In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.
|EPBC Act Listing Status||Listed as Endangered as Zieria baeuerlenii|
|Recovery Plan Decision||
Recovery Plan required, included on the Commenced List (1/11/2009).
|Adopted/Made Recovery Plans||
National Recovery Plan for Zieria baeuerlenii (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010m) [Recovery Plan] as Zieria baeuerlenii.
Federal Register of
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Zieria baeuerlenii.
Amendment to the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (11/04/2007) (Commonwealth of Australia, 2007f) [Legislative Instrument] as Zieria baeuerlenii.
Documents and Websites
|State Listing Status||
|Scientific name||Zieria baeuerlenii |
|Reference||Australian Systematic Botany 15 (3): 318, fig. 17, 18, map fig. 19 (2002)|
Zieria sp. 1 (sp. 'M'; Bomaderry) 
Zieria baeuerlenii Armstrong ms. 
Zieria baeuerlenii J.A.Armstrong ms. 
This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.
Scientific name: Zieria baeuerlenii
Common name: Bomaderry Zieria
Other names: Bomaderry Creek Zieria
This species was formerly known as Zieria sp. 1 (sp. 'M'; Bomaderry) (Briggs & Leigh 1990).
Bomaderry Zieria was once thought to be a sterile hybrid between Z. cytisoides and Z. littoralis. However, none of the postulated parents occur close to its habitat at Bomaderry Creek (Briggs & Leigh 1990; Barratt 1997). Furthermore, genetic research has shown a hybrid origin is unlikely. Thus, Z. baeuerlenii remains a distinct species (Barratt 1997; NSW NPWS 2002i).
The Bomaderry Zieria is a many-branched to somewhat straggly shrub which grows to an average height of 76 cm. Plants are generally clonal, with several stems emerging from a common rootstock. Leaves are opposite, small, and comprised of three leaflets (trifoliate), with both surfaces covered with a dense velvety layer of mostly stellate hairs. The central leaflet is 6-18 mm long and 4-12 mm wide, whilst the secondary leaflets are similar in shape but slightly smaller (approximately three-quarters the size). Flowers are produced from August to October. The flowers are about 8 mm across, white to pinkish, with four broad lanceolate petals, arranged in small 3-7 flowered clusters arising from the leaf axils on a common stalk up to 10 mm long. Four large, green, leaf-like bracts surround each flower cluster. Fruit has never been recorded (Barratt 2007).
There is only one known population of the Bomaderry Zieria which occurs at 49 sites. The population is scattered within an area of about 0.5 km x 1 km of bushland on either side of Bomaderry Creek, north of Nowra (Barratt 2007; NSW DECCW 2010m).
The first collection of this species was made in 1883, but the collector gave the somewhat vague locality description of 'lower Shoalhaven'. The second collection was made in 1943 from 'Bomaderry Creek' and probably refers to the current population, rediscovered in 1987.
The current extent of occurrence is 26 ha. There are no data to indicate a decline in extent (NSW DECCW 2010m).
The area of occupancy is probably about 1-2 ha. There have been losses of individuals at some sites, leading to a marginal loss in area of occupancy in the last 20 years (Barratt 2007).
There are ex-situ collections of the Bomaderry Zieria at the Australian National Botanic Gardens, Wollongong Botanic Gardens, Booderee National Park and Botanic Gardens at Jervis Bay. Nineteen of the twenty clones are maintained in the collections (Barratt 2007).
A detailed survey was conducted in 1998 at the Bomaderry bushland with some additional plants found (NSW DECCW 2010m).
Of the existing sole population, there were 1254 emergent stems in 2007 (Barratt 2007). The longevity of stems is not known.
There was a decline of 159 stems (11%) between 1999 and 2007 (Barratt 2007). The decline is not attributable to any one particular threat. It may have been a fluctuation due to the dry conditions experienced in some years between 2001 and 2010.
Thirty-three of the 49 sites occur in Bomaderry Creek Regional Park.
The species occurs on a sandstone plateau north of the Shoalhaven River across an extremely narrow altitudinal range of only 10 m (34-44 m ASL) on gentle slopes and has no pronounced aspect preference (Barratt 2007; NSW DECCW 2010m).
