This ecological community includes plants, animals and other organisms associated with a tall forest to woodland structure, with a canopy dominated by eucalypts and an understorey of small trees, shrubs, grasses, other herbs and climbers. It is found on the floodplains of the eastern and southern watershed of the Great Dividing Range from central and southern New South Wales to eastern Victoria.
River-flat eucalypt forest on coastal floodplains of southern New South Wales and eastern Victoria
Status: Critically Endangered on the EPBC Act list
Government evidence of impact of climate change:
Conservation Advice for the River-flat eucalypt forest on coastal floodplains of southern New South Wales and eastern Victoria
The altered local micro climate may; in turn; adversely impact patches of the ecological community within and adjacent to urban developments.
This process operates in addition to any temperature rise due to global climate change.
Climate Timing Major impacts of climate change are likely to be played out through change Ongoing interactions with other threatening processes; including habitat loss and degradation; invasion of exotic species and changes to Severity hydrological and fire regimes (Auld Keith 2009 Dunlop Major Brown 2008).
A generally warming and drying climate in southern and eastern Scope Australia is likely to significantly reduce run off to coastal rivers and Whole streams within the range of the ecological community (DCC 2009).
Climate change is likely to intensify drought events (Dai 2012 Mitchell et al. 2016); which may exacerbate mortality in eucalypt populations.
Latitudinal shift in the distribution of this ecological community is a plausible response to climate change; but the area to shift into may not be available or suitable; because of coastal development; soil types or competition with other vegetation communities (Paice Chambers 2016).
Fires frequency; intensity and size are expected to increase under climate change as temperatures rise; rainfall variability increases; droughts become more severe and ecosystem dynamics alter; resulting in changed biomass fuel loads and types.
The projected hotter; drier; windier conditions associated with climate change caused by greenhouse warming would extend the period of fuel drying and increase rates of fire spread (Harrison Kelley 2017).
Table 2 Key threatening processes which may be relevant to the ecological community EPBC listed key threatening processes NSW listed key threatening processes Land clearance Clearing of native vegetation Removal of dead wood and dead trees Loss of hollow bearing trees Alteration to the natural flow regimes of rivers and streams and their floodplains and wetlands High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition Loss of climatic habitat caused by Anthropogenic climate change anthropogenic emissions of greenhouse gases Loss and degradation of native plant and animal Loss and degradation of native plant and animal habitat by invasion of escaped garden plants; habitat by invasion of escaped garden plants; including aquatic plants including aquatic plants Novel biota and their impact on biodiversity Invasion; establishment and spread of Lantana camara Invasion of native plant communities by exotic perennial grasses Invasion and establishment of exotic vines and scramblers Invasion of Native Plant Communities by African Olive (Olea europaea subsp. cuspidata) Competition from feral honeybees Apis mellifera L.
Other threats; such as potential adverse impacts from climate change are likely to exacerbate these threats and further contribute to loss of integrity over time.
Bushfire frequency; intensity and size are expected to increase because of climate change; as temperatures rise; rainfall variability increases; droughts become more severe and ecosystem dynamics alter resulting in changed biomass fuel loads and types.
The projected hotter; drier; windier conditions associated with climate change will extend the period of fuel drying and increase rates of fire spread (Harrison Kelley 2017); as was seen during the 2019 20 fire season.
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).
Increasing drought under global warming in observations and models.
The nature of some areas of the ecological community has changed structurally due to clearing; followed by regrowth that is likely to be subject to altered fire and water regimes and livestock grazing. 3.1 Threat table Table 1 outlines the key threats facing the ecological community.
Once established; weeds can change nutrient cycling; species composition; structure; habitat values and fire regimes in the ecological community (Good et al. 2017).
Sustained high frequency fire will lead to a loss of eucalypts and other plant species; a reduction in vegetation structure and a corresponding loss of animal species in the ecological community (NSW OEH 2017b).
Mega fires; such as those experienced in the 2019 2020 fire season; can burn a significant proportion of the ecological community (an estimated 50 percent of the ecological community was within the extent of the 2019 20 bushfires (DAWE 2020b)) and the surrounding vegetation in a single event; which compounds these detrimental impacts.
Species composition of this ecological community is influenced by; amongst other things the size of the patch; proximity of other native vegetation; seasonal conditions (e.g. rainfall and temperature); latitude; inundation frequency; hydrological conditions and disturbance history (including fire and grazing).
Monitor the outcomes of fire and the consequences of other threats.
Once established weeds can change nutrient cycling; species composition; structure; habitat values and fire regimes in the ecological community (Good et al. 2017).
The Grey headed Flying fox; for example; underwent an estimated 30 percent decline in abundance over a decade and it suffered more recent large declines due to heat stress and fire (TSSC 2001 NSW OEH 2019).
Inappropriate fire regimes; grazing by stock and invasive herbivores; invasion by weeds; and hydrological alteration have resulted in the loss of groundcover and understorey structure and flora species.
Reduction in integrity through altered fire regimes Fire regimes have been changed throughout the extent of the ecological community; in association with the growth of agriculture and urban development.
Sustained high frequency fire will lead to a loss of plant species; a reduction in vegetation structure and a corresponding loss of animal species in the ecological community (NSW OEH 2017b).
Mega fires; such as those experienced in the 2019 20 fire season; can burn a significant proportion of the ecological community (an estimated 50 percent of the ecological community was within the 2019 20 fire extent (DAWE 2020b)); as well as burning the surrounding vegetation in a single event; which compounds these adverse impacts.
Many of the underlying threats have ongoing detrimental impacts; most evident from invasive flora; fauna; diseases and inappropriate fire regimes.
Koalas generally favour habitats on soils with higher fertility and soil moisture such as the ecological community; particularly during times of high temperature and drought (Ellis et al. 1995).
For instance; do not burn areas in or adjacent to the ecological community when key; threatened or functionally important flora and fauna (that may be adversely impacted) are flowering; nesting or otherwise reproducing. o Consider weather conditions.