Environment Institute Science Seminar Series 2009 Are river red gums being pushed to the edge? Presented by: Dr Anne Jensen

Are River Red Gums being pushed to the edge? Dr Anne Jensen Environment Institute Science Seminar Series 2009 Banrock 2005 Banrock 2008

Characteristics of River Red Gums occur throughout Australia along watercourses indicator of semi-permanent fresh water deep-rooted perennial trees, >200-1000 y old require relatively fresh water every 2-3 y can survive flooding up to 2 y can tolerate water up to half seawater in shallow root zone <2 m from surface

occur throughout Australia along watercourses

indicator of semi-permanent fresh water

deep-rooted perennial trees, >200-1000 y old

require relatively fresh water every 2-3 y

can survive flooding up to 2 y

can tolerate water up to half seawater in shallow root zone <2 m from surface

Red gums at higher density on inside bends where flood frequency higher, sandier soils

Water Sources for Red Gums two sets of roots, shallow and deeper, to use soil moisture and shallow groundwater often rely on freshwater lens over more saline groundwater trees >15m from streams use groundwater rather than surface water floods replenish freshwater lenses and shallow water tables rain replenishes soil moisture

two sets of roots, shallow and deeper, to use soil moisture and shallow groundwater

often rely on freshwater lens over more saline groundwater

trees >15m from streams use groundwater rather than surface water

floods replenish freshwater lenses and shallow water tables

rain replenishes soil moisture

Responses of River Red Gums germinate in response to water availability after decline starts, respond to stress with epicormic growth (similar to fire response) under stress, gradual decline until reach tipping point, then rapid decline and death ability to recover after stress but health never fully restored extreme stress, Melrose

germinate in response to water availability

after decline starts, respond to stress with epicormic growth (similar to fire response)

under stress, gradual decline until reach tipping point, then rapid decline and death

ability to recover after stress but health never fully restored

How do Red Gums grow? millions of tiny seeds peak flowering mostly in summer peak seed rain in summer for Murray, winter for Mt Torrens seed rain coincides with greatest likelihood of soil moisture seeds & chaff 500 μ m

millions of tiny seeds

peak flowering mostly in summer

peak seed rain in summer for Murray, winter for Mt Torrens

seed rain coincides with greatest likelihood of soil moisture

Less seed from stressed trees Annual seed rain in healthy trees >10-40,000 m -2 Annual seed rain in stressed trees ~ 10 times less <6,400 m -2 declining to <<1,000 m -2 10 seed trees ha -1 sufficient for eucalypt recruitment (Cremer 1965) Stop press: minimal seed rain from healthy trees on Murray floodplain as drought continues 2004 2005 2006 2007

Where do Red Gums get water? soil moisture from rainfall soil moisture and freshwater lens from flood surface water within 15 m Water availability River Murray Water availability other regions soil moisture from rainfall local shallow aquifers replenished by seasonal surface flows and periodic floods seasonality of peak flows (% by month ) Mean monthly rainfall (118 y)

soil moisture from rainfall

soil moisture and freshwater lens from flood

surface water within 15 m

soil moisture from rainfall

local shallow aquifers replenished by seasonal surface flows and periodic floods

Red Gums in Trouble – Mid and Lower Murray Murray survey data 2002, 2004 All Murray eucalypts (along 700 km): 52% decline in 2002 76% decline in 2004 At Chowilla Ramsar site (17,700 ha): 54% decline in 2002 89% decline in 2004 No improvement since 2004 – now 13 years since last effective over-bank flows in Lower Murray

Murray survey data 2002, 2004

All Murray eucalypts (along 700 km):

52% decline in 2002

76% decline in 2004

At Chowilla Ramsar site (17,700 ha):

54% decline in 2002

89% decline in 2004

Red Gums in Trouble – Lower Lachlan Booligal wetlands near Hay, Lachlan River decline in health 1993 – 2008 no long-term decline in rainfall 10 large dams, 323 weirs 50% decrease in flow reaching Booligal major changes in timing of flows (seasonality, frequency, duration) 85% of river red gums died in past 12 years decline accelerated since 2005 Source: Armstrong, Kingsford & Jenkins (2009)

Booligal wetlands near Hay, Lachlan River

decline in health 1993 – 2008

no long-term decline in rainfall

10 large dams, 323 weirs

50% decrease in flow reaching Booligal

major changes in timing of flows (seasonality, frequency, duration)

85% of river red gums died in past 12 years

decline accelerated since 2005

Booligal Swamps, Lower Lachlan Source: Armstrong, Kingsford & Jenkins (2009)

Red Gums in Trouble – Mid-North SA Northern & Yorke region regional decline in rainfall regional increase in temperature significant regional water extractions Mambray Creek Beautiful Valley Creek, Wilmington

