RYDE FLORA and FAUNA STUDY 2007 - City of Ryde - NSW ...

Biosphere Environmental Consultants Pty Ltd
Ryde Flora and Fauna Survey 2007 35
area from further fragmentation by erecting a fence bordering the fire trail adjacent to
the cemetery and filling the area with large branches, preventing access from the Sand
Track. Now that the area is protected other species can recruit into the quadrat.
Three quadrats erected in Terrys Creek catchment failed the classification due to a
low number of positive diagnostic species. Terrys Creek contains almost double the
number of weeds along the creek than any other catchment. The Acacia binervia and
Coachwood/Christmas bush quadrats had a high number of weed species due to their
close proximity to the creek (16% of the Coachwood/Christmas bush quadrat and 8%
in the Acacia binervia quadrat). As a result, the Acacia binervia quadrat contained 7
more native species. The Pembroke Park quadrat had the lowest number of positive
diagnostic species. It also contained 16% weed species coming from impacts above
the quadrat. These are residential development, runoff from the sandstone ridge, a fire
trail that is mown regularly, rabbits plus an infestation of Bridal Creeper (Asparagus
asparagoides) that smothers the understorey.
Burrows Park, Minga Reserve and the north west end of Barton Reserve in the
Buffalo Creek catchment, Forrester and Forsyth Reserves in the Terrys Creek
catchment, and Pryor Park and the north end of Portius Park in the Kittys Creek
catchment are all located on Wianamatta Shale derived soils. The vegetation has
previously been classified as Blue Gum High Forest (Benson & Howell, 1994). The
topography of all parks is below 100m ASL and the parks no longer satisfy that listing
(DECC NSW, 2006). One quadrat was erected on this soil type, at Burrows Park,
which fulfilled the requirements for Map Unit 15: Turpentine Ironbark Forest (Tozer,
2003). Memorial Park, located on an alluvial floodplain along the Parramatta River
could be considered to be part of the Cumberland Plain Alluvial Eucalyptus
Woodland community that is found nowhere else in Ryde.
The classifications contained in this survey and listed by Tozer (2003) are equivalent
to the following Endangered Ecological Communities listed on Schedule 1 of the
NSW TSC Act (1995).
The model developed by Tozer (2003) can be utilised by Council managers to
determine native plant diversity and, as pointed out in the 2006 study, to also alert
them to a gradual loss of native species richness. Loss of, or change in, the positive
diagnostic species may point to a gradual degradation of the area or a change in
vegetation community type.
Once diversity is noticed to be decreasing, it is important to look for the source of the
disturbance and to take measures to correct it. Oculus (1999) lists the factors that
contribute to the loss of native plant diversity in the Ryde municipality: lack of
maintenance and weed control (all Pembroke Park quadrats), continuation of
threatening processes (Memorial Park) and increased stormwater runoff into bushland
with associated increase in nutrient levels and erosion (or flooding) (all Pembroke
Park quadrats) as well as fragmentation by mountain bike riders (Pimelia curviflora
quadrat). Lack of diversity may also be due to an inappropriate fire regime (a threat in
the Field of Mars Reserve communities and Somerset Park).