Australian Natural Resources Atlas

Natural Resource Topics

Rangelands Biophysical Resources - Australia

Location map of rangelands in Australia.

Biophysical resources are soil, nutrients, water, plants and wildlife. Information on these resources can be used to assess how well landscapes conserve soils and recycle plant nutrients and how the condition of landscapes is changing.

One of the best ways to see long term changes in the landscape is with historical photographs of the same site through time. Photographic sequences are available for all States and most regions.

Water availability and sustainability

Water resources are a key limiting factor to development, including agricultural enterprise, urban and mining activities. Water use needs to be managed in the context of sustainability-flow regimes for surface water and yield for groundwater.

Water resource characterisation and assessments of use against sustainability criteria are undertaken at irregular intervals, with the last assessment being Australian Water Resources Assessment 2000. See Water Availability in the Atlas navigation menu in the bottom frame.

How has landscape function changed?

Landscape function refers to how well soil and soil nutrients are conserved and how efficiently rain is converted into plant material. Conservation of soil, water and nutrients is the primary objective of sustainable land management. In rangelands, nutrient-cycling concentrates nutrients within patches of perennial plants (trees, shrubs and grasses). 

Loss of perennial plants and destruction of the associated nutrient-enriched patches initiates landscape degradation. In fragile or non-resilient landscapes, degradation may result in catastrophic losses of soil and nutrients, excessive run-off and significant decreases in plant production and rainfall use efficiency - producing a dysfunctional landscape.

Landscape function is assessed using measures of landscape patchiness and rainfall use efficiency. Simply stated, landscapes with many patches of perennial vegetation (perennial grasses or woody plants) will efficiently retain and utilise resources and are 'functional'. Density of woody plants and perennial grass frequency are two common measures of patchiness. At broad scales, vegetation cover is estimated by satellites.

State agencies collect data on landscape function from both ground-based monitoring programs and using remote sensing. For example:

Change in vegetation cover from Landsat satellite data?

Landsat satellite imagery provides information on vegetation response to rainfall and allows an assessment of landscape function. Australia-wide coverage, regular updating and archiving mean that images can be chosen by season and climate history. The images can be used to provide an indirect measure of vegetation cover and change over time. Field verification and the collection of objective data at permanent monitoring sites are required to refine satellite-based interpretations and improve understanding of complex landscape processes. The strength of using remote sensing for monitoring is that image databases consist of objective, consistently processed data, free of value-based interpretation.

Two Audit projects have defined, applied and demonstrated methods for applying Landsat data which has not yet been undertaken at a national level. The following is an example of the outputs for the Stony Plains Bioregion in South Australia. For the full project report, click here [PDF - 1.757MB].

Location map of Stony Plains Bioregion

Satellite image and photograph of Stoney Palins region

Caption: Landsat-derived vegetation cover map at the paddock scale in the Stony Plains bioregion (March 1988). The cover index is calculated from the visible reflectance bands of the Landsat image. Vegetation levels are represented by red (lowest cover) through to orange, yellow, green, light blue and dark blue (highest cover). The location of the photograph is marked by the white square on the image. A uniform cover of bladder saltbush and scattered dead finish occurs on the Gibber plain on the left hand side of the fence, with barley Mitchell grass, feathertop wiregrass and common bottlewashers on the more heavily grazed right hand side of the fence. Grazing by cattle only occurs in this area for short periods when surface water is available. To the right side of the fence, the bladder saltbush has been substantially reduced by intense grazing from sheep and cattle over several decades. The image indicates cover differences, but interpretation of causes and effects on plant communities is provided from other knowledge and ground data.

Change in landscape function from monitoring site data

Monitoring site data variables include vegetation patchiness, woody plant density, frequency of perennial grasses and soil surface condition. The following is an example of one type of data collected in the Kimberleys.

Average change in perennial grass frequency
Vegetation Group Number of Sites Mean frequency Statistical significance
1994-1996 1997-1999
Black Soil Plains 113 74.4 80.7 Significant
Curly Spinifex 69 83.7 85.7 Not significant
Coastal Vegetation 12 86.2 89.2 Not significant
Frontage Grass 13 70.0 75.4 Not significant
Limestone Grass 14 39.9 47.1 Not significant
Northern Ribbongrass 32 88.5 85.7 Not significant
Southern Ribbongrass 64 75.0 76.6 Not significant
Soft Spinifex 23 84.9 86.5 Not significant
All Sites 340 77.3 80.5 Significant
Average crown cover
Black Soil Plains 113 1.8 1.4 Significant
Curly Spinifex 69 13.2 13.8 Not significant
Coastal Vegetation 12 1.0 0.5 Not significant
Frontage Grass 13 7.9 9.3 Not significant
Limestone Grass 14 6.7 4.8 Significant
Northern Ribbongrass 32 12.5 12.5 Not significant
Southern Ribbongrass 64 6.1 5.6 Not significant
Soft Spinifex 23 5.0 7.7 Not significant
All Sites 340 6.6 6.6 Not significant
*Note: Two tailed paired T-Test
Not significant= P>0.05
Caption: Changes in Kimberley grasslands, Western Australia. Average change in perennial grass frequency and average crown cover estimates for all woody species taller than 1m, by vegetation group. Data came from monitoring sites assessed between 1994 and 1996 and reassessed between 1997 and 1999. The frequency of perennial grasses can be used as a broad indicator of landscape function.

