Environment Institute Science Seminar Series 2009 Are river red gums being  pushed to the edge? Presented by:  Dr Anne Jen...
Are River Red Gums  being pushed to the edge? Dr Anne Jensen Environment Institute Science Seminar Series 2009 Banrock 200...
Characteristics of River Red Gums <ul><li>occur throughout Australia  along watercourses </li></ul><ul><li>indicator of se...
Red gums at higher density on inside bends  where flood frequency higher,  sandier soils
Water Sources for Red Gums <ul><li>two sets of roots, shallow and deeper, to use soil moisture and shallow groundwater </l...
Responses of River Red Gums <ul><li>germinate in response to water availability </li></ul><ul><li>after decline starts, re...
How do Red Gums grow? <ul><li>millions of tiny seeds </li></ul><ul><li>peak flowering mostly in summer </li></ul><ul><li>p...
Less seed from stressed trees Annual seed rain in healthy trees >10-40,000 m -2 Annual seed rain in stressed trees  ~ 10 t...
Where do Red Gums get water? <ul><li>soil moisture from rainfall </li></ul><ul><li>soil moisture and freshwater lens from ...
Red Gums in Trouble – Mid and Lower Murray <ul><li>Murray survey data 2002, 2004 </li></ul><ul><li>All Murray eucalypts  (...
Red Gums in Trouble – Lower Lachlan <ul><li>Booligal wetlands near Hay, Lachlan River </li></ul><ul><li>decline in health ...
Booligal Swamps, Lower Lachlan Source: Armstrong, Kingsford & Jenkins (2009)
Red Gums in Trouble – Mid-North SA <ul><li>Northern & Yorke region </li></ul><ul><li>regional decline in rainfall </li></u...
Northern Regional Die-back Since 1980s <ul><li>survey Murraytown to Gammon Ranges </li></ul><ul><li>every major creek in F...
1911 1983 2009 King Tree, Wirrabara Forest Historic photos supplied by ForestrySA
Northern & Yorke  red gum condition survey 2008 <ul><li>4 catchments surveyed </li></ul><ul><li>only 11% of sites surveyed...
Northern & Yorke Case Study –  Booleroo Whim Creek <ul><li>serious decline 2004-2005 </li></ul><ul><li>trees defoliated, d...
Northern & Yorke Case Study –  Mambray Creek <ul><li>serious to extreme stress most trees </li></ul><ul><li>catchment in p...
Northern & Yorke Case Study –  Wakefield River <ul><li>natural saline groundwater inflows? </li></ul><ul><li>accelerated b...
Red Gums in  Trouble -- Flinders <ul><li>Flinders Ranges creeks stressed since 1980s </li></ul><ul><li>decline apparent be...
Can we save our Murray Red Gums? <ul><li>The  Living Murray Program: </li></ul><ul><li>need 3000 GL pa for healthy working...
The Living Murray Program <ul><li>22 watering sites on Chowilla Icon Site </li></ul><ul><li>only ‘spot’ sites, ~5% of whol...
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 <ul><li>need to put significant amounts of water back (~30%)  now </li></ul><ul><li>clima...
Environmental flows <ul><li>what flows do red gums need at each site? </li></ul><ul><li>how can water sources be managed t...
Defining environmental flows <ul><li>need to understand hydrological relationships and water sources for trees at each sit...
What is the local Red Gum cycle?
What moisture conditions are critical? <ul><li>river red gum responded better to rain than flood  (moist soil preferred me...
Water to extend effect of  rain or flood, and to match seed rain <ul><li>rain can trigger local germination </li></ul><ul>...
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  (V...
Note:  it took 13 years to work out best use of environmental allocations Source: Victorian Dept of Sustainability & Envir...
Lower Murray floodplain trees are dying  -- can’t wait for next high flow event or  official environmental flows! <ul><li>...
What if we lose our Red Gums? <ul><li>exposed soils </li></ul><ul><li>higher temperatures </li></ul><ul><li>rising groundw...
Research Questions <ul><li>what costs and impacts of major loss of red gums from Murray floodplain? </li></ul><ul><li>same...
Water is the key! Banrock 9 May 2009
Acknowledgements <ul><li>Assoc Profs Keith Walker & David Paton, University of Adelaide </li></ul><ul><li>Land and Water A...
