Download Lecture #19, Climate Change and Invasive Species

Ocean/Envir 260
Lecture #19:
Climate Change and Invasive
Species in the Puget Sound
Ecosystem
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Climate Change
“There are two major drivers
of the future environmental
quality in this region: the
specific effects of global
warming combined with the
size and scale of the human
footprint.”
-- Foreword to “Uncertain Future,”
report to Puget Sound Action Team
from UW Climate Impacts Group
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Climate Change and
Invasive Species
• Related issues
• Warmer climate will:
– Introduce new species
– Change some existing
species to “invasives”
– Create disturbances, new
vulnerabilities
• New species may better
suit new conditions
The mountain pine
beetle (left) is
threatening British
Columbia forests
(brown trees above
are dead), where it
now can survive
most winters
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Invasive Species
• No clear definition
– Alien: originated elsewhere
(can be challenge to know)
– Weed: a species we don’t
like
• Can be native or not
– Colonizer: thrives in
disturbed habitats
• Can be native or not
Ocean/ENVIR 260 Autumn 2010
Lecture 19
Zebra mussels encrusting
water current measuring device
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© 2010 University of Washington
Alien Species
• Brown and Sax:
– Generally increase local biodiversity, while
decreasing global biodiversity
• Common species spread, rare/endemic species are lost
• Simberloff:
– “Guilty until proven innocent”
• Risk from invasives is too great
• Sagoff:
– Aesthetic, moral, spiritual choice, no scientific
basis for preference
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Invasive Species
• Humans?
– Escaped evolutionary
setting
– Highly adaptable
generalists
– Alter their environment
dramatically
Olduvai Gorge, Tanzania, where fossil of
Homo habilis, dated 1.85 to 1.6 million
years old, was discovered
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Climate Change
• Today’s focus:
– What do we know confidently
about climate change in the
Puget Sound region?
• Reduced snow pack
• Oceans: higher, more acidic
• New ecological communities
– How can we adapt?
Cover for report excerpted
in Course Pack
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
“No-Analog”
Communities
• Species respond differently,
unpredictably to climate
change
–
–
–
–
Move?
Rapid evolution?
Unchanged?
Extinction/extirpation?
• Result: new ecological
communities
Pacific Northwest oak communities, like
others, are unlikely to stay the same
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Reduced Snow Pack
• Warmer temperatures cause:
– More precipitation falls as rain
– Earlier, more rapid melting
• Mid-elevations most affected
– Higher: snow pack remains
– Lower: no snow pack now
• Reduced water supply
– Biggest human impact?
Measuring snow pack
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
River Flows
• More flooding
– More runoff not stored
in snow pack
– More rain-on-snow
• Causes worst floods
• Human impacts
• Ecological impacts
– Salmon eggs lost
– More, larger disturbances
Flooded Snoqualmie River Valley, 2006
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
River Flows
• Change flow regimes
– Less snow, earlier melt
– “Snow-dominated”
become “transitional”
– “Transitional” become
“rain-dominated”
• Ecological impacts
– Challenges for
outmigrating salmon
Projected changes to average flows in
Snohomish River—note 2040s and 2080s
(Source: UW Climate Impacts Group)
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
River flows
• Summer flows lower
– Intensifies competition with
human needs
• Higher water temperatures
– Higher air temp
– Less water to absorb solar input
– Cool sources (snow melt) reduced
• Results:
– More stress, new communities
Dry stream bed
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Puget Sound
• Strong links to ocean:
– Higher sea level
• Three feet by 2100?
• Worse in South Sound
– Increased acidification
• From CO2 uptake
• Shelled zooplankton, larvae fare worst
– Warm-water species enter system
– Changes in coastal upwelling?
• Affect nutrients, food web
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Puget Sound
• Water quality changes
– Higher temperatures
– Different freshwater inflows
• Affects salinity, flushing
– More biological productivity
in surface waters
– Lower DO in deep waters
Ocean/ENVIR 260 Autumn 2010
Lecture 19
Hood Canal: even more serious
challenges for “dead zones” with
low dissolved oxygen
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© 2010 University of Washington
Puget Sound
• Habitat changes
– Shoreline at risk from rising
sea level
– Changed salinity further
threatens salt marshes
• Food web changes
– Shoreline and plankton are
both key
– Unpredictable impacts
Salt marsh on Indian Island, near Port
Townsend
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Terrestrial Habitats
and Species
• Species move north,
higher elevations
• More disturbances
– Forest fires
– Floods
– Winds?
• Invasive species
• New ecological
communities
Snoqualmie wildlife corridor, fragmented by
I-90 and “checkerboard” land ownership
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Adaptive Strategies
• Guiding principles:
– Focus on processes,
systems, connectedness
– Many of best actions to
address climate change are
already top priorities for
ecosystem
– Adaptive management
• Monitor, learn as go
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Forest management
• Ecosystem and carbon benefits:
– Longer rotations
– Reduce/stop clearcuts
• Leave more live trees,
snags, downed wood
– Maintain forest cover
• Less conversion to
development
– 1B metric tons, next
50-75 years?
• Across western WA, OR
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Adaptive Strategies
• Multi-benefit actions:
– Water conservation
• Address reductions in supply
• Enhance in-stream uses
– Riparian restoration
•
•
•
•
Habitat benefits
Shade, microclimate
Reduce flood hazards
Increase resilience,
connectedness
Lake Whatcom, the source of water supply
for the City of Bellingham. Many households
served by the City have no water meters.
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Adaptive Strategies
• Floodplain management
– Keep development out
– Levees: remove, set back
• Reduces flood risks
• Improves habitat values
• Low-impact development
– Reduces stormwater impacts
– Recharges groundwater
• Cooler, higher summer flows
FEMA floodplain map, portion of
middle Skagit River; projected flows
do not yet include climate change
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington
Recap: climate change
and invasive species
• Climate change and increased human footprint
are primary drivers of ecological change
• In Puget Sound, water supply is biggest known
human concern for climate impacts
• Major changes coming to marine, freshwater,
and terrestrial ecosystems
• Many adaptive strategies for climate are top
priority actions in their own right
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Ocean/ENVIR 260 Autumn 2010
Lecture 19
© 2010 University of Washington