The Castlereagh Scribbly Gum and Agnes Banks Woodlands ecological community is located in the Sydney Basin Bioregion. It occurs primarily in the Castlereagh area in the north-west of the Cumberland Plain (also referred to as the Cumberland sub-region), with other known occurrences near Holsworthy, Kemps Creek and Longneck Lagoon.
Castlereagh Scribbly Gum and Agnes Banks Woodlands of the Sydney Basin Bioregion
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
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Approved Conservation Advice (including listing advice) for Castlereagh Scribbly Gum and Agnes Banks Woodlands of the Sydney Basin Bioregion
Other ongoing threats include Climate change.
Climate change is expected to cause increasing damage to the ecological community; through changed temperature and rainfall patterns.
These losses are compounded by climate change; and together with a range of ecological characteristics of the community; as well as the nature of the ongoing threats; severely limit the likelihood of recovery.
Climate change Climate change is now understood to pose a serious long term threat to terrestrial and aquatic ecosystems and to have the potential to change the ecology of these environments; through changed species composition and function (Dunlop et al.; 2012).
Not only does climate change directly threaten species that cannot adapt; it is also likely to exacerbate existing threats; including loss of habitat; altered hydrological regimes; altered fire regimes and invasive species.
In summary; these include Continued clearing; degradation; and fragmentation will limit the ability of the ecological community to adapt and or migrate in response to climate change Invasion by non native plant species is likely to increase in intensity; spread; and diversity; with some such species taking advantage of climate change induced effects such as periodic depletion of ground cover due to drought and over grazing Altered native flora and fauna species mix and Altered fire regimes due to changed climate and weather; and due to changed vegetation structure and composition.
Conversely; small; fragmented remnants can be more susceptible to catastrophic events (such as extreme weather events); weed and feral animal incursion; and potential impacts from climate change (NSW DECCW; 2010).
Reduction in integrity through climate change As described in Appendix C Description of Threats; climate change is likely to compromise the integrity of the community both directly and by altering the survival rates of constituent species.
These losses are compounded by climate change; and together with a range of ecological characteristics of the community; as well as the nature of the ongoing threats; severely limit the likelihood of recovery.
In addition to clearance and fragmentation of native vegetation; key threats to the ecological community occurring as a result of increasing urbanisation are Inappropriate fire regimes; particularly increased fire frequency (e.g. due to arson).
Key threats include clearance and fragmentation of remnants as well as weed invasion and altered fire regimes (particularly due to arson).
In addition to direct stress on plants and animals; this is likely to result in changed habitat features and food availability; as well as being expected to compound other threats such as weeds and altered fire regimes.
Clearing; severe fragmentation; urbanisation; weed invasion; altered fire regimes; changes to vegetation structure and loss of faunal components have severely reduced the integrity of the ecological community.
The main threats are vegetation clearance due to agriculture and; more recently; urban expansion altered fire regimes and weed invasion.
Altered fire regimes The vegetation composition of Castlereagh Scribbly Gum and Agnes Banks Woodlands is influenced by a range of factors including its recent disturbance history and patch size (NSW Scientific Committee; 2000; 2010).
Leary (2007) also comments on the substantial reduction and modification of ground cover; due to the alteration of fire regimes.
Key threats include clearance and fragmentation of remnants as well as weed invasion and altered fire regimes (particularly due to arson) (NSW Scientific Committee; 2010 Steenbeeke; pers. comm.; 2014).
In addition to direct stress on plants and animals; this is likely to result in changed habitat features and food availability; as well as being expected to compound other threats such as weeds and altered fire regimes.
Loss of structural integrity has also occurred due to under scrubbing; inappropriate fire regimes and a variety of other impacts from rural residential development and recreational use.
Once established weeds adversely affect native species through direct competition or by altering ecosystem processes; such as disrupting food webs or dispersal agents (as when natural pollinators visit weeds rather than native species) or changing fire regimes (for instance the establishment of more flammable invasive grass species into a patch).
It is also likely to interact with other threats; such as changed fire regimes or the invasion of weeds.
Summary Substantial clearing; severe fragmentation; urbanisation; weed invasion; altered fire regimes; changes to vegetation structure and loss of faunal components have substantially reduced the integrity of the ecological community across its range.