Water Research Centre
The Environment Institute
NCCARF WORKSHOP
CALPERUM STATION, CHOWILLA FLOODPLAIN, SA RIVERLAND
Thursday to Saturday 2-4 JUNE 2011
GOOD SCIENCE TO SUPPORT EFFECTIVE MURRAY FLOW MANAGEMENT
This workshop addressed key research and management questions, combined with a special opportunity to see the
recovery of the Chowilla Floodplain and Riverland region following recent extended and extensive inundation.
This workshop is part of the Water Resources and Freshwater Biodiversity Program under the National Climate
Change Adaptation Research Facility (NCCARF). It addresses a key priority identified for the program, to promote
effective networking and provide a forum for exchanges of ideas between research and management.
Figure 1
Mark Schulz of Department for Water explaining operation of the Pilby Creek downstream bank on the Chowilla Floodplain
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Introduction
Justin Brookes welcomed participants and emphasised the role of the network in developing partnerships, opportunities
and publications. Participants included staff from the Department for Water, both state and regional offices, Department
of Environment and Natural Resources regional office, SARDI research staff, and Water Research Centre staff
(Appendix 1). There was a good mix of research, policy and on-ground management expertise. The presentations and
discussions are summarised in this report.
Thursday 2 June
0800-1100 Travel Adelaide to Calperum
1100-1300 Set-up and visit to floodplain for lunch
1300-1500 Workshop Session 1
1500-1530 Afternoon tea
1530-1730 Workshop Session 2
1830 Outdoor barbeque dinner, overnight Calperum
Friday 3 June
0730-0830 Breakfast
0830-1030 Workshop Session 3
1030-1430 Visit to floodplain
1430-1630 Workshop Session 4
1630-1700 Pack up
1700-2000 Travel Calperum to Adelaide
Optional field trip: Saturday 4 June
8am travel back to Adelaide via Clarks Floodplain near Berri and Banrock Station, to see benefits of flooding,
arrive Adelaide 5pm
Outcomes:
• report back to NCCARF
• research priorities and recommended follow-up
• summary to be published on WRC & NCCARF websites, WRC newsletter, NCCARF newsletter
• opportunities for input to Discussion Paper on freshwater biodiversity issues for SE Australia coordinated by
Kane Aldridge
Quotable comments:
We are over-managing because we mis-managed in the past -- Justin
Use water intelligently in times of plenty to build resilience for drought – Justin
Dilution is the solution, timing will keep you smiling – Todd
The logistics of delivery are determining environmental watering priorities, ecological objectives are secondary
– Todd
Rivers are currently managed from an anti-drought scenario, leaving rivers too wet and floodplains too dry –
Todd
It is important to manage patches in a landscape context, and to maintain resilience at all ecological scales -Dan
Variability is the driver – Kane
Connectivity is the key to resistance and resilience. – Kane
We need to manage the system well while we have water, to build resilience for droughts – Kane
Engineers ask 'what does the environment need?' Ecologists ask 'what do you want to manage for?' – Anne
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Session 1
Theme: Water management in a variable climate
A regulated river for the future: interactions between research, management and monitoring - Justin Brookes
Justin presented the context of future climate change impacts on flow, water regime, nutrient status and stratification. He
summarised future management issues as being a little about climate change, and a lot about land management. He
suggested that research needs to target providing advice at the relevant scale, and that we need to be working to
minimise the impacts of climate change. For example, cyano-bacterial blooms are expected to increase as temperature
rises, so we should look for ways to control nutrient availability. He concluded that we should be aiming to provide the
right science to inform good policy, planning and management. He used the South East region as a case study, with the
original 47% area of wetlands now reduced to 6% and in declining health. Over 4000 wetlands are now threatened by
regional groundwater drawdown by blue gum plantations over an area of 200 km 2. Drawdown exceeding 1.5 m would
mean the loss of all SE wetlands. Justin concluded that we need to articulate what we want from our landscapes to plan
for appropriate management actions.
