The main factors that make the threatened ecological community eligible for listing in the Critically Endangered category are its historic losses to clearing and resulting fragmentation; and ongoing threats to its integrity and function; including invasive species and risks associated with unsuitable fire regimes that are increased by climate change.

Urban development also results in hydrological change and eutrophication through urban runoff; water diversion and groundwater extraction; as well as regional climate change; for example; due to urban heat islands (Coutts et al 2007).

Increasingly warm and dry conditions associated with a changing climate will likely influence the frequency; spatial extent and intensity of fires.

Climate change Timing ongoing Climate change projections for the region include higher and severe average and maximum temperatures; substantially declining weather Severity major rainfall; particularly in the cooler months; as well as more compound extreme events such as drought; heat waves and an increase in days of dangerous fire weather (Hennessy et Scope whole al. 2005 BOM and CSIRO 2020).

According to Dunlop et al. (2017) The ESBS community is regarded as particularly vulnerable to climate change.

Climate change is likely to increase weather conditions associated with substantial wildfires and exacerbate fire impacts; causing losses of large areas of native vegetation and fauna (Hennessy et al. 2005 Deb et al. 2020).

Given the very particular dependence of the ecological community on suitable fire regimes; with a very small and fragmented area; in the context of climate change and extreme fire weather; the risk of substantial damage by unplanned fire is high even in the larger and most intact remnants.

Climate change is also likely to cause other losses and changes beyond those associated with unplanned fire; with changes in precipitation; incursions of invasive species and increases in temperature extremes that may be beyond tolerances of some species in the ecological community (Dunlop et al. 2017).

As climate changes throughout the region there is an increased risk of drought and fire; such as those that burned vast areas of the south east coast of Australia in late 2019 and early 2020 (Hennessy et al. 2005 Deb et al. 2021).

Beyond the risks of fire; the ongoing change in climate towards overall hotter and drier conditions with greater extremes will place pressures on many species in the ecological community.

They also change over time; for example; in response to disturbance (by logging; fire; or grazing); or to the climate and weather (e.g. seasons; floods; drought and extreme heat or cold).

Clearing; fragmentation; soil loss and substantial disturbance; changed fire regimes; weeds; feral animals; and other types of damage have reduced the ecological community s historical floristic variability and condition (NSW Scientific Committee 2002 NSW Threatened Species Scientific Committee 2017).

However; as the time since fire increases beyond 15 years (DECC 2009a Lambert Lambert 2015a); species diversity typically declines as short lived species senesce and remain present primarily in the seed bank until cued to emerge as seedlings by another fire.

Fire frequency may also be increased in the edges of patches; for example as low fuel asset protection zones for nearby urban areas or by arson.

Increased human populations near natural areas may lead to their appreciation but there is increased pressure on these areas; with problems including profusion of pedestrian tracks; bike and four wheel drive trails; weed invasion (including from escaped garden plants); disease spread; cubby construction; social activities; golf ball accumulation and collection; changed fire frequency and intensity (including through arson or fire prevention); rubbish dumping (including construction waste); mowing or tidying up native areas; flower and firewood collection.

Declines in species diversity are least likely to occur under a variable fire regime (frequency; severity and season) (Keith et al. 2002) High frequency fires are likely to lead to declines in obligate seeders (intervals c.7 years); although the threshold of sensitivity is likely to be longer in dry years; and prevent juvenile re sprouters attaining fire tolerance ( c.14 years) (Tozer et al. in review).

Other fire related threats relevant to this community include fire drought interactions; fire predator interactions; fire herbivore interactions (notably rabbits; deer); fire competition interactions (notably weeds); fire fragmentation interactions (for example; see Driscoll et al. 2021) and disturbance from fire suppression operations; including application of fire retardants.

Loss of vegetation structure and composition may enhance the invasion or spread of exotic species Introduction of fire without effective pest control may expose regenerating seedlings to herbivory from rabbits (or native fauna) which may negatively impact the lower strata (Lambert Lambert 2015a Lambert et al. 2015 Strauch 2015) and lead to a subsequent increase in predation by feral or native predators on native fauna (Hoerr 2021).

The large area burned in this fire also creates a risk that any subsequent fires may occur before maturity of some plant and animal species.

These invasive plants compete with and exclude native plant species typical of the ecological community and cause change in ecological function; for example; by changing fire behaviour.

Interactions with fire are likely to exacerbate impacts of invasive species; particularly through post fire predation; herbivory and weed invasion.

With the loss of traditional burning regimes since non Indigenous settlement and changes in land use and landscape; the fire ecology of the ecological community is greatly altered right across its range.

As with the damage by rabbits after fire at North Head and the dispersal of weeds by foxes; the interactions between different drivers of landscape change can lead to more extreme or unpredictable results.

Fire is a key driver of change in ecological character and condition of Eastern Suburbs Banksia Scrub.

Other fire related threats relevant to this community include fire drought interactions; fire predator interactions; fire herbivore interactions (notably rabbits; deer); fire competition interactions (notably weeds); fire fragmentation interactions (for example; see Driscoll et al. 2021) and disturbance from fire suppression operations; including application of fire retardants.