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McCaskill M.R.,Jobs | Kearney G.A.,36 Paynes Road
Crop and Pasture Science | Year: 2016

Temperate pastures that leak water below the root zone have been linked to an increase in dryland salinity in southern Australia through their conservative use of stored water. An experiment was conducted at Hamilton in south-western Victoria to test the hypothesis that deep-rooted, summer-active perennial pasture species can substantially reduce leakage. On topographic crests the experiment compared lucerne and chicory with a traditional perennial ryegrass variety with low summer activity, whereas on the poorly drained valleys the comparison was between tall fescue, kikuyu and a perennial ryegrass variety with high summer activity. Lucerne developed a buffer of dry soil to a depth of at least 5m. An empirical relationship with June-September rainfall indicated that with this dry buffer, leakage below the root zone would not occur even in the wettest of years. Chicory developed a dry buffer to the depth of measurement (3m), but plant density gradually declined and leakage started to occur 5 years after sowing. The perennial ryegrass with low summer activity had leakage nearly every year. On the valleys kikuyu was initially the most effective at drying the soil in summer, but its density declined at the expense of annuals and 3 years after sowing it became wetter than the other treatments. None of the pasture options on the valley fully controlled leakage, but both the summer-active perennial ryegrass and tall fescue were persistent and there was little difference in their capacity to extract summer moisture. This study showed that four characteristics were associated with a pasture that controlled leakage - summer activity, persistence, adequate density and deep rootedness. Of the species tested only lucerne satisfied all these criteria. © CSIRO 2016. Source


Dodd A.J.,University of Melbourne | McCarthy M.A.,University of Melbourne | Ainsworth N.,Jobs | Burgman M.A.,University of Melbourne
Biological Invasions | Year: 2016

The early detection of newly naturalised alien species is vital to ensuring the greatest chance of their successful eradication. Understanding where species naturalise most frequently is the first stage in allocating surveillance effort. Using Australia’s Virtual Herbarium, we compiled the collection records for all plant species in Australia. We controlled for potential spatial biases in collection effort to identify areas that have an elevated rate of first records of alien species’ occurrence in Australia. Collection effort was highly variable across Australia, but the most intense collection effort occurred either close to herbaria (located in cities) or in remote natural environments. Significant clusters of first records of occurrence were identified around each state’s capital city, coinciding with higher collection effort. Using Poisson point process modelling, we were able to determine the relative influence of environmental and anthropogenic factors on the spatial variation in the risk of species naturalisation. Effort-corrected naturalisation risk appeared to be strongly related to land use, road and human population densities, as well as environmental factors such as average temperature and rainfall. Our paper illustrates how the risk of naturalisation at a location can be estimated quantitatively. Improved understanding of factors that contribute to naturalisation risk enhances allocation of surveillance effort, thereby detecting novel species sooner, and increasing the likelihood of their eventual eradication. © 2015, Her Majesty the Queen in Right of Australia as represented by: Sally Salmon. Source


Black H.,James Hutton Institute | Mele P.,Jobs
IOP Conference Series: Earth and Environmental Science | Year: 2015

Our interests in soil change are moving away from soil properties and increasingly towards changes in the processes and functioning of soils. Soil organisms are fundamental to dynamics and change in soils through their fundamental role in soil processes [1]. However it is only with recent technical and theoretical advances that we have started to establish quantitative relationships between soil biology and soil change (c.f. [2]). It is this predictive understanding that will enable us to fully integrate soil biology into the effective monitoring and sustainable management of soils. This paper outlines some of the recent advances in soil biology and discusses their relevance to monitoring and management. © Published under licence by IOP Publishing Ltd. Source


Boyd D.,Jobs
IOP Conference Series: Earth and Environmental Science | Year: 2015

The 'Risk management through soil moisture monitoring' project has demonstrated the capability of current technology to remotely monitor and communicate real time soil moisture data. The project investigated whether capacitance probes would assist making informed pre- and in-crop decisions. Crop potential and cropping inputs are increasingly being subject to greater instability and uncertainty due to seasonal variability. In a targeted survey of those who received regular correspondence from the Department of Primary Industries it was found that i) 50% of the audience found the information generated relevant for them and less than 10% indicted with was not relevant; ii) 85% have improved their knowledge/ability to assess soil moisture compared to prior to the project, with the most used indicator of soil moisture still being rain fall records; and iii) 100% have indicated they will continue to use some form of the technology to monitor soil moisture levels in the future. It is hoped that continued access to this information will assist informed input decisions. This will minimise inputs in low decile years with a low soil moisture base and maximise yield potential in more favourable conditions based on soil moisture and positive seasonal forecasts © Published under licence by IOP Publishing Ltd. Source


Dodd A.J.,University of Melbourne | Burgman M.A.,University of Melbourne | Mccarthy M.A.,University of Melbourne | Ainsworth N.,Jobs
Diversity and Distributions | Year: 2015

Aim: To identify the temporal patterns of plant naturalization in Australia, particularly the interaction between taxonomy, geographic origin and economic use. Location: Australia. Methods: From Australia's Virtual Herbarium, we compiled a database of information for the entire naturalized flora of Australia. We then examined the database in discrete time intervals to determine the changes in patterns of naturalized species taxonomy, geographic origin and economic use over time. Results: Contrary to prevailing hypotheses, we found no evidence to indicate that the rate of alien flora naturalization is increasing in Australia. The number of naturalized species has grown linearly during the period 1880-2000, with the underlying rate of new species detected per thousand specimens declining over the same time period. Despite this, the diversity of both species taxonomy and geographic origin has increased over the last 120 years, leading to increased rates of growth in the total phylogenetic diversity of the Australian flora. Main Conclusions: By classifying species according to their likely origin and economic use, we are able to infer the circumstances driving the patterns of naturalization. In particular, we identify how the contribution of individual pathways has changed since European settlement corresponding with the socio-economic development of the continent. Our study illustrates how the changing nature of 'high-risk' pathways is relevant to directing interventions such as biosecurity regulation. © 2015 John Wiley & Sons Ltd. Source

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