Context of environmental water delivery – Heather Hill & Tony Herbert
Heather outlined the structure of the Environmental Water Management (EWM) team, their roles and responsibilities,
and the processes for delivering environmental water. The key roles of the Office of the Commonwealth Environmental
Water Holder (CEWH) and The Living Murray program (TLM) were outlined. The state EWM team is developing a bid
for sufficient water to provide a spring pulse in late spring, expected to reach flows of 15,000 ML/d. This would be
combined with raising the weir at Blanchetown by 50 cm, and would provide 1000 GL in outflows at the barrages for
2010-11. There is a separate bid for 13 GL for watering wetlands sites on the Chowilla floodplain. There is also a
proposal to establish an environmental water bank under the control of the SA Minister, to allow application of water to
priority SA sites independent of the upstream states.
Tony outlined a number of issues, including construction constraints, uncertainty around MDBA volumes, and delivery
constraints. The CEWH and TLM planning processes are still evolving and time-consuming. Other issues still to be
resolved include multiple use of environmental releases, shepherding environmental water, and measuring and
accounting for environmental flows. For the future, issues focus around implementation, monitoring, developing low flow
solutions, and finding the best use for available water. Managing recession rates is also an issue. Planning for
environmental flows needs to take in all these complexities, while including sufficient flexibility to respond to changing
seasonal river conditions.
Canvassing the role(s) of groundwater in vegetation management – Andrew Telfer
Andrew presented the interesting idea of trees as natural piezometers, with their state of health providing an indicator of
water regime and groundwater status. He showed evidence that regional groundwater is displacing the fresh water lens
in the water table from under floodplain trees into the river, leaving the trees without their fresh water source. Andrew
also challenged the viewpoint that salt is accumulating in the floodplain, and argued instead that the absence of fresh
water from small floods is exposing the ecosystem to the full impact of the salt store, without any fresh water to buffer
the impact. There is evidence that salt accumulation is minimal, but the change in fresh water availability is far more
significant.
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Sub-group workshop: What can we learn from the past that can help us in the future?
Key points from this discussion are listed below (more detail in Appendix 2):
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Long term consistent data sets are needed to cover variety of conditions
Set up study sites with long term commitment to maintain research, eg universities, undergraduate courses and
camps
Develop hypotheses and test them!
Undertake adaptive management properly (see previous point)
Ensure collation of data on environmental watering effects and river red gum condition
Use consistent language
Promote multi-use of water for multiple benefits at multiple locations
Understand risk of engineering solutions, impact of disconnecting sections of ecosystem
Beware tipping points!
Figure 2 Discussion groups consider what they can learn from the past
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Session 2
Theme: Managing with less water
Water regulators for environmental benefits – Mark Schultz
Mark outlined the watering program which has been undertaken on the Chowilla floodplain since 2004 to address the
impacts of lack of natural flooding. It has been found that pumping provides insufficient volume, frequency and duration,
and irrigation is impractical on a floodplain of over 17,000 ha. Weir pool raising using Weirs 5 & 6 inundated 200 ha.
Pumping and gravity-fed flows have reached 22 individual sites. However, in order to have a significant benefit for the
broader Chowilla floodplain, the engineering option of installing a regulator on Chowilla Creek has been approved. This
structure can water 8,000 ha of floodplain at pool level, using the 3 m head difference between Weirs 5 & 6. It is
anticipated that the regulator would be operated for 90 days, 1 year in 3, simulating flows of 10,000 ML/d. This would
water 70% of river red gum communities and 30% of black box communities at Chowilla, and all wetlands. There would
be extensive benefits for biodiversity, frogs, plants, soil, etc. The structure would be transparent at all other times, to
reduce the impact on fish movements. The existing Slaneys and Pipeclay weirs will be upgraded with fishways and
radial gates.
The environmental operations plan aims to reproduce the natural variability in the water regime, including base
flows, pulse flows and floods. There will be measurable biological and site objectives. Hypotheses will be tested on the
ability to meet these objectives.
Risks involved in delivering environmental water – Todd Wallace
Todd outlined some key lessons learned from managed watering trials. It has been found that ponded water will become
rapidly hypoxic and/or anoxic regardless of the seasonality of flows and the type of wetland. It is better to have a
minimum of 10% flow exchange. Returning water from wetlands to the mainstream with high biomass and high nutrients
is likely to improve fish recruitment.