Most of the sites where the Bomaderry Zieria occurs have well drained shallow sandy soils derived from Nowra Sandstone and contain many sandstone outcrops. The 49 extant sites occur across a range of eucalypt open forest, sclerophyll woodlands with shrubby understorey and closed scrub. The most common tree species in the forest/woodland communities are Red Bloodwood (Corymbia gummifera), Grey Gum (Eucalyptus punctata), Spotted Gum (C. maculata), Blue-leaved Stringybark (E. agglomerata), a Stringybark (E. imitans) and Turpentine (Syncarpia glomulifera) (Barratt 2007; NSW DECCW 2010m). The most common species in the closed-scrub communities is Tea-tree (Leptospermum sejunctum). Across the open-forest/woodland communities, the most common understorey shrub is also Leptospermum sejunctum. The most common herb/forb species are Mat-rush (Lomandra confertifolia) and Wiry Panic (Entolasia stricta) (Barratt 2007; NSW DECCW 2010m).
The Bomaderry Zieria relies on vegetative propagation for persistence (NSW DECCW 2010m).
Sexual maturity, life expectancy and natural mortality are concepts not particularly applicable to clonal plants.
Over the last 20 years there has been no observed fruit set, and assessment of pollen viability has indicated that pollen may have a low viability. The species probably spreads via root suckers. Evidence so far indicates that the species is incapable of sexual reproduction (NSW DECCW 2010m).
The species' most distinguishing feature are the leaves which are divided into three leaflets.
Surveys may be conducted at any time of the year. An area should be surveyed using transects spaced no more than 10 metres apart as smaller plants may not be seen at greater transect separations. The entire area of suitable habitat should be traversed to ensure proper survey coverage.
Threats included in the Bomaderry Zieria Recovery Plan (NSW DECCW 2010m) are:
Browsing by rabbits
Regrowth is likely to be browsed by rabbits, as indicated by scrapings and dung in the vicinity of plants. At such times, when other vegetation may be scarce or unpalatable, the fresh shoots of the Bomaderry Zieria are vulnerable to browsing. There are so few Bomaderry Zieria plants remaining that even minor levels of browsing may be significant, particularly for some of the genetically distinct sub-populations.
Weeds are prevalent on the margins of the Bomaderry bushland. For example, Lantana (Lantana camara), Crofton weed (Ageratina adenophora), Mother of Millions (Bryophyllum delagoense; Bryophyllum x houghtonii), Kikuyu grass (Pennisetum clandestinum), Giant Parramatta grass (Sporobolus fertilis), Black-eyed Susan (Thunbergia alata), Morning Glory (Ipomoea indica) and Purpletop (Tridens flavus) are common in places. Some sites are impacted by weeds, particularly Mother of Millions (B. delagoense; B. x houghtonii). It is unlikely that weeds can be eliminated in the Bomaderry bushland, as the surrounding urban area provides a constant source of weed propagules. Ongoing work will be required to manage the weeds.
Impacts from recreational activities
The Bomaderry Zieria occurs in a relatively small patch of urban bushland, in close proximity to tracks, picnic areas and recreational facilities such as tennis courts. Use of these recreational facilities has the potential to adversely impact the Bomaderry Zieria population.
Powerline and water main maintenance activities
Some of the sub-populations occur adjacent to easements for powerlines and water mains. Maintenance of these utilities or access tracks has the potential to adversely impact these sub-populations.
Inappropriate fire regimes
Although the species resprouts after fire, too frequent burning may exhaust the reserves of the plants and cause local extinction, particularly if rainfall in between the fires has been low. Some senescence has been noted where the plants are overtopped by Tea-tree and Kunzea vegetation, indicating that a fire may be beneficial to reduce competition for resources.
The proposed north Nowra link road, between North Nowra and Bomaderry, NSW has the potential to seriously compromise the conservation status of the species. One site where the plant occurs would probably be eliminated by the road construction, while a number of other plants, located within a few metres of the proposed road verge, could potentially be impacted by weed invasion. Changes to the hydrology of the area, due to road construction, could also impact the population.
