http://hdl.handle.net/10453/24 2013-05-25T03:14:01Z http://hdl.handle.net/10453/19431 Innovations in Institutions to Improve Weed Funding, Strategy and Outcomes Martin Paul; Verbeek Miriam; Riley Sophie; Bartel Robyn; Le Gal Elodie In spite of much public and private effort, expenditure and creativity, reports show that the economic and environmental cost of weeds in Australia continues to grow. Australians face the sustainability challenges of a large and bio-diverse country, major resource exploitation industries, and a relatively small pool of funds and human resources to provide for protection and restoration. To effectively manage these combined challenges and ensure the sustainability of the Australian environment and equitable outcomes for Australians in general, Australians need to create legal, social, managerial and economic strategies that are far more effective than those used to date. To do so requires institutional as well as technological innovation. There has been increasing recognition over the past couple of decades that approaches to weed management must include better processes, particularly in engaging people in solutions, as well as more effective application of biophysical and social science. Weeds arrive in Australia and, in large part, continue to spread in Australia because of the activities of people. 2012-01-01T00:00:00Z http://hdl.handle.net/10453/18221 Linking soil O2, CO2, and CH4 concentrations in a wetland soil: Implications for CO2 and CH4 fluxes Elberling Bo; Askaer Louise; Jã¸Rgensen Christian; Joensen Hans; Kuhl Michael; Glud Ronnie; Lauritsen Frants Oxygen (O2) availability and diffusivity in wetlands are controlling factors for the production and consumption of both carbon dioxide (CO2) and methane (CH4) in the subsoil and thereby potential emission of these greenhouse gases to the atmosphere. To examine the linkage between highresolution spatiotemporal trends in O2 availability and CH4/CO2 dynamics in situ, we compare high-resolution subsurface O2 concentrations, weekly measurements of subsurface CH4/CO2 concentrations and near continuous flux measurements of CO2 and CH4. Detailed 2-D distributions of O2 concentrations and depth-profiles of CO2 and CH4 were measured in the laboratory during flooding of soil columns using a combination of planar O2 optodes and membrane inlet mass spectrometry. Microsensors were used to assess apparent diffusivity under both field and laboratory conditions. Gas concentration profiles were analyzed with a diffusion-reaction model for quantifying production/ consumption profiles of O2, CO2, and CH4. In drained conditions, O2 consumption exceeded CO2 production, indicating CO2 dissolution in the remaining water-filled pockets. CH4 emissions were negligible when the oxic zone was >40 cm and CH4 was presumably consumed below the depth of detectable O2. In flooded conditions, O2 was transported by other mechanisms than simple diffusion in the aqueous phase. This work demonstrates the importance of changes in near-surface apparent diffusivity, microscale O2 dynamics, as well as gas transport via aerenchymous plants tissue on soil gas dynamics and greenhouse gas emissions following marked changes in water level. 2011-01-01T00:00:00Z http://hdl.handle.net/10453/18220 High nutrient transport and cycling potential revealed in the microbial metagenome of Australian sea lion (Neophoca cinerea) Faeces Lavery Trish; Roudnew Ben; Seymour Justin; Mitchell James; Jeffries Thomas Metagenomic analysis was used to examine the taxonomic diversity and metabolic potential of an Australian sea lion (Neophoca cinerea) gut microbiome. Bacteria comprised 98% of classifiable sequences and of these matches to Firmicutes (80%) were dominant, with Proteobacteria and Actinobacteria representing 8% and 2% of matches respectively. The relative proportion of Firmicutes (80%) to Bacteriodetes (2%) is similar to that in previous studies of obese humans and obese mice, suggesting the gut microbiome may confer a predisposition towards the excess body fat that is needed for thermoregulation within the cold oceanic habitats foraged by Australian sea lions. Core metabolic functions, including carbohydrate utilisation (14%), protein metabolism (9%) and DNA metabolism (7%) dominated the metagenome, but in comparison to human and fish gut microbiomes there was a significantly higher proportion of genes involved in phosphorus metabolism (2.4%) and iron scavenging mechanisms (1%). When sea lions defecate at sea, the relatively high nutrient metabolism potential of bacteria in their faeces may accelerate the dissolution of nutrients from faecal particles, enhancing their persistence in the euphotic zone where they are available to stimulate marine production. 2012-01-01T00:00:00Z http://hdl.handle.net/10453/18210 Oocysts and high seroprevalence of Neospora caninum in dogs living in remote Aboriginal communities and wild dogs in Australia King Jess; Brown Graeme; Jenkins David; Ellis John; Fleming Peter; Windsor Peter; Slapeta Jan Canines are definitive hosts of Neospora caninum (Apicomplexa). For horizontal transmission from canines to occur, viable oocysts of N. caninum must occur in the environment of susceptible intermediate hosts. Canids in Australia include wild dogs and Aboriginal community dogs. Wild dogs are those dogs that are not dependent on humans for survival and consist of the dingo, feral domestic dog and their hybrid genotypes. Aboriginal community dogs are dependent on humans, domesticated and owned by a family, but are free-roaming and have free access throughout the community. In this study the extent of N. caninum infection was determined in a total of 374 dogs (75 wild dogs and 299 Aboriginal community dogs) using a combination of microscopic, molecular and serological techniques. Oocysts of N. caninum were observed in the faeces of two juvenile Aboriginal community dogs (2/132; 1.5%). To estimate N. caninum prevalence, a new optimised cut-off of 18.5% inhibition for a commercial competitive ELISA was calculated using a two-graph receiver-operating characteristic (TG-ROC) analysis and IFAT as the gold standard resulting in equal sensitivity and specificity of 67.8%. Of the 263 dog sera tested the true prevalence of N. caninum antibodies was 27.0% (95% confidence limit: 10.3-44.1%). The association between the competitive ELISA results in dogs less than 12 month old and older dogs was significant (P=0.042). To our knowledge this is the first large scale parasitological survey of the Aboriginal community dogs and wild dogs from Australia. The high prevalence of N. canilium infection in Aboriginal community dogs illustrates that horizontal transmission of N. caninum is occurring in Australia. These results demonstrated that N. caninum in dogs is widespread, including the semi-arid to arid regions of north-western New South Wales and the Northern Territory. The populations of free-ranging dogs are likely to be important contributors to the sylvatic life cycle of N. caninum. 2012-01-01T00:00:00Z