Flora survey for Hamersley Drive recreation - Environmental ...

FRNP Improvement Project: Culham Inlet to Hamersley Inlet GF Craig– July 2010
Analysis of data
Tracks and waypoints were downloaded from the GPS units using OziExplorer® software. Tracks and
waypoints were saved as .plt/.wpt and .txt files (UTM/UPS and hddd.ddddd o ), the latter allows importing
of data into Excel® spreadsheets.
Plant species were recorded in a MAX V3 data table, a software program developed by DEC’s Western
Australian herbarium which links datasets to the Census of Western Australian Plants master list. The
‘relevé number’ was entered into the database.
To assist in clarifying the vegetation units, Anne Rick used PRIMER® multivariate analysis to produce
dendrograms that grouped relevés on the basis of species similarity. Both Newbey’s (Chapman and
Newbey 1987) and the author’s data were included in the analysis. Only perennial species were
included, and for the Newbey data, only those species with > 0.5 abundance. Relevés with only a few
species recorded were excluded as they skewed the data.
Once the vegetation units had been clarified using the PRIMER® analysis, species lists for each unit
were prepared. Vegetation units were mapped using a combination of field data, PRIMER® analysis
and interpretation of orthophotos.
Digitising
Digital files including waypoints of each species of threatened flora encountered during the survey and
line work of the vegetation map (1:10 000 scale) were sent to Meredith Spencer in 2009 and Janet
Newell in 2010 (DEC Albany) for digitising. Final maps were provided as shapefiles for compatibility
with ArcMap.
3. Desktop Assessment
Physical Environment
Climate
A Mediterranean climate of warm to hot summers and cool, wet winters is generally experienced. The
nearest weather station is Hopetoun North, for which the last 13 years of data is available (Table 1).
Mean maximum temperature recorded at Hopetoun in the hottest month (February) is 26 o C. Mean
minimum temperature in the coldest months (July-August) is 8 o C. The highest recorded temperature of
48 o C was recorded on 6 January 2010, while the lowest of -0.3 o C was in July 2000. Frosts have been
recorded by farmers in the catchment during winter and spring, but are usually rare on the coast.
The rainfall is typical of a Mediterranean climate with a pronounced winter maximum and a long dry
summer. The mean annual rainfall on the coast is about 500 mm, but has been highly variable over the
past 10 years with the maximum of 610 mm in 2001, followed by a very dry year in 2002 when only
274 mm fell. Sporadic heavy rainfall events can occur in summer as a result of cyclonic events in the
north of the State - the highest monthly rainfall of 185 mm was recorded in January 2000.
Annual evaporation is generally 1500 mm.
Morning wind speeds are typically 17-22 km/h and increase in the afternoon to average 20-29 km/h. On
the hottest recorded day, i.e. 6 January 2010, the strong winds from the NNW had only 5% Relative
Humidity at 3 pm (BOM, 2010), the strongest wind gust was not recorded!
Climate Change is predicted to impact the south coast of Western Australia. Changes in temperature
and rainfall patterns may lead to changes in the physical condition of the region and to the growing
season, incidence of frost and flood events etc.
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