There are at least 19 genetically distinct sub-populations of the Bomaderry Zieria. Some of these sub-populations consist of a very small number of plants, being represented by only a handful of stems over a few square metres of ground.
Given the extremely small population size, stochastic events have the potential to cause local extinctions. The most likely event is prolonged drought. Other possibilities include disease, and potentially fire or associated fire suppression operations such as the creation of fire breaks in emergency situations.
The primary issue limiting the recovery of the Bomaderry Zieria is the absence of sexual reproduction. Conservation of the species is dependent on the maintenance of existing plants. These may have the capacity to persist in the long term in the absence of other threats. There are no population viability models for the species. The species may once have been more extensive, but has lost the ability to set seed.
In NSW, the TSC Act makes provision for the identification and declaration of Critical Habitat. In response to a public nomination, 54 ha of the bushland were formally identified by the NSW Minister of the Environment as Critical Habitat for the Bomaderry Zieria in 2003. The boundary of the Critical Habitat coincides with a significant portion of the upper part of the local watershed, providing protection from pollutants and water borne pathogens such as Phytophthora cinnamomi. However, the identified Critical Habitat has not been declared by the Minister of the Environment, primarily due to the creation of the Bomaderry Creek Regional Park which protects most of the population.
Bomaderry Creek Regional Park
The Fire Management Plan (2006) and draft Bomaderry Creek Regional Park Plan of Management contain specific measures to protect the Bomaderry Zieria (NSW DECCW 2006b).
The Fire Management Plan requires:
- No hazard reduction more often than every 7 years.
- No slashing more often than every 10 years.
- No tree removal, use of foam or other fire retardants or earthmoving equipment on the Bomaderry Zieria habitat.
The draft Park Plan of Management contains a provision requiring a monitoring program for the Bomaderry Zieria and implementation of recovery actions.
Bomaderry Zieria Recovery Plan
Proposed recovery actions from the Bomaderry Zieria Recovery Plan (DECCW 2010m) are:
Reduce rabbit numbers - elimination of all rabbits is unlikely, but an ongoing program of rabbit control is necessary to maximise the survival potential of the species. Rabbit control is particularly important after fires or other disturbances and during drought.
Control weeds - several plant colonies are affected by weeds, particularly Mother of Millions. An ongoing program of weed control is required, as re-invasion is likely from the urban areas surrounding the Bomaderry bushland.
Minimise pedestrian and trampling impacts - erect fencing to direct pedestrian traffic away from sites, or, if more appropriate, re-route tracks. At sites where fences are erected, signs will also be installed explaining the purpose of the fences in protecting the Bomaderry Zieria and its habitat.
Monitoring - monitoring of all colonies should occur every five years. Separate targeted monitoring should be conducted where concern exists regarding particular threatening processes and also following fires to increase our understanding of the species response to fire. All ramets at all locations will be counted in the monitoring.
Investigate the impacts of fire - initiate experimental burns and/or pruning of dense vegetation over some of the population and associated habitat to determine the effect of both fire and removal of dense vegetation.
Maintain ex-situ collections - due to the small overall population size, presence of several distinct genotypes, active threats and the relatively high risk of chance events eliminating some genotypes, ex-situ collection must be part of the recovery strategy. There are ex-situ collections of the species at Wollongong Botanic Gardens, Australian National Botanic Gardens and Booderee Botanic Gardens (with the largest collection). It is important that these collections be maintained, especially while there are active and on-going threats.
Terry Barratt has prepared a thesis for his Honours degree on the Bomaderry Zieria (Barratt 1999). He also conducted monitoring in 2007 under contract to the NSW Department of Environment, Climate Change and Water.
Management documents for the Bomaderry Zieria include:
- Draft National Recovery Plan for the Bomaderry Zieria, Zieria baeuerlenii (NSW DECCW 2010m)
- Recommendation Report for the Identification of Critical Habitat for the Bomaderry Zieria (Zieria baeuerlenii) (NSW National Parks and Wildlife Service).