Northern & Yorke region

regional decline in rainfall

regional increase in temperature

significant regional water extractions

Northern Regional Die-back Since 1980s survey Murraytown to Gammon Ranges every major creek in Flinders Ranges stressed average or above rainfall in previous decade primary causes thought to be rising saline groundwater &/or falling fresh groundwater secondary causes bird & insect attack, mistletoe, compaction, grazing Palmer (1991), Dept of Envt & Planning survey of groundwater conditions and possible salinisation from Melrose & Orroroo to Quorn & Flinders bore holes to 4 m found no shallow groundwater salinities not detrimental to red gum health suggested drought (man-made & natural) is primary cause Jolly, Dendy & Walker (1992), CSIRO & Dept of Envt & Planning

survey Murraytown to Gammon Ranges

every major creek in Flinders Ranges stressed

average or above rainfall in previous decade

primary causes thought to be rising saline groundwater &/or falling fresh groundwater

secondary causes bird & insect attack, mistletoe, compaction, grazing

Palmer (1991), Dept of Envt & Planning

survey of groundwater conditions and possible salinisation from Melrose & Orroroo to Quorn & Flinders

bore holes to 4 m found no shallow groundwater

salinities not detrimental to red gum health

suggested drought (man-made & natural) is primary cause

Jolly, Dendy & Walker (1992), CSIRO & Dept of Envt & Planning

1911 1983 2009 King Tree, Wirrabara Forest Historic photos supplied by ForestrySA

Northern & Yorke red gum condition survey 2008 4 catchments surveyed only 11% of sites surveyed found to be healthy significant improvement in March 2009 after rainfall

4 catchments surveyed

only 11% of sites surveyed found to be healthy

significant improvement in March 2009 after rainfall

Northern & Yorke Case Study – Booleroo Whim Creek serious decline 2004-2005 trees defoliated, dying, stag ends 3 floods in 2007 good recovery but epicormic growth vulnerable to future droughts

serious decline 2004-2005

trees defoliated, dying, stag ends

3 floods in 2007

good recovery but epicormic growth

vulnerable to future droughts

Northern & Yorke Case Study – Mambray Creek serious to extreme stress most trees catchment in park, so limited water diversions may miss local rainfall local stories of streams avulsing (changing path) multiple significant flows needed for recovery

serious to extreme stress most trees

catchment in park, so limited water diversions

may miss local rainfall

local stories of streams avulsing (changing path)

multiple significant flows needed for recovery

Northern & Yorke Case Study – Wakefield River natural saline groundwater inflows? accelerated by local drainage to alleviate dryland salinity? need local investigation, local data 1985 1994

natural saline groundwater inflows?

accelerated by local drainage to alleviate dryland salinity?

need local investigation, local data

Red Gums in Trouble -- Flinders Flinders Ranges creeks stressed since 1980s decline apparent before drought water extractions thought to be cause severe decline in most creeks on plains in 2009 what is drought effect? --Cadnia example Sliding Rock Creek upstream Sliding Rock Creek downstream of Cadnia

Flinders Ranges creeks stressed since 1980s

decline apparent before drought

water extractions thought to be cause

severe decline in most creeks on plains in 2009

what is drought effect? --Cadnia example

Can we save our Murray Red Gums? The Living Murray Program: need 3000 GL pa for healthy working river minimum 1500 GL pa to halt decline agreed ‘First Step’ 500 GL pa 2004-2009 time is up 30 June 2009 only ~170 GL pa returned on paper cannot deliver in drought

The Living Murray Program:

need 3000 GL pa for healthy working river

minimum 1500 GL pa to halt decline

agreed ‘First Step’ 500 GL pa 2004-2009

time is up 30 June 2009

only ~170 GL pa returned on paper

cannot deliver in drought

The Living Murray Program 22 watering sites on Chowilla Icon Site only ‘spot’ sites, ~5% of whole floodplain difficulties of delivering water not enough water need repeated seasonal watering often wrong timing not watered watered

22 watering sites on Chowilla Icon Site

only ‘spot’ sites, ~5% of whole floodplain

difficulties of delivering water

not enough water

need repeated seasonal watering

often wrong timing

Small Amounts of Water Not Enough New seedlings and dense new leaves after watering, but some trees did not recover

Progress too Slow

Bottom Line for the River Murray need to put significant amounts of water back (~30%) now climate change means even less water (~ 50% less than now) = need to adapt / use less easier to prevent than repair damage, so need to allocate and deliver water for river health ASAP To sustain a healthy working river:

need to put significant amounts of water back (~30%) now

climate change means even less water (~ 50% less than now) = need to adapt / use less

easier to prevent than repair damage, so need to allocate and deliver water for river health ASAP

Environmental flows what flows do red gums need at each site? how can water sources be managed to benefit red gums? what timetable and scale of flows is needed? how can this be delivered?

what flows do red gums need at each site?

how can water sources be managed to benefit red gums?

what timetable and scale of flows is needed?

how can this be delivered?

