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Flora Management Threatened Species

Threatened Flora of the Park

Original text by Jamie Slaven, revised and updated by Dr Steven Douglas in 2023 

Berowra Valley National Park is home to some several rare and threatened native plant taxa, some of which have very restricted areas of occurrence. None are endemic (confined to) the National Park, but some do not extend far beyond it.

Persoonia mollis subsp. maxima 

Persoonia mollis subsp. maxima is a tall shrub which grows 2-6 m high with soft hairy young branchlets, buds and young leaves. This very rare plant has small yellow flowers and produces small green fruit, which become purplish-brown and soft when mature. Mature plants have a single trunk. 

This species is listed as Critically Endangered. It is highly restricted in distribution and known only from three creek catchments in northern Sydney. Berowra Valley National Park and neighbouring bushland support most of these populations including the Calna Creek population and Berowra Creek population which adjoin the suburbs of Galston, Hornsby Heights, Mt Colah and Mt Kuring-gai.  

The habitat for Persoonia mollis subsp. maxima is deep gullies and on steep upper hillsides of narrow gullies on Hawkesbury sandstone, which support relatively moist, tall forest consisting of Sydney Red Gum Angophora costata and Sydney Peppermint Eucalyptus piperita, often with Turpentine Syncarpia glomulifera, NSW Christmas Bush Ceratopetalum gummiferum, Coachwood Ceratopetalum apelatum and Black Wattle Callicoma serratifolia. Some isolated records of this species have been on ridge-tops in woodland dominated by Scribbly Gum Eucalyptus haemastoma and Grey Gum Eucalyptus punctata

The main threats to the remaining populations include inappropriate fire, along with weed invasion, reduced water quality and rubbish dumping. 

Darwinia biflora 

Darwinia biflora is a small erect or spreading shrub to 80 cm high and is in the Myrtaceae family along with eucalypts, ti-trees, bottlebrushes and many other genera. The flowers are small and green, surrounded by two red bracteoles. The flowers are in pairs, hence their name “bi-flora”. Flowering occurs mainly in autumn and sometimes throughout the year with mature fruits from May to August. 

This species is classified as Vulnerable and is largely restricted to northern Sydney in an area between Maroota in the north, North Ryde in the south, Berowra in the east, and Kellyville in the west. There is an outlying western population at Springwood in the lower Blue Mountains, and a credible record of a now-extinct population from Waterfall, probably in Royal National Park. Most of the populations occur in the Hornsby Local Government Area. Darwinia biflora is found in the Berowra Valley National Park with relatively large populations around Hornsby Heights, Mt Colah, Mt Kuring-gai and Berowra. It is found on the Mittagong Formation (often poorly drained clayey soils) and upper Hawkesbury Sandstone, usually with ‘ironstone’ (laterite). Associated vegetation includes Scribbly Gum Eucalyptus haemastoma, Red Bloodwood Corymbia gummifera, Dwarf Apple Angophora hispida Heath Banksia Banksia ericifolia, and Black Sheoak Allocasuarina littoralis

Destruction and degradation of habitat is the main threat to this species as it usually grows on ridge-tops and plateau edges that have been and continue to be lost to land clearing for housing, industry, powerlines, and rural-residential use. Habitat degradation from weed invasion, inappropriate fire regimes, and illegal track creation are other threats to this species. 

Threatened Ecological Communities 

Ecological communities are natural assemblages of species, primarily plants, usually associated with certain environmental conditions such as rock type, soil type, landscape position, and other aspects of geography. They may also be associated with specific fauna species. 

Threatened ecological communities (TECs) are classified the same as species: Critically Endangered, Endangered, and Vulnerable. They are declared under both NSW and Commonwealth laws. In some cases, the definition is the same under both laws, but often there are differences, and not just those relating to the scale of assessment. This text only deals with the TECs listed under NSW law. 

Berowra Valley National Park contains the following TECs based on composite mapping provided by the NSW environment agency’s Vegetation Science team. Links are provided to the agency’s profile pages for each TEC, and the associated pages provide further links to the official definitions of the TEC and to associated publications and projects: 

Hornsby Shire contains additional TECs, some of which may be present in the National Park to a minor degree that is too small to have been detected in various mapping projects. For examples, Sydney Turpentine-Ironbark Forest is present in the Shire but is not mapped within Berowra Valley National Park. Additionally, much of the Blue Gum High Forest that is mapped in the Park is not typical of this TEC (which primarily occurs on shale ridgetops and slopes) and is instead a variant known as Blue Gum Diatreme Forest (or Glen Forest in earlier mapping).  

