This has been attributed at least in part to anthropogenic climate change; and if so; this trend is likely to continue; exacerbating the altered hydrology caused by river regulation.
The sediments and dunes surrounding the lake provide a record of past water levels and reflect climatic changes in the region over the last 10 000 000 years (Environment Australia; 2001). 6.2.8 Biodiversity In total; over 500 species of plants and animals have been recorded at the site.
Threats hydrological change through water regulation and diversion climate change decline in Eucalypt woodland health recreation terrestrial and aquatic invasive species declining surface water quality . .
Key Threats River regulation; climate change (reduced rainfal); decline in Eucalypt woodland condition; introduced species and potentially; recreational activities.
Based on climate change predictions simple modelling estimated that environmental flows as a result of water saving in the Wimmera Glenelg Rivers could be negated by 2030; however this is indicative only; due to climate change uncertainties and the simplified modelling techniques used (Victorian Government; 2003).
At the time of writing the water allocation system is being amended to allow for climate change impacts on all entitlement holders.
If catchment rainfall and environmental water releases are sufficient; the resulting improvements in flood frequency and duration should help to mitigate further impacts on the ecological character of Lake Albacutya by improving River Red Gum health and recruitment and restoring aquatic habitat and nutrient cycling. 9.1.2 Climate change Climate describes long term trends in weather parameters in terms of their average; range and variability.
The research proposes that the subtropical ridge of high pressure over eastern Australia has increased in intensity as a result of climate change; resulting in rain bearing storms that normally benefit southern Australia being pushed further south and into the southern ocean.
The vast majority of models show a decrease in run off in the Wimmera region as a result of climate change.
The extreme high global warming scenario was predicted to result in a decrease in run off of up to 47 in one model to an increase of run off of 1 in another.
The extreme low global warming scenario was predicted by the various models to cause a reduction in run off ranging from 0 to 16 .
If climate change occurs as predicted it can be expected to cause major hydrological and ecological changes to Lake Albacutya through reducing run off in the region and therefore flow in the Wimmera River.
Under both the medium and high global warming scenarios it is predicted that Lake Albacutya would be unlikely to ever fill.
Even under the low global warming scenario it is predicted that Lake Albacutya would fill less often.
It is clear that climate change could pose a severe threat to the hydrological regime of the lake; which is already under significant pressure from river regulation.
An increase in the occurrence of extreme weather events is also frequently predicted in climate change models.
High global warming Medium global warming Low global warming change in mean annual runoff ps gfdi cnrm csiro mroc giss aom nmcm mri mpi des miub ncar ccsm ncar pcm cccma cocma t Figure 9.3 Climate change predictions for runoff in the Wimmera region for the year 2030 from a range of models (CSIRO; 2007) Ecological Character Description for the Lake Albacutya Wetland of International Importance 9.1.3 Decline in Eucalypt woodland health Widespread dieback of River Red Gums has been well documented in the area (Wouters; 1993) and this has been attributed to a lack of regular flooding; as has the notable lack of River Red Gum regeneration in the area.
Key Threats River regulation; climate change (reduced rainfall); decline in Eucalypt woodland condition; introduced species and potentially; recreational activities.
Climate change Average rainfall in the Wimmera River catchment over about the last 10 years has been significantly lower than the long term catchment average.
This has been attributed; at least in part; to anthropogenic climate change and is expected to continue.
The vast majority of various climate change prediction models; compiled by CSIRO (2007) predict a significant decrease in run off; with a median estimate of a decrease of 17 from 1990 to 2030.
Over the longer term; human induced climate change also poses a threat; with a predicted reduction in catchment rainfall contributing pressure to the already stressed hydrology.
More recently the threat of climate change and predictions of reduced catchment rainfall may; if they eventuate; add to the hydrological stresses.
An extended drought has been evident since Ecological Character Description for the Lake Albacutya Wetland of International Importance about 1995 which continues at the time of writing; and this has been attributed; at least in part; to the effects of climate change (Steffen; 2009).
This recent reduced capture of catchment flows has been primarily a result of the drought and subsequent reduced streamflows experienced in the catchment from 1995 (National Water Commission; 2005); and this has recently been attributed at least in part to climate change (Steffen; 2009) and if this is correct then this trend is likely to continue.
