Introduction
The sub-regional boundaries reflect Interim Biodiversity Regionals of Australia (IBRA) sub-regions and cropping zones in the South West of Western Australia (SWWA) and a range of socio-economic differences (Table 1).
Sub-Regions
The Avon sub-regional boundaries are principally based on major natural topographical divides formed by the Avon River Basin’s river and lake systems. However, these boundaries also have a close relationship to environmental, social and industry boundaries, and boundaries between rainfall and land systems.
Avon Arc
The Avon Arc is characterised by (relative to the rest of the ARB):
- Higher rainfall
- Higher population density
- Rapidly increasing population
- Town economies greatly influenced by services industries
- Land area dominated by agriculture
- Increasing urban and peri-urban land use
- Opportunities for alternative industries
- Early clearing, high level of local extinctions
- Water quality problems and Avon / Swan River impacts
- High-quality land use planning
- Salinity largely stabilised, with the exception of eastern marginal catchments.
Central Wheatbelt
The Central sub-region is characterised by:
- Moderate population density
- Moderate declining population
- Economy reliant on agriculture
- Scattered low-level mining activity
- Muted structural adjustment in agricultural industry leading to increasing economic stress
- Early settlement, high clearing rates, extensive local extinction
- Moderate access to essential social services
- Salinity well developed and continuing throughout.
Eastern Wheatbelt
The Eastern sub-region is characterised by:
- Low population density
- Rapidly declining population throughout 2000–2010
- Limited access to essential social services
- Economy largely dominated by agriculture
- The emerging influence of mining on the local economy
- Ongoing structural adjustment in agricultural enterprises
- Later clearing, moderate clearing rates, important ecological refuges
- Salinity continuing to develop throughout.
Southern Wheatbelt
The Southern Region is characterised by:
- Low population density
- Moderately declining population
- Limited access to essential social services
- Economy dominated by agriculture
- Ongoing structural adjustment in agricultural enterprises
- Very recent clearing, relatively lower clearing rates, important ecological refuges
- Salinity continuing to develop throughout
The Great Western Woodland
The Great Western Woodland is characterised by:
- Limited clearing
- Domination of mining, traditional and conservation land uses
- Significant areas of UCL (83%) open to future change in land use
- Key NRM threats associated with changes to fire management, feral animal control, weed invasion and vegetation disturbance
- Limited largely inactive pastoral leases.