Environment Institute Science Seminar Series 2009 Adapting to a drier Australia Presented by:  Assoc. Prof. Justin Brookes
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Science Seminar Series 6 Anne Jensen

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Dr Anne Jensen presents a insight into the plight of the river red gum and asks us: ‘Are river red gums being pushed to the edge?’

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  • Science Seminar Series 6 Anne Jensen

    1. 1. Environment Institute Science Seminar Series 2009 Are river red gums being pushed to the edge? Presented by: Dr Anne Jensen
    2. 2. Are River Red Gums being pushed to the edge? Dr Anne Jensen Environment Institute Science Seminar Series 2009 Banrock 2005 Banrock 2008
    3. 3. Characteristics of River Red Gums <ul><li>occur throughout Australia along watercourses </li></ul><ul><li>indicator of semi-permanent fresh water </li></ul><ul><li>deep-rooted perennial trees, >200-1000 y old </li></ul><ul><li>require relatively fresh water every 2-3 y </li></ul><ul><li>can survive flooding up to 2 y </li></ul><ul><li>can tolerate water up to half seawater in shallow root zone <2 m from surface </li></ul>
    4. 4. Red gums at higher density on inside bends where flood frequency higher, sandier soils
    5. 5. Water Sources for Red Gums <ul><li>two sets of roots, shallow and deeper, to use soil moisture and shallow groundwater </li></ul><ul><li>often rely on freshwater lens over more saline groundwater </li></ul><ul><li>trees >15m from streams use groundwater rather than surface water </li></ul><ul><li>floods replenish freshwater lenses and shallow water tables </li></ul><ul><li>rain replenishes soil moisture </li></ul>
    6. 6. Responses of River Red Gums <ul><li>germinate in response to water availability </li></ul><ul><li>after decline starts, respond to stress with epicormic growth (similar to fire response) </li></ul><ul><li>under stress, gradual decline until reach tipping point, then rapid decline and death </li></ul><ul><li>ability to recover after stress but health never fully restored </li></ul>extreme stress, Melrose
    7. 7. How do Red Gums grow? <ul><li>millions of tiny seeds </li></ul><ul><li>peak flowering mostly in summer </li></ul><ul><li>peak seed rain in summer for Murray, winter for Mt Torrens </li></ul><ul><li>seed rain coincides with greatest likelihood of soil moisture </li></ul>seeds & chaff 500 μ m
    8. 8. 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
    9. 9. Where do Red Gums get water? <ul><li>soil moisture from rainfall </li></ul><ul><li>soil moisture and freshwater lens from flood </li></ul><ul><li>surface water within 15 m </li></ul>Water availability River Murray Water availability other regions <ul><li>soil moisture from rainfall </li></ul><ul><li>local shallow aquifers replenished by seasonal surface flows and periodic floods </li></ul>seasonality of peak flows (% by month ) Mean monthly rainfall (118 y)
    10. 10. Red Gums in Trouble – Mid and Lower Murray <ul><li>Murray survey data 2002, 2004 </li></ul><ul><li>All Murray eucalypts (along 700 km): </li></ul><ul><li>52% decline in 2002 </li></ul><ul><li>76% decline in 2004 </li></ul><ul><li>At Chowilla Ramsar site (17,700 ha): </li></ul><ul><li>54% decline in 2002 </li></ul><ul><li>89% decline in 2004 </li></ul>No improvement since 2004 – now 13 years since last effective over-bank flows in Lower Murray
    11. 11. Red Gums in Trouble – Lower Lachlan <ul><li>Booligal wetlands near Hay, Lachlan River </li></ul><ul><li>decline in health 1993 – 2008 </li></ul><ul><li>no long-term decline in rainfall </li></ul><ul><li>10 large dams, 323 weirs </li></ul><ul><li>50% decrease in flow reaching Booligal </li></ul><ul><li>major changes in timing of flows (seasonality, frequency, duration) </li></ul><ul><li>85% of river red gums died in past 12 years </li></ul><ul><li>decline accelerated since 2005 </li></ul>Source: Armstrong, Kingsford & Jenkins (2009)
    12. 12. Booligal Swamps, Lower Lachlan Source: Armstrong, Kingsford & Jenkins (2009)
    13. 13. Red Gums in Trouble – Mid-North SA <ul><li>Northern & Yorke region </li></ul><ul><li>regional decline in rainfall </li></ul><ul><li>regional increase in temperature </li></ul><ul><li>significant regional water extractions </li></ul>Mambray Creek Beautiful Valley Creek, Wilmington
