Showing papers by "Cooperative Research Centre published in 2007"

Systematic Conservation Planning

Abstract: The realization of conservation goals requires strategies for managing whole landscapes including areas allocated to both production and protection. Reserves alone are not adequate for nature conservation but they are the cornerstone on which regional strategies are built. Reserves have two main roles. They should sample or represent the biodiversity of each region and they should separate this biodiversity from processes that threaten its persistence. Existing reserve systems throughout the world contain a biased sample of biodiversity, usually that of remote places and other areas that are unsuitable for commercial activities. A more systematic approach to locating and designing reserves has been evolving and this approach will need to be implemented if a large proportion of today's biodiversity is to exist in a future of increasing numbers of people and their demands on natural resources.

Granulocyte-Macrophage Colony-Stimulating Factor (CSF) and Macrophage CSF-Dependent Macrophage Phenotypes Display Differences in Cytokine Profiles and Transcription Factor Activities: Implications for CSF Blockade in Inflammation

Abstract: GM-CSF and M-CSF (CSF-1) can enhance macrophage lineage numbers as well as modulate their differentiation and function. Of recent potential significance for the therapy of inflammatory/autoimmune diseases, their blockade in relevant animal models leads to a reduction in disease activity. What the critical actions are of these CSFs on macrophages during inflammatory reactions are unknown. To address this issue, adherent macrophages (GM-BMM and BMM) were first derived from murine bone marrow precursors by GM-CSF and M-CSF, respectively, and stimulated in vitro with LPS to measure secreted cytokine production, as well as NF-κB and AP-1 activities. GM-BMM preferentially produced TNF-α, IL-6, IL-12p70, and IL-23 whereas, conversely, BMM generated more IL-10 and CCL2; strikingly the latter population could not produce detectable IL-12p70 and IL-23. Following LPS stimulation, GM-BMM displayed rapid IκBα degradation, RelA nuclear translocation, and NF-κB DNA binding relative to BMM, as well as a faster and enhanced AP-1 activation. Each macrophage population was also pretreated with the other CSF before LPS stimulation and found to adopt the phenotype of the other population to some extent as judged by cytokine production and NF-κB activity. Thus, GM-CSF and M-CSF demonstrate, at the level of macrophage cytokine production, different and even competing responses with implications for their respective roles in inflammation, including a possible dampening or suppressive role for M-CSF in certain circumstances.

A physics-based approach to modelling grassland fires

Abstract: Physics-based coupled fire–atmosphere models are based on approximations to the governing equations of fluid dynamics, combustion, and the thermal degradation of solid fuel. They require significantly more computational resources than the most commonly used fire spread models, which are semi-empirical or empirical. However, there are a number of fire behaviour problems, of increasing relevance, that are outside the scope of empirical and semi-empirical models. Examples are wildland–urban interface fires, assessing how well fuel treatments work to reduce the intensity of wildland fires, and investigating the mechanisms and conditions underlying blow-up fires and fire spread through heterogeneous fuels. These problems are not amenable to repeatable full-scale field studies. Suitably validated coupled atmosphere–fire models are one way to address these problems. This paper describes the development of a three-dimensional, fully transient, physics-based computer simulation approach for modelling fire spread through surface fuels. Grassland fires were simulated and compared to findings from Australian experiments. Predictions of the head fire spread rate for a range of ambient wind speeds and ignition line-fire lengths compared favourably to experiments. In addition, two specific experimental cases were simulated in order to evaluate how well the model predicts the development of the entire fire perimeter.

Effects of Foveal Ablation on Emmetropization and Form-Deprivation Myopia

Abstract: Purpose Because of the prominence of central vision in primates, it has generally been assumed that signals from the fovea dominate refractive development. To test this assumption, the authors determined whether an intact fovea was essential for either normal emmetropization or the vision-induced myopic errors produced by form deprivation.

Reassessment of tissue Na(+) concentration as a criterion for salinity tolerance in bread wheat.

Abstract: Wheat is the most important crop grown on many of world’s saline and sodic soils, and breeding for improved salinity tolerance (ST) is the only feasible way of improving yield and yield stability under these conditions. There are a number of possible mechanisms by which cereals can tolerate high levels of salinity, but these can be considered in terms of Na + exclusion and tissue tolerance. Na + exclusion has been the focus of much of the recent work in wheat, but with relatively little progress to date in developing highyielding, salt-tolerant genotypes. Using a diverse collection of bread wheat germplasm, the present study was conducted to assess the value of tissue Na + concentration as a criterion for ST, and to determine whether ST differs with growth stage. Two experiments were conducted, the first with 38 genotypes and the second with 21 genotypes. A wide range of Na + concentrations within the roots and shoots as well as in ST were observed in both experiments. However, maintenance of growth and yield when grown with 100 mM NaCl was not correlated with the ability of a genotype to exclude Na + either from an individual leaf blade or from the whole shoot. The K + :N a + ratio also showed a wide range among the genotypes, but it did not explain the variation in ST among the genotypes. The results suggested that Na + exclusion and tissue tolerance varied independently, and there was no significant relationship between Na + exclusion and ST in bread wheat. Consequently, similar levels of ST may be achieved through different combinations of exclusion and tissue tolerance. Breeding for improved ST in bread wheat needs to select for traits related to both exclusion and tissue tolerance.

