NSW Bitou Bush Threat Abatement Plan - Department of ...

Threat Abatement Plan - Invasion of native plant communities by Chrysanthemoides monilifera
2. Zieria prostrata J.A. Armstrong (Rutaceae)
Zieria prostrata is a small multi-stemmed prostrate shrub 0.5–1 m in diameter, which forms a low
mat. It occurs on exposed headland sites in low coastal heath. In more sheltered aspects, it grows
in association with open to sparse shrublands, characterised by coast banksia (Banksia integrifolia
var. integrifolia) and coastal wattle (Acacia sophorae) (NPWS 1998). It has a very restricted
distribution and is known from only four headlands within Moonee Beach NR, 20 km north of
Coffs Harbour. The four sites have approximately 1,000 plants in total. There is some genetic
variation between the four sites (NPWS 1998). To maintain the full genetic diversity, all four
locations need be protected.
Two recovery plans have been prepared and implemented for Z. prostrata (see Griffith 1992;
NPWS 1998). The main threat is displacement by exotic weeds, including bitou bush, lantana and
kikuyu. Bitou bush poses a major threat as it shades individual plants with its dense canopy. A
pest management plan has been prepared for Moonee Beach NR. Weed control has been
undertaken for many years and the immediate threat of weed invasion has been alleviated at all
four sites. Bitou bush still poses a serious threat of re-invasion and ongoing follow-up
maintenance/control is required in the immediate vicinity and in the surrounding areas.
3. Chamaesyce psammogeton (P.S. Green) P.I. Forst & R.J.F. Hend. (Euphorbiaceae)
Chamaesyce psammogeton (synonyms: C. sparrmani, Euphorbia sparrmani) is a prostrate
perennial herb that forms mats to 1 m in diameter. It grows on incipient fore-dunes in Spinifex
hirsutus communities, and exposed headlands, as well as on the beach aspect of the fore-dune
with a range of herbs, vines, shrubs and grasses. It occurs sporadically north from Jervis Bay into
Queensland, as well as on Lord Howe Island. Some botanists considered it to be in danger of
extinction (Clarke and Carolin 1991) and its final determination under the TSC Act was based on
the fact that it was formerly widespread and is now only known from a few small populations (see
NSW SC 1998a). A comparison of present and historical records in New South Wales showed
that it had disappeared from some areas (e.g. Sydney: Heyligers 1998). Despite this, new
populations have been recorded (e.g. Yuraygir NP: Flower and Clarke 2001). The majority of the
records in the NPWS Atlas of NSW Wildlife are from one survey (see Clarke 1989), which
suggests that the distribution of this species is not fully known.
Bitou bush is one of the main threats to C. psammogeton (i.e. by growing over it due to its
prostrate habit and preference for sand dunes). Populations on the seaward edge of incipient dunes
are less threatened, as bitou bush rarely establishes in these areas. These populations are
threatened by other factors however (e.g. beach erosion and the removal of habitat). The sites
recorded by Clarke (1989) need to be revisited to establish if the species is still present, and if so,
the threat posed by bitou bush.
4. Senecio spathulatus A. Rich (Asteraceae)
Senecio spathulatus is a prostrate perennial herb with ascending or erect ends 15–50 cm in length.
A recent taxonomic revision incorporated S. anacampserotis DC into this species (see Walsh and
Entwisle 1999). Senecio spathulatus occurs on seashores from Eden, Victoria to Myall Lakes NP.
Recent botanical surveys did not observe it between Nadgee and Sydney however (McDougall
pers. comm.). Herbarium specimens were collected in the 1980s from Mungo Corner, Myall
Lakes NP, Fingal Spit, Port Stephens, Connell Hill, Kurnell and Cronulla Recreation Reserve.
Bitou bush is present at all the locations documented in the 1980s. Control programs are in place
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