Change in landscape function using NOAA satellite data

Normalised Difference Vegetation Index (NDVI) derived from NOAA data provides daily estimates of green vegetation at 1 x 1km resolution. Decreasing trends in minimum NDVI probably indicates decreasing perennial cover. the technique is still developmental but suggests areas where State agencies should direct their ground-based efforts.

Base analysis (trend from 1992-2003)

Map of Base analysis (trend from 1992-1999)

Click here to view map

Link to images of the base NDVI values for individual years (the lowest NDVI value for each pixel for the year):

Change in rainfall use efficiency at broad scales using NOAA satellite data is a direct measure of landscape function. Rainfall use efficiency is the amount of vegetation produced from the annual rainfall on a defined area of land.

Water use efficiency (trend from 1992-1999)

Click here to view map

What are the changes to biodiversity in the Rangelands?

Native vegetation

Most of Australia's rangelands is dominated by native species.

In northern and eastern Australia the dominant vegetation types are eucalypt woodland with a grassy understorey, eucalypt forest and acacia woodland with a grassy understorey and open grasslands. The distribution of forest and woodland is determined by water availability and soil type-little water and low fertility limit the height and density of trees.

In central and central-western Australia the dominant vegetation type is shrubland where acacias, eucalypts and casuarina species dominate the tree layer with a grassy or shrubby understorey. Common plants are the mallee (multi-stemmed eucalypts) and mulga (e.g. Acacia aneura).

Chenopod species including bluebush and saltbush are widespread, particularly across the southern half of the rangelands. The chenopods form communities which are drought- and salt-tolerant and of reasonable palatability to grazing stock. Grasslands are also widely distributed with tussock grasses such as Mitchell grass (common in the central east). Hummock or spinifex grasslands cover large areas of inland Australia and are a dominant understorey layer across vast areas of north-western Australia where acacias and eucalypts form the dominant overstorey.

The benefits of tracking changes in Australia's native vegetation are far from well documented however, the link between vegetation and animal biodiversity is well recognised.

Native fauna

The most substantial changes to rangelands biodiversity have been to mammal fauna. This loss occurred as a rapid response to pastoral settlement. Feral predators have had an impact on fauna in all rangelands environments. Other threatening process include:

  • change in fire regime;
  • weeds;
  • mining;
  • hunting and harvesting;
  • clearing;
  • horticulture;
  • pesticides;
  • changed water regimes; and
  • climate change.

There is currently no operational Australia-wide system for monitoring biodiversity, however, biodiversity monitoring activities are ready to implement and could use existing ground-based sites for vegetation monitoring. Additional sites will be needed to collect information on non-pastoral areas.

The following map is an example of the type of product that can be produced using existing information:

Map of total known and predicted occurence of threatened vertebrate fauna in rangelands

Supporting Information

Long-term photographic records

Photosequences provide a local record of change and are particularly useful as tools for raising awareness. The Rangeland Information System makes available photosequences for many bioregions across the rangelands. Go to photographic sequences.

Regional resource condition assessments

Much of Australia's rangelands has been mapped into land systems or land units using consistent resource inventory techniques. Many of these surveys and pastoral lease inspections include estimates of resource condition based on field traverse by combining estimates of soil erosion and vegetation state. Although the surveys were not designed to be repeated, they provide baselines with which to compare recent change and highlight areas where condition is poor.

Further Information

The Australian Rangelands Information System Operational Manual Version 1.0 (A. Holm, November) (available October 2001) [PDF]

"Developing an analytical framework for monitoring biodiversity in Australian rangelands" (Tropical Savannas CRC 2000):

  • Summary
  • "The Framework" [PDF - 320KB]
  • Background Paper 1 - "A review of changes in status and threatening processes" [PDF - 2MB] and Appendices A & B [PDF -6MB]
  • Background Paper 2 - "A review of pastoral monitoring programs and their real and potential contribution to biodiversity monitoring" [PDF - 1.2MB]
  • Background Paper 3 - "A review of Information gathered from existing biodiversity monitoring programs" [PDF - 663KB]
  • Background Paper 4 - "Approaches to broad-scale monitoring of biological diversity - a brief" [PDF - 131KB]
  • Case Study 1 - "Biodiversity monitoring in Cape York Peninsular" [PDF - 92KB]
  • Case Study 2 - "Biodiversity monitoring in the Gascoyne-Murchison Strategy area" [PDF - 243KB]
  • Manual for biodiversity monitoring [PDF - 124KB]

"Indices of change in ecosystem function (cover) for northern South Australia using Landsat TM data" report (by A.Brook, R.Tynan & M.Flemming, 2001) [PDF - 1.7MB]

"Regional land condition and trend assessment in Tropical Savannas" report (by R. Karfs, R. Applegate, R. Fisher, D. Lynch, D. Mullin, P. Novelly, L. Peel, K. Richardson, P. Thomas & J. Wallace, 2000):

"Indices of change in ecosystem function at the national scale using AVHRR NDVI data" report (by S.Cridland, 2000) [PDF - 380KB]

The EPBC Protected Matters Search Tool provides information on threatened, marine protected or migratory species, Ramsar sites, Commonwealth areas, and World Heritage Areas for any nominated area in Australia.

"Ecosystem function analysis of rangelands monitoring data" report (by D. Tongway & N.Hindley, 1999) [PDF - 166KB] and Summary

Homepage of Birds Australia

Homepage of Australian Biological Resources Study

Homepage of The Australian National Insect Collection

Homepage of State of the Environment

Link to Map maker to make a map using this information.

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