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| April 2006 | National Research Flagship | www.csiro.au/healthycountry/ |
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| April 2006 | National Research Flagship | www.csiro.au/healthycountry/ |
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Giving revegetation strategies the edge
Revegetation to counter land degradation has been taking place for some years with mixed success. State and regional agencies are now planning large-scale revegetation programs. In Victoria, for example, over a million hectares have been targeted for revegetation over the next 20 years. Better access to incentive schemes, equipment and expertise is also encouraging landowners to revegetate less productive land. Revegetation has traditionally been seen as 'people planting trees'. The landscape was not recognised as a complex system that relied on more than just trees for its success. Water for a Healthy Country Flagship is taking revegetation one step further and looking at the whole system – plants and animals, soils and water – so that revegetation is a whole process improving water availability and quality across catchments. Seeding rather than planting Re-planting areas cleared of native vegetation is critical to addressing dryland salinity and biodiversity loss on farm land. Peter Thrall (CSIRO Plant Industry) and colleagues in collaboration with DPI Victoria and the North Central Catchment Management Authority have demonstrated that growing wattles with the soil bacterium, Bradyrhizobium, significantly improves their survival and growth rates. A major output from this research has been the commercialisation of an inoculant for use with native wattles (Wattle Grow, Becker Underwood Pty Ltd). Non-host plants, such as eucalypts, also benefit from growing in association with wattles, because of the increased nitrogen inputs to the soil. As part of a National Action Plan for Salinity and Water Quality (NAP) project, the team are also hoping to identify salt tolerant Bradyrhizobium strains that, when coupled with salt tolerant wattles, produce tress that perform better in saline conditions. Early results show considerable variation in the salt tolerance of Bradyrhizobium strains. Together with DPI Victoria and several of the Catchment Management Authorities located in NAP priority regions in Victoria (North Central, Glenelg-Hopkins, Mallee and Goulburn Broken), large-scale direct-seeding trials will be established in 2006 to evaluate the nitrogen-fixing capability and potential for salt-tolerant strains of Bradyrhizobium to increase plant establishment in saline soils. The knowledge gained through these projects will benefit revegetation programs, providing a sustainable solution to major environmental problems associated with the loss of native vegetation. Invertebrates Invertebrates play a crucial role in plant life by providing pollination, nutrient and water cycling, pest control and soil health services – essential processes for the structural and functional integrity of the landscape. Revegetation strategies that encourage the colonisation of a diverse and abundant invertebrate fauna will lead to better plant establishment, greater biodiversity and greater prospects for sustainability. The Flagship team is examining a number of invertebrate-mediated processes in revegetated and remnant vegetation in agricultural landscapes, including:
Saul Cunningham (CSIRO Entomology) and his team are examining whether insect damage may make eucalypts 'leaky', thereby reducing their capacity and efficiency as water pumps in potentially saline areas. The project will first quantify the effect and, if it is deemed significant, will devise management solutions that reduce rates of herbivore damage. Acacias have a pioneering role in colonising degraded sites. It is thought that their generation of nitrogen, together with carbon and nutrients in their leaf litter, are significant factors in speeding up colonisation. Saul and fellow-entomologist Matt Colloff are comparing diversity of insects in soil, litter and on foliage at revegetation sites of different ages, with and without acacias, to gain insights into how much difference these plants make. The soils of many revegetation sites have been significantly altered since they were originally cleared. Matt and his team are examining the role of soil insects as ecosystem 'engineers' to determine:
These research
activities represent a holistic, complementary approach to putting science
and design into revegetation strategies. This work is undertaken in
collaboration with landowners and revegetation practitioners from State
Agencies (e.g. Department of Primary Industries, Victoria), community groups
and NGOs (e.g. Greening Australia) and supports the implementation of
initiatives such as the Natural Heritage Trust and the National Action Plan
for Salinity and Water Quality.
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IN THIS EDITION:
Building a Water Resources Observation Network Science supporting the Living Murray Giving revegetation strategies the edge Real-time monitoring helps irrigators to be water wise Determining requirements for managed aquifer recharge in WA Assessing land condition and sediment delivery in Great Barrier Reef catchments A community creating its future options WaterSmart Irrigation in the Murray Meet some scientists from the Water for a Healthy Country Flagship Meet some students from the Water for a Healthy Country Flagship |
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Water for a Healthy
Country Flagship |
Phone: +61 02 6246 4565 Fax: +61 03 6246 4564 | editor.healthycountry@csiro.au www.csiro.au/healthycountry/ |
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Land
clearing and loss of vegetation have significant impact on water quality and
availability in a landscape. Plants and invertebrates both play an important
role in filtering water running into watercourses, helping to retain water
in a profile, reducing run-off and improving soil health. This research is
providing the science needed to maximise the effectiveness of revegetation
programs and developing holistic, complementary approaches that support the
design and implementation of revegetation programs.