Bushfires 'down under': patterns and implications of contemporary Australian landscape burning

Abstract: Australia is among the most fire-prone of continents. While national fire management policy is focused on irregular and comparatively smaller fires in densely settled southern Australia, this comprehensive assessment of continental-scale fire patterning (1997-2005) derived from ∼ 1k m 2 AdvancedVery High Resolution Radiometer (AVHRR) imagery shows that fire activity occurs predominantly in the savanna landscapes of monsoonal northern Australia. Sta- tistical models that relate the distribution of large fires to a variety of biophysical variables show that, at the continental scale, rainfall seasonality substantially explains fire patterning. Modelling results, together with data concerning seasonal lightning incidence, implicate the importance of anthropogenic ignition sources, especially in the northern wet-dry tropics and arid Australia, for a substantial component of recurrent fire extent. Contemporary patterns differ markedly from those under Aboriginal occupancy, are causing significant impacts on biodiversity, and, under current patterns of human popula- tion distribution, land use, national policy and climate change scenarios, are likely to prevail, if not intensify, for decades to come. Implications of greenhouse gas emissions from savanna burning, especially seasonal emissions of CO2, are poorly understood and contribute to important underestimation of the significance of savanna emissions both in Australian and probably in international greenhouse gas inventories. A significant challenge for Australia is to address annual fire extent in fire-prone Australian savannas.

Constraints on recovery: using molecular methods to study connectivity of aquatic biota in rivers and streams

Abstract: Summary 1. The ‘Field of Dreams Hypothesis’ states ‘if we build it, they will come’, referring to the assumption that if habitats are restored, species will recolonise them. However, the ability of a species to recolonise a restored site will depend not only on the appropriate habitat being present, but also on the ability to get there. This is likely to depend on both the species’ dispersal behaviour and the position of a site in the landscape. 2. Animals with good potential for dispersal are more likely to be able to disperse to newly restored sites. Similarly, sites in lowland streams with limited altitudinal differences between sites may be easier to reach than upstream sites. This is because upstream sites are connected to one another via lowland streams that have different characteristics and therefore may be difficult for animals to traverse. 3. In this paper, genetic data from a range of freshwater species that have been analysed in my laboratory are used to assess the importance of life cycle and position in the landscape (i.e. upland versus lowland streams) on connectivity patterns (and thus recolonisation potential) among populations. 4. In general, contemporary dispersal across catchment boundaries is negligible, except for aquatic insects with an adult flight stage. Dispersal among streams within catchments appears to be more limited than was predicted from knowledge on life histories, except for fish in lowland rivers and streams. 5. As predicted, dispersal of fish, crustaceans and molluscs among streams within catchments is significantly greater in lowland rivers than in upland streams. 6. Overall, these analyses suggest that, with the exception of most insects, and fishes in lowland rivers, natural recolonisation of restored sites is only likely from sites within the same stream. If a species has disappeared from the whole stream, then restoration of habitat alone may not be sufficient for its re-establishment.

On the relationship between fronts of the Antarctic Circumpolar Current and surface chlorophyll concentrations in the Southern Ocean

Abstract: [1] We reexamine the relationship between circulation, bathymetry, and surface chlorophyll in the Southern Ocean, using new high-resolution maps of the frontal structure of the Antarctic Circumpolar Current (ACC) derived from satellite altimetry. The maps reveal that the ACC consists of multiple filaments or jets. By averaging surface chlorophyll measurements along streamlines, we show that the fronts define the limits of zones with similar concentrations and seasonality of surface chlorophyll. The overall pattern of surface chlorophyll is consistent with strongest upwelling of nutrient-rich deep water south of the Polar Front (PF). However, the distribution of chlorophyll in the Southern Ocean is concentrated in a number of persistent blooms, observed downstream of islands and bathymetric features. In contrast to previous studies, we find little evidence that the fronts of the ACC are associated with enhanced productivity, at least where the fronts are distant from topography. Rather, we find that most regions of elevated chlorophyll in the open Southern Ocean can be explained by upwelling of nutrients (both macronutrients and micronutrients) where the ACC interacts with topography, followed by downstream advection. The upwelling is shown to be the consequence of the bottom pressure torque established by the large-scale flow, rather than being due to small-scale instabilities of the jets. The interaction of the flow with the topography therefore establishes both the large-scale dynamical balance of the ACC and determines the productivity of the open Southern Ocean.

