Climate change and high elevation
aquatic ecosystems:
Some thoughts based on current
studies
Kathleen R. Matthews
Sierra Nevada High Mountain Lakes
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>10,000 lakes & ponds above 2500 m
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Water level depends on snowpack & summer thunderstorms
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Primarily found in Wilderness on federal lands
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Typically small (<10 ha), shallow (<10 m), and clear
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Most (99%) historically fishless
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Native aquatic species include amphibians, garter snake,
zooplankton
What changes are predicted for high elevations
in the Sierra Nevada if warming occurs?
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More precipitation during winter-bigger snowpack
Longer winter
More precipitation during the summer from
tropical storms
How might the changes affect high elevation aquatic
organisms?
Rana muscosa in the Sierra Nevada
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Endemic to high elevation Sierra Nevada
Have declined throughout most of its range
Warranted for federal listing
Adults are highly aquatic & tadpoles overwinter 3-4
years before metamorphosis into adults
Recent surveys show most breeding occurs in
shallow ponds that freeze in winter and sometimes
disappear in summer if precipitation is low
Other high elevation amphibians
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Hyla regilla & Bufo canorus- adults more terrestrial
& one year tadpole phase
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Interaction between amphibians—condition of Rana
muscosa increases when they are found with high
numbers of Hyla tadpoles
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Possibly influenced more by length of summer and
air/water temperature
Rana muscosa
Condition
Garter snakes
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Thamnopis elegans elegans
Only snake found in the High Sierra
Highly aquatic and an amphibian predator
Snakes are most numerous in areas with higher
abundance of amphibians, and snakes have
disappeared in areas with amphibian declines
Their abundance & distribution will be affected by
amphibian changes
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
Inches
Bishop Pass Snow Water Content, 1989-2003
60
50
40
30
20
10
0
20
10
0
0
5 /1
4 /1
3 /1
2 /1
1 /1
9 /1
10
9 /1
20
8 /1
30
8 /1
40
7 /1
50
7 /1
60
6 /1
Snowpack, 00-01
6 /1
5 /1
30
4 /1
40
3 /1
Snowpack, 99-00
2 /1
60
1 /1
0
1 2 /1
10
1 2 /1
20
1 1 /1
30
1 0 /1
40
W a te r c o n te n t i n i n c h e s
50
1 1 /1
50
W a te r c o n te n t i n i n c h e s
9 /1
8 /1
7 /1
6 /1
5 /1
4 /1
3 /1
2 /1
1 /1
1 2 /1
1 1 /1
1 0 /1
W a te r c o n te n t i n i n c h e s
60
1 0 /1
9 /1
8 /1
7 /1
6 /1
5 /1
4 /1
3 /1
2 /1
1 /1
1 2 /1
1 1 /1
1 0 /1
W a t e r c o n t e n t in in c h e s
Snowpack 97-98
Snowpack, 98-99
60
50
40
30
20
10
0
9 /2 9
9 /2 2
9 /1 5
9 /8
9 /1
8 /2 5
8 /1 8
8 /1 1
8 /4
7 /2 8
7 /2 1
7 /1 4
7 /7
6 /3 0
A c c u m u la t io n ( in c h e s )
Dusy Basin Rain, 2000-2003
5
2003
4
3
2001
2
1
2000
2002
0
PSW aquatic research in high-elevation lakes
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Role of introduced trout on native aquatic
organisms
Use GIS & 3-D mapping to determine:
ƒ Changes in habitat availability and water volume
Using tagging and count surveys on amphibians and
reptiles, determine factors contributing to:
ƒ survival
ƒ growth
ƒ movement
ƒ site fidelity
Dusy Basin: Overview Map
30.
2
5
6
2
11
30.
1
4
31
10
1
9
7
8
3
33
Maximum depth & 1998 egg mass locations
in Dusy Basin study lakes
Number egg masses
Max. depth (m)
12
10
8
6
4
2
0
1
2
3
4
Lake number
5
6
7
100
90
80
70
60
50
40
30
20
10
0
1
2
3
4
5
Lake number
6
7
Lake 5
Fall 1997
~1,000 R muscosa tadpoles.
Pond at capacity.
July 1998
177% normal snowfall in 97/98
winter. ~80% R. muscosa tadpoles
survived
Lake 2
July 1999
• 4,000 R. muscosa tadpoles (1st-3rd yr)
September 1999
• No tadpole survival
Lake 5
Fall 1999
Over 1,000 tadpoles (1st – 3rd yr)
~ 10% survival to 2000
Fall 2000
~ 200 tadpoles (mostly 1st yr)
Lake 5: Bathymetry
Lake 5: Volume Change
7/05/2002
V:276.7m3
A: 819 m2
7/28/2002
V:203.7m3
A: 603 m2
8/15/2002
V:140.8m3
A: 323 m2
Can we make predictions about climate change by
looking at responses of aquatic communities to
current extremes in precipitation?
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Determine populations responses to the current
climate variability
Quantify responses of aquatic species to changes in
precipitation, water volume, lake drying, etc.
Develop models to determine important climate
variables influencing amphibian and reptile
populations, and make predictions for future
climate changes