Ruabon-Tutunup Bio-landscape

Posted on Dec 23, 2014


Ruabon – Tutunup BiolandscapeTerrestialBiodiversity

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 Ruabon-Tutunup bio-landscape is a very high value area to the east of Busselton, within the City of Busselton and Shire of Capel and within the Geographe Bay catchment.

The Ruabon-Tutunup 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.

It includes reserves such as the Tuart Forest National Park, Ludlow State Forest, Capel Nature Reserve, Ruabon Townsite Nature Reserve and Millbrook State Forest. Rivers that flow through this bio-landscape are the Abba River, Ludlow River and the Capel River.

Significant to the bio-landscape is the presence of a continuous east-west vegetated corridor, one of only three remaining on the Swan Coastal Plain. The continuous vegetation within the Ruabon-Tutunup road and rail reserve, although narrow, links the Vasse-Wonnerup wetlands and Ludlow State Forest to the State Forest of the Whicher Scarp.

Patches of remnant vegetation occur within the bio-landscape, outside of the Tuart Forest National Park and State Forest, in smaller conservation reserves, road reserves, river reserves and private property. Due to the extent of clearing within the bio-landscape, these patches perform important landscape functions as stepping stones within regionally and locally important ecological linkages. Vegetation along the waterways have been been identified as being important regional ecological linkages as has the Ruabon-Tutuanup corridor.

Again due to the extensive clearing that has occurred in the past along the entire Swan Coastal Plain, 4 of the vegetation associations present are well under-represented with there being less than 10% remaining of the Bassendean 1136, Bassendean 973, Bassendean 990 and Pinjarra 1136 vegetation associations and 10-30% remaining of the Bassendean 1000, Bassendean 949 and Bassendean 4 vegetation associations.


Ironstone soil typical of the Busselton Ironstone threatened ecological community (Tim Swallow 2011)

Ironstone soil typical of the Busselton Ironstone threatened ecological community (Tim Swallow).

There are a number of threatened ecological communities located within this bio-landscape including:

  • SCP10b – Shrublands on southern Swan Coastal Plain Ironstones (Busselton area) (Commonwealth listed as Endangered)
  • SCP 10a – Shrublands on dry clay flats (part of the Critically Endangered Commonwealth listed Clay pans on the Swan Coastal Plain)
  • SCP07 – Herb rich saline shrublands in clay pans (part of the Critically Endangered Commonwealth listed Clay pans on the Swan Coastal Plain)
  • SCP1b – Eucalyptus calophylla woodlands on heavy soils of the southern Swan Coastal Plain (Vulnerable)
  • Whicher Scarp C2 – Whicher Scarp Jarrah woodland of deep coloured sands(Priority 1)
  • Whicher Scarp G2 – Shrublands of near permanent wetlands in creeklines of the Whicher Scarp (Whicher Scarp community G2) (Priority 1)
  • Swan Coastal Plain Paluslope Wetlands (Priority 1)
  • SCP1a – Eucalyptus haematoxylonE. marginata woodlands on Whicher foothills (Priority 3)

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

There are 130 DRF and 99 priority flora populations identified within the bio-landscape including species such as long-stalked feather flower, swamp honeypot, grand spider orchid, southern tetraria and Vasse feather flower.

There are also 9 endangered and 20 priority fauna populations identified such as the brush-tailed phascogale, quenda, water-rat, eastern great egret and western brush wallaby.

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

Projects

SWCC has been working over the last few years with a number of landholders within this area to undertake on-ground works to improve the connectivity of the corridors, and has resulted in over 100 hectares of land rehabilitated through revegetation and weed control targeting species such as Watsonia, Arum Lily, Kikuyu and Lovegrass. SWCC continues its work in the area into the future which will hopefully include controlled burns, more revegetation and ongoing weed control.

More can be found out about what was achieved by SWCC and its partners in 2011-2013 in the Ruabon- Tutunup Corridor here and in protecting endangered plant species that occur in association with the endangered ecological community, Busselton Ironstones here.

Source:

  •  2009 Biodiversity Sub-Strategy for the South West Catchments Council Prepared for the South West Catchments Council by Ecosystem Solutions Pty Ltd 2009.

 

Header and thumbnail images supplied by Tim Swallow.

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