How Resource Dependency Can Influence Social Resilience within a Primary Resource Industry.

Abstract: Maintaining a healthy balance between human prosperity and environmental integrity is at the core of the principles of Ecological Sustainable Development. Resource-protection policies are frequently implemented so as to regulate the balance between resource access and use, however, they can inadvertently compromise the ability of resource users to adapt and be resilient. Resource users who are especially dependent on a resource are more seriously compromised. But how do we define and measure resource dependency? And how do we assess its ability to influence social resilience? In this study, a conceptual model of resource dependency is developed in terms of: (i) occupational attachment, (ii) attachment to place, (iii) employability, (iv) family attitude to change, (v) business size, (vi) business approach, (vii) financial situation, (viii) level of specialisation, (ix) time spent harvesting, and (x) interest in and knowledge of the environment. The model of resource dependency and its effect on social resilience are (quantitatively and qualitatively) tested and explored using the commercial fishing industry in North Queensland, Australia. Results show that occupational attachment and employability were important influences as were business size and approach. Results can be used to identify vulnerability to institutional change and guide policy development processes.

Rapid freshening of Antarctic Bottom Water formed in the Indian and Pacific oceans

Abstract: [1] Repeat hydrographic sections occupied in 1995 and 2005 reveal a rapid decline in the salinity and density of Antarctic Bottom Water throughout the Australian Antarctic Basin. The basin-wide shift of the deep potential temperature-salinity (θ − S) relationship reflects freshening of both the Indian and Pacific sources of Antarctic Bottom Water. The θ − S curves diverge for waters cooler than −0.1°C, corresponding to a layer up to 1000 m thick over the Antarctic continental slope and rise. Changes over the last decade are in the same direction but more rapid than those observed between the late 1960s and the 1990s. When combined with recent observations of similar freshening of North Atlantic Deep Water, these results demonstrate that dense water formed in both hemispheres is freshening in response to changes in the high latitude freshwater balance and rapidly transmitting the signature of changes in surface climate into the deep ocean.

Gpnmb is induced in macrophages by IFN-gamma and lipopolysaccharide and acts as a feedback regulator of proinflammatory responses.

Abstract: The process of inflammation requires the selective expression of a suite of genes in cells of the macrophage lineage. To identify candidate regulators of inflammation, we used cDNA microarrays to compare the transcriptome of inflammatory macrophages (thioglycolate-elicited peritoneal macrophages), bone marrow-derived macrophages, nonadherent spleen cells, and fibroblasts. We identified genes that were macrophage restricted and further elevated in inflammatory macrophages, and characterized the function of one such gene, gpnmb. Gpnmb mRNA expression was enriched in myelomonocytic cell lines and macrophage-related tissues and strongly up-regulated during macrophage differentiation. Epitope-tagged GPNMB expressed in RAW264.7 cells exhibited a perinuclear distribution and colocalized with the Golgi marker coat protein β. Upon activation of macrophages with IFN-γ and LPS, GPNMB translocated from the Golgi apparatus to vesicular compartments scattered toward the periphery. Gpnmb overexpression in RAW264.7 cells caused a 2-fold reduction in the production of the cytokines IL-6 and IL-12p40 and the inflammatory mediator NO in response to LPS. DBA mice, which have an inactivating point mutation in the gpnmb gene, exhibited reduced numbers of myeloid cells, elevated numbers of thioglycolate-elicited peritoneal macrophages, and higher levels of proinflammatory cytokines in response to LPS. Thus, GPNMB acts as a negative regulator of macrophage inflammatory responses.

Antibiotic-resistant Escherichia coli in wastewaters, surface waters, and oysters from an urban riverine system.

Abstract: The antibiotic resistance (AR) patterns of 462 Escherichia coli isolates from wastewater, surface waters, and oysters were determined. Rates of AR and multiple-AR among isolates from surface water sites adjacent to wastewater treatment plant (WWTP) discharge sites were significantly higher (P < 0.05) than those among other isolates, whereas the rate of AR among isolates from oysters exposed to WWTP discharges was low (<10%).

