapidly when seed addition is prevented. Some form of direct control of established 'H. hirta' plants in combination with providing appropriate grazing management to encourage competition between grasses will assist in the control of 'H. hirta'

Factors Affecting Germination of Coolatai Grass ('Hyparrhenia hirta')

Coolatai grass is an invasive, perennial grass from Africa and the Middle East that has infested large areas of northern New South Wales, Australia, and also occurs in other Australian states. An understanding of the seed germination ecology of Coolatai grass can assist in predicting its potential distribution and developing effective management strategies. The effects of various environmental factors on Coolatai grass seed germination were investigated in a series of laboratory experiments. The effect of diurnal alternating temperatures (5–45 C) with a 12-h photoperiod were examined on a thermogradient plate. Seed germination occurred at almost all temperature combinations from 5 to 45 C. At moderate temperatures the speed of seed germination was very high; at 30/20 C more than 80% of seeds were germinated within 12 h. Germination was slightly enhanced by the presence of light, but length of photoperiod did not affect germination. Germination at neutral pH was over 90%, and declined to 65% at acidic (pH 4) and alkaline (pH 10) pH levels. Germination was completely inhibited at an osmotic stress of −0.55 MPa or greater and was reduced by 50% at −0.37 MPa. Greater germination in relatively dry soil conditions compared with native species may contribute to the establishment of this species in the field. Results indicate that Coolatai grass seeds can germinate over a wide range of diurnal temperatures, light regimes, pH levels, and under marginal water stress. These characteristics help explain the successful invasion of Coolatai grass and provide evidence that this species is capable of establishing in many parts of Australia