Sensing vegetation remotely

All governments, agri-businesses and local communities utilise natural resource information to improve their understanding of environmental impacts and trade-offs needed to optimise productivity and achieve sustainable resource use. Use of data about the occurrence, condition and use of natural resources is pervasive throughout these activities. A relatively large range of botanical, biological, physical, cultural and other data about native vegetation can be collected and mapped. To help make the survey, mapping, monitoring and management of vegetation more efficient and cost-effective, a number of innovative techniques have been developed. For example, mapping the extent of native vegetation at the catchment and regional level can be done using a combination of data collected from ground-based activities and remote sources such as aircraft and satellites 184 (Figure 10).

The Land Monitor 185 initiative is an example of how remotely-sensed data can support vegetation management at a catchment scale. Land Monitor is being used to map and monitor changes in the area of salt-affected land, and to predict areas at risk from future salinisation. The initiative monitors changes in the amount and quality of remnant vegetation and areas of revegetation using satellite imagery, digital elevation models of a catchment, and other useful environmental data (Figure 11). Trends in vegetation condition and salinity can be determined using the time-series data collected.

Remotely-sensed data such as the satellite imagery used in the Land Monitor initiative and other spatial environmental data can usually be obtained from the State and Territory agencies who provide vegetation maps (Table 6). If such agencies do not hold these data then they can provide advice about how to obtain them for your region. In Victoria, a ‘Land Channel’ facility 186 provides access to a range of satellite imagery and environmental data on catchments in digital format. These datasets can be loaded into a laptop computer using GIS (geographic information system) software to generate catchment or paddock scale maps and spatial analyses 187. ArcView and associated software are commonly used for storing, analysing and presenting data on vegetation. The Australian Centre for Remote Sensing 188 (part of Geoscience Australia) provides a range of satellite imagery and environmental data that can be useful for managing vegetation at the catchment level. Very high resolution satellite imagery (around 1 metre) is now also available and can be obtained from two distributors 189,  190.

	Action: 2.9
	Examine information and reports on the use of satellite imagery and other technologies that can be used to improve understanding of the extent and condition of native vegetation at the catchment level; see http://www.nasa.gov
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Figure 10: Example of remote-sensing and ground-based survey applications in vegetation mapping. At the top, a (MODIS) satellite image for a catchment is used to investigate the role that native vegetation surrounding a homestead plays in conservation. A higher resolution (IKONOS) satellite image is used to further examine the area, then both images are used to create detailed vegetation maps to support on-ground restoration and monitoring activities.



Source: Reinke, R., Gibbons, P., Zerger, A., Jones, S. D., (2004) Monitoring Australian Native Vegetation Condition Using Multi-Sensor Earth Observations, The 12th Australasian Remote Sensing and Photogrammetry Conference, Fremantle, Western Australia, 18–22 October 2004

Figure 11: Example of a map created using the Land Monitor approach showing changes in the condition of vegetated areas over time.



Source: “Supplied by SRSS, DLI for the Land Monitor project. The information contained in this vegetation map is necessarily based in part upon various assumptions and predictions. The Land Monitor Project accepts no responsibility for any inaccuracies in this vegetation map and persons relying on this salinity map do so at their own risk. Visit http://www.landmonitor.wa.gov.au”

Surveying vegetation

A range of techniques can be employed for surveying vegetation. The State and Territory agencies providing vegetation maps typically include information on the field survey methods that were used to create these maps, and can provide information and advice on vegetation survey. State and Territory herbaria, and bodies such as catchment management authorities have professional staff who can also provide up-to-date advice on vegetation survey.

Recently a number of survey techniques, at a number of scales, have been summarised in the report Biodiversity Monitoring in the Rangelands 191. Those relevant to native vegetation included photo points, plot-based and transect surveys, airborne photography and satellite mapping. Key issues identified for planning biodiversity monitoring systems are: management applications, scale (reporting, inference), cost-effectiveness and efficiency, surrogacy and usefulness, power of message, stage or readiness, applicability to different tenures and environments, and sensitivity (time and thresholds). Monitoring techniques were assessed for their value in measuring a wide range of pressures, such as weeds, fire and grazing, and the biotic responses of plants, ecosystem attributes and selected fauna to landscape change.

	Action: 2.10
	Learn more about survey techniques and their application by reading Biodiversity Monitoring in the Rangelands. The approaches described can be used in all NRM regions, with some modification.
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