However it now appears that the drought affecting southern Australia from 1995 is at least partly a result of anthropogenic climate change and that reduced rainfall and catchment runoff are likely to continue.
In summary then; it is concluded that the surface water hydrology has not changed significantly since the time of listing; however it does appear to be undergoing change as a result of anthropogenic climate change and this trend should be monitored. 5.2 Eucalypt woodland The River Red Gum health at Lake Albacutya has been surveyed once in 1993; 11 years after listing; when significant dieback was recorded.
Table 6.1 Critical benefits services; components and processes that contribute directly to the Ramsar values of Lake Albacutya and potential threats Benefit service Description Potential threats Ramsar criteria Critical components processes Morphology Hydrology Near natural wetland representativeness River regulation Climate change Lake Albacutya is a representative example of a near natural intermittent subterminal lake within the Murray Darling Drainage Division.
Waterbirds Hydrology Eucalypt woodland River regulation Climate change Decline in Eucalypt woodland health Recreation Invasive species Declining surface water quality Waterbird habitat 3; Supports more than 5 of the south eastern Australian population of Freckled Duck; more than 4.5 of the Banded Stilt population and 1 of the Australasian shoveler population.
Waterbirds (Freckled Duck; Banded Stilt and Australasian Shoveler) Hydrology Eucalypt woodland River regulation Climate change Decline in Eucalypt woodland health Recreation Invasive species Declining surface water quality 3; Supports threatened species Supports breeding populations of nationally vulnerable Regent Parrot. 2 of the national population recorded at site.
Figure 9.3 Climate change predictions for runoff in the Wimmera region for the year 2030 from a range of models Figure 9.4 Driver stressor model for Lake Albacutya Ecological Character Description for the Lake Albacutya Wetland of International Importance List of tables Table 1.1 Details of the Lake Albacutya Ramsar site Table 2.1 Land use; with average annual precipitation and run off across the Wimmera Avon River Basin .
This has been attributed at least in part to anthropogenic climate change; and if so; this trend is likely to continue; exacerbating the altered hydrology caused by river regulation.
Threats hydrological change through water regulation and diversion climate change decline in Eucalypt woodland health recreation terrestrial and aquatic invasive species declining surface water quality . .
Based on climate change predictions simple modelling estimated that environmental flows as a result of water saving in the Wimmera Glenelg Rivers could be negated by 2030; however this is indicative only; due to climate change uncertainties and the simplified modelling techniques used (Victorian Government; 2003).
At the time of writing the water allocation system is being amended to allow for climate change impacts on all entitlement holders.
The research proposes that the subtropical ridge of high pressure over eastern Australia has increased in intensity as a result of climate change; resulting in rain bearing storms that normally benefit southern Australia being pushed further south and into the southern ocean.
The vast majority of models show a decrease in run off in the Wimmera region as a result of climate change.
The extreme high global warming scenario was predicted to result in a decrease in run off of up to 47 in one model to an increase of run off of 1 in another.
The extreme low global warming scenario was predicted by the various models to cause a reduction in run off ranging from 0 to 16 .
If climate change occurs as predicted it can be expected to cause major hydrological and ecological changes to Lake Albacutya through reducing run off in the region and therefore flow in the Wimmera River.
Under both the medium and high global warming scenarios it is predicted that Lake Albacutya would be unlikely to ever fill.
Even under the low global warming scenario it is predicted that Lake Albacutya would fill less often.
It is clear that climate change could pose a severe threat to the hydrological regime of the lake; which is already under significant pressure from river regulation.
An increase in the occurrence of extreme weather events is also frequently predicted in climate change models.
Climate change Average rainfall in the Wimmera River catchment over about the last 10 years has been significantly lower than the long term catchment average.
This has been attributed; at least in part; to anthropogenic climate change and is expected to continue.
The vast majority of various climate change prediction models; compiled by CSIRO (2007) predict a significant decrease in run off; with a median estimate of a decrease of 17 from 1990 to 2030.
Over the longer term; human induced climate change also poses a threat; with a predicted reduction in catchment rainfall contributing pressure to the already stressed hydrology.
More recently the threat of climate change and predictions of reduced catchment rainfall may; if they eventuate; add to the hydrological stresses.
