Flora survey for Hamersley Drive recreation - Environmental ...

FRNP Improvement Project: Culham Inlet to Hamersley Inlet GF Craig– July 2010
Declared Rare and Priority Flora
Six species of Declared Rare flora were found adjacent to Hamersley Drive, principally on the wave-cut
bench south of East Mt Barren or on the western flanks of the mountain. Twelve species of Priority Flora
were located in the survey area, however a further four which had been collected previously were not
found. A summary of each species is given below and full details of GPS locations and population
numbers given in Appendix 4.
Declared Rare flora (Figure 2)
Adenanthos ellipticus Oval-leaf Adenanthos (Vulnerable)
Endemic to the Fitzgerald River National Park, this species grows on the summit and south-west slopes
of East Mt Barren, extending onto the wave-cut bench south of the mountain. It is a
relatively slow growing plant that is killed by fire, but regenerates readily from seed.
Field observations (Robinson and Coates 1995) suggest a high susceptibility to
Phytophthora dieback.
This population was surveyed by DEC Albany in 2008 and estimated to be 30,000+
mature plants and approximately 10,000 seedlings in the burnt area (2006
prescribed burn). In addition, Adenanthos ellipticus is known to occur on Thumb
Peak and West Mt Barren. Less than 1% of the East Mt Barren population will be
impacted by the Hamersley Drive upgrade.
No.
Plants
% EMB
population
% all
populations
Hamersley Drive upgrade 350 0.9 0.7
1
East Mt Barren 40,000+
2
Thumb Peak 10,000+
2
West Mt Barren 1,000+
1 DEC Albany 2008
2 Robinson & Coates 1995
Eucalyptus burdettiana Burdett Gum (Endangered)
Burdett gum is a multi-stemmed mallee, up to 4m high. It has smooth bark and glossy green leaves
9 cm long and 1.7 cm wide. It has stalkless clusters of 7 to 11 flowers on a flattened flower stalk. The
floral tubes are not fused and they have very long, horn-shaped bud caps that are slightly warty. This
species only grows on and around East Mt Barren.
Prior to this survey E.burdettiana was recognised to occur in 2 populations, with population 1 divided into
5 sub-populations (1A, 1B, 1C, 1D & 1E). The total number of plants was believed to be 239, however
these numbers fluctuated across visitation from the 1980’s to 2000’s particularly in populations 1A and
1B. Ellen Hickman’s survey estimates the population to consist of 3500 – 4000
plants, with 1571 plants actually waypointed. 42 plants were identified within the
25 m road buffer. Therefore the plants deemed to be under threat from the
proposed road works constitutes 1.2% of the entire population on East Mt Barren.
Population 1E was visited but no plants located and after review of notes on this
population it is believed to be equivalent to population 1C. E.burdettiana plants
were found on all slopes of East Mt Barren with the exception of the extreme
eastern slopes, populations 1A, 1B, 1C and 1D all merge and as such the
subdivision of these populations is irrelevant. Specific comments on each
population are presented in Appendix 4.
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