The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.
|Threat Class||Threatening Species||References|
|Biological Resource Use:Gathering natural materials:Removal of bush rocks||Zieria baeuerlenii in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006wy) [Internet].|
|Climate Change and Severe Weather:Droughts:Drought||Zieria baeuerlenii in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006wy) [Internet].|
|Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence)||Zieria baeuerlenii in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006wy) [Internet].|
|Human Intrusions and Disturbance:Recreational Activities:Disturbance, especially from human recreational activities and development||National Recovery Plan for Zieria baeuerlenii (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010m) [Recovery Plan].|
|Human Intrusions and Disturbance:Recreational Activities:Soil disturbance and/or trampling due to bushwalking||National Recovery Plan for Zieria baeuerlenii (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010m) [Recovery Plan].|
|Human Intrusions and Disturbance:Recreational Activities:bicycles (off road)||National Recovery Plan for Zieria baeuerlenii (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010m) [Recovery Plan].|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Oryctolagus cuniculus (Rabbit, European Rabbit)||
The threat posed by pest animals to biodiversity in New South Wales (Coutts-Smith, A.J., P.S. Mahon, M. Letnic & P.O. Downey, 2007) [Management Plan].
National Recovery Plan for Zieria baeuerlenii (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2010m) [Recovery Plan].
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Pennisetum clandestinum (Kikuyu)|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation||Ageratina adenophora (Crofton Weed, Catweed, Hemp Agrimony, Mexican Devil, Sticky Agrimony, Sticky Eupatorium)|
|Ipomoea cairica (Coastal Morning-glory, Morning Glory, Mile-a-minute, Five-leaved Morning Glory)|
|Bryophyllum tubiflorum (Mother-of-millions)|
|Lantana camara (Lantana, Common Lantana, Kamara Lantana, Large-leaf Lantana, Pink Flowered Lantana, Red Flowered Lantana, Red-Flowered Sage, White Sage, Wild Sage)|
|Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds|
|Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Presence of pathogens and resulting disease|
|Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Slashing and herbicide application for weed control|
|Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity)|
|Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes|
|Pollution:Garbage and Solid Waste:Dumping of household and industrial waste|
|Residential and Commercial Development:Housing and Urban Areas:Habitat loss, modification and fragmentation due to urban development|
|Species Stresses:Indirect Species Effects:Low genetic diversity and genetic inbreeding|
|Species Stresses:Indirect Species Effects:Low numbers of individuals|
|Transportation and Service Corridors:Roads and Railroads:Development of roads and railroads|
|Transportation and Service Corridors:Utility and Service Lines:Habitat modification due to maintenance of water pipeline easement|
|Transportation and Service Corridors:Utility and Service Lines:Powerline easement maintenance and construction; mortality due to collision with powerlines|
Barratt, T. (1999). The Bomaderry Zieria, a seedless entity?. Hons. Thesis. University of Wollongong.
Barratt, T. (2007). Survey and Monitoring for Zieria baeuerlenii at Bomaderry Bushland, 2007. Unpublished report for the Nowra Area of the NSW National Parks and Wildlife Service.
Briggs, J.D. & J.H. Leigh (1990). Delineation of Important Habitats of Threatened Plant Species in South-Eastern New South Wales. Canberra: Australian Heritage Commission.
NSW Department of Environment, Climate Change and Water (NSW DECCW) (2006b). Bomaderry Creek Regional Park Fire Management Plan. Hurstville, NSW: DECCW.
NSW Department of Environment, Climate Change and Water (NSW DECCW) (2010m). National Recovery Plan for Zieria baeuerlenii. [Online]. Queanbeyan, New South Wales: Department of Environment, Climate Change and Water. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/zieria-baeuerlenii.html.
NSW National Parks & Wildlife Service (2002i). Recommendation for the Identification of Critical Habitat for the Bomaderry Zieria (Zieria baeuerlenii). [Online]. NSW National Parks & Wildlife Service. Hurstville, NSW. Available from: http://www.environment.nsw.gov.au/resources/nature/bomaderryZieriaDraftRecommendation.pdf.
This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.
Citation: Department of the Environment (2014). Zieria baeuerlenii in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 22 Aug 2014 09:41:22 +1000.