The Coastal Upland Swamps in the Sydney Basin Bioregion ecological community includes a range of vegetation and fauna associated with periodically waterlogged soils on the Hawkesbury sandstone plateaux. It is endemic to NSW, occurring within the eastern part of the Sydney Basin IBRA bioregion.
Coastal Upland Swamps in the Sydney Basin Bioregion
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
Conservation Advice (including listing advice) for Coastal Upland Swamps in the Sydney Basin Bioregion
It is acknowledged that many threats; notably impacts of subsidence; inappropriate fire regimes and climate change still pose significant risks to the ecological community; even where it occurs on conservation tenure.
Changes in climatic conditions and fire frequency associated with climate change.
The main mechanisms leading to altered hydrological processes are the fracturing of rock strata associated with subsidence and climate change.
Climate change The Coastal Upland Swamps community has a strong association with high levels of climatic moisture.
Available climate modelling; to date for the region; predicts that temperatures will become warmer and that rainfall patterns will be drier (NSW Scientific Committee; 2012).
Results suggest that in response to climate change; hydrologically suitable environments for the Coastal Upland Swamps will contract and shift in a south west direction; with the northern boundaries moving south more rapidly than southern margins (Keith et al.; 2014).
Key threatening processes The following listed key threatening processes are most relevant to the ecological community National (EPBC Act) Land clearance Loss of terrestrial climatic habitat caused by anthropogenic emissions of greenhouse gases Novel biota and their impact on biodiversity NSW (TSC Act) Anthropogenic climate change Alteration of habitat following subsidence due to longwall mining Clearing of native vegetation Herbivory and environmental degradation caused by feral deer APPENDIX D ELIGIBILITY FOR LISTING AGAINST THE EPBC ACT CRITERIA Criterion 1 Decline in geographic distribution There are insufficient data to estimate historical (since 1750) changes in swamp area in detail.
It was found that there was a net expansion of sample swamps (mean increase of 10.2 range 3 32 ) into surrounding woodland; likely attributable to increasing climatic moisture during this period.
Over its entire range; these threats may cause the ecological community to be lost in the near future (in this case; 50 years being a relevant timescale); due to the combined impacts of hydrological change resulting from geological subsidence; inappropriate fire regimes and the predicted decline in climatic moisture as a result of climate change (Keith; 2013).
Decadal change in wetland woodland boundaries during the late 20th century reflects climatic trends.
High frequency fire threatening structurally dominant species and low variability fire regimes; potentially threatening non dominant species.
Eucalypt woodland FIRE REGIMES Increasing moisture availability Banksia thicket Declining moisture availability FIRE REGIMES Sedgeland Restioid heath FIRE REGIMES Cyperoid heath FIRE REGIMES Ti tree thicket Restioid rush like plants belonging to the family Restionaceae Cyperoid sedges belonging to the family Cyperaceae Figure 1 A cause effect process model summarising ecosystem dynamics in the Coastal Upland Swamps (adapted from Keith; 2013).
Various other published and unpublished studies have also recognised the Coastal Upland Swamp as a distinctive community (NSW Scientific Committee; 2012) APPENDIX C DESCRIPTION OF THREATS Interactions between hydrological processes and fire regimes are crucial to the development of the Coastal Upland Swamps.
Note that these predictions do not take into account declines exacerbated by changes in hydrological regimes resulting from mining activities (Keith et al.; 2014) or impacts from more frequent fire events; or other disturbances.
In their study examining wetland dynamics; Keith et al. (2010) concluded that fire frequency parameters on their own are a poor predictor of spatial patterns in swamp vegetation changes.
The eastern pygmy possum; southern emu wren and beautiful firetail are additional species from the upland swamps that may be threatened by fire (DECC; 2007b).
There were also significant declines in non woody resprouting species (Keith et al.; 2007) This represents a considerable shift in the diversity of understorey species and lifeforms as a consequence of altered fire hydrological regimes and interactions.
Such impacts are difficult to predict but can include desiccation; decreased water quality; increased erosion and increased susceptibility to extreme weather events.