    14. 14. Northern Regional Die-back Since 1980s <ul><li>survey Murraytown to Gammon Ranges </li></ul><ul><li>every major creek in Flinders Ranges stressed </li></ul><ul><li>average or above rainfall in previous decade </li></ul><ul><li>primary causes thought to be rising saline groundwater &/or falling fresh groundwater </li></ul><ul><li>secondary causes bird & insect attack, mistletoe, compaction, grazing </li></ul><ul><li>Palmer (1991), Dept of Envt & Planning </li></ul><ul><li>survey of groundwater conditions and possible salinisation from Melrose & Orroroo to Quorn & Flinders </li></ul><ul><li>bore holes to 4 m found no shallow groundwater </li></ul><ul><li>salinities not detrimental to red gum health </li></ul><ul><li>suggested drought (man-made & natural) is primary cause </li></ul><ul><li>Jolly, Dendy & Walker (1992), CSIRO & Dept of Envt & Planning </li></ul>
    15. 15. 1911 1983 2009 King Tree, Wirrabara Forest Historic photos supplied by ForestrySA
    16. 16. Northern & Yorke red gum condition survey 2008 <ul><li>4 catchments surveyed </li></ul><ul><li>only 11% of sites surveyed found to be healthy </li></ul><ul><li>significant improvement in March 2009 after rainfall </li></ul>
    17. 17. Northern & Yorke Case Study – Booleroo Whim Creek <ul><li>serious decline 2004-2005 </li></ul><ul><li>trees defoliated, dying, stag ends </li></ul><ul><li>3 floods in 2007 </li></ul><ul><li>good recovery but epicormic growth </li></ul><ul><li>vulnerable to future droughts </li></ul>
    18. 18. Northern & Yorke Case Study – Mambray Creek <ul><li>serious to extreme stress most trees </li></ul><ul><li>catchment in park, so limited water diversions </li></ul><ul><li>may miss local rainfall </li></ul><ul><li>local stories of streams avulsing (changing path) </li></ul><ul><li>multiple significant flows needed for recovery </li></ul>
    19. 19. Northern & Yorke Case Study – Wakefield River <ul><li>natural saline groundwater inflows? </li></ul><ul><li>accelerated by local drainage to alleviate dryland salinity? </li></ul><ul><li>need local investigation, local data </li></ul>1985 1994
    20. 20. Red Gums in Trouble -- Flinders <ul><li>Flinders Ranges creeks stressed since 1980s </li></ul><ul><li>decline apparent before drought </li></ul><ul><li>water extractions thought to be cause </li></ul><ul><li>severe decline in most creeks on plains in 2009 </li></ul><ul><li>what is drought effect? --Cadnia example </li></ul>Sliding Rock Creek upstream Sliding Rock Creek downstream of Cadnia
    21. 21. Can we save our Murray Red Gums? <ul><li>The Living Murray Program: </li></ul><ul><li>need 3000 GL pa for healthy working river </li></ul><ul><li>minimum 1500 GL pa to halt decline </li></ul><ul><li>agreed ‘First Step’ 500 GL pa 2004-2009 </li></ul><ul><li>time is up 30 June 2009 </li></ul><ul><li>only ~170 GL pa returned on paper </li></ul><ul><li>cannot deliver in drought </li></ul>
    22. 22. The Living Murray Program <ul><li>22 watering sites on Chowilla Icon Site </li></ul><ul><li>only ‘spot’ sites, ~5% of whole floodplain </li></ul><ul><li>difficulties of delivering water </li></ul><ul><li>not enough water </li></ul><ul><li>need repeated seasonal watering </li></ul><ul><li>often wrong timing </li></ul>not watered watered
    23. 23. Small Amounts of Water Not Enough New seedlings and dense new leaves after watering, but some trees did not recover
    24. 24. Progress too Slow
    25. 25. Bottom Line for the River Murray <ul><li>need to put significant amounts of water back (~30%) now </li></ul><ul><li>climate change means even less water (~ 50% less than now) = need to adapt / use less </li></ul><ul><li>easier to prevent than repair damage, so need to allocate and deliver water for river health ASAP </li></ul>To sustain a healthy working river:
    26. 26. Environmental flows <ul><li>what flows do red gums need at each site? </li></ul><ul><li>how can water sources be managed to benefit red gums? </li></ul><ul><li>what timetable and scale of flows is needed? </li></ul><ul><li>how can this be delivered? </li></ul>
    27. 27. Defining environmental flows <ul><li>need to understand hydrological relationships and water sources for trees at each site </li></ul><ul><li>need to know local cycles of trees </li></ul><ul><li>allocate flows in pulses, allow over-bank flooding, recharge of shallow water tables </li></ul><ul><li>annual in-channel allocations not effective </li></ul>
    28. 28. What is the local Red Gum cycle?