An extended drought has been evident since Ecological Character Description for the Lake Albacutya Wetland of International Importance about 1995 which continues at the time of writing; and this has been attributed; at least in part; to the effects of climate change (Steffen; 2009).
The regional climate has a crucial role in defining the ecological character of Lake Albacutya; by controlling the hydrology of the lake; primarily the frequency and duration of lake filling and emptying. 4.2.2 Landforms The land surrounding Lake Albacutya is mostly gently undulating to flat.
This recent reduced capture of catchment flows has been primarily a result of the drought and subsequent reduced streamflows experienced in the catchment from 1995 (National Water Commission; 2005); and this has recently been attributed at least in part to climate change (Steffen; 2009) and if this is correct then this trend is likely to continue.
However it now appears that the drought affecting southern Australia from 1995 is at least partly a result of anthropogenic climate change and that reduced rainfall and catchment runoff are likely to continue.
In summary then; it is concluded that the surface water hydrology has not changed significantly since the time of listing; however it does appear to be undergoing change as a result of anthropogenic climate change and this trend should be monitored. 5.2 Eucalypt woodland The River Red Gum health at Lake Albacutya has been surveyed once in 1993; 11 years after listing; when significant dieback was recorded.
Regular fuel reduction burning as well as fire suppression has the potential to impact on ecological values of the park by modifying the natural fire regime (DSE; 2003).
Changes in the fire regime; including frequency; intensity or season; can reduce the abundance and diversity of native vegetation resulting in a loss of fauna habitat.
Regular fuel reduction burning as well as fire suppression has the potential to impact on ecological values of the park by modifying the natural fire regime (DSE; 2003).
Changes in the fire regime; including frequency; intensity or season; can reduce the abundance and diversity of native vegetation resulting in a loss of fauna habitat.
The limit of acceptable change for a short duration flood is described as a shallow flood of at least 9 months duration which should occur every 8 years on average.
Ecological Character Description for the Lake Albacutya Wetland of International Importance In summary; then; the limits of acceptable change for hydrology are a shallow flood of at least 9 months duration should occur every 8 years on average (low confidence level) a 24 months duration lake full overflow event should occur every 20 years on average (medium confidence level as the actual period of overflow has a degree of uncertainty).
It is reasonable to conclude that future flood events will attract a similar variety and number of waterbirds if Lake Albacutya periodically continues to develop a healthy and mature aquatic ecosystem capable of supporting predatory guilds; and if sufficient alternate habitat areas occur to support waterbird populations nationally and internationally.
There is a possibility of wind erosion of lakebed sediment due to disturbance by sheep in some sections and the effects of prolonged drought conditions on lakebed vegetation; however there is no evidence that significant impacts of this threat currently occurring.
Alternatively; the more recent records from 1993 may represent a baseline for short; low flow events; while the previous records from around the time of listing may be representative of the end phase of a large flood event of longer duration.
The reliability of these annual returns was estimated at 72 based on historical inflows (Victorian Government; 2003); however due to ongoing drought conditions; actual returns to 2009 have been minimal and have been targeted at slowing the decline of high value waterways including the lower Wimmera River; but have had no impact on the hydrology of Lake Albacutya.
The limit of acceptable change for a short duration flood is described as a shallow flood of at least 9 months duration which should occur every 8 years on average.
It is reasonable to conclude that future flood events will attract a similar variety and number of waterbirds if Lake Albacutya periodically continues to develop a healthy and mature aquatic ecosystem capable of supporting predatory guilds; and if sufficient alternate habitat areas occur to support waterbird populations nationally and internationally.
There is a possibility of wind erosion of lakebed sediment due to disturbance by sheep in some sections and the effects of prolonged drought conditions on lakebed vegetation; however there is no evidence that significant impacts of this threat currently occurring.
Flood pulses reaching Lake Albacutya have been influenced; over time; by changes including increasing regulation of the Wimmera River since the 1800s which has resulted in reduced frequency and duration of flooding (Ecological Associates; 2004). expansion of land clearing which has probably decreased evapotranspiration and increased run off in the higher rainfall upper catchment (Bond and Cottingham; 2008); although catchment rainfall remained essentially the same (see Figure 2.3).

Download