In order to manage the risk of negative outcomes from watering, managers should maximise water exchange, avoid
ponding of water, and avoid watering in summer. Some other lessons learned include:
 the presence of water is not enough
 adding water does not establish connectivity links
 magnitude, frequency, timing, duration, variability and rate of change of levels all major factors, and all need to
vary.
Other issues include connectivity, the influence of source water (eg thermal pollution, turbidity), and the conditions
required fro successful recruitment (eg ensuring food sources). A key point was that downsizing of river systems is likely
to create a 'dead zone' between the riparian and terrestrial ecosystems, which will be hostile and present a barrier to
connectivity. Todd's definition of resilience included latitude (room to move), resistance to negative impacts, and
precariousness, a measure of the risk of a change of state.
Multi-annual changes and water fluctuations at Lake Kinneret under future climate change – Ilia Ostrovsky
Ilia provided an international perspective with his account of competing interests and water management issues around
Lake Kinneret in northern Israel. This is the only large freshwater lake in Israel, and provides 50 % of national water
needs for agriculture and drinking. Current issues arise from the impacts of draining an upstream lake, Lake Hula, in the
1950s to provide arable land and reduce malaria. In the period 1958-1993, the degradation of peat soils led to dust
storms of infertile black dust which smothered crops and released nitrates. The Hula restoration project in 1994-96 lifted
the water table to saturate peat soils and prevent nutrients flowing downstream to Lake Kinneret. Management issues
relate to interactive effects, including silt covering stones which provide fish habitat, a decrease in phytoplankton,
destabilisation of the trophic chain. Fish numbers are determined by a complex interaction of the number of fishermen,
visibility, depth, habitat and catch effort. Better management is dependent on better understanding of the science of the
ecosystem functions and interactions.
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Session 3
Theme: Building ecosystem resilience
What is ecosystem resilience and how do we get it? - Dan Rogers
Dan provided a thought-provoking exploration of what ecosystem resilience means, noting that it is a topic of the
moment, with many different interpretations. His suggested definition of resilience is 'the capacity of a system to absorb
disturbance without shifting to another state.' He looked at state and transition theory, and the observation that small
changes in controlling variables can result in step changes into a different state. These changes may not be reversible,
if thresholds and boundaries prevent moving back to the original state. Resilience is defined by the degree a controlling
variable can change without a change of state. Dan gave examples of Easter Island, where forest shifted to grassland
due to deforestation, and the Mt Lofty Ranges, where open grassy woodlands have shifted to annual grasses under
grazing pressure.
A management approach would be to maintain resilience in 'good' states, and reduce resilience in 'bad' states,
having clearly defined what is 'good' and set out explicit landscape conservation goals. It is important to manage
patches in a landscape context, and to maintain resilience at all ecological scales. For example, we need to determine
how much river red gum forest is needed across the landscape to maintain ecological values.
How do we get resilience?
 Know the controlling variables
 Know the thresholds for change of state, and how close to it
 Manage what controlling valuables you can
 Cross your fingers and give it your best shot!
Key references:
Walker, Holling, Carpenter & Kinzig (2004). Ecology & Society 9(2), 5.
Walker & Salt (2009). Resilience Thinking.
www.resiliencealliance.org
www.ecologyandsociety.org
Limits of change in the Coorong and Lower Lakes – Mike Geddes
Mike defined resilience as the capacity to adapt to stress and change, including climate change, and considered what
we can do to increase resilience. He reviewed the effects of the millennium drought on the Lower Lakes to identify
lessons for future dry conditions with less inflows. The South Lagoon of the Coorong underwent a change of state, with
such high salinities that there was a phytoplankton bloom, supporting large numbers of brine shrimp and 2 species of
birds. The North Lagoon has been saved by dredging, with a small area near the Murray Mouth maintained as a marine
environment refuge.
The emergency management responses in recent times have separated sub-sections of the ecosystem, with
negative side-effects through disrupting connectivity across the system. Fro the future, there are several point for action.
