floodplains, fish habitat, and climate change resilience
TRANSCRIPT
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Floodplains, Fish Habitat, and Climate Change Resilience
Tim Beechie NOAA Fisheries, Northwest Fisheries Science Center, Seattle, WA
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What is resilience?
• Ability of an ecosystem to maintain its structure and functions despite environmental change
• For salmon, resilience more commonly means persistence of the species despite climate change
• Floodplains confer climate change resilience through: • Habitat diversity
• Thermal diversity
• Species diversity
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1970-1999
Seattle
Portland
Boise
Banff
Data source: http://www.hydro.washington.edu/2860/report/
Rainfall
Snowmelt 2070-2099
Seattle
Portland
Boise
Banff
Rainfall
Snowmelt
Transitional
Transitional
Change in flow regime
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Increased water temperature
1970-1999 >30 26-30 22-26 18-22 14-18 10-14 <10
2070-2099 >30 26-30 22-26 18-22 14-18 10-14 <10
Beechie et al. 2013 Beechie et al. 2013
bkw pool
scr pool
glide
lg riffle
hg riffle
Young scroll bar channel
Riffle dominated
Higher habitat diversity
bkw pool scr pool glide lg riffle hg riffle
Young abandoned main stem
Mixed riffle and pool
Higher habitat diversity
pool glide lg riffle hg riffle
Old abandoned main stem
Pool / pond dominated
Higher habitat diversity
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Surface water temperature patterns in the Sauk River floodplain
Thermal diversity
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Longer hyporheic flow paths regulate stream temperature
Poole et al. 2008
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Longer hyporheic flow paths regulate stream temperature
955 m 955 m
955 m
175 m
175 m
175 m
SW SW
SW
Poole et al. 2008
Higher invertebrate diversity
• Young channels dominated by gatherers
• Older channels dominated by scrapers
Main channel <5 years 5-25 years 25-75 years >75 years
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Higher growth rate
Mainchannel Floodplain
Jeffresetal.2008Enclosedexperiment,sameageChinook
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More salmonids in side channels
mainstem
floodplain
Bellmore et al. 2013, Pess et al. 2008
MC CSC DSC
Elwha River Methow River
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What can floodplains do for climate change resilience?
Restoration action Temperature increase
Low flow decrease
Peak flow increase
Increase resilience
Longitudinal connectivity Y Y N Y
Floodplain connectivity Y N Y Y
Restore incised channel Y Y Y Y
Restore in-stream flow Y Y N N/Y
Riparian rehabilitation Y N/Y N N
Sediment reduction N N N N
In-stream habitat N N N N
Nutrient enrichment N N N N
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Reducing climate change effects through restoration
Levee
Mainstemhabitatsonly
Mainstem
Pond
Floodrefuge
Groundwaterchannel
Side-channel
Waples et al. 2008
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Reducing climate change effects through restoration
Levee
Mainstemhabitatsonly
Mainstem
Pond
Floodrefuge
Groundwaterchannel
Side-channel
Waples et al. 2008
And restoring incised channels
Reduce temperature Increase low flow Decrease peak flow (or its effect) John Day
River basin
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Summary • Connected or restored floodplains confer
resilience through • Habitat diversity • Thermal diversity • Species diversity
• They also can ameliorate peak flow and high temperature effects through • Flood attenuation and refugia • Thermal refugia