    29. 29. What moisture conditions are critical? <ul><li>river red gum responded better to rain than flood (moist soil preferred medium) </li></ul><ul><li>water-stressed seedlings (moisture <5%) died in 1-2 d </li></ul><ul><li>optimal soil moisture was 15-30% </li></ul><ul><li>soil moisture >10% was sufficient to maintain seedlings </li></ul>Experimental results for Murray red gums:
    30. 30. Water to extend effect of rain or flood, and to match seed rain <ul><li>rain can trigger local germination </li></ul><ul><li>floods can trigger larger germination events </li></ul><ul><li>match biennial or annual seed cycles in healthy trees </li></ul><ul><li>be aware variable, reduced seed from stressed trees </li></ul><ul><li>monitor for rain or flood-triggered germination and aim to maintain soil moisture >10% </li></ul>Twin Creeks, Chowilla
    31. 31. Barmah-Millewa icon site http://thelivingmurray.mdbc.gov.au/iconsites/barmah_millewa_forest Cover
    32. 32. Barmah-Millewa Forest 150 GL environmental allocation Barmah Lake : Spring floods sustain moira grasslands and marshes (Victorian Dept of Sustainability & Environment)
    33. 33. Note: it took 13 years to work out best use of environmental allocations Source: Victorian Dept of Sustainability & Environment
    34. 34. Lower Murray floodplain trees are dying -- can’t wait for next high flow event or official environmental flows! <ul><li>not enough water for flood watering </li></ul><ul><li>adapting irrigation technology to apply 5mm pw might keep seedlings alive --- until next environmental flows </li></ul>Interim measures needed in the short term
    35. 35. What if we lose our Red Gums? <ul><li>exposed soils </li></ul><ul><li>higher temperatures </li></ul><ul><li>rising groundwater levels </li></ul><ul><li>changed water balance </li></ul><ul><li>potential for salinisation of soil surface </li></ul><ul><li>lost habitat </li></ul><ul><li>soil erosion </li></ul>What would be the consequences? how far can this red gum be pushed before it falls over?
    36. 36. Research Questions <ul><li>what costs and impacts of major loss of red gums from Murray floodplain? </li></ul><ul><li>same question, other regions? </li></ul><ul><li>what is relationship between mature red gums and salt & water balance of Murray floodplain? </li></ul><ul><li>is recruitment of red gums being suppressed? what are key factors? </li></ul><ul><li>what irrigation regime would support mature red gums? </li></ul><ul><li>what are TBL benefits of sustainable red gum communities? </li></ul>
    37. 37. Water is the key! Banrock 9 May 2009
    38. 38. Acknowledgements <ul><li>Assoc Profs Keith Walker & David Paton, University of Adelaide </li></ul><ul><li>Land and Water Australia scholarship </li></ul><ul><li>SARDI Women’s Suffrage Centenary Science Bursary </li></ul><ul><li>Renmark to the Border Local Action Planning Committee grant </li></ul><ul><li>MDB NRM Board community grant </li></ul><ul><li>Nature Foundation SA Inc grant </li></ul><ul><li>SA Dept Land, Water & Biodiversity Conservation grant </li></ul><ul><li>Bjarne Jensen and all field volunteers </li></ul><ul><li>Emma Vasey, Liz Ankor, Priya Wilson and Claire Adams for seed counts </li></ul><ul><li>Scott Mills for time-lapse video production </li></ul><ul><li>Overland Vineyards, Banrock Station Wines, Steve Clark, Department for Environment and Heritage for access to sites </li></ul><ul><li>Northern & Yorke NRM Board </li></ul><ul><li>Strategic Reserve funding through the National Action Plan for Salinity and Water Quality </li></ul>Jane from Orange Emma Chief field assistant Bjarne
    39. 39. Environment Institute Science Seminar Series 2009 Adapting to a drier Australia Presented by: Assoc. Prof. Justin Brookes

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