The Murray-Darling Basin Plan needs to be amended to incorporate greater climate change effects, much greater than
the 3% reduction in flows currently allocated. The case for end-of-system flows needs to be clearly stated, emphasising
the need for flow to run the most important estuary in Australia, and to export salt from the Basin. Connectivity needs to
be improved and maintained, and current barriers need to be removed. The barrages should be operated in a
biologically transparent way. The eastern Mt Lofty Ranges catchments need to be managed as estuaries and refuges
for small native fish.
The South Lagoon will require intervention to allow recovery in the short to medium term. This may include
pumping highly saline water out of the South Lagoon and monitoring for re-establishment of Ruppia tuberose; it may be
necessary to import propogules of R. tuberosa. The ecology of the South Lagoon in the mid to long term requires the
return of water from the South East via Salt Creek.
A rise of up to 50 cm in sea level rise is predicted by 2050. This would cause over-topping of the barrages and
the low lying parts of the islands. For the longer term a position needs to be developed on whether the barrages will be
“defended” or Lake Alexandrina transitioned into a more estuarine state.
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Incorporating variability back into the Lower Lakes to improve resilience – Kane Aldridge
Kane talked about how variability is the natural driver of the ecosystem, but it is very difficult to replicate. The natural
end-of-system flows had huge variability from 0-200 GL/d, with spring floods and low summer flows. The water was
fresh 95% most of the time, with occasional short saline spikes. Water level was also highly variable. In the past, the
ecosystem was macrophyte-dominated, but now it is phytoplankton-dominated. The change in water level is the key
driver in this change. Connectivity is the key to resistance and resilience.
The Lower Lakes in its natural state had a disproportionately high number of species, including 130 species of
plants. Waterbirds numbers were above 100,000. Since the drawdown from 2006, there has been a complete loss of
macrophyte beds and bird numbers dropped by 89%. The vulnerability of this important ecosystem became apparent
during low flows, with macrophytes limited to a very small area in the Goolwa Channel and vulnerable to rising salinity in
that section of the ecosystem. Investigation has shown that the impacts of barrage operation since 1940 include
increased water depth, erosion of shorelines, stable water levels, lower variability and reduced habitat complexity, thus
significantly reducing suitable habitat for macrophytes. With the stress of rising salinity, the macrophytes had no gradient
or connectivity to migrate to more suitable locations. For the future, with predictions of more severe drought conditions,
management needs to create variability, build resilience and create salinity gradients. We need to manage the system
well while we have water, to build resilience for droughts.
Figure 3
Field visit to Pilby Creek downstream bank to view issues with fish passage
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Session 4
Theme: Delivering the goods
What are the key environmental outcomes desired from environmental flows? – Anne Jensen
Anne looked at options for delivering the appropriate water regime (quantity, quality, seasonality, frequency and
duration) in freshwater ecosystems which evolved with 100% but now have less than 50% of natural flows, with less
than 30% of natural flows in the Lower Murray. Anne highlighted the links between rainfall, surface flows and
groundwater as water sources for freshwater ecosystems, with shallow groundwater often the most critical source.
Rainfall is also a critical factor in maintaining soil moisture between flood events. Some of the key elements of the water
regime include the need for flooding 1 in 2-3 years in most freshwater ecosystems of south-eastern Australia, and the
importance of source water, eg Murray water provides maximum photic depth, while Darling water is highly turbid with
very limited photic depth.
The optimum package of environmental flows should be variable, for example over a 10 year period to include a
mixture of 1 large flood, 2 medium floods, 3 small floods, 3 low flow years and 1 drought, in random order. Timing is
important, with natural flood peaks occurring in late spring-early summer to coincide with maximum spring rainfall. Soil
moisture is the key to germination and survival of seedlings of key floodplain species such as river red gums, black box
and lignum. Optimal soil moisture of 15-30% will maintain seedlings through summer following germination. Maximum
effect from environmental watering would thus come from watering following spring rainfall and/or late spring floods, to
maintain soil moisture for as long as possible. The complexity of getting watering conditions right was highlighted with
examples of the Barmah-Millewa Forest, mid-north ephemeral rivers, and South East wetlands. Some future research
questions include definition of critical environmental flow needs (to contrast with critical human needs), identification of
critical elements of the water regime (eg reinstatement of small floods), and assessment of environmental outcomes
produced by different flow regimes. It will be essential to learn from the effects of the 2011 flooding for application in
future environmental watering.
