Grevillea banyabba  |  

Threats The Banyabba Grevillea is threatened by climate change; invasive species; disease; and habitat loss; disturbance and modifications.

Table 1 Threats impacting the Banyabba Grevillea Threat Status and severity a Evidence Climate change Inappropriate fire Timing current A high frequency fire regime ( 15 years) is likely to regimes Confidence known reduce the population size and vigour of the Banyabba Grevillea; following the destruction of adult Consequence major plants; depletion of soil stored seed banks and Trend increasing invasion of introduced grasses (Sheringham Extent across the entire Westaway 1995 DECCW 2010 OEH 2020a).

This type of event is increasingly likely to reoccur as a result of climate change.

Such events are Extent across the entire increasingly likely to happen due to climate change. range Such changes in climate may cause widespread plant mortality in forest ecosystems; as many plants are vulnerable to drought stress and hydraulic failure (Allen et al. 2010 Choat et al. 2012).

Understand and ameliorate the effects of climate change on the species by mitigating interactions with other threats such as fire; disease and habitat degradation.

The species is threatened by several fire related threats; including high frequency fire; fire drought interactions; fire disease interactions; and fire promoted weed invasion.

Additionally; small population sizes and inbreeding may reduce genetic variation and increase the likelihood of population extinction following stochastic events; such as disease or fire (NPWS 1999 OEH 2020a).

Fire intensity and severity varied across the bushfire extent; with many patches burning at extreme intensity and severity while others remained unburnt (DPIE 2020).

The life history traits of the Banyabba Grevillea predispose it to high risk of population decline or extinction; resulting from short fire intervals; fire disease interactions; high fire severity and cumulative exposure to high risks (Gallagher 2020).

Interactions between fire and seed predators may also elevate risks of decline; especially under small or patchy fires (Regan et al. 2003).

Extent across the entire Once established; introduced grasses can alter range community structure; fuel load and fire regimes (D’Antonio Vitousek 1992 NSW Scientific Committee 2003 Rossiter et al. 2003 Flory et al. 2015).

These altered fire regimes can create conditions that are detrimental to the maintenance of native species and favourable to the establishment and spread of introduced grasses (D’Antonio Vitousek 1992 Grigulis et al. 2005).

Small population sizes and inbreeding may reduce genetic variation and increase the likelihood of population extinction in the Banyabba Grevillea; following stochastic events; such as disease or bushfire (NPWS 1999 OEH 2020a).

The species is threatened by several fire related threats; including high frequency fire; fire drought interactions; fire disease interactions; and fire promoted weed invasion.

Indeed; dieback of leaves and branches in Consequence moderate mature individuals has been attributed to this Trend increasing drought event (DPIE 2021).