The Great Western Woodlands (GWW) comprises a 16-million hectare mosaic of temperate woodland, heathland and mallee vegetation in south-west Western Australia. It is the largest remaining intact temperate or 'Mediterranean' woodland in the world and is unique in being able to survive on as little as 250 mm annual rainfall. The Supersite site comprises a mosaic of temperate woodland, healthland and Mallee vegetation.
The region has remained relatively intact since European settlement, owing to the variable rainfall and lack of readily accessible groundwater. Other temperate woodlands around the world have become highly fragmented and degraded through agricultural use.
The GWWL thus provides a unique opportunity to study how semi-arid woodland ecosystems function at site and landscape scales, and how naturally functioning, intact ecosystems can adapt to climate change. The woodlands also offer significant potential to inform climate-resilient restoration of the Western Australian wheatbelt.
On January 21, 2014 a storm at Credo delivered 130 mm of rain in one event, equivalent to about half of the average annual rainfall. The event also filled the usually dry, fresh-water lakes on Credo to 4.5 m depth (see above). See the phenocam images from the flux tower here .
Key research questions
The key research questions in the GWW relate to the impacts of climate change and management on the fundamental flows of energy, carbon, water and nutrient stocks, and on biodiversity, in semi-arid woodland ecosystems nationally and globally.
- Are old-growth semi-arid woodlands carbon sources or carbon sinks?
- Where do woodland eucalypts obtain their water from?
- How do topographic mosaics regulate floristic composition and provide resilience to climate change?
- What are the ecological determinants of the Menzies line (the striking boundary between the GWW and mulga) and will it shift under climate change?
TERN SuperSites core 1 ha
The SuperSites core 1 ha (100 m x 100 m) is located within the fetch of the flux tower and is the focal site of recurrent monitoring.
Permanently marked plots at the GWWL SuperSite
TERN AusPlots sites in the GWW SuperSite (Credo)
There are nine AusPlots sites in the GWW SuperSite within the Credo Proposed Conservation Reserve. These sites are of particular value to the Department of Parks and Wildlife WA, that surveyed similar localities back in the 1980s for the Goldfields Regional Survey. Birdlife Australia has carried out bi-annual bird surveys at these plots and a subset have had equipment installed (acoustic recorders, dendrometers and litter fall traps) to complement other measures of woodland dynamics.
There are six AusPlots sites within the OzFlux tower footprint, located in the key woodland types on Credo Proposed Conservation Reserve:
|WAA COO 0020||Eucalyptus salmonophloia||Salmon gum plot (Core 1 ha)|
|WAA COO 0021||Eucalyptus salubris||Gimlet plot|
|WAA COO 0022||Eucalyptus clelandii||Blackbutt plot|
|WAA COO 0023||Eucalyptus transcontinentalis||Redwood plot|
|WAA COO 0024||Acacia incurvaneura and A. caesaneura||Mulga plot|
|WAA COO 0025||Atriplex nummularia, A vesicaria, & Maireana sedifolia||Chenopod plot|
These plots are being monitored on an ongoing basis.
Three additional AusPlots on Credo outside the flux tower footprint include:
|WAGCOO0001||Salmon gum woodland|
|WAGCOO0002||Eucalyptus oldfieldii Mallee shrub land|
|WAGCOO0004||Chenopod shrub land|
TERN Australian Transect Network plots at the GWW SuperSite
The TERN South West Australian Transitional Transect (SWATT) intersects the GWW SuperSite in the Sandplains region with a series of plots marked and surveyed.
AusPlots and Transect monitoring data will be available through TERN’s Eco-informatics facility, which manage the data using its ÆKOS data repository. The data will also be available through the Soils 2 Satellite portal and the WA Government's NatureMap .
SWATT data can be accessed via TERN's AEKOS Data Portal at www.aekos.org.au/collection/wa.gov.au/swatt
2013 AusPlot data for the Great Western Woodlands Supersite can be found at: www.aekos.org.au/home- then search for ‘Credo’ (for six plots around the GWW Flux tower) or ‘Great Western Woodlands’ (for plots in the broader GWW Supersite).
Other permanently marked plots at the GWW SuperSite
Salmon gum - Wheatbelt woodlands
Permanently marked 20 x 20 m plots have also been established by Judith Harvey for a Master's by Research study looking at the floristic patterns in Salmon gum (Eucalyptus salmonophloia) woodlands. Results indicate five main floristic communities including two in the Great Western Woodlands, two in the adjacent WA wheatbelt and one community that overlaps the two regions. This adds weight to calls for greater protection of the highly cleared Salmon gum woodlands in the wheatbelt.
Gimlet Fire-age plots
A set of around 70 sites within the Gimlet woodlands has been used to study how fire shapes vegetation composition and diversity. The study involved selecting plots that were last burnt between about five to 400-plus years ago, estimated using satellite imagery, tree rings and allometric relationships. A range of characteristics have so far been compared across the plots (plant composition and diversity, litter and fire fuels, woodland structure and ant composition). One of the findings from this study was that fuel availability peaked at intermediate time since fire (about 35-150 years) suggesting a bottleneck of higher fire flammability before the development of mature woodlands.
Further summaries can be found at:
Gosper C, Yates CJ, Prober SM. 2013. Changes in plant diversity and vegetation composition with time-since-fire in Gimlet woodlands . Information Sheet 68/2013 Department of Environment and Conservation, Science Division.
Gosper C, Yates CJ, Prober SM, Wiehl G. 2013. Ageing long-unburnt Gimlet woodlands . Information Sheet 65/2013 Department of Environment and Conservation, Science Division.
