Monitoring groundcover: an online tool for Australian regions

[摘要] Investments made through the Australian Government’s National Landcare Program aim to improve the condition of Australia’s natural resources. The agricultural components of these programs have mostly focused on improving the condition of the national soil asset by encouraging farmers to adopt land management practices that reduce the risk of soil loss through wind and water erosion, manage soil acidification, and improve the carbon content of their soil.Is the Program having an impact on the condition of the soil resource? This has been a difficult question to answer despite the Program’s significant investment in research to improve monitoring and reporting. Recent advancements in satellite remote sensing have led to the production of datasets depicting vegetation and soil cover for the Australian continent which can be used to monitor and report on wind and water erosion risk. This report presents the results of a project to deliver public online access to a dataset of vegetation and soil cover produced monthly (2001-present) from the MODIS satellite with 500 metres spatial resolution. Specifically, the dataset estimates three cover types: photosynthetic vegetation (PV), non-photosynthetic vegetation (NPV) and bare soil (BS). These three fractions are referred to as “fractional cover”. The sum of PV and NPV equals to Total Vegetation Cover (TVC). In areas with sparse or no tree cover TVC is equivalent to the ground cover (i.e. the vegetation cover in contact with the soil surface). The online tool helps regional natural resource management organisations: 1) view and report on ground cover change for their organisations, 2) plot time-series of mean ground cover for an area, 3) understand the decile ranking of the ground cover level for the month by comparing it to the same month in other years, and 4) understand how many percentage points the ground cover level is above or below the long term mean for each pixel and 4) understand if the ground cover level is normal. The tool can also be used by industries and policy makers to inform them of ground cover change, and will provide the basis for Department of Agriculture and Water Resources’ reporting on improvements in resource condition at the national level. The Australian reporting tool (https://map.geo-rapp.org/#australia) is part of a global online tool for accessing vegetation fractional cover with a spatial resolution of 500 metres. The tool, named Rangeland and Pasture Productivity Map (RaPP Map), provides ready access and the ability to query very large datasets for users without remote sensing or GIS experience. RaPP Map complements other Australian initiatives such as VegMachine© (vegmachine.net) and FarmMap4D Spatial Hub (farmmap4d.com.au), which deliver higher spatial resolution (30 metre) but lower temporal resolution (3 monthly seasonal compilations) of ground cover data to end users.The MODIS fractional cover datasets have been used by the New South Wales Office of Environment and Heritage DustWatch program since 2012 to monitor and report on ground cover change for inland organisations in south eastern Australia at risk of wind erosion. Future developments proposed include: training for natural resource management organisations in the use of the tool, improvements in the tool to facilitate target setting, replacing MODIS-derived products with higher spatial resolution Landsat and Sentinel products, and exploration of whether the effects of antecedent (sum of rainfall over previous months) rainfall on vegetation cover levels can assist in the separation between rainfall and anthropogenic (land management) effects on vegetation cover.The report includes an Appendix with a step-by-step guide to using the current (September 2018) version of the tool to visualise and interrogate vegetation cover and related environmental data.

[发布日期] 2018-11-21 [发布机构] CSIRO

[学科分类] 地球科学(综合)