The Table below shows the very small areas of TECs mapped in the Park. The total area of the Park is 3884 hectares, meaning that the total area of all mapped TECs within it is only 0.6% of the Park. 

Threatened Ecological Community (TEC) Hectares in BVNP Percentage area of BVNP Percentage of Hornsby LGA outside BVNP 
Blue Gum High Forest 2.14 0.055 0.452 
Coastal Saltmarsh 2.69 0.069 0.158 
Coastal Upland Swamp 1.56 0.040 0.046 
Duffys Forest Ecological Community 5.70 0.147 0.030 
Riverflat Eucalypt Forest on Coastal Floodplains 2.16 0.056 0.019 
Swamp Oak Floodplain Forest 7.45 0.192 0.825 
SSTF Shale-Sandstone Transition Forest – – 0.010 
Sydney Turpentine-Ironbark Forest – – 0.901 
Swamp Sclerophyll Forest on Coastal Floodplains – – 0.011 
Cooks River/Castlereagh Ironbark Forest – – 0.002 
Totals:   21.7 0.6 2.5 

In general, formal conservation reserves such as Berowra Valley National Park lack TECs that are associated with more arable landscapes such as the shale ridgetops that supported taller and straighter trees, with better soil for farming, more gentle terrain, and less fire risk. Many TECs are now rare and threatened because they represent landscapes that were preferred for logging, farming, and later housing and industry.  

Most formal conservation reserves are dominated by sandstone-based terrain that is infertile, unsuited to agriculture, can be steep, and often has a high fire risk. In many ways, our bushland reserves are comprised of land areas that were or are not economically significant for other land uses. They are biodiverse, contain significant populations of threatened species, and otherwise ecologically and culturally significant, but they rarely contain significant areas of some TECs, and often lack TECs completely. 

Maps of the TECs in the Park and in the Shire are not provided here because they are not meaningful at this scale. The TEC map of the Park shows only tiny areas of TECs when produced at A4 scale. Readers interested in TECs and their mapping in Greater Sydney can explore the resources available here: https://datasets.seed.nsw.gov.au/dataset/threatened-ecological-communities-greater-sydney. Note that TEC maps are often composites of various mapping projects, and that Plant Community Type (PCT) mapping, which is the modern standard in NSW, is rarely able to be directly translated into TEC maps because almost all TECs were declared prior to PCT mapping and classification. 

Key Threatening Processes 

Key Threatening Processes (KTPs) are listed under both NSW and Commonwealth laws and threaten or have the capability of threatening the survival or evolutionary development of a species, population or ecological community. Numerous KTPs are currently listed, and additional listings are expected. No KTPs have been delisted at this time. All KTPs are meant to be addressed by Threat Abatement Plans. Some KTPs are the same or at least similar under the different laws, but some are significantly different. Most KTPs relate to threats such as land clearing, weed invasion, feral animals, diseases, inappropriate fire, and removal of key habitat components such as hill-topping sites, wetlands, hollow-bearing trees and logs. 

Examples of some listed KTPs relevant to Berowra Valley NP or adjoining areas that affect it include: 

  • bushrock removal; 
  • Invasion of native plant communities by exotic perennial grasses; 
  • Infection of native plants by Cinnamon Fungus Phytophthora cinnamomi
  • competition from feral honeybees Apis mellifera
  • introduction of the large earth bumblebee Bombus terrestris
  • infection by Psittacine Circoviral (beak and feather) disease affecting endangered psittacine species and populations; 
  • importation of Red Imported Fire Ants Solenopsis invicta (Buren 1972) into NSW; 
  • removal of dead wood, dead trees and logs; 
  • competition and grazing by the feral European Rabbit Oryctolagus cuniculus 
  • alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands; 
  • clearing of native vegetation; 
  • loss and/or degradation of sites used for hill-topping by butterflies; 
  • high-frequency fire resulting in the disruption of life-cycle processes in plants and animals and loss of vegetation structure and composition; 
  • predation by the Feral Cat Felis catus
  • invasion of native plant communities by Chrysanthemoides monilifera
  • predation by Gambusia holbrooki (Plague Minnow) – a small freshwater fish; 
  • predation by the European Red Fox Vulpes vulpes

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