River Restoration in Victoria, Australia: Change is in the Wind, and None too Soon

Abstract: Stream restoration has become a multibillion dollar industry worldwide, yet there are few clear success stories and the scientific basis for effective stream restoration remains uncertain. We compiled data on completed river restoration projects from four management authorities in Victoria, Australia, to examine how the available data could inform the science of restoration ecology in rivers, and thus improve future restoration efforts. We found that existing data sources are limited and much historical information has been lost through industry restructuring and poor data archiving. Examining records for 2,247 restoration projects, we found that riparian management projects were the most common, followed by bank stabilization and in-stream habitat improvement. Only 14% of the project records indicated that some form of monitoring was carried out. It is evident that overall there is little scientific guidance and little or no monitoring and evaluation of the projects for which we had information. However, recent advances with mandatory, statewide reporting and an increased emphasis on project design and monitoring strongly suggest that the design, implementation, monitoring, and reporting of stream restoration projects have improved in recent years and will continue to do so.

Are exotic natural enemies an effective way of controlling invasive plants

Abstract: Classical biological control (the introduction of exotic natural enemies) is often advocated as a tool for managing invasive species. Here, we review the effectiveness of biocontrol and explore the factors that determine whether it is an appropriate response to the invasive species problem. Although there have been some successes, biocontrol is generally poorly evaluated and, in many cases, its impact is unknown. In particular, there is limited understanding of the nature of the invasive species problem and no clear targets against which 'success' can be gauged. In addition, exotic natural enemies could act as invasive species in their own right. To improve the role of biocontrol in invasive species management, we need a better ecological understanding of the impacts of both the biocontrol agents and the target invasive species.

The effects of ethanol and glycerol on the body and other sensory characteristics of Riesling wines

Abstract: The effect of ethanol and glycerol concentration on the body, sweetness, acidity, aroma and flavour intensity, and perceived viscosity and hotness of three Riesling wines was assessed. The ethanol and glycerol contents of the wines were adjusted by addition to give three realistic levels (5.2, 7.2, 10.2 g/L glycerol and 11.6, 12.6 and 13.6 v/v ethanol). The nine treatment combinations (3 glycerol × 3 ethanol) were rated on the above attributes by a panel of trained tasters. Increased alcohol levels resulted in increased perceived hotness in all wines, and in higher body and perceived viscosity in two of the three wines. The effect of increasing glycerol content was less consistent with only one of each of the three wines showing increased viscosity and body. However, the mean viscosity ratings given to wines with 10 g/L glycerol was higher than at 5 g/L at all alcohol levels and for all wines, suggesting that differences in glycerol concentration typically displayed between dry white table wines can affect their perceived viscosity. Neither alcohol nor glycerol consistently affected sweetness, acidity, aroma or flavour intensity. Higher ratings of the abstract term 'body' were most commonly associated with higher ratings of flavour and/or perceived viscosity, suggesting that for the majority of tasters, these two attributes contributed to their interpretation of the term 'body'. Perceived hotness was not an important component of body, while the role of acidity in body perception was taster dependent.

Role of the Southern Annular Mode (SAM) in Southern Ocean CO 2 uptake

Abstract: A biogeochemical ocean general circulation model, driven with NCEP-R1 and observed atmospheric CO2 history, is used to investigate and quantify the role that the Southern Annular Mode (SAM), identified as the leading mode of climate variability, has in driving interannual variability in Southern Ocean air-sea CO2 fluxes between 1980 and 2000. Our simulations show the Southern Ocean to be a region of decreased CO2 uptake during the positive SAM phase. The SAM induces changes in Southern Ocean CO2 uptake with a 2-month time lag explaining 42% of the variance in the total interannual variability in air-sea CO2 fluxes. Our analysis shows that the response of the Southern Ocean to the SAM is primarily governed by changes in $\Delta$pCO2 (67%), and that this response is driven by changes in ocean physics that control the supply of nutrients to the upper ocean, primarily Dissolved Inorganic Carbon (DIC). The SAM is predicted to become stronger and more positive in response to climate change and our results suggest this will decrease the Southern Ocean CO2 uptake by 0.1 PgC/yr per unit change in the SAM.

The role of type I interferons in TLR responses

Abstract: Recent advances in unravelling the complexities of the signalling pathways that constitute innate immunity have highlighted type I interferon as a key component in the response to infection. Here we focus on the emerging field of pattern-recognition receptor signalling, specifically Toll-like receptors and retinoic acid inducible gene-like helicases, from the perspective of this 50-year-old cytokine. The type I interferon gene family encompasses more than 20 subtypes, whose nature and properties have been extensively studied during its relatively long history. In this review we update and integrate available data on the mechanics of activation of the interferon genes and the role of this cytokine family in the innate immune response.