Whicher 1 Bio-landscape

Posted on Dec 23, 2014


Whicher 1 bio-landscapeTerrestialBiodiversity

Priority Bio-landscapes were identified across the region in the 2009 Biodiversity Sub-strategy. A 5 km by 5 km grid was placed across the region and those landscapes that had the highest concentrations of biodiversity value within the region were identified. Those landscapes that were identified as having a combination of high rarity for flora/fauna/communities and vegetation associations were classified as Highest Priority bio-landscapes. Those that were identified as having high rarity for flora/fauna/communities but the vegetation associations within them were not rare were classified as Second Priority Bio-landscapes. The full report can be read here: 2009 Biodiversity Sub-Strategy

The Whicher 1 bio-landscape is found to the south of Busselton, within the City of Busselton and within the Geographe Bay catchment. It is located on the southern Swan Coastal Plain and at the foothills of the Whicher Scarp.

The Whicher 1 bio-landscape is identified as a high priority bio-landscape within the 2009 Biodiversity Sub-strategy due to the presence of rare vegetation associations as well as high rarity for flora, fauna and ecological communities.

Two rivers flow through this bio-landscape being the Vasse and Sabina Rivers and one reserve is found here being the Fish Road Nature Reserve. All vegetation within this bio-landscape is fragmented with large amounts of clearing having occurred in the past for the development of agriculture. Remnant vegetation remaining along the rivers, roadsides and private property perform very important landscape functions as stepping stones within regionally important and locally important ecological linkages. Vegetation along the Vasse River has been identified as being an important regional ecological linkage, providing landscape connections from the Vasse-Wonnerup wetlands and coast to the State Forest of the Whicher Scarp.

Due to the high level of clearing of the Swan Coastal Plain in the past, two of the vegetation associations present are well under-represented with there being less than 10% remaining of the Pinjarra 1136 vegetation association and  10-30% remaining of the Pinjarra 949 vegetation association.

Additionally, there are a number of threatened ecological communities located within this bio-landscape, including;

  • SCP07 – Herb rich saline shrublands in clay pans (part of the Critically Endangered Commonwealth listed Clay pans on the Swan Coastal Plain)
  • SCP10a – Shrublands on dry clay flats (part of the Critically Endangered Commonwealth listed Clay pans on the Swan Coastal Plain)
  • SCP02 – Southern wet shrublands – Swan Coastal Plain (Endangered)
  • SCP1a – Eucalyptus haematoxylonEucalyptus marginata woodlands on Whicher foothills (Priority 3)
  • SCP 1b – Eucalyptus calophylla woodlands on heavy soils of the southern Swan Coastal Plain (Vulnerable)
  • Whicher A1 – Central Whicher Scarp Mountain Marri woodland (Priority 1)
  • Whicher Scarp C1 – Central Whicher Scarp Jarrah woodland (Priority 1)
  • Whicher Scarp F1 – Sabina River Jarrah and Marri woodland (Whicher Scarp community F1) (Priority 1)

More information on the Commonwealth listed communities can be found on the Glimpses into disappearing landscapes website here.

More can be found out about the last three TECs, the Whicher Scarp ecological communities in the report,  A Floristic Survey of the Whicher Scarp A report for the Department of Environment and Conservation as part of the Swan Bioplan Project April 2008 (Keighery BJ et al., 2008).

There are 12 DRF and 18 priority flora populations identified within the bio-landscape including species such as the Glossy leafed hammer-orchid, Royce’s waxflower, Vasse Featherflower, and Graceful cord rush.

Threatened fauna identified in this bio-landscape include the Baudin’s cockatoo, Carnaby’s cockatoo and forest red-tailed black cockatoo, chuditch and 2 priority fauna species; quenda and carter’s freshwater mussel.

Whicher 1 bio-landscape and Climate Change 

Projected level of risk due to:

Decreasing rainfall

Best case   VeryHighCircle

Worst caseVeryHighCircle

 

Increasing temperature

Best case   ModerateCircle

Worst caseHighCircle

 

  • where Best Case = MIROC5 and Worst case = CanESM2 at 2090 and RCP8.5; see more here
  • Decreasing rainfall = annual rainfall change as % of initial
  • Where Very High = greater than 25% reduction; High = 20-25% reduction; Moderate = 15-20% (Note: no where in the region is there projected to be less than 15% reduction in rainfall).
  • Increasing temperature = change in maximum summer temperature
  • Where Very High = greater than 4 degree increase (maximum projected being 4.7 degrees within the Region); High = 3-4 degree increase; Moderate = 2.5 – 3 degree increase; Low = 2 – 2.5 degree increase (Note: no where in the region is there projected to be less than a 2 degree increase which although lower than the very high 4 degree increase, will still have significant impacts on the environment).

This analysis is a simplistic way of looking at the potential risk of an asset to projected changes in rainfall and temperature. Assets may respond to climatic changes differently and species may be able to adapt in ways we don’t yet fully understand.

SWCC Strategic Priority

The Whicher 1 bio-landscape is identified as a first order priority asset within SWCC’s NRM Strategy under the Terrestrial Biodiversity theme.

Projects

 

 

References

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