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?
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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].
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.
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.
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What are the changes to biodiversity in the Rangelands?
Native vegetation
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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.
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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:
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Supporting Information
Long-term photographic records
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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.
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Regional resource condition assessments
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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.
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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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Newsletter
What's new
New 'Land Use of Australia, Version 3' data showing irrigation, agriculture and landuse for the years 1992, 1993, 1996, 1998, 2000 and 2001 have been added to the Map Maker.
More on land use data....
Australian Water Resources 2005 data has been added to the Map Maker.
More on the water data...
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