Figure 4
Field visit to partially constructed Chowilla regulator
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Discussion Can we balance needs of ecosystem components with different water needs?
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Need to manage systems differently, doesn’t need more water, eg manipulate weir pools
Need to tailor solutions, be sure to get targeted outcome, eg for fish with respect to varying levels
Put weir pools both up and down in prescribed pattern, eg spring high to autumn low
Manage instream flows constructively for environmental outcomes
Vary rate of delivery of entitlement to meet environmental needs (within SA’s power to vary monthly delivery
within total)
Main river channel is refuge, under-valued, manage to enhance habitat complexity
Under dry scenario, manage for variability, eg induce spawning, many fish do well in low flows, food available
High flow specialists don’t spawn in low flows – spawn in high flows, don’t know where, upstream?? No
recruitment in L Vic water 2003 for golden perch? (check with Kat & Sandra)
Source water, more productive from Murray but not from storage, need to be able to specify water quality
needed, esp turbidity and temperature
Take irrigators off backwaters as ‘works & measures’ solution, or find innovative solutions, eg SIS to reduce
salinity impacts
Articulate costs of irrigation, failed crops, disposal, wasted water applications and include in equations
Need big picture assessment of true costs and investments, compare production with cost of buying out
marginal producers, assess viability
Designate compact, efficient irrigation areas stacked back behind river to reduce impact on valley,
concentrate/minimise salt impacts
Better planned & directed irrigation development, more efficient, suitable soils, most effective use of water and
choice of crops, 'more crop per drop'
CC may mean more Darling water, higher turbidity, need to demonstrate ecological preference/need for Murray
water to engineers
Clarify definitions, eg resilience, resistance, variability, water regime, sustainability
Wrap up information in easily-digestible format for managers, provide case studies
Good to discuss broader-scale concepts, definitions, language, applications, how specific projects fit into bigger
picture
Discussion Paper
• Dan & Justin? Will combine on paper???
• Kane’s paper on concepts, how do we build robust ecosystems in CC context, how can we transition
• Models, eg Chowilla experience, SE case studies
• Kane working very hard!
• Contributions welcome, literature, case studies – see Todd
• Kat has stuff too to input to paper
Outputs
• Fact sheets on learnings, how to apply
• What do managers need? Contribute to risk assessments, see Chowilla model
• Need long term data sets for long term management!!
• More opportunities for students to see on-ground problems and issues
• Students can contribute to long term data sets
• Set up forum with Dept for Water (Kane’s presentation + others, coordinate with Heather)
• Set up forum with SARDI (coordinate with Kat)
• Feedback to NCCARF -- great opportunity to listen and learn.
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APPENDIX 1
Workshop Participants
Participant
Kane Aldridge
Justin Brookes
Katherine Cheshire
Simon Frankel
Mike Geddes
Heather Hill
Tim Inkster
Anne Jensen
Sandra Leigh
Erin Lenon
Ilia Ostrovsky
Dan Rogers
Lucie Rubiopleimpont
Mark Schultz
Andrew Telfer
Rebecca Turner
Todd Wallace
Figure 5
Institution
University of Adelaide
University of Adelaide
SA Research & Development Institute
Department of Environment & Natural Resources
University of Adelaide
Department for Water
SA Murray-Darling Basin NRM Board
University of Adelaide
SARDI
Department for Water
University of Adelaide visitor (Israel)
Department of Environment & Natural Resources
University of Adelaide external student (France)
Department for Water
Australian Water Environments
Department for Water
University of Adelaide
Field visit to Monoman Island watering site, Chowilla Floodplain
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APPENDIX 2
Notes from Discussion Session 1
What can we learn from the past that can help us in the future?
