ENVIRONMENTAL IMPACT ASSESSMENT GUIDELINES Dillwynia tenuifolia E. sideroxylon may also be present or co- The following information is provided to dominant. Melaleuca decora often forms assist authors of species impact a secondary canopy layer. D. tenuifolia is statements, development and activity frequently abundant in such localities. proponents, and determining and consent authorities, who are required to prepare Habitat containing any of the following or review assessments of likely impacts threatened species, Dodonaea falcata, on threatened species pursuant to the Grevillea juniperina, Micromyrtus provisions of the Environmental minutiflora, Persoonia nutans, Pultenaea Planning and Assessment Act 1979. parviflora and Styphelia laeta, is also These guidelines should be read in likely to be suitable for D. tenuifolia. conjunction with the NPWS Information Other key associated species may Circular No. 2: Threatened Species include: Aristida spp., Bursaria spinosa, Assessment under the EP&A Act: The ‘8 Daviesia ulicifolia, D. sieberi, Entolasia Part Test’ of Significance (November stricta, Hakea sericea, Lepidosperma 1996) and with the accompanying laterale, Lissanthe strigosa, Melaleuca “Threatened Species Information” sheet. nodosa and Ozothamnus diosmifolius. Survey Life cycle of the species D. tenuifolia is best surveyed during the Proposals which are likely to affect the peak flowering period (August to March, life cycle of the species, such that a local but especially September - Maryott- population is put at risk of extinction, Brown & Wilks 1993, Benson & would include proposals that: McDougall 1996) when it is easiest to • result in total destruction of habitat; observe and identify. • result in a partial destruction or Non-flowering plants are superficially modification (including changes to similar to many other heath-like plants, hydrology and nutrification of the and may be overlooked when spindly and soil substrate) of the habitat or the growing in thick scrub. vegetation structure which may result D. tenuifolia has been reported to have in dense monospecific regrowth of been confused with D. glaberrima and D. large shrubs, trees or invasion of sieberi, but can be identified from other alien species; • pea species by its relatively soft and long result in a requirement for frequent (4-12mm), linear, terete leaves with an fire hazard reduction, so that the apex which is frequently recurved. The seedbank cannot be adequately inflorescence is 1- or rarely 2-flowered, replenished; borne on a peduncle < 3mm long, • increase vehicular, bike or pedestrian occurring terminally or in the upper leaf access to a population; or axils (Harden 1991). In open areas it may • increase rubbish dumping and have a distinct form - a low and compact associated weed invasion or arson shrub with arching branchlets. (for example, through adjacent residential development). Surveys should initially concentrate in open areas within woodland/open forest, Threatening processes particularly targeting areas possessing laterised gravels, or low rises which have “High frequency fire resulting in the a well developed or regenerating low disruption of life cycle processes in shrub layer. Eucalyptus fibrosa is likely plants and animals and loss of vegetation to be a dominant canopy species. structure and composition” is listed in Eucalyptus globoidea, E. longifolia, the NSW Threatened Species E. parramattensis, E. sclerophylla and Conservation Act 1995 as a key threatening process. D. tenuifolia is fire May 2002 sensitive and is therefore vulnerable to 120m in diameter. Thus distances, high frequency fires. between groups of plants, greater than this are likely to result in populations Clearing of native vegetation is listed as which are isolated. Therefore, activities a key threatening process and is pertinent which create such gaps are likely to be for the consideration of impact causing further isolation or assessment for D. tenuifolia. fragmentation of the species. Threatening processes currently affecting the species include clearing, slashing, Regional distribution of the habitat grazing, trampling and habitat D. tenuifolia is confined to the Sydney modification through altered fire regime, Basin Biogeographical Region urban runoff, weeds, rubbish dumping, indiscriminant vehicular and pedestrian access. Limit of known distribution The current known limits of distribution Viable local population of the is Yango in the north, Woodford and species Kurrajong Heights in the west, Kemps Creek vicinity in the south and Dean All populations should be considered Park in the east. viable unless proven otherwise ie. they consist of a few individuals in highly Adequacy of representation in insecure, disturbed and weed impacted locales such as roadsides. conservation reserves or other similar protected areas A significant area of habitat D. tenuifolia is recorded from Agnes The NPWS considers that generally, all Banks, Windsor Downs Castlereagh and viable populations should be considered Mulgoa Nature Reserves, Scheyville, as occupying a significant area of habitat Blue Mountains and Yengo National until such times as adequate and Parks (NPWS 1997) and the proposed representative examples across the ADI Regional Park. species range are conserved. A number of significant sites are on Where it can be demonstrated Commonwealth, State and local conclusively that a population is very government controlled lands where the small and non-viable, and where intentions of the managers concerned are adequate representative reservation unknown. Until protection of these occurs within the nearby vicinity, that populations is ensured, this species must area of habitat could be considered be considered inadequately reserved. insignificant. Critical habitat Isolation/fragmentation Critical habitat cannot be declared for D. Rymer (1999) found that the genetic tenuifolia as it is not listed on Schedule 1 neighbourhoods within a large of a of the NSW Threatened Species population of D. tenuifolia to be approx. Conservation Act 1995. For Further Information contact Threatened Species Unit Conservation Programs and Planning Division, Central Directorate NSW NPWS PO Box 1967, Hurstville NSW 2220 Phone 02 9585 6678. www.npws.nsw.gov.au References Benson, D McDougall, L. (1996) Ecology of Sydney plant species Part 4. Cunninghamia 4(4):603. Harden, G. H. (Ed.) (1991) Flora of New South Wales Vol. 2. UNSW Press, Kensington. Maryott-Brown, K. and D Wilks (1993). Rare and endangered plants of Yengo Natoinal Park and adjacent areas. NPWS, June 1993 May 2002 Miller, R. T. Cumberland Flora & Fauna Interpretive Services 13 Park Rd, Bulli, NSW 42846768 NSW NPWS (1997) Urban Bushland Biodiversity Survey. Native Flora of Western Sydney. NSW NPWS, Hurstville. Rymer, D. (1999). The Reproductive Biology And Population Genetics Of The Rare And Threatened Plant, Dillwynia tenuifolia (FABACEAE). Honours Thesis, University of Western Sydney, Hawkesbury. IMPORTANT DISCLAIMER The NSW National Parks and Wildlife Service and the editor expressly disclaim all liability and responsibility to any person, whether a purchaser or reader of this document or not, in respect of anything done or omitted to be done by any person in reliance upon the contents of this document although every effort has been made to ensure that the information presented in this document is accurate and up to date. May 2002.