Defining environmental flows need to understand hydrological relationships and water sources for trees at each site need to know local cycles of trees allocate flows in pulses, allow over-bank flooding, recharge of shallow water tables annual in-channel allocations not effective

need to understand hydrological relationships and water sources for trees at each site

need to know local cycles of trees

allocate flows in pulses, allow over-bank flooding, recharge of shallow water tables

annual in-channel allocations not effective

What is the local Red Gum cycle?

What moisture conditions are critical? river red gum responded better to rain than flood (moist soil preferred medium) water-stressed seedlings (moisture <5%) died in 1-2 d optimal soil moisture was 15-30% soil moisture >10% was sufficient to maintain seedlings Experimental results for Murray red gums:

river red gum responded better to rain than flood (moist soil preferred medium)

water-stressed seedlings (moisture <5%) died in 1-2 d

optimal soil moisture was 15-30%

soil moisture >10% was sufficient to maintain seedlings

Water to extend effect of rain or flood, and to match seed rain rain can trigger local germination floods can trigger larger germination events match biennial or annual seed cycles in healthy trees be aware variable, reduced seed from stressed trees monitor for rain or flood-triggered germination and aim to maintain soil moisture >10% Twin Creeks, Chowilla

rain can trigger local germination

floods can trigger larger germination events

match biennial or annual seed cycles in healthy trees

be aware variable, reduced seed from stressed trees

monitor for rain or flood-triggered germination and aim to maintain soil moisture >10%

Barmah-Millewa icon site http://thelivingmurray.mdbc.gov.au/iconsites/barmah_millewa_forest Cover

Barmah-Millewa Forest 150 GL environmental allocation Barmah Lake : Spring floods sustain moira grasslands and marshes (Victorian Dept of Sustainability & Environment)

Note: it took 13 years to work out best use of environmental allocations Source: Victorian Dept of Sustainability & Environment

Lower Murray floodplain trees are dying -- can’t wait for next high flow event or official environmental flows! not enough water for flood watering adapting irrigation technology to apply 5mm pw might keep seedlings alive --- until next environmental flows Interim measures needed in the short term

not enough water for flood watering

adapting irrigation technology to apply 5mm pw might keep seedlings alive --- until next environmental flows

What if we lose our Red Gums? exposed soils higher temperatures rising groundwater levels changed water balance potential for salinisation of soil surface lost habitat soil erosion What would be the consequences? how far can this red gum be pushed before it falls over?

exposed soils

higher temperatures

rising groundwater levels

changed water balance

potential for salinisation of soil surface

lost habitat

soil erosion

Research Questions what costs and impacts of major loss of red gums from Murray floodplain? same question, other regions? what is relationship between mature red gums and salt & water balance of Murray floodplain? is recruitment of red gums being suppressed? what are key factors? what irrigation regime would support mature red gums? what are TBL benefits of sustainable red gum communities?

what costs and impacts of major loss of red gums from Murray floodplain?

same question, other regions?

what is relationship between mature red gums and salt & water balance of Murray floodplain?

is recruitment of red gums being suppressed? what are key factors?

what irrigation regime would support mature red gums?

what are TBL benefits of sustainable red gum communities?

Water is the key! Banrock 9 May 2009

Acknowledgements Assoc Profs Keith Walker & David Paton, University of Adelaide Land and Water Australia scholarship SARDI Women’s Suffrage Centenary Science Bursary Renmark to the Border Local Action Planning Committee grant MDB NRM Board community grant Nature Foundation SA Inc grant SA Dept Land, Water & Biodiversity Conservation grant Bjarne Jensen and all field volunteers Emma Vasey, Liz Ankor, Priya Wilson and Claire Adams for seed counts Scott Mills for time-lapse video production Overland Vineyards, Banrock Station Wines, Steve Clark, Department for Environment and Heritage for access to sites Northern & Yorke NRM Board Strategic Reserve funding through the National Action Plan for Salinity and Water Quality Jane from Orange Emma Chief field assistant Bjarne

Assoc Profs Keith Walker & David Paton, University of Adelaide

Land and Water Australia scholarship

SARDI Women’s Suffrage Centenary Science Bursary

Renmark to the Border Local Action Planning Committee grant

MDB NRM Board community grant

Nature Foundation SA Inc grant

SA Dept Land, Water & Biodiversity Conservation grant

Bjarne Jensen and all field volunteers

Emma Vasey, Liz Ankor, Priya Wilson and Claire Adams for seed counts

Scott Mills for time-lapse video production

Overland Vineyards, Banrock Station Wines, Steve Clark, Department for Environment and Heritage for access to sites

Northern & Yorke NRM Board

Strategic Reserve funding through the National Action Plan for Salinity and Water Quality

Environment Institute Science Seminar Series 2009 Adapting to a drier Australia Presented by: Assoc. Prof. Justin Brookes