Ancistrachne maidenii (a perennial grass) - vulnerable species listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the perennial grass Ancistrachne maidenii(A.A. Ham.) Vickery as a VULNERABLE species on Schedule 2 of that Act. Listing of vulnerable species is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. Ancistrachne maidenii (A.A. Ham.) Vickery (Family Poaceae) has been described by Harden (1993, Flora of NSW, Vol. 4) as: a scrambling perennial with slender, rigid decumbent stems and ascending branches. Leaves: sheath sparsely hairy; ligule ciliate; blade subcordate at the base. Racemes terminal or axillary, c. 4 cm long, the latter ones shorter and partially enclosed in the sheath. Spikelets falling entire at maturity, 2.5 - 3 mm long. Lower glume abaxial, a hyaline scale to 0.25 mm long or often reduced or absent. Upper glume distinctly 5 - nerved, subequal to the spikelet, obtuse to subacute and, together with the lower lemma, sprinkled with fine, mostly curved, tubercle-based hairs. Lower lemma similar to the upper glume, distinctly 7 - nerved, sterile, without a palea. Fertile floret elliptic to lanceolate, obscurely nerved, produced into a short but distinct mucro to 0.25 mm long, the palea subequal to the lemma and similar in texture. Flowers summer. Grows on sandstone - derived soils.
2. Ancistrachne maidenii is restricted to northern Sydney, around Berowra Waters, Brooklyn and Wisemans Ferry. Surveys have indicated that the species may have specific habitat requirements, with populations occurring in distinct bands in areas associated with a transitional geology between Hawkesbury and Watagan soil landscapes.
3. There are seven known populations, four of which are reserved. Due to the growth form of the plant it is difficult to make individual counts. However the area occupied at each location is known and the total area of occupancy is estimated to be approximately 3.5 hectares. Five locations (including three of the reserved ones) have an area of occupancy of less than 75 square metres. Small populations are more susceptible to catastrophic events and localised extinction. Locations are known from the following NPWS reserves: Berowra Valley Regional Park, Dharug National Park.
4. Four of the populations occur along roadsides and are susceptible to road maintenance, weed spraying and inappropriate fire regimes. A further two populations occur along walking tracks and may be susceptible to track maintenance, widening and trampling.
5. Threats include the small size of populations, road and track works and urban development. Surveys along urban creeklines failed to record the species, indicating a possible sensitivity to pollution or weed invasion. The risk of extinction is high due to low population numbers.
6. In view of 3, 4 and 5 above the Scientific Committee is of the opinion that Ancistrachne maidenii is likely to become endangered unless the circumstances and factors threatening its survival or evolutionary development cease to operate, and is therefore eligible for listing as a vulnerable species.
Proposed Gazettal date: 23/7/99
Exhibition period: 23/7/99 - 27/8/99