Nutrient Network plots
The GWWL supersite includes 40 plots that form part of the global Nutrient Network experiment to understand the role of global change drivers (nutrients and herbivores) on ecosystem dynamics. These are located at Mt Caroline on the wheatbelt side of the GWWL Supersite, and have been monitored annually since 2008. They are contributing to global tests of ecological theory such as the role of diversity in ecological stability and the relationship between productivity and diversity.
TERN AusCover activities at the GWWL SuperSite
AusCover has run airborne LiDAR and hyperspectral campaigns at Credo station with ground calibration with SLATS star transects, leaf sampling, tree structure and LAI measures. Phenocams are installed on the flux tower to Integrate flux measurements and phenology to understand the impacts of climate change on Australian landscapes.
Slideshare presentation : Phenocam Network: Australian Phenology Product Validation: Phenocam Network. 2014. K. Davies, M. Liddell, N. Weiand, C. Macfarlane, J. Byrne, V. R. des Dios, M. Boer, C. Maeir, N. Boulain, J. Cleverly, D. Eamus, G. Koerber, W. S. Meyer.
TERN eMAST activities at the GWWL SuperSite
Plant ecophysiological measurements are being collected across a number of the TERN SuperSites including GWW by Owen Atkin's team (ANU) in a collaboration with TERN's eMAST facility. The aim is to look at ecosystem hydrology, net CO2 exchange and primary productivity in wet/dry and winter/summer.
Slideshare presentation : Plant ecophysiological measurements at TERN SuperSites. 2013. O. Atkin, K. Bloomfield, L. Weerasinghe.
TERN OzFlux at the GWWL SuperSite
OzFlux maintains the flux tower instrumentation that continuously measures exchanges of carbon dioxide, water vapour and energy between the terrestrial ecosystem and atmosphere.
Flux data is available from the OzFlux data portal.
Part of the responsibilities of running a flux tower is ensuring tower rescue skills are kept up to date.
WA Department of Parks and Wildlife collaboration
The Western Australian Department of Parks and Wildlife (DPaW) manage the Credo Proposed Conservation Reserve and Credo site facilities, including the Field Studies Centre and accommodation on site. DPaW are collaborators on a range of projects including:
- Pathways to weed invasion in the Great Western Woodlands - An analysis of pathways to weed invasion into the GWW given rapidly increasing mineral exploration, mining and tourism, altered fire regimes and climate change.
- Fire regimes and effects of fire in gimlet (Eucalyptus salubris) woodlands - A study of the response of plant species composition, diversity and vegetation structure to fire in ‘fire-sensitive’ Mediterranean-climate woodlands to inform natural resource management in the GWW.
- Flora and vegetation of Credo Station - A study on the floristic patterns of the greenstone ranges and the major habitats on Credo Station.
- Forrestania Fire Mosaic project - A study using visual fuel assessments and quantitative structural measurements in Gimlet woodlands to better predict the consequences of fires on biodiversity conservation and the protection of human lives and assets.
- Climate-resilient revegetation of multi-use landscapes: exploiting genetic variability in widespread species - A study examining patterns of climate adaptation in widespread Eucalyptus species relevant to re-vegetation of multi-use landscapes, including populations of E. salubris from throughout the WA wheatbelt and Great Western Woodlands.
Postgraduate Projects and Post-docs associated with the GWW SuperSite
- Henrique Togashi, Macquarie University (Supervised by Colin Prentice). Improving the representation of plant carbon and water use in ecosystem models with measurements from contrasting environments.
- Keren Raiter, University of Western Australia (Supervised by Richard Hobbs and Hugh Possingham). The cryptic and the cumulative: migrating regional ecological impacts of mining and exploration in SW Australia's Great Western Woodlands.
- Judith Harvey, Curtin University (Supervised by Laco Mucina and Suzanne Prober). Environmental controls of floristic variation and vegetation structure in salmon gum woodlands of the GWW.
- Dr Natalia Restrepo, Prof Alfredo Huete, University of Technology Sydney. Integrating remote sensing, landscape flux measurements, and phenology to understand the impacts of climate change on Australian landscapes.
Presentations on the GWW SuperSite:
The Great Western Woodlands SuperSite in Western Australia
S. Prober, C. Macfarlane, R. Silberstein, K. Thiele, S. van Leeuwn, C. Yates, M. Byrne, G. Cook, C. Gosper, J. Harvey, I. Kealley, A. Liedloff, K. Raiter.
Multi-century changes in plant diversity and composition after fire in Eucalyptus salubris communities of the Great Western Woodlands .
C. Gosper, S. Prober, C. Yates.
- Climate-resilient revegetation of multi-use landscapes: exploiting genetic variability in widespread species
- Fire regimes and effects of fire in gimlet (Eucalyptus salubris) woodlands
- Flora and vegetation of Credo Station
- Forrestania Fire Mosaic project
- Modelling tree growth in a semi-arid woodland ecosystem
- Pathways to weed invasion in the Great Western Woodlands
- Phenology Validation
- Plant Physiology Campaign - TERN Australian Supersites
- Regional variability in Salmon Gum woodlands in the GWW
- Terrestrial Ecosystem Research Network Acoustic Sensing
- The cryptic and the cumulative: mitigating regional ecological impacts of mining and exploration in south-western Australia’s Great Western Woodlands
- Tracking change and trend in vegetation condition at selected sites on Credo station, Great Western Woodlands
For more on GWWL research: www.greatwesternwoodlands.org.au/