Long term data sets:
 Retain existing data
 Under variety of conditions
 Baseline data based on established hypotheses
Management aims/outcomes clearly defined:
 Establishing framework of support for collaborations
 Development of common understanding/ approach
 Long term commitment
 Holisitic approach
 Establish 'study sites'
Education:
 Managers/decision makers/ policy
 Researchers
 Public
'Adaptive management':
 Can work if framework established
Irrigation:
 Don't put irrigation in saline groundwater zones
 More diversity, move from permanent plantings to annuals in variable environment
Water allocation:
 Mt Lofty WAP has same problems as Murray, over-allocation
Engineering solutions:
 Trying to engineer environment, result is managed disconnected sub-sections, eg Chowilla regulator
 Concerns about Windsor approach, proposition that infrastructure can manage environment
 18 'winners' are targets, but what about rest of environment
Managing floods:
 Flood mitigation vs environmental flows for environmental benefits
 further development on floodplain
 Short term baseline
 Need to point to advantages of water on floodplain
 To learn from past need long term data/monitoring
 Long term funding not there
 Need smart monitoring, eg local rainfall gauges
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APPENDIX 3
Field Trips
Chowilla Floodplain
The visit to Chowilla Floodplain included stops at Monoman Island Horseshoe, Pilby Creek, the new floodplain
connector channel, Chowilla regulator, and Werta Wert. The watering site at Monoman Island was fully flooded, and
temporary banks were removed to allow free flows during the flood events. Understorey plants were thriving, and areas
of regeneration resulting from earlier waterings were growing strongly. At PIlby Creek downstream bank, it was noted
that the underwater outflow pipes acted as a barrier to fish. The contrast in vegetation health upstream and downstream
of the bank was noted, with very stressed trees downstream of the bank. Concerns were expressed about the
permanent nature of the bank, and the lack of fish passage, given that the bank was installed as a temporary measure.
Concerns were also expressed about the pipe culvert structure installed in the new floodplain connector
channel, as this will be a barrier to fish movement.
The group appreciated the opportunity to visit the partially-constructed Chowilla regulator, following Mark
Schultz's detailed presentation about the proposed operation of the structure. The final site visited was Werta Wert,
which has shown good recovery after multiple waterings during the drought period, and has been fully inundated during
the flood. Red gum seedlings only 1-2 days old were detected in photographs taken of the debris strandlines along the
lagoon (Figure 6).
Figure 6
Red gum seedlings only 1-2 days old (circled) were discovered in strandlines of Azolla and small woody debris at the
Werta Wert watering site, Chowilla Floodplain
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Clarks Floodplain and Banrock Station
Sites visited on the optional Saturday field trip included Clarks Floodplain, downstream of Weir No 4 at Bookpurnong.
This site is invaluable to demonstrate cause and effect, with highland irrigation driving displacement of saline regional
groundwater into the root zone of floodplain vegetation, resulting in significant death and decline in river red gums and
black box. The site also lacks small to medium floods, with the last flow through key flood runners in 1996. This flood
has fully inundated the flood runner to the top of its bank, as well as some lower-lying lignum flats on the floodplain.
Water was still pooled behind a temporary bank. Surprisingly, some mature trees had died in the flood. We speculated
that the cause might have been the shock of flooding after the long period of moisture stress.
Figure 7
Clarks Floodplain environmental watering site had been inundated for several months, but it was noted that several trees
had died during the flood, and hundreds of red gum saplings generated by watering had also drowned in the flood
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At Banrock, we visited an area of very stressed black box above the flood level which had declined even further in
health during the flood. There were also instances of mature red gums along the mainstream at Banrock which had
died during the flood. On the other hand, we were delighted to discover thousands of young river red gums along
strandlines of azolla and woody mulch over sandy soils along the banks of Banrock Creek.
Figure 8
Mass germination of red gum had occurred in strandlines adjacent to Banrock Creek at the downstream end of Banrock
Station floodplain. Seed rain from adjacent trees has fallen either on receding floodwaters or on newly exposed moist soil .
Stranded Azolla and small woody debris form a protective layer which acts as mulch and provides refuge from seed-eating
ants.
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Figure 9
Drought conditions on Chowilla highland and black box communities on Chowilla floodplain in 2006 in contrast to current
recovery conditions viewed on field tour
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